# Swifty's build of Nemett Lynx



## Swifty (May 9, 2014)

I have finally managed to clear a few thing up, so have made a start on preparing to make the Nemett Lynx 15cc SOHC Four Stroke. What material I didn't have on hand, I purchased this morning, all except for the cast iron needed for the cylinder liner. I have ordered the timing pulleys and belt, and will get the bearings shortly.

Apart from mine, Gus is about to start on his, and Doubletop from NZ has one on the go already.

I better go and clean my workbench up ready to make a start, the first piece to be machined will be the crankcase, fortunately I already had a machined block that was the correct size for the height, with minimum to be machined off the other sides. This was fortunate, as I don't have a bandsaw and I would have had to order a block cut to size. All the other material, I just call into my supplier and buy offcuts.

I will try and take a lot of photos and post often on the progress, so stay tuned.

Paul.


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## gunna (May 9, 2014)

Swifty said:


> All the other material, I just call into my supplier and buy offcuts.



Hi Paul, care to name your supplier?
I will be following along with interest.
Ian.


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## Swifty (May 9, 2014)

Hi Ian, I buy my aluminium from Capral, the nearest to me is in Lynbrook, but there are a few stores around Melbourne. There are always small plate offcuts available as well as rounds. I have in the past purchased aluminium plates from scrap metal dealers.

The plate aluminium is definitely better than the common extruded type, can't recall the grade without looking it up.

Paul.


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## gus (May 9, 2014)

Here comes the Nemett-Lynx Engine Epidemic.

Tool Cabinet completed today. Looks like the C.I. Liner will be done Monday 12  2014. 
Now looking for extended 12mm end mill to cut crankcase.


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## gunna (May 10, 2014)

Swifty said:


> Hi Ian, I buy my aluminium from Capral, the nearest to me is in Lynbrook,



Thanks, Paul,
That seems to be the only one in the whole south-east according to their web site.

Ian.


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## Swifty (May 10, 2014)

I started on the crankcase as I had a piece of machined aluminium that was a 70mm cube. I've had the piece for years and it worked out well as the crankcase is 70mm high, so all I had to do was fly cut 2 sides down to size. I'm not worried about getting a mirror finish as a quick rub with some wet and dry paper will clean up scratches.




Next step was to hold it in the vice and pick up the edges with an edge finder and drill a small center drill hole in the correct position for the main bore.




After mounting my 4 jaw chuck, I held the block against the face of the chuck using a center in my tail stock. The jaws were then tightened using some pieces cut from a soft drink can as protectors. This method of holding with a center while I tighten the jaws gets the piece very close.




I then used my dial indicator to finally zero the block in position.




After using a couple of different drills to remove a lot of material, I bored the hole to size.




I intend to bore the cylinder locating hole in my mill using the boring head.

Paul.


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## gus (May 10, 2014)

Gus will monkey see,monkey do the crankcase.You beat me hands down. Still reading the C.I. Liner print and jotting down work instructions.Will be  Monday 12 May to see some work done.


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## Swifty (May 10, 2014)

I'm looking forward to seeing you make a start on yours Gus.

Paul.


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## Swifty (May 11, 2014)

Mothers Day today, so not a lot got done in the workshop. However I managed to mill out the interior of the crankcase. The aluminium that I used was actually a piece of Alumold, a high grade tooling alloy used for injection dies and blow moulds, its very tough to machine, but I got there in the end. I roughed it out with a bigger cutter, then milled closer with a used 12mm long series end mill, then using a new cutter I finished it to size.





Here it is deburred and cleaned up.





Now comes the messy part, I have to clean up all the swarf produced.

Paul.


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## gus (May 11, 2014)

Plan to machine the Cast Iron liner tomorrow followed by the cylinder jacket. Will shop for the long series 12 mm end mill. Looks like I need to buy two, to rough cut and finish cut. Not so sure I can get as good finish as yours.Will try and no rush.


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## Swifty (May 12, 2014)

A little bit more progress, drilled and bored the cylinder locating hole in the top face. The boring head is a Koroda, dial 0,01 cut on dia and that's all it takes, love it.





Next, I drilled and tapped the oil union hole in the corner and the 6 cylinder hold down tapped holes. I tapped under power in the mill and used the pitch circle hole function on the readout for positioning.





Now I have to drill and tap the other faces.

Paul.


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## gus (May 12, 2014)

Will be tough for Gus to match up. Have mark,center punch,spot drill and tap the WW-1 way.
Just found extra length 12 mm end mill ex-stock Singapore. No HSS but Carbide . Will Gus a bomb. Landed cost still cheaper than buying from ArcEuroTrade,UK. Will use the roughing mill followed by XL Carbide Mill.


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## Swifty (May 12, 2014)

Gus, having a digital readout sure makes things easy, but so long as you are careful, you will be OK doing it manually. Where you can, you should first drill holes in the pieces that get clamped down, then you can spot through these holes for a perfect match up.

Paul.


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## gus (May 12, 2014)

Swifty said:


> Gus, having a digital readout sure makes things easy, but so long as you are careful, you will be OK doing it manually. Where you can, you should first drill holes in the pieces that get clamped down, then you can spot through these holes for a perfect match up.
> 
> Paul.



Will spot mating faces.This way the holes will align. Have to do it the WW-1 way. Will turn and possibly finish C I liner tomorrow. Then turn Cylinder Jacket.
Looks like major items done by end May.

There is an epidemic spreading. Nemett Virus has mutated---------Jaguar,Bobcat,Lynx etc etc etc and ha ha. Looks like the two of us spread the epidemic. After the Nemetts what else will happen???? Ha Ha ha. Will look out.


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## Swifty (May 12, 2014)

I'm always on the lookout for my next project, maybe a 4 cylinder of some sort, water cooled.

Paul.


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## Swifty (May 12, 2014)

I went out this morning and bought the bearings that I needed, the only hick up was with the hardened bush for the conrod big end needle bearing. The bush fits on the 7mm dia pin on the crankshaft, the supplier would have had to order one in, so I made a design change on the spot. I have a load of through hardened dowel pins, so I will change the original pin size from 7mm to 10mm, and run the rollers directly on the hard pin.

I've just ordered the cast iron for the sleeve, enough for 2 pieces, so I should get it in a couple of days. It's cheaper for me to pay the postage than drive a 3 hour round trip to get it. I plan to tackle the sleeve as soon as it arrives, I will bore out the hole first, then mount it on a mandrel and finish the outside. Next step will be to bore the aluminium cylinder and shrink it on to the liner. I will then use the same mandrel to finish the outside of the cylinder. I used this method on my Rupnow hit and miss engine and it works well.

Paul.


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## Swifty (May 13, 2014)

I drilled and tapped the rest of the holes in the crankcase today, however, I decided to leave one hole out. There are 4 x M3 and 4 x M2.5 tapped holes holding the back on the crankcase, but the M2.5 tapped hole in the center of the top edge clashes with a tapped hole in the top face. If you look closely at the pictures in the magazine, you will notice that the builder has omitted it as well.





I used my tapping stand to tap all the blind holes. I made it using my ER20 collet holder.





Paul.


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## AussieJimG (May 13, 2014)

I like the tapping stand, it just went on my Tuit list

Jim


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## gus (May 13, 2014)

Paul,

You are making good progress. Liner done and moving on to Cylinder Jacket. And again a big dia. job for a small lathe.The next would be the elaborate outer-end. Too msny hole and some very unforgiving.Guess I leave the hole for day after. Buying material wise,I am a few train stations away from supplier.
My ceiling would be a two cylinder in-line or vee type.


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## Swifty (May 15, 2014)

I machined the back cover for the crankcase today, clamped it down because I thought that it may lift in the vice when i milled the recess.





Next on the list was the 2 angle pieces that fasten on either side of the crankcase, I had some 10.8mm thick plate (where does that size come from) and not having a band saw I used a slitting saw in the mill to cut off 2 pieces.





After flycutting them to size, I machined them to create the "angle profile".





Drilled all the fastening holes, and here we have all the parts on the crankcase sheet finished.





My cast iron arrived today, so parted off a piece and drilled and bored it to size, came out perfectly parallel, just gave it a light hone with the brake hone tool. I intend to turn the outside whilst its mounted on a mandrel, in order to reuse a mandrel that I used on my Rupnow engine, I bored 2 short pieces of bar and shrunk them onto the mandrel. I will carry on machining that tomorrow.

Paul.


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## AussieJimG (May 15, 2014)

It's looking good Paul, I am watching with interest.

Are you taking the Rupnow engine to the Bendigo Show?

Jim


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## Swifty (May 15, 2014)

Bendigo Show? I didn't know that it was on, can you give me some details, I will also try to google it. I could make a day trip or even stay overnight, wouldn't bring up anything to show, but I would be keen to see what's around. I don't usually buy any modeller magazines as I find that they concentrate on trains a lot.

Paul.


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## gus (May 15, 2014)

Looking good. Looks like we have a deal. Paul is working from botttoms up and Gus from top down. Looks like the Nemett-Lynx is well covered. Should finish the Outer-head today and trying very hard not to rush.
Take care.


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## Swifty (May 16, 2014)

I mentioned that I plan to reuse a mandrel by shrinking on some sleeves to allow for a larger bore. Here is a photo showing the mandrel with the sleeves on tight.





And here we have the remachined mandrel ready to accept the cast iron liner.





It was easy going after that to machine the outside of the liner concentric to the inside.





Just had to trim to length and chamfer one end. Another use for my ER20 collet holder. The shank is 20mm dia and I have made a block to hold it in the toolpost, it's ideal for holding small boring bars etc.





And here is the finished liner.





Next step was to part off the aluminium bar to the rough lengths needed for the cylinder outer, the cylinder head and the crankcase front. It was sticking out a bit too far, so I centered the end, used a revolving centre in the tailstock for support, then parted to leave a 12mm spigot in the centre. 





Next step was to use a 13mm dia drill to put a hole in the centre, when I reach the parting, the piece just's hangs on the drill. No danger of it being flung around. The last piece will be used for the head, so no hole in this one.





I will also be using the mandrel at a later date to machine the crankcase front.

Paul.


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## gus (May 16, 2014)

Swifty said:


> Bendigo Show? I didn't know that it was on, can you give me some details, I will also try to google it. I could make a day trip or even stay overnight, wouldn't bring up anything to show, but I would be keen to see what's around. I don't usually buy any modeller magazines as I find that they concentrate on trains a lot.
> 
> Paul.



Please copy me on the Bendigo Show dates. If I can get a cheapy flight to Melbourne and take the train to Bendigo. Heard about this show and its all Steam Engines etc etc. There is a very good restaurant serving Kilpatrick Oysters and Rack Of Lamb. Can't recall the name.


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## Swifty (May 16, 2014)

I haven't be able to find out anything about this years show, only previous years. Will keep you informed.

Paul.


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## Jasonb (May 16, 2014)

Although their site is out of date it does seem to suggest that its a bi-annual show so not likely to be another until 2015

http://bendigosocofmodeleng.wix.com/to-publish#!coming-events


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## Swifty (May 16, 2014)

Thanks for the link Jason, I did come across it, but it wouldn't open on my iPad. Next time I'm on my desktop I will check it out.

Paul.


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## mattty (May 16, 2014)

Hi Swifty I noticed that you are using metric plans, could you let me know where I can purchase them. Thanks Matt


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## Swifty (May 16, 2014)

Hi Matt, the plans were issued in "The Best Of Model Engineer, volume 3". I purchased mine on line, but they are still in newsagents at the moment. I see that you are in NSW, you should be able to get one. I scanned the drawings and printed them out on A3 sheets, that way I can write on the drawings without damaging the magazine, also easer to read as well.

Paul.


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## Swifty (May 16, 2014)

Jasonb said:


> Although their site is out of date it does seem to suggest that its a bi-annual show so not likely to be another until 2015
> 
> http://bendigosocofmodeleng.wix.com/to-publish#!coming-events



I checked out the web site, as Jason wrote, it appears that it will be held next year.

Paul.


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## Swifty (May 17, 2014)

Next part to work on was the cylinder jacket. I bored out the centre hole and gave it a minutes work with the hone, and this gave me a nice tap fit for the liner. Everything was then mounted on my mandrel and the OD and length was finished.





Next, I necked down the bottom end that attaches top the crankcase.





Now I have to come clean, this is my second attempt at this part. I started to do the fins using a power hacksaw blade as a parting tool. The blade was 1.6mm thick, I ground relief on each side and ground the height to centreline. Now the trouble started, the first cut didn't look too bad, the next one took off at an angle and ruined everything. I will grind a 3/8"toolbit tonight to the correct size for my next attempt. At least I have the first one to try it out on. The only positive thing to come out of it was that it only took me an hour to get back ready to put the fins on.

Paul.


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## ruzzie (May 17, 2014)

2014 Model Engineering Exhibition 

4 - 5 October
12th Melbourne Model Engineering Exhibition
Engineering Hall, Monash University, Wellington Road, Clayton.

Saturday 4 October 9.00am - 5.00pm
Sunday 5 October 9.00am - 4.00pm

The 12th biennial exhibition by local clubs with exhibits featuring model steam and IC engines, hot air engines, trains, clocks, machine tools, boats and planes. Also trade stalls selling model engineering supplies and materials. One of the largest, if not the largest, model engineering exhibitions in Australia.

Organised by the Melbourne Society of Model & Experimental Engineers (Inc) More details at www.msmee.org.au or phone (after hours) 03 9528 4878


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## Swifty (May 17, 2014)

Thanks for that Ruzzie, I hope that it's OK with you, I posted this information under shows and events. I did mention that it was you who brought it to my notice.

Paul.


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## AussieJimG (May 17, 2014)

Swifty said:


> Thanks for the link Jason, I did come across it, but it wouldn't open on my iPad. Next time I'm on my desktop I will check it out.
> 
> Paul.



Jason is right. I was led into error (not for the first time) by Reg who shall remain nameless.

It looks like it is in Melbourne this year on 4/5 October. Here is the link: http://www.onlymelbourne.com.au/melbourne_details.php?id=15862#.U3fdZ_mSwXw

It would be good to meet up and swap lies.

Jim


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## Swifty (May 17, 2014)

I've already put in I'm my diary Jim, as you said, it would be great to catch up with any members going.

Paul.


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## Swifty (May 18, 2014)

Cutting the fin grooves went better this time. I included a photo of a trial assembly, the tapered nose piece is still only roughed out on the taper at this stage. I will finish it tomorrow sometime, although we will have our grandson over for the day, so maybe during his nap time.





Paul.


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## gus (May 18, 2014)

Looking good.  You have four parts done and Gus only three. Hopefully by Tuesday,I get the crankcase done.

(Fishing today outside Port Limits of Singapore was bad.Rough seas and ships anchored on top of my best spots. But we had good dinner. No fish.)


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## mattty (May 19, 2014)

Hi Paul, I have had no luck buying the mag, where online did you purchase yours.

 Thanks Matt


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## Swifty (May 19, 2014)

Hi Matt, here is a link for the magazine. I ordered mine through this site, they do deliver to Australia.
http://www.model-engineer.co.uk/forums/postings.asp?th=87249#

Paul.


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## Swifty (May 19, 2014)

I finished turning the nose piece of the engine today, next I set it up in my mill and indicated the centre.




Next, I drilled the fastening holes. I used a circle function on my readout, a lot quicker than using a rotary table.




I used 2 drill bits to locate the nose piece in my vice, then milled the belt hole with an 8mm end mill.




I drilled the fastening holes in the cylinder the same way I did the nose piece.




I thought that the easiest way to drill the holes in the cylinder that hold down the head, was to attach the cylinder to the crankcase. This solved alignment problems, all I had to do was find the centre. I worked out the holes positions with basic trigonometry and drilled all my holes. I will use my tapping stand to tap the blind holes.




And here is another assembly with a few more parts on it. The cylinder hold down screws are a real pain to do up, I'm considering tapering the last few fins or milling grooves to allow better access with a hex key. I took this photo before I drilled the rest of the holes in the cylinder, but you can see the screws in the photo above.




Paul.


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## Jasonb (May 19, 2014)

Have you tried a ball ended hex wrench, the ones on the bobcat are the same but can be driven with one of those. A cut down "L" key will do to finally tightening


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## Brian Rupnow (May 19, 2014)

Swifty---Looking very, very good.---Brian


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## Swifty (May 19, 2014)

Jasonb said:


> Have you tried a ball ended hex wrench, the ones on the bobcat are the same but can be driven with one of those. A cut down "L" key will do to finally tightening



Hi Jason, that's exactly what I used, even with the ball end key, it was still a pain. I cut up an old key to do the final tightening.

Paul.


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## gus (May 19, 2014)

You are making good process .th_wav
 Gus is still trying to get out the mess of the Outer-Head. :wall:
Planning to use the 10mm Champion plug. Have reports about the 1/4'' plugs easily gets fouled. 
I am now making a DIY counterbore to recess spark plug hole. Using Grade 8 hex bolt.


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## Swifty (May 20, 2014)

Brian, thanks very much for your comment, I'm trying to keep all my machining neat and tidy looking.

Gus, I started on machining the head today, the spark plug was one area I was not sure about. I immediately thought about using a 10mm thread plug as I have one left over from the Rupnow H & M, but I'm concerned that it will be too large. The thread may interfere with the valve, and a  larger counterbore is needed to get a tube spanner in, which may also interfere. I don't have any other plugs, and would have to buy the tap as well as the plug. The other option is to make a plug from scratch, I will consider my options for a while longer.

To the members that make their own plugs, what is the central pin made out of, I seem to recall that some just use silver steel, would a TIG welding electrode be feasible ?

Paul.


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## AussieJimG (May 20, 2014)

Have  you thought of using hex headed screws to hold the cylinder?

Jim


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## Swifty (May 20, 2014)

AussieJimG said:


> Have  you thought of using hex headed screws to hold the cylinder?
> 
> Jim



That's an option Jim, I just checked the across corners size and it just a bit less than 8mm, so there is still room to turn them. However, I just seen to like the look of cap screws on this engine. 

Paul.


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## gus (May 21, 2014)

Swifty said:


> Brian, thanks very much for your comment, I'm trying to keep all my machining neat and tidy looking.
> 
> Gus, I started on machining the head today, the spark plug was one area I was not sure about. I immediately thought about using a 10mm thread plug as I have one left over from the Rupnow H & M, but I'm concerned that it will be too large. The thread may interfere with the valve, and a  larger counterbore is needed to get a tube spanner in, which may also interfere. I don't have any other plugs, and would have to buy the tap as well as the plug. The other option is to make a plug from scratch, I will consider my options for a while longer.
> 
> ...



Hi Paul,
Saw your message while fishing far out at sea and could reply due to lack of line.
Drilling the spark plug from top is risky and no guarantee,I won't hit and destroy valve holes. I drilled from bottom up.  Some end milling required so as to make drilling spot on.Must ensure you get the 25 degrees angle. See fotos of top and bottom Outer-head. I used my DIY boring head to counterbore top to take spark plug.
Good Luck.          Gus will work crankcase tomorrow. Fishing not too bad today but my friend landed a 4 kg Barra.


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## Swifty (May 21, 2014)

Hi Gus, I've been working on the cylinder head for my engine today, I'm still undecided about the spark plug. I will post some pictures tomorrow. I have ordered a 1.5mm slitting saw to machine the grooves in the top, so will have to wait for that to arrive. Still have plenty of other parts to work on.

I received my toothed wheels and belt from a local supplier the other day, one thing I didn't realise was that the spigot on the small wheel will disappear when I bore the hole in the centre. No problem though, I have decided to make my own wheel by broaching the teeth.


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## gus (May 21, 2014)

Swifty said:


> Hi Gus, I've been working on the cylinder head for my engine today, I'm still undecided about the spark plug. I will post some pictures tomorrow. I have ordered a 1.5mm slitting saw to machine the grooves in the top, so will have to wait for that to arrive. Still have plenty of other parts to work on.
> 
> I received my toothed wheels and belt from a local supplier the other day, one thing I didn't realise was that the spigot on the small wheel will disappear when I bore the hole in the centre. No problem though, I have decided to make my own wheel by broaching the teeth.



Hi Paul,

I used 2mm end mill to cut the O/H slots/fins. Was nail biting. With only 2 short and shallow groooves to cut,I took my time and came out with good fins/grooves and no broken 2mm mill.

Now about work on crankcase. Taking my time and taking note of vital dimensions. Will be fun.

Fishing yesterday was not the best with fishing guide but we were happy with the 4 kg Barra and Snappers. Can be viewed on my FB.

I am about to look for timing gear and belt.


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## Brian Rupnow (May 21, 2014)

Gus--I just spent most of the day machining the crankcase body for my engine, which is based on a similar engine by the same gentleman who designed the Lynx.--I will tell you right now----You are in for a LOT of milling.---Brian


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## Swifty (May 21, 2014)

I have decided to go with the 1/4 x 32 plug, I have ordered the tap, plug and ignition today from Australian suppliers, so will see the parts shortly.

Gus, the slitting saw is nearly cheaper than buying one small cutter, the only problem is that I will have to make a new holder as I could not get a bore to suit my existing holder.


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## Swifty (May 22, 2014)

The postman bought 2 presents for me today, my 1/4x32 tap from a local supplier and my 1.5mm slitting saw from Shanghai. I paid $6.93 including postage for the saw and included in the package was a $5 voucher for my next purchase, great will have to see what else I need.

Now I have to make a holder for the saw, then continue on with the head.

Paul


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## Swifty (May 23, 2014)

After making a holder for the new 1.5mm slitting saw, I could carry on machining the head. The saw saved heaps of time, too me about 10 minutes to mill all the slots in the top of the head. The only things left to do now are to counterbore the spark plug hole, I'm waiting until I receive the spark plug to check the counterbore depth required, and tap the M2 holes that hold the carby and exhaust on.









The cylinder head has been the most involved part so far, a lot of operations.

Paul.


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## Swifty (May 23, 2014)

Access to the screws to tighten the cylinder to the crankcase has been on my mind for days, the screws were a bit hard to get to with a hex key. I decided to bite the bullet and machine some clearance in the fins to aid in getting a key in there. There's no turning back now, however I think that I like the look of the cylinder this way, it breaks the "finny" look up a bit.





Paul.


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## gus (May 23, 2014)

Hi Paul.

That was a good idea cutting into the fins. A bit dicey. And good aiming too. And good looking.I may have to do the same for the screws. One step at a time.


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## Swifty (May 23, 2014)

It was actually quite easy to machine the grooves through the fins, I mounted the cylinder on the crankcase with one screw, held the crankcase in the vice at 20 degrees, centred the cylinder and moved in 5.5mm from when I touched the first fin. After that, I just undid the one screw and rotated the cylinder until all the grooves were done.

Paul.


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## gus (May 23, 2014)

Brian Rupnow said:


> Gus--I just spent most of the day machining the crankcase body for my engine, which is based on a similar engine by the same gentleman who designed the Lynx.--I will tell you right now----You are in for a LOT of milling.---Brian



You are right. With a very small milling machine,excavating took ages. After 4 hours today and two more tomorrow,I am about finished. That dead tired ,body and soul. Looking backwards,perhaps I should have used plates to fabricate crankcase. :wall:The major parts done. Will be quite a story to tell when I meet Paul and AussieJim and RodW when we get together at the Melbourne Model Engine Show in October 2014.th_wav


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## Brian Rupnow (May 23, 2014)

I've always wanted to visit Australia. October, ---Let me talk to my wife---


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## Swifty (May 23, 2014)

Great idea Brian, it will be the middle of spring here then and it can be great at that time of year.

Paul.


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## gus (May 24, 2014)

Swifty said:


> The postman bought 2 presents for me today, my 1/4x32 tap from a local supplier and my 1.5mm slitting saw from Shanghai. I paid $6.93 including postage for the saw and included in the package was a $5 voucher for my next purchase, great will have to see what else I need.
> 
> Now I have to make a holder for the saw, then continue on with the head.
> 
> ...




Hi Paul,
Please advise slit saw supplier address.


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## gus (May 24, 2014)

Brian Rupnow said:


> I've always wanted to visit Australia. October, ---Let me talk to my wife---



Brian .

See you at the October 2014 Melbourne Show. Australia is quite a country.

Crocodile Dundee country up north. Been there in 1999.


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## Swifty (May 24, 2014)

Hi Gus, here is the link direct to the supplier, http://www.uxcell.com/80mm-15mm-22mm-milling-cutter-72t-slitting-saw-blade-p-339395.html

I bought mine through eBay for only $6.95 posted, I see that they are charging a higher price through their store. Check eBay, there are quite a few suppliers.

Edit: I just checked my order info, my saw has 50 teeth and is 75mm dia.

Paul.


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## gus (May 24, 2014)

Swifty said:


> Hi Gus, here is the link direct to the supplier, http://www.uxcell.com/80mm-15mm-22mm-milling-cutter-72t-slitting-saw-blade-p-339395.html
> 
> I bought mine through eBay for only $6.95 posted, I see that they are charging a higher price through their store. Check eBay, there are quite a few suppliers.
> 
> ...




Thanks for the link.


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## AussieJimG (May 24, 2014)

Brian Rupnow said:


> I've always wanted to visit Australia. October, ---Let me talk to my wife---



If you are coming, please put aside a couple of days to visit and to explore Canberra and the surroundings. We have a guest cottage on the property for just this purpose.

Jim


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## Brian Rupnow (May 24, 2014)

AussieJimG--If I were to come to Australia I would have to leave my return to Canada "open ended". I have always been fascinated with Australia, and if I do come, it will be a once in a lifetime thing for my wife and I.--Who knows?--You might end up with a grumpy old man and his beautiful young wife as cottage guests!!--Brian


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## Swifty (May 25, 2014)

I keep plodding away whenever I have some spare time, I have been working on the cam box that sits on top of the cylinder head, I made an alteration to the holes that hold the camshaft bearings, these are the holes on the front and back, the drawing states 10.5mm dia. but I wanted a bigger hole so I used a reground cutter that was 11.7mm dia. The idea around using the bigger hole is for 2 reasons, firstly it will enable me to have more material surrounding the needle roller, original only had 1.25mm per side, and I'm hoping that I can make the cams integral with the shaft instead of using loctite to hold the lobes on, if I do it this way, I will need to slip the cams in through the holes.

Here is the cam box with fastening holes drilled and slot roughed out with drill.





And here is the slot after milling.





I cant resist having trial assemblies, no fasteners, just to see how its shaping up.





Paul.


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## Brian Rupnow (May 25, 2014)

Nice work Swifty. It is coming together very well.---Brian


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## Swifty (May 25, 2014)

Swifty said:


> and I'm hoping that I can make the cams integral with the shaft instead of using loctite to hold the lobes on, if I do it this way, I will need to slip the cams in through the holes.



Looking at the drawings further, the cams may fit through the hole size called up on the drawing, no matter, I still achieve my purpose of making the bearing surround bigger. The instructions call up for the cam lobes to be loctited on to the shaft, this would have made it fairly permanent anyway, and the shaft with cams attached would have to be able to be removed through the existing hole. I'm still going to look at beefing the cams up a bit though.

Paul.


----------



## gus (May 25, 2014)

Swifty said:


> Looking at the drawings further, the cams may fit through the hole size called up on the drawing, no matter, I still achieve my purpose of making the bearing surround bigger. The instructions call up for the cam lobes to be loctited on to the shaft, this would have made it fairly permanent anyway, and the shaft with cams attached would have to be able to be removed through the existing hole. I'm still going to look at beefing the cams up a bit though.
> 
> Paul.



Good idea.  Will do same. 

Had a great day .
An old friend and fishing guide took
us to his spots. Brought two but lost 6 Groupers due to snaggy terrain.
Will be many return matches. Gus & Co versus the Groupers.


----------



## Swifty (May 27, 2014)

I machined up the bronze bearing housings for the camshaft box, in the rear housing, the holes are countersunk as the timing adjuster fits flush up against this. I mentioned in an earlier posting that the local purchased 20 tooth wheel will lose the shoulder when I ream it out, so I had a go at making my own. I turned up a blank, ground a broach to suit the tooth profile, placed the blank in a chuck on my rotary table and broached the teeth by moving the spindle up and down. I forgot to take a picture of this operation, but you can see the purchased and home made wheels in the picture below. Also in the picture, in the top left corner, the bearing housings snuck in.





Paul.


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## Swifty (May 27, 2014)

Started work on the crank now, I turned the web out of some hot rolled steel, then put it in the mill to drill/ream the other holes. While in that setup, I milled a witness for the material that has to be removed, I then held it sideways and roughed it out. Next I pressed in a couple of 10mm dowel pins and returned it to the vice, this enabled me to mill both sides in one setup, using the witness previously milled as my guide. Deburred and rounded a few corners, and this part was ready.














Next step was to make a start on the shaft, I used a piece of 1/2" 4140 that I had, put it in the lathe and turned one end down to 10mm press fit for the web and also drilled a centre in the end. I reversed the part and trimmed the shaft down to length and put a centre in this end as well. I then pressed the 2 parts together with a bit of loctite for good measure. The drawing also shows three M3 holes put in the join of the shaft to the web to actually key the parts together as well, I'm not sure why there needs to be 3, I would have thought that one would have been enough.

Here is a picture of the shaft attached to the web, I intend to finish turn the shaft between centers, using a pin in the web as a driver against the chuck jaw. For a centre in the chuck end, I always use a piece of scrap stock and turn the centre 60 deg in place.





Paul.

Footnote: The Australian / English spelling of CENTRE is always being corrected by my computer to spell it CENTER, so you might see the 2 different versions in my post. I think that I will have to load the English dictionary to fix this.


----------



## Swifty (May 28, 2014)

I carried on machining the crankshaft today, first thing to do was put a piece of material in the chuck and turn a centre on to it, this is so it runs spot on true.




I roughed out the shaft, then swapped over tools for the finish turning. 4140 sure is a pain to get a nice finish, I ended up with some wet and dry paper to smooth the finish. The fits on the 2 bearings are a nice finger push on the shaft. Next to last thing to do was screw cut the M8 thread on the end.




Final operation was to machine a groove for an E clip, 4mm from the end of the thread, this is a safety device in case the nut comes loose. Here is the finished crankshaft.




I'm working down in size with the parts now, I may do the prop driver and washer next, this will finish all the parts that attach to the front of the crankshaft.

Paul.


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## Swifty (May 30, 2014)

I finished turning the prop spinner and the taper lock today, then milled the grooves on the face of the spinner and drilled the driving pin holes.
I don't know why I need the grooves when there will be 2 pins in the spinner to drive the prop, did them anyway. I didn't take any photos while I was machining the parts, only the finished items. I still have to mill a slit on the taper lock, I just ordered a 0.5mm slitting saw to do it with.





Paul.


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## gus (May 30, 2014)

Hi Paul,

You are leading and I am falling behind which is good. Will monkey see,monkey do. The two day one nite fishing trip was bad.Spots overfished.And its weekend fishing again.

Trying hard not to rush. Two reworks by now. Will turn the crankshaft the ''Swifty'' way.
No distraction for next week planned. Will be good progress.


----------



## Jasonb (May 30, 2014)

Swifty said:


> I don't know why I need the grooves when there will be 2 pins in the spinner to drive the prop, did them anyway.


 
After Malcom had a prop come off the prototype while doing a demo at a show he decided to play extra safe.

J


----------



## Swifty (May 30, 2014)

Jasonb said:


> After Malcom had a prop come off the prototype while doing a demo at a show he decided to play extra safe.
> 
> J



Hi Jason, yes that's what the E clip is on the shaft for, I was just wondering why the driving grooves are needed when there are two pins doing the driving of the prop. Thanks for looking at my posts.

Paul.


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## gus (May 31, 2014)

Swifty said:


> Hi Jason, yes that's what the E clip is on the shaft for, I was just wondering why the driving grooves are needed when there are two pins doing the driving of the prop. Thanks for looking at my posts.
> 
> Paul.



Hi Paul,

Will be puttting on the CI Pulley. I have Prop-Phobia. Seen some my  rich class mates get bad cuts from aero-model props. Will use lock nuts and Loctite for insurance.
Next week will cut crank disc.


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## Swifty (May 31, 2014)

Hi Gus,

I will also be using a flywheel to run it, but will have a prop for display purposes only. I value my fingers too much to run it with the prop. That's the reason that I made the crankshaft the longer size to suit a prop, I will just design my own flywheel to suit the length.

Paul.


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## Swifty (Jun 3, 2014)

Next item to machine is the con rod. I started off with some plate aluminium and bored / reamed the big and small end positions, and drilled where I needed a radius in the corner, the position for these was drawn up on my CAD and the sizes taken.




Next step was to set up the rotary table and indicate the centre, I then clamped down my milling plate. To make it easy to set the holes up, I turned locating pins that I held in the quill in the zero position, located the hole and clamped the con rod down. I then proceeded to mill the outside radius.









Here we have both ends done ready to be finished milled to thickness.




And here is the con rod, just need to drill an oil hole in the small end and clean up with some filing and emery.




Paul.


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## gus (Jun 3, 2014)

Very well done con-rod.
 As for mine it will be next week's. 
Cam box just done. Poor poor productivity.
Six hours to complete cam-box and cover and mount on outer-head.:hDe:


----------



## AussieJimG (Jun 3, 2014)

So it looks like we could have two Nemett-lynxs at Melbourne?

Jim


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## Swifty (Jun 3, 2014)

Machined the piston this morning, nothing remarkable about the turning, although I did use 1"stock so I can grab it in my 5C collet block later. I left the piston attached and clamped the bar in the collet block and held it vertical in the mill to enable me to mill the slot for the con rod.




Next I clamped the block horizontal to drill the pin hole.




And here we have the finished piston loosely placed on the con rod.




Now I will have to make the pin and the rings.

Paul.


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## Swifty (Jun 5, 2014)

A few more bits done today, although no photo's as it's all pretty simple work. I made the gudgeon pin (wrist pin) with brass inserts in either end, turned the spacers for the crankshaft, tapped my small timing gear and finally adjusted the slack in the crankshaft when everything is nipped up tight. All up, a pretty quite day.

Paul.


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## gus (Jun 5, 2014)

AussieJimG said:


> So it looks like we could have two Nemett-lynxs at Melbourne?
> 
> Jim



The more ,the merrier. One in Singapore and all alone.


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## gus (Jun 5, 2014)

Swifty said:


> A few more bits done today, although no photo's as it's all pretty simple work. I made the gudgeon pin (wrist pin) with brass inserts in either end, turned the spacers for the crankshaft, tapped my small timing gear and finally adjusted the slack in the crankshaft when everything is nipped up tight. All up, a pretty quite day.
> 
> Paul.



As for poor Gussy, its the Cam-Box rework. All done and quite fast too.The slot hole looks good compared to last. Now undecided which item to make next.


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## Swifty (Jun 6, 2014)

After I realised that I had cut the ring grooves in the piston only half their depth, I set the piston up carefully and machined the grooves to the correct depth. Next step was to machine the rings from some cast iron bar stock. I rough turned the outside, drilled and bored the inside finished, then finished the outside.




Next I selected a narrow grooving tool that I would use for parting off, the tool was only 0.9mm wide, this allowed me to get the maximum number of rings from the bar.




I ended up with 7 rings to work with, should be enough to allow for breakages.




The next part makes me nervous, I have to split the rings.

Paul.


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## Brian Rupnow (Jun 6, 2014)

Swifty--I'm glad you are doing this now. Like Gus, I have never made rings before either, but plan on doing so for the engine I am currently building. I am following with great interest.  I made my cams today, and they are almost identical to the Lynx cams, so you may want to have a look at my cam journey!!---Brian


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## Swifty (Jun 6, 2014)

Well, all that worry about splitting the rings was for nothing, it was the simplest operation yet. I followed Malcolm's advice and used No.3 Morse taper to place the rings over and tapped them down with a piece of copper pipe. The rings split at their weakest point, it was all over in no time.








Now I have to make the heat treating fixture, clamp the rings and heat them up to set the correct "free" gap.

Paul.


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## Swifty (Jun 7, 2014)

Continuing on with the rings, I machined a clamp out of some 25mm mild steel bar, I previously gapped the rings at 2.5mm and measured the maximum inside diameter, this was 24mm as Malcolm states in his instructions, so I turned the step to this size and left the length 0.5mm short for clamping. Stacked up all the rings and tightened the end washer, then bought them to red heat for a few minutes, I concentrated the heat on the ends rather than directly on the rings.

After taking my wife out for a stroll and coffee (have to keep in the good books), before unclamping, I gave the now cold rings a light wire brush to remove the slight scale and and a light rub with some fine wet and dry paper. I unscrewed the clamp, took all the rings off and gave then a light rub on some 2000 grit wet and dry paper on either side. I then held them in a toolmakers vice and filed the gap with a needle file, trying each one in the cylinder until the closed gap was about 0.1mm.

Here's a photo of the clamped rings cooling down.




And the now finished rings, the open gap is 2.5mm which I was aiming for. I think that all the mystery about making piston rings is now behind me, and will not hesitate to make them in the future.




Now Brian and Gus, go for it.

Paul


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## gus (Jun 7, 2014)

OK. Maestro. Just waiting for good results. Best looking piston rings.The Nemett Engines sure led us to new discovery of our hidden talents.


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## Swifty (Jun 7, 2014)

Hi Gus, we all need to challenge ourselves sometime, I think that it was fear of defeat that made me nervous about making rings. I have had the rings on the piston, they expand nicely to get them on, I won't actually assemble the piston to the cylinder just yet, will wait until final assembly.

Paul.


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## gus (Jun 7, 2014)

Swifty said:


> Hi Gus, we all need to challenge ourselves sometime, I think that it was fear of defeat that made me nervous about making rings. I have had the rings on the piston, they expand nicely to get them on, I won't actually assemble the piston to the cylinder just yet, will wait until final assembly.
> 
> Paul.



I have been breaking rings and having to wait for new rings to arrive.

The Webster,Rupnow and now Nemett Engines are taking us to new grounds.
We no longer fear tuning carbs,valve timing and ignition timing. Spent too much time tuning  Webbie and Rupnow engines.

I have yet to cut a conventional shaft. Seen the Power Press Shops in our neighbourhood cutting crankshafts for power press. Also watched the maestros using shapers to cut vee slides too. The vee ways were so smooth and they mated with some scraping.Scraping is an art.
Also seen them using hammer and chisel to cut ''X'' oil grooves into the cast iron bushes.


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## Brian Rupnow (Jun 7, 2014)

In the Jaguar ring instructions, Malcolm shows the ring ends held apart with a 2.5mm thick shim while held in the fixture and heated up as you show. Has he changed that method in the Lynx instructions? There is no information about gapping the rings prior to the heat treat. It just says to split them as you have done, then put them in the fixture spread open with the wedge, and then heat treat with wedge in place. Gapping is done after the heat treat is completed. I don't see any wedge in your heat treat fixture.---Brian


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## Swifty (Jun 7, 2014)

Brian, you are correct in what you say, Malcolm also suggests on the drawing of the heat treatment fixture, that you can adjust the small diameter on the fixture to hold the gap at 2.5mm without an insert. That's why I gapped a ring with a 2.5mm slip gauge and measured the diameter needed before finishing the fixture. I thought that it would save me making an insert and it worked out well.

Paul.


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## Swifty (Jun 9, 2014)

I have been pecking away at a few small bits today, the bronze valve guides, the brass sump and filler plugs, and the breather. The breather has an M5 thread only 2.5mm long, so I made a short piece of brass threaded to M5, tapped the knurled top piece to suit and soft soldered the 2 together. This method gives me a thread all the way up to the end.





Paul.


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## gus (Jun 9, 2014)

All these bits n pieces drive us mad when we about to cross the finishing line and there is still a pile of miscellaneous to machine. The " Carb'' is another trap.

I am about to move the '' bits & pieces'' territory.


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## Swifty (Jun 9, 2014)

Hi Gus, I have been studying the cam manufacture, still not quite clear on it yet, I understand what they are saying regarding milling them, but still have to be sure before I start.

Paul.


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## gus (Jun 9, 2014)

Swifty said:


> Hi Gus, I have been studying the cam manufacture, still not quite clear on it yet, I understand what they are saying regarding milling them, but still have to be sure before I start.
> 
> Paul.



OK Maestro.  

Not a productive day. Boring Head must be modified to take it into smaller ID
boring. Made adapter. Big End bored to 14 mm but needle bearing O.D. is  
14.04/5 mm. Could have used a reamer to drill and ream to 14mm plus and Loctited. Half morning wasted to modify BH.:rant:

But I did get a press fit using bench vice to press in needle bearing.
Will profile mill Con-Rod tomorrow. Perhaps made my own oil hardeded bush for crankpin.

Kind od enjoyed doing the bits & pieces.

As for the cam machining,I am a wee bitty lost. Have yet to read Brian's
thread on his cam milling.


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## Brian Rupnow (Jun 9, 2014)

Guys--A word of warning.--I have seen the cam drawing for the Lynx, and unless you have a cad program or are a real geometry maniac, there is very little information on that cam profile. I was able to model it with my 3D software, and can provide any missing dimensions if you want them.---Brian


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## Jasonb (Jun 9, 2014)

There is all the info on the cam needed in the article eg Duration, lift, base radius and flank radius plus the table of offsets if you want to use the same method as you used on the Jaguar. Could also be done with the boring head and rotary table method if Gus does not have Z-axis DRO using the info provided.

J


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## Brian Rupnow (Jun 9, 2014)

Jason--I only looked at the drawing, not any of the specs. I hold by what I say----there is very little info on that drawing to create the cam from.--Brian


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## Jasonb (Jun 9, 2014)

Did you not look at the whole set of drawings? Probably why Malcom included a whole separate drawing page dedicated to just the cam, sheet 14 of 15 which is what all the past builders have used to make the cam from.


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## Brian Rupnow (Jun 9, 2014)

Jason--No, I didn't look at the whole set of drawings. Gus was remarking on how tiny the cams were. I had just made the Jaguar cams, so I looked at the drawing of the Lynx cam to try and get some idea of size comparison. I couldn't tell by looking at the drawing, and as I said, the dimensions that I would use for comparison are not there. There is enough information to generate the dimensions, but you can not tell by just a quick look at the Lynx drawing. I offered to supply any dimensions that Gus might not be able to generate. Gus keeps remarking about his WW2 technology, so I thought I would help him with a couple of dimensions if he needed them.


----------



## gus (Jun 9, 2014)

Jasonb said:


> Did you not look at the whole set of drawings? Probably why Malcom included a whole separate drawing page dedicated to just the cam, sheet 14 of 15 which is what all the past builders have used to make the cam from.




Hi Jason,

Thanks the reminder. Now looking at Sht 14. Believe my fear of the unknown
is over. Will mill cam using offset and RT. I have a bad habit of misreading and learn by these bad mistakes.


Hi Paul,

Have you got this sheet which comes with instructions. I am not sure it is in the Magazine. Will glad to send over.


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## Jasonb (Jun 10, 2014)

Gus sheet 14 is in the special eddition Vol 3 but it is missing some details, I think the link for the corrected one is at teh beginning of this thread if not let me know and I'll dig it out.

Edit, here it is anyway.

http://www.model-engineer.co.uk/sites/7/documents/NE15iss3.pdf


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## Swifty (Jun 10, 2014)

Hi Gus, yes I have the sheet with the degrees and offsets for the cams, just have to fully understand the steps, I may do a dummy run first with a piece of scrap.

Paul.


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## Brian Rupnow (Jun 10, 2014)

Swifty--Having just traveled this cam road yesterday or the day before I will tell you what worked for me. Center the chuck on the rotary table directly below the center of the quill in the Y axis. With a 3/8" or 10mm endmill in the quill. Set the rotary table to 300 (or whatever Malcolm suggests for the Lynx---it was 300 for the Jaguar). Bring the cutter down and touch off the part to be milled and set the quill vernier to zero. Lock the Y axis--all the milling will be done with the table moving in the X axis. You will have a known dimension from the size of stock you are using to the major diameter of the cam. (I measure that major diameter as 0.472" (12 mm) on the Lynx cam.) Move the table in the X axis until the part is no longer directly below the quill. Advance the quill whatever distance is required to get down to the major diameter and take a cut, then back the part out from under the quill, again moving only in the X axis. This will leave a flat spot on the top of the cam. Then you start with the table, advancing the quill however many mm is called for and turning the rotary table however many degrees are asked for and each time taking a pass under the cutter in the X axis. When you have went completely through the tables, leave the part in the chuck, and don't advance the quill any more. Just rotate the chuck in 1 degree increments and take a cut each time without moving the quill. Eventually you will have worked your way all the way through until your last cut comes tangent with the flank on the other side of the cam.  This is majorly tedious business. I never had a true appreciation for how many degrees there were in a circle till I cut a cam using this method.---Brian


----------



## gus (Jun 10, 2014)

Brian Rupnow said:


> Swifty--Having just traveled this cam road yesterday or the day before I will tell you what worked for me. Center the chuck on the rotary table directly below the center of the quill in the Y axis. With a 3/8" or 10mm endmill in the quill. Set the rotary table to 300 (or whatever Malcolm suggests for the Lynx---it was 300 for the Jaguar). Bring the cutter down and touch off the part to be milled and set the quill vernier to zero. Lock the Y axis--all the milling will be done with the table moving in the X axis. You will have a known dimension from the size of stock you are using to the major diameter of the cam. (I measure that major diameter as 0.472" (12 mm) on the Lynx cam.) Move the table in the X axis until the part is no longer directly below the quill. Advance the quill whatever distance is required to get down to the major diameter and take a cut, then back the part out from under the quill, again moving only in the X axis. This will leave a flat spot on the top of the cam. Then you start with the table, advancing the quill however many mm is called for and turning the rotary table however many degrees are asked for and each time taking a pass under the cutter in the X axis. When you have went completely through the tables, leave the part in the chuck, and don't advance the quill any more. Just rotate the chuck in 1 degree increments and take a cut each time without moving the quill. Eventually you will have worked your way all the way through until your last cut comes tangent with the flank on the other side of the cam.  This is majorly tedious business. I never had a true appreciation for how many degrees there were in a circle till I cut a cam using this method.---Brian





Hi Brian,

Sounds humanly possible though a wee bitty tedious but if a best cut cam profile is done to drawing then its like pulling up a 20 kg Grouper with 1 kg sinker from 200 meters sea depth. W/o the fish then pulling up the 1 kg sinker is murder.:rant:
Been studying Malcom's fotos and instructions but got no where than skin depth. 
Was good to have a team with members individually working on the Nemett Engines and sharing their experience.th_wavth_wav
I am still stuck with the con-rod but will complete today. Finished con-rod will
look passable.


----------



## gus (Jun 10, 2014)

Swifty said:


> Hi Gus, yes I have the sheet with the degrees and offsets for the cams, just have to fully understand the steps, I may do a dummy run first with a piece of scrap.
> 
> Paul.




OK.

Will wait for your good news and then proceed. This way the unknowns and fears conquered. Will be next week to work on valves and cams.


----------



## Swifty (Jun 10, 2014)

The chart shows distances to move the quill up with each increment of rotation. Since I have a knee mill, I will be working by locking the quill and moving the knee, I would rather move the knee up, but if I do it the way stated on the chart I will have to move the knee down. The only trouble with moving the knee down is that I usually overshoot the amount then come back up to the reading required, this prevents any mistake caused by the knee sticking.

Paul.


----------



## gus (Jun 11, 2014)

Swifty said:


> The chart shows distances to move the quill up with each increment of rotation. Since I have a knee mill, I will be working by locking the quill and moving the knee, I would rather move the knee up, but if I do it the way stated on the chart I will have to move the knee down. The only trouble with moving the knee down is that I usually overshoot the amount then come back up to the reading required, this prevents any mistake caused by the knee sticking.
> 
> Paul.



Hi Paul,

Scratching my head now. All I have is a mini vertical end mill and no DRO.
Looks I may have to cannabalise a cheapy China Digital Caliper to read the quill movment. Will be fun. Failure of which I will fall back on to the 
Rupnow H&M Engine cams. The vroom vroom will be no fun.

Also have to rig up the RT get the angle setting for each cut. I have a "Made in Singapore'' Digital Angle Readout. At best will be ''Bush Engineering''.


----------



## Swifty (Jun 11, 2014)

Gus, can you rig up a dial indicator to set your depths?
Another idea would be to use a digital tire tread depth gauge fron eBay, just like a mini vernier.

Paul.


----------



## Brian Rupnow (Jun 11, 2014)

Gus--Many years ago I cannibalized a 4" digital caliper and attached it to my quill.This is a good deal, because with the push of a button I can have it read out in millimeters or in inches. It was a very easy change/add on, and you can zero it at any point.---Brian.


----------



## AussieJimG (Jun 11, 2014)

Swifty said:


> Gus, can you rig up a dial indicator to set your depths?
> Another idea would be to use a digital tire tread depth gauge fron eBay, just like a mini vernier.
> 
> Paul.



I have successfully used a dti on its magnetic stand on top of the mill and reading the depth from the top of the drawbar nut (increment by increment while the mill is stationary of coiurse).

Jim


----------



## Brian Rupnow (Jun 11, 2014)

Gus--Are you really sure you want to shut your mill off and start it again 120 times?


----------



## doubletop (Jun 12, 2014)

Swifty  Tagging along for the ride.     It looks like its going well and those rings are easy aren't they?   When I refurbished my Simplex loco I purchased 4 rings from the UK at 10 quid each. I was recently given a 1 mtr bar of spun cast iron, allowing for parting off, enough to make 240 Simplex rings. That's nearly NZ$5000 worth!  Now I know the score, not a case of making a profit but taking the P155.      Back to your build...    Pete


----------



## gus (Jun 12, 2014)

doubletop said:


> Swifty  Tagging along for the ride.     It looks like its going well and those rings are easy aren't they?   When I refurbished my Simplex loco I purchased 4 rings from the UK at 10 quid each. I was recently given a 1 mtr bar of spun cast iron, allowing for parting off, enough to make 240 Simplex rings. That's nearly NZ$5000 worth!  Now I know the score, not a case of making a profit but taking the P155.      Back to your build...    Pete



Hi Pete,

We can go into mini piston ring mfg biz. Made to order. Minimum 10 pcs at S$3---S$5. Most likely we will do it for an IOU beer for beginners building same size IC Engines.

Bought some 3/4'' rings from USA and they just won't ship to Singapore. Had to have a friend to speed mail out. :wall:


----------



## gus (Jun 12, 2014)

Brian Rupnow said:


> Gus--Are you really sure you want to shut your mill off and start it again 120 times?




Most likely. Just hope the motor won't pack shop on me.:rant:

Piston just done and cylinder sleeve honed with poor man's equipment.:hDe:


----------



## Swifty (Jun 12, 2014)

Gus, don't shut the mill off each step, rig up the indicator somehow on the quill, there must be some easy way of mounting one.

Pete, thanks for following along, the metre length of cast iron bar was a nice score.

No progress today on the engine, I'm going fly fishing tomorrow and needed to get a new fly line, and of course that was followed with a new fly reel, hopefully will get a couple of trout to make it worthwhile.

Paul.


----------



## gus (Jun 12, 2014)

Swifty said:


> Gus, don't shut the mill off each step, rig up the indicator somehow on the quill, there must be some easy way of mounting one.
> 
> Pete, thanks for following along, the metre length of cast iron bar was a nice score.
> 
> ...



Please post catch or Fisherman with New Fly-Rod and Reel.


----------



## Swifty (Jun 12, 2014)

gus said:


> Please post catch or Fisherman with New Fly-Rod and Reel.



Will do my best Gus.

Paul.


----------



## Swifty (Jun 13, 2014)

gus said:


> Please post catch or Fisherman with New Fly-Rod and Reel.



Gus, this is for you, no picture of me holding fish as they weren't cooperating, but I have included a picture of the new fly reel.
We can only fish enclosed waters at the moment as the rivers are shut for the spawning season.









Paul.

Edit, don't know why the pictures come out upside down, look fine in photobucket. I rotated the pics in photobucket and re pasted the link, but they still come out upside down.


----------



## gus (Jun 13, 2014)

Swifty said:


> Gus, this is for you, no picture of me holding fish as they weren't cooperating, but I have included a picture of the new fly reel.
> We can only fish enclosed waters at the moment as the rivers are shut for the spawning season.
> 
> 
> ...




This Fly-Reel cost a bomb. There are no fly-fishing spots in Singapore,
Fly-Fishermen have to book trips to Australia,New Zealand etc.
Mongolia is good for fly-fishing but trips there cost an arm and a leg.

Not happy with the first con-rod as cranking is not smooth. Big end bore was taper and needle bearing got mis-align. You will laugh how I got around it.
Bored the big end on the lathe.Four jaw won't take it . Used the three jaw to hold con-rod blank.Very odd way of job holding. The lathe is best and fastest to reduce bar thickness. End Milling will take ages. Happy with results. Will finish off con-rod next Monday.Its weekend fishing.


----------



## Swifty (Jun 13, 2014)

gus said:


> This Fly-Reel cost a bomb. There are no fly-fishing spots in Singapore,
> Fly-Fishermen have to book trips to Australia,New Zealand etc.
> Mongolia is good for fly-fishing but trips there cost an arm and a leg.



Actually the reel was on special, $80 off. I have been to New Zealand on several fly fishing trips, including being taken by helicopter to the back country and being left at a hut on the river for several days.

Paul.


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## gus (Jun 13, 2014)

Swifty said:


> Actually the reel was on special, $80 off. I have been to New Zealand on several fly fishing trips, including being taken by helicopter to the back country and being left at a hut on the river for several days.
> 
> Paul.



My very first fly fishing was disastrous. Using my own DIY flies ,I did attract some Tilapias to the surface but they just won't bite. Flies here cost too much.
I have no other flies to present so called it a day.

Went back to resort hotel room,the ceiling fan ate my line and rod tip.

Was in Yellow Stone Park,USA. The rivers there are fly country. So many fly shops selling wide range of fly equipment which I could afford to buy as they were top range.When the season is on, the fish bite like crazy.

Did try crappy fishing.My USA boss landed 30 and Gus one. Bait was minnows.This was in 1977. Long time ago when Gus was 33 and a budding manufacturing engineer training in Campbellsville,Kentucky.Gave fly fishing a miss.


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## Swifty (Jun 14, 2014)

I turned a piece of brass to do a trial run of the cams. My final intention is to cut the 2 cams on the one piece of material with the correct degree of rotation between them. The trial looks ok, of course I haven't filed the burrs off or smoothed out the machining, I just have to check that I have offset the lobes to the correct orientation.





Paul.


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## doubletop (Jun 14, 2014)

Swifty  That looks great. So we'll be seeing a set of cams by the end of the weekend?  Pete


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## Swifty (Jun 14, 2014)

Hi Pete, while I have the rotary table set up on the mill, I will be following on with making the real cams, I just hope everything goes well with it.

Paul.


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## Swifty (Jun 14, 2014)

Looks like I have the offset between my cams incorrect, the rear cam should be 180 degrees around from where it currently is. That's an easy fix on the final article.

Paul.


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## gus (Jun 14, 2014)

Swifty said:


> Looks like I have the offset between my cams incorrect, the rear cam should be 180 degrees around from where it currently is. That's an easy fix on the final article.
> 
> Paul.




Hi Paul,

Please take and post fotos of your cam cutting. 

Had a great day fishing. Caught in a mini storm. No sweat at all in sheltered
inland waters. See my post.


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## Brian Rupnow (Jun 14, 2014)

Swifty--I made my cams that way on purpose, to reverse the rotation of the engine. I use my variable speed electric drill for a starter, and if I turn the engine counterclockwise like Malcolm planned it, the chuck loosens off the drive spud in the drill.---Brian


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## Swifty (Jun 15, 2014)

Well fellers, after much winding of the mill table handle and of the rotary table, I now have a finished cam. I machined my two cams on the one piece, I thought that this would eliminate the need to get the correct angle of rotation, and it also gives me a greater bearing surface to loctite the cams to the shaft. Sorry about the picture overload, but I thought it best to show as much as possible.

First pic is the setup.




Here we have the first cut down to depth.




And the first cam finished.




And both cams finished.




Close up of the two cams.




Cams mounted on the shaft.




And cams mounted in the cam box.




Paul.


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## Swifty (Jun 15, 2014)

Gus, I seem to recall that you don't have degree markings on your home made rotary table, so this method of machining the cams, that is described in the build article, may be difficult. But here is a run down on how I machined both cams in the one piece. You need to set your rotary table to the angle shown at the top of the left hand column, touch the top of the blank and mill down 2mm. From here you have to rotate one degree and move the quill up to the reading shown, then take a cut across, repeat by rotating one degree at a time, and moving the quill up to the corresponding reading. When you come to the bottom of the figures on the left hand column, you will have one flank of the cam cut. Next step is to machine the other flank, this is what the right hand column is showing. Back your table away from the cutter, rotate to the angle shown on top of the right hand column and move the quill up to the figure shown. Machining is a similar process to the first flank, except the quill is bought down to the readings this time. When you reach the bottom of the right hand column you will be back to your zero reading. Leave the quill at this reading and take cuts across the cam at one degree rotations until you reach the angle shown on the top of the left hand column, your initial starting point.

To machine the other cam, you will need to subtract 105 degrees from the figures shown in the tables, and move on in one degree increments from there. This will ensure the correct angle between the cams.

For the cam blank, just machine it with a 7mm gap between the two lobes, this will give you 13mm centres between the cams.

Paul.


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## gus (Jun 16, 2014)

Swifty said:


> Gus, I seem to recall that you don't have degree markings on your home made rotary table, so this method of machining the cams, that is described in the build article, may be difficult. But here is a run down on how I machined both cams in the one piece. You need to set your rotary table to the angle shown at the top of the left hand column, touch the top of the blank and mill down 2mm. From here you have to rotate one degree and move the quill up to the reading shown, then take a cut across, repeat by rotating one degree at a time, and moving the quill up to the corresponding reading. When you come to the bottom of the figures on the left hand column, you will have one flank of the cam cut. Next step is to machine the other flank, this is what the right hand column is showing. Back your table away from the cutter, rotate to the angle shown on top of the right hand column and move the quill up to the figure shown. Machining is a similar process to the first flank, except the quill is bought down to the readings this time. When you reach the bottom of the right hand column you will be back to your zero reading. Leave the quill at this reading and take cuts across the cam at one degree rotations until you reach the angle shown on the top of the left hand column, your initial starting point.
> 
> To machine the other cam, you will need to subtract 105 degrees from the figures shown in the tables, and move on in one degree increments from there. This will ensure the correct angle between the cams.
> 
> ...



Thanks. Will be next week cam cutting. Now fighting a mild flu. In a way crippled but bored/reamed the timing gears and spacers for the crankshaft.
Will spent next week tooling and cutting cams.


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## AussieJimG (Jun 16, 2014)

That's a great post Swifty, and the cams came out well.

Jim


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## Swifty (Jun 16, 2014)

Thanks Jim, I think that I will heat treat the cam today. The surface came up well with a bit of work with fine wet and dry paper. I have started on making the valves now.

Paul.


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## gus (Jun 16, 2014)

Swifty said:


> Thanks Jim, I think that I will heat treat the cam today. The surface came up well with a bit of work with fine wet and dry paper. I have started on making the valves now.
> 
> Paul.




Are you case-hardening it ?  Thought of using ''Grade 5'' Hex Bolt to cut cam and heat treat plus oil quench. ''Grade 5''is just machineable with my Sakai and HSS cutters.


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## Swifty (Jun 16, 2014)

I made the cam out of silver steel, I am actually thinking about trying to flame harden it by spinning it in the lathe, applying a quick heat to the lobes and quenching it. This way only the lobes will be hard and the rest will stay soft, but I may have trouble getting enough heat quick enough. I use to send out work to a dedicated flame hardening business years ago, the flame was followed directly by a water quench. 

Paul.


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## Swifty (Jun 17, 2014)

I have been working on the valves today, following the build instructions, I turned the stems over length, finished the valve dia. and turned the valve seat in one setup.





Next I turned the valve caps that will contain the spring, I made sure that they were both the same by using one valve in the head and checking the size of the caps.





Next thing to do was to turn up a bush with a 12mm OD and a 3mm reamed hole in the centre, I then used my new 0.5mm slitting saw to cut through one side of the bush so I can clamp the valves to finish them. I turned the head of the valve down to thickness first on both, then trimmed the valve stems to finished length, carefully checking the finished size to only allow 0.05mm gap under the cams. I had previously marked each valve as inlet and exhaust. Last job was to turn the "E" ring groove, 0.5mm wide. I'm going to have to befriend a micro surgeon to help me get the "E" rings on when the valves are in position.

Here are the finished valves and caps.





Paul.


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## gus (Jun 17, 2014)

The valves look great but how are you going about to lap same. 
Will be next week for Gus to work on valves and rings.

Meanwhile I am working at a lame duck space.


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## Swifty (Jun 22, 2014)

Gus, I did manage to lap the valves, but it was difficult. In hindsight, it would have been ideal to leave the stems longer so I could grip them for lapping. But in the end I did manage to get enough grip on them to get a good witness from lapping.

Apart from machining the tensioner, I haven't done much the last few days. Between looking after our grandson and other commitments, there has been no spare time. Tomorrow is another busy day, but after that I will be able to progress further.

Paul.


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## Swifty (Jun 23, 2014)

Well after a bit of a break, I wandered back into the garage tonight and decided to loctite the cams onto the shaft and drill and tap an M3 hole for a grub screw in the timing pulley. I will start to get a move on from now.





Paul


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## gus (Jun 23, 2014)

Great work. Gus is still recovering and the good news is he lost 2 kilos and the bad news is he is not up to cranking speed. 

The mini timing gear on the crankshaft. There is no excess to drill/tap to fast same other than Loctite. Please advise.


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## Swifty (Jun 23, 2014)

Gus, you could put a small pin through one shoulder into the shaft, but seeing that the shaft is only 4mm dia. it may weaken it too much. By making the cams out of one piece instead of separate gives a lot more area for the loctite to hold on to. Brian loctited his as two pieces, and so far it seems to be hanging on.

Edit. I had thought of making the cams and shaft in one piece, but decided against it in the end.

Paul.


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## gus (Jun 24, 2014)

Thanks for the good advice.  Still lethargic which is good. When the hands moved too fast than the brains,mistakes happen. Still struggling to read prints right and get dimensions,measurements and fits to specs.
Been making too many mistakes and time wasted to rectify. Making a new piece is faster than reworking and compromising. Cutting new outerhead now and about to finish. I have a very good looking pencil stand cum paper weight for my wife.:hDe:


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## Swifty (Jun 25, 2014)

I managed to put a couple of hours work in today, rummaged around and found a suitable spring for the valves and turned up 2 spring retainer washers. With these parts in hand, I assembled the valves in to the head, it took me about 5 minutes on each one to get the E clip in place, I have to work in the tappet hole as the groove on the valve ends up below the surface of the head, making it a real pain to get the E clip on.

The picture below shows the top of the valves, one valve / spring assembly already has the tappet in place on top.





I still need to harden the cams and tappets, but wanted to do a trial assembly.





Paul.


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## gus (Jun 25, 2014)

*''E'' clip insertion.*
After the umpteenth time putting on and taking of the ''e'' clip , I found a sure fire way. Use a very robust stamp collector's forceps  to pick up and insert into valve stem slot. Will try taking foto and post.
New Outerhead about done and I am very happy with same. Looks like I can still reclaim cylinder jacket other than cutting a replacement.


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## Swifty (Jun 25, 2014)

Hi Gus, the biggest problem with the E clips is that I'm working down the tappet hole, I have to hold down the spring and washer then try to put the E ring on down inside the tappet hole. Only have room for a jewellers screwdriver to push the ring in, it's really a three hand job.

Paul.


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## AussieJimG (Jun 25, 2014)

Philjoe05 threaded the end of the valves on his Bonzer so he could easily adjust the spring tension. That might also be appropriate for retaining valve springs in a hole.

Jim


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## Swifty (Jun 25, 2014)

It's done now Jim, but I will keep that method in mind.

Paul.


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## gus (Jun 26, 2014)

Swifty said:


> Hi Gus, the biggest problem with the E clips is that I'm working down the tappet hole, I have to hold down the spring and washer then try to put the E ring on down inside the tappet hole. Only have room for a jewellers screwdriver to push the ring in, it's really a three hand job.
> 
> Paul.



Yes .It is but I did it with two hands. One pushing down the retainer down past the notch. Pick up the ''e'' clip with the right hand and insert. Takes a bit of practice.
Will get my wife or friend to take a close-up shot.Monkey see.Monkey do.


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## Swifty (Jun 28, 2014)

On a trial assembly, the valves seem to be leaking despite initially lapping them, they are a bit hard to grip for lapping, so I decided to mill a groove in each valve to enable the use of a screwdriver. I used a 1mm carbide cutter and made the groove 3mm long x 0.5mm deep, while it was set up, I milled an additional 0.05mm deep groove 90 deg to the slot on the exhaust valve to identify it.





Now to try it out and do a bit of lapping.

Paul.


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## gus (Jun 29, 2014)

Good Idea. With the new Outer-Head,I have to relap the valves. 
*Valve Spring*

Valve springs made with the prescribed SWG 20 piano wire turned out to very stiff. Now looking for one or two size down wire for new springs. Will use S.Steel wire from my fish tackle box.


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## Swifty (Jun 29, 2014)

Hi Gus, I was lucky with the valve spring, I found a spring that was perfect, just had to cut it in half, which gave me the correct length for 2.

Paul.


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## Swifty (Jun 29, 2014)

I'm just pecking away at small bits at the moment, can't seem to get enough time for machining. Despite that, I have made the hall effect sensor holder, with slight modifications to the one drawn. The build instructions call for the sensor itself to be glued or siliconed to the holder, making it permanent, but I'm using the "D" shaped sensor holder that comes with the ignition kit, and will glue this in place. This way it will enable easy replacement of the hall sensor in case it fails.









Now, I think that it's time for a big clean up of my workshop, I always clean up a bit as I go, but its time to empty swarf trays and remove the swarf from corners where it seem to end up.

Paul.


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## doubletop (Jun 30, 2014)

Swifty said:


> ................ I'm using the "D" shaped sensor holder that comes with the ignition kit, and will glue this in place. This way it will enable easy replacement of the hall sensor in case it fails.


Paul

Neat idea

Pete


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## gus (Jun 30, 2014)

I am also pecking away. Will machine the last valve piece,lap and install. After this will stop to '' Bush Engineer'' an electronic speed controller for my friend to load fishing lines. He sells a hundred or two of cheapy M.I.C. Spinners and with free line thrown in. The cheapy M.I.C. Rheostat Sewing Machine Rheostat does last too long w/o overheating. 

Now that I am about to really finish up the ''Lynx"",I am enjoying just looking and messing with same.


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## Swifty (Jul 1, 2014)

I spent a few hours cleaning up all the swarf that gets missed on my quick clean ups, I then mixed some degreaser with hot water and washed down the lathe and milling machine, having a knee mill, I spent a bit of time avoiding bumping my head on the table, after that a good spray with WD40 and oil to all the ways.

On to a bit of machining, I had a piece of bronze that was ideal for a flywheel, a bit of a clean up and bore the centre to suit the taper lock on the prop shaft, each side of the bronze had a step on it, so that was just cleaned up and left. Next thing to make will be an adaptor that fits in my battery drill, put a couple of driving pins on it and drill the driving holes on the flywheel. 





Paul.


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## gus (Jul 1, 2014)

You are making good progress. About to finalise the Fishing Line Power Spooler Foot Pedal Speed Controller.
The mockup is 100% ''Bush'' from Crocodile Dundee. Latest by this Friday should complete and run.
Looks like nrext week will be ''Cam Prepping Time'' follow by Cam Cutting Time.


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## Swifty (Jul 5, 2014)

I've made a start on the carburetor, here is a picture of the basic pieces, there is still a bit more machining to do yet. I still have to have a close look at Malcolm's drawings, as his photo's are different from what he has drawn.





Paul.


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## Brian Rupnow (Jul 5, 2014)

Swifty--That looks great. I built that same carburetor last week, only converted to inches using imperial #4-40 fasteners. It works great.---Brian---(send me your real address to [email protected])---Brian


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## Jasonb (Jul 5, 2014)

Couple of pics of my one assembled if that helps, as drawing except trumpet shape to outside of intake.


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## Swifty (Jul 5, 2014)

Thanks for that Jason.

Paul.


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## Swifty (Jul 9, 2014)

Well, with a bit of help from Jason and Brian, I now have my version of the Lynx carburetor. Despite the drawings being hard to interpret, I only ended up with 2 extra holes, one M2 hole I plugged, the other doesn't matter. It's times like these that I wished that I had a small bench top lathe. Turning the 2mm dia. spray bar was a bit of a challenge on my 14 x 40 lathe, but in the end I got there. I also made the inlet manifold.













I'm on the home stretch now, I only have to make the exhaust manifold, some sort of stand, fuel tank and hook up the electrics.

Paul.


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## gus (Jul 9, 2014)

In the far distance,I hear an engine running soon.

Now upgrading the Rotary Table which had a 71 t worm wheel to  60 t gear(ex-USA) so that I could graduate the 360 degree table. With this done , other prepps required before cutting cam.


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## Swifty (Jul 13, 2014)

Anyone that thinks retirement will give them plenty of time to do the things they like, is in for a big surprise. After being retired for 11 years now (no I'm not that old, I did retire at 51) I still have trouble finding enough machining time. I have just spent the last couple of days on things other than machining. 

Despite this, I did have time to get in the workshop this evening and ponder how to determine which end on the neodymium magnet is the south pole, the one needed to trigger the Hall effect sensor. After googling about it, the best way was to use a compass to find out, the north arm of a compass will point to the south end of the magnet. For anyone interested, here is one site showing how to do it.https://www.kjmagnetics.com/blog.asp?p=which-pole-is-north

Further reading on the hall sensors appears to show that the pole on the magnet is not so critical so long as the sensor can be turned around to activate the correct side. This make the idea of mounting the sensor in a non permanent way ideal.

Paul.


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## gus (Jul 13, 2014)

Swifty said:


> Anyone that thinks retirement will give them plenty of time to do the things they like, is in for a bid surprise. After being retired for 11 years now (no I'm not that old, I did retire at 51) I still have trouble finding enough machining time. I have just spent the last couple of days on things other than machining.
> 
> Despite this, I did have time to get in the workshop this evening and ponder how to determine which end on the neodymium magnet is the south pole, the one needed to trigger the Hall effect sensor. After googling about it, the best way was to use a compass to find out, the north arm of a compass will point to the south end of the magnet. For anyone interested, here is one site showing how to do it.https://www.kjmagnetics.com/blog.asp?p=which-pole-is-north
> 
> ...



Thanks for timely info. Will follow your post on magnet and pole effect.
Still taking my sweet time upgrading the R/table. Engraving cutters coming in next week to graduate the table disc and Knob dial. Did think of  marking on the lathe but graduating and calibration a big problem. Fishing was great last weekend but we had great time recalling past fishing trips over beer and lunch.


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## Swifty (Jul 15, 2014)

It's strange, but the closer that I get to finishing this engine, the less time I have to work on it. I managed to make some supports for the engine this morning, they will eventually be fastened to a piece of timber.





Paul.


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## gus (Jul 16, 2014)

Engine is another Paul Swifty's Masterpiece .th_wav

I am having the same problem,slowing down but taking my sweet time. Hand Wheel graduated and number stamped. Numbers 1-----6 done good with a jig to hold stamp and job and alignment with eyeball. Messed the first piece with too hard hammer blows. This time two blows 4'' high gave me the depth. Could never stamp straight and tidy in Trade School. SW Monsoon blowing outside and fishing will be bad this weekend.:wall:

Take care in the machineshop. Gus tripped over some flexible cord and if not for the skating and judo training I could have knocked the back of my head on the shoe locker and gone. Was able to spun around in time to land on my hands.    Will improve housekeeping with personal safety in mind.


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## Swifty (Jul 16, 2014)

Take care Gus, I caught my toe on a garden hose last week, it was the leg with bad arthritis in the knee, it sure hurt. This cold weather that we are having is really playing up with my joints, I seem to have arthritis in every one of them, the only way to get relief in this cold weather is to visit the local hot springs for a few hours. 

I managed to get some tubing for the crankcase breather, now I have to make a bender for it.

Paul.


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## Swifty (Jul 17, 2014)

Another day, another short bit of work done. I made an adapter with 2 drive pins to fit my battery drill, and I added a piece to the flywheel with 2 corresponding holes so I can crank it over.





I also made a start on the fuel tank, a piece of 38mm dia tube, I turned up a couple of ends for it, they had a short location on the inside dia, After cleaning the tube with some emery, I dipped each end into the flux bottle to make sure it was coated. I then put the end plates on and smeared a little bit more flux on. Using a gentle flame with the Mapp torch, I brought it to the correct temp to melt the silver solder and worked my way around the end, being sure that the solder followed the heat. I found in the past that if I had the torch on full it was too much heat and hard to control. Of course, I drilled a hole where the filler cap will go before soldering, this saves having the ends blow off as it heats up. A soak for about 60 minutes in a citric acid bath cleaned up all the excess flux inside and outside. Citric acid is a great way to clean things.





Paul.


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## doubletop (Jul 17, 2014)

Swifty

Its looking good!!

You may want to think about how you are going to get the starter dog to disengage. If you have the starting problems I had and Brian described well on his thread you find that once the engine fires it wants to go off faster than the speed of your drill but it can't decouple and the drill then becomes a brake and the engine stops. What you end up with is a few farts and then nothing. Take a look at my thread and the helio starter with sprag clutch.

Pete


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## Swifty (Jul 17, 2014)

Will check it out Pete, I may have to go to the helix type starter that I made for the Rupnow hit and miss. The holes in the mating part are 0.5 mm bigger than the pins, if anything, it will let me turn over the motor for bedding in the valves.

Paul.


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## johnny1320 (Jul 17, 2014)

Why not just add a one-way bearing to the starter shaft with the drive pins. It's a beautiful engine you've got there.


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## Swifty (Jul 17, 2014)

I've often thought about using one way bearings (sprag bearings). When I make a multi cylinder engine, I will use a permanent starter motor with sprag bearing.

Paul.


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## AussieJimG (Jul 17, 2014)

For what it is worth Paul, I have used a driving dog with a release ramp like the one in the photo because I thought I needed it. The problem here was that when turning the engine over trying to adjust the carby, every time it fired it kicked the starting drill off and the engine would stop.

So I dispensed with the ramps (which were a pain to cut anyway) and now I am using the simple version shown in the flywheel. It works fine and disengages without any problems.

I know that others use the Sprag clutch idea but I am not sure how accurate the alignment needs to be between the starting drill and the crankshaft.

Jim


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## Swifty (Jul 18, 2014)

Hi Jim, your ramp starter is virtually identical to my Rupnow one.

Paul.


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## Swifty (Jul 18, 2014)

_"That's funny, I don't recall seeing that on the drawings"_ I decided to add a bit extra to the crankcase, a dipstick hole. I turned up a 12mm dia x 32mm long piece of aluminium with a M6 hole, I then quickly drew up the modification in CAD to see what angle was best and also where to machine the hole. I then set the crankcase cover up in the vice at 30 deg and used a 10mm cutter to rough it out followed by a 12mm cutter. A bit of 2 part epoxy was used to glue the piece in, I used the excess epoxy to build up around the part on the inside. The dipstick was made easily from a bit of brass and some 3mm silver steel for the stick part, it may be hard to see on the photo, but there is a small groove in the stick at the full level.









Paul.


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## doubletop (Jul 18, 2014)

Swifty said:


> I've often thought about using one way bearings (sprag bearings). When I make a multi cylinder engine, I will use a permanent starter motor with sprag bearing.
> 
> Paul.



Paul

One of these helio starters from hobby king







Modified with a few bits of silver steel to become






Pete


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## Brian Rupnow (Jul 18, 2014)

Swifty--I like that dipstick very much.---Brian


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## Swifty (Jul 18, 2014)

Pete, that sure makes a nice starter.

Brian, thanks for you comment on the dipstick, I hope that it will solve one of the problems that you mentioned about not knowing how much oil is in there.


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## Swifty (Jul 19, 2014)

I fiddled around with the breather tube and fittings today, I plan to thread the top of the fitting that screws into the crankcase then make a cap for it, I will use an O ring as an olive to grab the tube. The way it is now will be fine for a test run.





I have mounted the motor on a temporary board for the time being, the 360 deg graduated disc is one of a pair that I have had for years, I knew that it would come in to use one day, perfect for setting the timing.





Paul.


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## Swifty (Jul 20, 2014)

I still have to get some tube to make the exhaust pipe, but that won't delay me starting the engine. This morning I set the cam timing and the ignition timing, it was straight forward using the degree wheel. I also put 35ml of engine oil in the crankcase, I intend to use a makeshift fuel tank for the initial attempt to start the engine.

I am using an Rcexl electronic ignition module, ever since it arrived in the mail, I was confused, as it has no earth lead coming out of the box. After googling for a while, I found the answer. The high tension lead for the spark plug has a metal sheath around it, this together with the metal spark plug cap acts as the earth. With that problem solved, I only have to hook up the ignition and temporary fuel tank and attempt to start the engine. Other things are stopping me from doing this at the moment, but by this time tomorrow I hope to have a runner.

Paul.


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## doubletop (Jul 20, 2014)

Swifty said:


> ..............
> 
> I am using an Rcexl electronic ignition module, ever since it arrived in the mail, .............
> 
> Paul.



Paul

You'll need to read my write up on the ignition systems on my build thread. These modules expect the sensor to be on the crankshaft and not on the camshaft as on this engine .

The camshaft is running at half the speed of the engine and the ignition unit times the pulse interval to determine the speed and then calculates the advance it needs to apply. With the sensor on the cam it gets the advance calculation wrong.

The worst time is when its starting. The ignition system is set up with the sensor at 27deg advanced. It gets the sensor pulse and waits for and interval the equivalent of 27deg to fire at TDC. However, as the cam is running at half speed the interval is calculated as twice as long as it should be and the ignition is fired at 27deg after TDC.

It will work to some extent but it one thing you are going to need to deal with to get it to run. With the three variables Carburation, Compression and Ignition, and you'll be chasing your tail like Brian. If you are going to run with a flywheel then just fix the magnet to that and find a way of mounting the sensor.


Pete


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## Swifty (Jul 20, 2014)

Thanks for the advice Pete, looks like I will have to rethink it a bit.

Paul.


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## Swifty (Jul 20, 2014)

Pete, could you please post a link to your build thread, I'm having trouble finding it.

Paul.


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## Swifty (Jul 20, 2014)

doubletop said:


> Paul
> 
> The camshaft is running at half the speed of the engine and the ignition unit times the pulse interval to determine the speed and then calculates the advance it needs to apply. With the sensor on the cam it gets the advance calculation wrong.
> 
> Pete



Hi Pete, surely the easiest thing to do is use 2 magnets on the camshaft, 180deg apart. That way the CDI will get the correct amount of pulses.

Paul.


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## Brian Rupnow (Jul 20, 2014)

Here is a link to Doubletop's Bobcat build.
http://www.modelenginemaker.com/index.php?topic=1796.0


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## Swifty (Jul 20, 2014)

Thanks Brian.

Paul.


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## Swifty (Jul 21, 2014)

I made a new magnet holder today, it has 2 magnets 180degrees apart, so seeing that the camshaft rotates at half the engine speed I should now be getting a signal every rotation of the crankshaft. I've had one attempt to start it, it pops a bit and fights with the drill that I am using for a starter, but won't take off yet. The compression is not all that great at the moment, the piston and rings appear to be a good seal, whenever I had the head off I held the palm of my hand over the cylinder and it certainly had good suction. I have lapped the valves in a couple of times, but they still must be leaking a bit.

There is a good spark, so I will just play around a bit more, if I can get it firing a bit more the valves may seat a bit better.

Paul.


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## Swifty (Jul 21, 2014)

Woo Hoo! That didn't take long, I now have a runner woohoo1. I was so excited that I grabbed my iphone and took a video. The valves are already seating better, giving more compression. I have stopped and started it a few times, it is still blowing out a bit of smoke as I oiled the cylinder and piston when I assembled it. I still have to make an exhaust pipe, I picked up some 3/8" stainless tube this morning, but I still have to make up a tube bender. I will post a video later when I can grab my sons HD camera.

The engine revs reasonably well, but needs a bit more attention to getting the mixture correct, it seemed to idle well.

Paul.


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## Cogsy (Jul 21, 2014)

Half an hour between posts and you got it running! Wow, that was easy . It's a great looking engine and I can't wait to hear what it sounds like.


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## gus (Jul 21, 2014)

Please post video. 

Taking my sweet time prepping for the cam cutting.Also taking a break.


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## AussieJimG (Jul 21, 2014)

Congratulations Swifty, there is nothing like the putter of a little feat to make the heart beat faster.

Jim


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## Swifty (Jul 22, 2014)

I spent a few hours today making a bender for the 3/8"stainless tube that I purchased to make the exhaust pipe, I have plenty of pipe for trials as it was only sold in 6mt lengths. I made the 2 wheels different sizes so I can interchange them for different bend rad's. I will make provision for a longer handle later as it took a bit of grunt to bend the tube.





And here is he exhaust pipe after soldering the flange on.





Now that I know that the motor runs, I will finish off the fuel tank and stand, and decide how I'm going to mount the whole lot.

Paul.


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## doubletop (Jul 22, 2014)

Swifty said:


> Hi Pete, surely the easiest thing to do is use 2 magnets on the camshaft, 180deg apart. That way the CDI will get the correct amount of pulses.
> 
> Paul.



Of course it is, and how simple would that be? Now you've got me thinking about the Bobcat timing as it has two magnets so that must be giving the CDI unit the correct timing.

After Brians experience's with the piston rings I'm begining to believe the the ring/valve seating is the most important aspect to get right, then the carb and then the ignition given some of the basic ignition set-ups that seem to work.

Pete


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## Swifty (Jul 22, 2014)

Pete, I'm very happy with the ignition, I will certainly be using that brand in the future. As soon as I started to get more firing as I cranked the motor and eventually having it run, the valves sealed better. When I turn the flywheel now, I can certainly feel the better compression. I still have to fiddle with the carburettor, but will finish the fuel tank first. 

I ran the engine in the garage, apart from the smoke, the smell of petrol has been hanging around all day. Next time I run it I may try shellite (white spirit) as a fuel. 

Paul.


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## Brian Rupnow (Jul 22, 2014)

Valves used to be my big Bugaboo with i.c. engines. After constructing a couple of the Geo Britnell valve seating tools, and following my strict regimen of 3 lapping sequences between the valves and seats, beginning with 350 grit, then with 400 grit, then 600 grit, before the engine is ever assembled seems to have sorted that problem out very well. I have built enough different kinds of carburetors now that even though the parts are minuscule, they don't frighten me.  I gave piston rings my best shot with the engine I just finished, based on the Nemett Jaguar drawings. I did get it to run---you seen the video. But--at the end of the day, the engine still had rotten compression, and wouldn't idle worth a damn. I pulled the rings out, reinstalled the piston configured for Viton rings, and immediately restored a LOT of compression and great low speed idling. Close examination of the rings showed areas of very little wear pattern--which indicated low or no sealing in that area. This was after 4 hours of "running in to seat the rings" powered by an electric motor. I will not make rings the way that is advocated by Malcolm Stride again. There are other ring making instructions available which advocate making the ring blank oversize on the outer diameter, then spreading and heat treating, then compressing the rings, clamping them in a compressed state on an arbor, and then turning a finishing pass on the o.d. of the rings to guarantee concentricity. If I ever decide to try making rings again, I may use that method.---And yes Swifty--I normally run all of my engines on Coleman camp fuel, which is basically Naptha gas. I was told by Gail in New Mexico that automotive pump gas releases more energy when it burns than Naptha, so I went and bought some high test automotive gasoline to try and get my engine to run with the cast iron rings. It did make a difference, and I was able to get the engine running with cast iron rings. However, at the end of the day, my garage stunk. I stunk. Even after a shower and change of clothes, I smelled like a friggin gas pump. The Coleman fuel is marvelous, in that it seems to leave no smell at all in the garage nor on me.-----Brian
P.S.--Gail in New Mexico must be right about more energy in automotive gas than in Naptha. The engine with cast iron rings would not start on Naptha, but did start and run on the automotive gas. The only explanation I have for that is that the greater amount of energy released by the pump gas gave enough extra "oomph" to the engine to let it make two complete cycles and still have enough impetus to fire again, even though the compression was less than optimum.


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## gus (Jul 22, 2014)

Hi Paul,

I am following behind and watching with great interest. Prepping up before cam cutting is still ongoing.
RT beefed up and graduated with engraving cutter. This is my very first time using engraving mill and doing a great job but table is graduated in 10 degrees div plus the 45 degree. After this will do dry run on paper on the cam profile.


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## doubletop (Jul 23, 2014)

I can't believe it only took you half an hour to get it started!! Maybe the double magnet trick is worth doing, regardless of the wasted sparks, I may give it a try 

*VIDEO REQUIRED PLEASE*​
Pete


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## Swifty (Jul 23, 2014)

Pete, I was most surprised that I had it going in such a short time. Because the camshaft is only going at half the speed of the crankshaft, there is no additional waste of spark with the 2 magnets. Even with a single magnet on the crankshaft there will be one wasted spark per cycle at the top of the exhaust stroke.

When I was cranking it over, I had the carburettor open about half way and slowly opened the needle valve until it started. I primed it first by holding my finger over the intake and drawing the fuel up.

I have to borrow a video camera off one of my sons to enable me to post a video. In the meantime, I'm finishing off the fuel tank and stand, so hang in there it won't be long.

Paul.


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## gus (Jul 23, 2014)

We are patiently waiting for video.

Speed Controller Device came in so looks like cam cuttting delayed.:wall::rant:
Space in the foot pedal box is crammed but I think I can get it snugly.Now on the Computer Desk.Windfall $$$$ about to come and have $$$ to travel.


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## doubletop (Jul 24, 2014)

Swifty said:


> Pete, I was most surprised that I had it going in such a short time. Because the camshaft is only going at half the speed of the crankshaft, there is no additional waste of spark with the 2 magnets. Even with a single magnet on the crankshaft there will be one wasted spark per cycle at the top of the exhaust stroke.
> 
> .



Paul

Sorry wrong way round mate. With two magnets you'll get a spark at every TDC, on compression and exhaust. With one magnet you'll only get a spark at the compression TDC.

Not that it matters some of the modern car ignition systems use one coil for a pair of plugs so one is doing wasted spark on the exhaust stroke while the other is firing on compression. 

Pete


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## Swifty (Jul 24, 2014)

Pete, I'm going to have to disagree with you, with one magnet attached to a flywheel directly on the crankshaft of a 4 stroke motor, the piston is at TDC twice per cycle, once on the compression stroke and once on the exhaust stroke, (ignoring spark advance) it fires every time it hits TDC. When I say cycle, I'm referring to 2 revolutions of the crank, inlet - compression = 1 rev, power stroke - exhaust = 1 rev.

Paul.


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## Swifty (Jul 24, 2014)

Just to make sure that I didn't have it the wrong way around, http://en.m.wikipedia.org/wiki/Wasted_spark

Paul.


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## Swifty (Jul 24, 2014)

I'm still thinking about the Rcexl CDI system, I assume that it is made for use on 2 and 4 stroke engines. On 2 strokes it definitely has to fire every revolution, but on 4 strokes it only really has to fire on every second revolution. This leads me to comment about a digital sensor that plugs into the ignition module to show engine revs (you do have to multiply the figure by 10 to get the correct revs). I assume that the system counts the number of "sparks" to work out the RPM, if this is correct, it will definitely need a spark every revolution to work out the correct RPM.

When I look at Brian Rupnows latest engine, he has the points working off the camshaft, so only gets a spark every second revolution, perfect for a 4 stroke engine.

Paul.


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## johnny1320 (Jul 24, 2014)

Would you not multiple by 2 Paul?


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## Brian Rupnow (Jul 24, 2014)

On many of my engines the ignition points run off a cam on the crankshaft. That is whats's known as the "waste spark" system. the extra spark occurring on the exhaust stroke does no harm.


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## johnny1320 (Jul 24, 2014)

Yes I agree Brian no harm using waste spark, I use it on my turbocharged methanol drag bike, makes around 500hp 1428cc


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## SixSixSevenSeven (Jul 24, 2014)

Many full size production engines going into cars used to use wasted spark setups anyway. Really not a huge issue. I think its a bigger issue whether or not it fires during combustion than whether it also fires during exhaust.


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## Swifty (Jul 24, 2014)

johnny1320 said:


> Would you not multiple by 2 Paul?



On the Rxcel site, they state that the multiplier is *10. I assume that if the display shows 300, the actual speed is 3000RPM.

Here are the specs.

1. Use PIC16f628a microcontrollers
2. Do not need batteries - powered from the ignition
3. Standard FUTABA plug(Black-Negative Red-Positive and White-Signal)
4. Uses high-brightness LED digital tube.
5. Input voltage range:3.5V-8.4V
6. Current consumption 25mA-60mA
7. Mini tachometer indicates up to 30000 rpm 
8. Actual RPM= Display Digital *10
9. Body Size: 41mm L x 17mm W x 12mm H 
10.Window Size: 30mm L x 15mm H 
11.Weight:8.5g   (0.3OZ)

Paul.


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## Swifty (Jul 25, 2014)

I finished the fuel tank and stand today, it's mounted up on the temporary board with the engine. I will have the video camera tomorrow, so with a bit of luck, hopefully I will have the video of it running soon. 

Paul.


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## doubletop (Jul 25, 2014)

Swifty said:


> Pete, I'm going to have to disagree with you, with one magnet attached to a flywheel directly on the crankshaft of a 4 stroke motor, the piston is at TDC twice per cycle, once on the compression stroke and once on the exhaust stroke, (ignoring spark advance) it fires every time it hits TDC. When I say cycle, I'm referring to 2 revolutions of the crank, inlet - compression = 1 rev, power stroke - exhaust = 1 rev.
> 
> Paul.



Paul

We're at cross purposes I was talking about 2 magnets on the camshaft to deal with the camshaft running at 1/2 crank speed. With a single cylinder you'll only need a single magnet on the crank. I won't go into multi cylinders as that depends on the configuration inline, flat or V and is a whole other subject beyond these CDI systems.

These CDI systems are intended to replace glow plugs making a glow engine a two stroke. So no camshaft and the sensor mounted on the crank. You'll have seen that from the parts and the instructions that came with it. By putting the sensor on the crank on a four stroke it will still work but with a wasted spark. But that doesn't matter.

By putting the sensor on the cam a with our engine the ignition will fire at TDC but the timing will be wrong as these units work out the advance based on engine speed. (actually pulse interval). Putting a second magnet on the cam will fix this problem, again with a wasted spark, again we don't care.

The rev counter module gets its signal from the sensor and displays RPM/10 basically to enable the unit to display RPM for high reving engines I understand 25000RPM  is possible with some. The units display would be pretty useless anyway as it will jitter so much you won't be able to read it. If you want the correct display you'll need the second magnet on the camshaft otherwise it will be displaying half speed,

Pete


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## Swifty (Jul 25, 2014)

Hi Pete, I think that we both have the same thoughts in our heads, just putting it across different ways. I have ordered a tachometer, they don't cost too much, more out of curiosity than anything else, the second magnet on the camshaft will, as you say, give me the correct reading to multiply by 10 to get the RPM (so long as I can read it).

One advantage that I see of this type of ignition system is, that it can readily be disconnected and used on other engines, so long as the spark plug is the same. I may buy another in the future to suit a bigger spark plug. Once I have an engine finished and running, more often than not, it just sits on the shelf, so why not reuse the ignition.

Paul.


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## Swifty (Jul 26, 2014)

At last we have a video of the engine running, it's not completely finished yet, I still need to polish it a bit, get some "O" rings to hold the fuel tank on and mount it up properly on a nice board. The carburetor still needs some tweaking, you should be able to hear it speeding up as I lean up the mixture screw, I haven't started to play with the idle mixture yet. The carburetor is only held on to the manifold with some loctite 515 sealant, I will have to find something more permanent.

 [ame]https://www.youtube.com/watch?v=pJEFec-pBUE&feature=youtu.be[/ame]

Paul.


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## Swifty (Jul 26, 2014)

I forgot to mention in my last post that I'm running the engine on shellite now (Coleman fuel). There is no noticeable difference to running it on petrol, except it doesn't smell the place out now. 

Paul.


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## doubletop (Jul 26, 2014)

Swifty said:


> Hi Pete, I think that we both have the same thoughts in our heads, just putting it across different ways. I have ordered a tachometer, they don't cost too much, more out of curiosity than anything else, the second magnet on the camshaft will, as you say, give me the correct reading to multiply by 10 to get the RPM (so long as I can read it).
> 
> One advantage that I see of this type of ignition system is, that it can readily be disconnected and used on other engines, so long as the spark plug is the same. I may buy another in the future to suit a bigger spark plug. Once I have an engine finished and running, more often than not, it just sits on the shelf, so why not reuse the ignition.
> 
> Paul.



Paul

As you say the tacho's are cheap and they help you understand what the engine is doing. There is a patch available to make it display the units but its not official and there's no way back. 

http://www.bittnar.info/en/tachometer-rcexl-alternative-firmware/

The units also trigger on one pulse so help with setting up the sensor trigger point.

I've used RCExcel and Pegasus and there are others out of China. There's no difference as far as I can tell. The usual case of one design and many clones. Hobby King have good prices if you are prepared to change the plug cap. I've got those off Ebay.

Like you once the engine is running it gets cleaned up and put on the shelf, but I do like to think I can get it out and give it a run without too much bother,

Pete


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## doubletop (Jul 26, 2014)

Paul

Wow!!! That's the best running version I've seen. Even Malcolm Strides doesn't sound that sweet.

Well done!!!

Pete


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## Swifty (Jul 26, 2014)

Thanks Pete, although it runs, idles well and revs, I'm thinking that the carby may have to have some mods done on it. Others try over the counter carbs, and probably get better results, but I like the fact that I make nearly everything.

Paul.


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## Brian Rupnow (Jul 26, 2014)

Swifty---A true masterpiece. Very, very nice.---Brian---What do you think needs to be done to the carby. I found that on my Jaguar carb, (which I believe is identical) that it works great except for the throttle idle stop screw.


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## johnny1320 (Jul 26, 2014)

Very nice Paul, I was wondering how the the valve clearance is adjusted on this engine?


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## Cogsy (Jul 26, 2014)

Runs beautifully, sounds great. Very impressive.


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## Swifty (Jul 26, 2014)

Johnny1320, the valve clearance is set when I built the motor, there is about 0.1mm clearance. If the valves bed in a bit, I will have to tweak the length of the valve stem to reset the clearance.

Brian, I will still have to play with the carb a bit yet, if I have it wide open and adjust the needle so it gets maximum revs, it doesn't run so well on idle, I haven't touched the idle jet screw yet, maybe that will fix it. The idle screw jet only appears to let in a bit more air in through the small hole, surely I only have to adjust the idle stop to get the same result, maybe I'm not looking at it correctly, still it's early days yet.

Paul.


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## Brian Rupnow (Jul 26, 2014)

Paul--The more it runs, the better the idle will get because your compression will increase. Malcolm stride says to let the engine warm up, then with the throttle wide open, close the needle jet to get max revs. Then open the needle valve just a little bit. Then close the throttle until the engine will still idle, but starts to stumble. Then open the air bleed screw until the revs pick up again. Then close the throttle a bit more until it starts to stumble, then open the idle screw a bit more. I have tried this and it "kind of" works. For something to think about---On the engine I built, with cast iron rings in it, I could get the engine to run "at speed" but couldn't get it to idle. I ran the engine on and off for four to six hours, and seen no improvement. Finally I gave up and put the piston with the Viton o-ring on it back in. By "feel" the compression doubled, and the engine would then idle right down to a "tick over' with no other alterations.---Brian


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## Jasonb (Jul 26, 2014)

Looking good Paul, as you say still needs a bit of a tweak as it seems a little slow to throttle respone and is dieing as teh revs increase.

The air bleed is designed to give a leaner mixture at lower revs, the idle stop really just sets the lowest speed and stopps you completely shutting off the engine.

J


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## johnny1320 (Jul 26, 2014)

Is it possible to put a shim under the cam box to adjust the valve clearance?


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## Swifty (Jul 26, 2014)

Johnny1320, you could use a shim, but it's far easier to adjust the valve stem.

Brian and Jason, thanks for that, I suppose that I should have read the end of Malcolm's article again to see the tuning advice. I will be doing that today.

I was worried a bit about all the smoke out of the exhaust, every one that I have watched on YouTube has the same problem.

Paul.


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## johnny1320 (Jul 26, 2014)

Thanks Paul, I am finishing drawings for a parallel twin that I hope to start soon, your engine sounds great and the finished product looks great!


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## gus (Jul 26, 2014)

Hi Paul.
Congrats.That was a MasterPiece built by a MasterCraftsMan. The roar is sweet,steady and cyclically firm because of intake and exhaust valves cam driven.
I am stuck with the Foot Pedal Speed Controller and trying to balance the gap between dead stop and full speed.Won't be till midweek to cam cutting. Fishing yesterday was good. Landed a 3 pounder Red Snapper.


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## Swifty (Jul 26, 2014)

Hi Gus, I have a friend coming over today to see the engine, I will try to tune the carby better then. I don't know how your neighbours are going to react when you get yours running, apartment living has it's downside sometimes.

I know how you feel about having to get other jobs out of the way before you continue, can be a real distraction sometimes, but the fishing should always be relaxing.

Paul.


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## SixSixSevenSeven (Jul 27, 2014)

doubletop said:


> Paul
> 
> As you say the tacho's are cheap and they help you understand what the engine is doing. There is a patch available to make it display the units but its not official and there's no way back.


many PIC ICSP programmers can actually take a firmware dump from an already programmed chip. This would serve as a way back to the original firmware. Dump existing firmware, reflash new firmware, don't like it, reflash to dumped firmware


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## bmac2 (Jul 27, 2014)

Wow Paul that is a beautiful engine. It runs great and (to me) has excellent throttle response.  Once again I see a new level to aspire to.  Thank you for posting this build, Ive learned a lot from it.


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## gus (Jul 28, 2014)

Fortunately its a small engine. No complains so far when I revved Webster and Rupnow engines.But the spinning sessions were very short. Will put a very good exhaust silencer if required.
 Now that the mental block ----------Foot Pedal Speed Controller is done,calibrated and dry tested with 110v supply,I can return to the Nemett-Lynx Engine.The M.I.C. carbon rheostat speed controllers don't last too long compared with original US made which lasted 10 years.

The RT Calibrated,table lapped with worm and wheel spun by Cordless Drill,I should have no chattering when I take heavier cuts. Put in USA worm and worm wheel and they mesh very well with no back lash. I had very bad back lash with the very first RT.


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## gus (Jul 28, 2014)

bmac2 said:


> Wow Paul that is a beautiful engine. It runs great and (to me) has excellent throttle response.  Once again I see a new level to aspire to.  Thank you for posting this build, Ive learned a lot from it.



Hi Bob,
Paul's Nemett-Lynx Engine ran and roar like a real engine. Very solid and smooth and good Vroom Vroom response. I am 2----4 weeks behind.


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## Swifty (Jul 29, 2014)

I've been having a couple of days break after getting the engine to run, however I did check out a couple of hobby shops in the local area and managed to get a nice 15" wooden propeller to use for display on the engine. The propeller is very light, I suppose that I will have to do at least one run with it mounted to see if the engine runs as well as it does with a flywheel.

A friend who came over the other day bought his latest acquisition, a 1/4 scale remote controlled dirt bike. It's the first time that I've seen one of these, it has a gyroscope in the rear wheel which stops it falling over, we had a ball trying it in the local park, it runs great.

Paul.


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## gus (Jul 29, 2014)

Hi Paul,

SOS SOS

Please advise cam blank diameter??? Will be finishing the preps and go into cam cutting. Having difficulty locating cam blank OD.


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## Swifty (Jul 30, 2014)

Hi Gus, I have a sketch of my blank and I used a 12mm dia for the cam outside dia. Where I got that size from, I can't recall, I had a quick look at the magazine article and can't see a size. I can only assume that I used the stated 2mm lift added to the base radius of 4mm. The 2mm lift is stated in the specs on the cam calc sheet.

Paul.


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## gus (Jul 30, 2014)

Hi Paul,

Thanks. Ypu are right Malcom's drawing has no cam blank O.D.
Over the next two weeks, a lot efforts will be put in and more work results to post. The Foot Pedal Speed Controller did perform
to expectations.This two year mental block done and gone.


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## Swifty (Jul 31, 2014)

I thought that I would just touch base, I have disassembled the engine to finish off bits like chamfers on corners, removing some machining marks etc. I'm not going for a lot of bling, a matt surface finish suits me. I noticed that the oil in the crankcase was already a very dirty colour after it's few short runs. 

I have a piece of oak for the base, but after spending quite a while trying to find my router bits, I finally recalled that I had lent them to one of my sons, I think that he is trying to build up his tool collection piece by piece at my expense. Anyway, after a quick phone call he will try to find where he has put them, so hopefully that won't be too long and I can continue with the base.

Paul.


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## Swifty (Aug 4, 2014)

I'm still working on the engine, I have reassembled it again after polishing machining marks out etc. I reset the cam timing, even going to the extent of using a dial indicator to check when the exhaust valve starts to move at the correct angle of rotation. I also set the ignition timing using a plunger style dial indicator fitted with a long point to poke down the spark plug hole to check TDC of the piston. The crankcase has been refilled with fresh oil and the flywheel refitted for starting. I now only have to finish the board to mount it on, stay tuned.

Paul.


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## Swifty (Aug 6, 2014)

Here is the final assembly of my engine, I will also post the photo's in the "Finished Projects" section. I will add a new video shortly.









Thanks everyone for following along, I hope to pull out a couple of part finished projects and finish them off next.

Paul.


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## Brian Rupnow (Aug 6, 2014)

Paul--It is gorgeous!!!  Congratulations from Brian.


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## johnny1320 (Aug 6, 2014)

That is one beautiful looking engine!


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## Swifty (Aug 6, 2014)

Thanks Johnny, I had a few short runs with the propellor yesterday but I will put the flywheel back on today so I can adjust the carburettor safely. I will then replace the prop and take a video.

Brian, I'm really flattered, you have given me 2 likes on this build. The further I got into this build, the less I explained and photographed the machining methods, I must try to show more methods in my next build. I took all the photos with my iphone except for the final ones, it was just so handy with the phone. I think the final assembled photos came out well, I'm pleased with them anyway.

Paul.


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## AussieJimG (Aug 6, 2014)

That's one for the mantlepiece where everyone can see and enjoy it. Congratulations.

Jim


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## gus (Aug 6, 2014)

A MasterPiece by a Maestro.  Hopefully my Nemett-Lynx can match.

Cam Cutting and heat treatment will happen today.


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## doubletop (Aug 7, 2014)

Love it!!

I may just have to replace my plastic prop with a wooden one.

Pete


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## Swifty (Aug 7, 2014)

All those that said that a spiral style starter drive was best are proven correct. With the propeller on, as soon as it fires it tries to drive the battery drill that I am using to start it, I generally cannot pull it away fast enough for it to continue running. It was no trouble when using the flywheel as it had enough momentom on to keep running, but the prop weighs practically nothing. I am currently modifying the starter drive plate to have ramps to allow it to uncouple easily.

Paul.


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## Swifty (Aug 8, 2014)

I've come to the conclusion, for the time being, that the propeller is just too light to keep the motor running. If I put the flywheel on, it starts and runs straight away, but when I change over to the prop on a still warm engine all it does is fire a bit and stop. It appears that it just needs the weight of the flywheel to keep it running. It doesn't matter, as I know it runs and the prop is only for display anyway. I might keep tinkering a bit longer, but I am calling it finished anyway.

Paul.


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## Swifty (Aug 28, 2014)

The tachometer finally arrived via that slow boat from China, it was simply a matter of plugging it straight in to the ignition. The maximum revs that I could get was just over 12,000 rpm, with idle speed just under 2000rpm. It looks like it is idleing slower, but I trust that the tachometer is correct. It still burn a lot of oil and does not appear to be very fuel efficient, but what the heck, it's only a model.

Paul.


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## fishy-steve (Sep 1, 2014)

Hi Swifty.
I've been directed here by Jason. Thanks Jason. 
I'm in the process of buying all that I need to make the Lynx. It will be my first build.
I've read the complete thread from start to finish and will now read it again but this time with a note pad to jot down the gems that it contains.

Thanks for taking the time to post this thread. I really enjoyed it. 

Steve.


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## Swifty (Sep 1, 2014)

Hi Steve, I hope that you are going to post on your progress with the build. Please ask any questions that you like and I will endeavour to help.

Paul.


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## gus (Sep 1, 2014)

fishy-steve said:


> Hi Swifty.
> I've been directed here by Jason. Thanks Jason.
> I'm in the process of buying all that I need to make the Lynx. It will be my first build.
> I've read the complete thread from start to finish and will now read it again but this time with a note pad to jot down the gems that it contains.
> ...




Hi Steve,
Paul Swifty is the best mentor Gus ever had. I tagged along with his post on Nemett-Lynx Engine so that I need not re-invent the machining/fitting skills to cut some very difficult components. Machining,drilling and tapping the Petrol Spray Bar today. Same part is so small and I get worried.


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## fishy-steve (Sep 2, 2014)

Swifty said:


> Hi Steve, I hope that you are going to post on your progress with the build. Please ask any questions that you like and I will endeavour to help.
> 
> Paul.



Hi Paul. 
You might live to regret that. 
Thanks.
Steve.


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## fishy-steve (Sep 2, 2014)

gus said:


> Hi Steve,
> Paul Swifty is the best mentor Gus ever had. I tagged along with his post on Nemett-Lynx Engine so that I need not re-invent the machining/fitting skills to cut some very difficult components. Machining,drilling and tapping the Petrol Spray Bar today. Same part is so small and I get worried.



Hi Gus.
I've read your thread  from start to finish also. I'm trying to glean as much info from both threads before starting my build. 
I'm using the  drawings from The best of model engineering magazine.
I've purchased the timing belt/pulleys and the bearings. I also managed to get the crank pin sleeve.

Steve.


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## Swifty (Sep 2, 2014)

Fishy-steve, if you can go to the Welcome area and tell us a bit about yourself, it will help other members to have an idea of your skills and equipment. You will find members very helpful with any questions that you may have, no matter how simple you may think they are.

Just a bit of a heads up about the drawings in the magazine for the Lynx, there is no distinction between solid, hidden or dimension lines. This makes it very difficult if you have limited experience with reading drawings, however if you take your time and check pictures on other builds, all should be ok. The only part that I had problems with was the carby, but nothing that ended up being a problem.

Paul.


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## fishy-steve (Sep 2, 2014)

Hi Paul.
I'll pop over there now.
As far as the drawings are concerned.  I'm finding the crankcase drawing "challenging"
If I'd produced a drawing like that when I took my Tech drawing O'level I think I would have failed.


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## gus (Sep 3, 2014)

fishy-steve said:


> Hi Paul.
> You might live to regret that.
> Thanks.
> Steve.



Hi Steve,

No worries. Paul is very helpful. He would have kindly mail over a very small/intricate/delicate part to Gus if Gus was about to throw in the towel and hang up the unfinished engine.
The Nemett-Lynx Carb Spray Bar was very scary to drill the 0.8 mm i.d. hole which happened to be 10 mm deep. This part now done and assembled.

Retirees have plenty of time.


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## Swifty (Sep 4, 2014)

Gus, I have some 0.40mm drills somewhere, left overs from when I was working. Would not even try to use them now.

Paul.


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## gus (Sep 4, 2014)

Swifty said:


> Gus, I have some 0.40mm drills somewhere, left overs from when I was working. Would not even try to use them now.
> 
> Paul.



Hi Paul,

Need your expert advice. Drills below 3 mm are difficult to regrind. Just thinking how many times cane we re-use the 0.8 drill and risk messing a job piece. May buy some more mini drills from TokyuHands. Celebrating our 
33rd Wedding Anniversary.


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## Swifty (Sep 5, 2014)

Hi Gus, I usually buy small drills in packs of 10. Once upon a time I would regrind drills as small as 1.5mm dia, but that was when my eyesight was great and I would dress a wheel on the small surface grinder and sharpen it there.

Paul.


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## gus (Sep 7, 2014)

SOS  SOS  SOS

Hi Paul,
The electronic ignition must be earthed. Please advise where is the earth. Battery positive or negative. By latest this Friday will spin engine. Plywood box for Rcexl done. Trying to make fool-proof connection to avoid frying the expensive Rcexl. And also following your practice use same for other engines too. Crimping the battery mini connectors is something new to me. A special S$30 Crimping Plier is a must to do a good crimping.Am glad I have this plier. The cable lugs are so mini. My ''71'' eyes can just see it.


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## Swifty (Sep 7, 2014)

Hi Gus, I had the same concern as you have about the earth, there is no additional wire needed as the earthing is taken care of by the steel spark plug cap and steel shrouded high tension cable. Did you get the 2 small springs for inside the cap, I've already lost one so am now very careful with the second.

Paul.


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## Cogsy (Sep 7, 2014)

The ignition I used on my Rupnow engine was either a clone or rebadged Rcexl and used the same earthing system as Paul says. What I did though was cut the cap off the end and change to a different connector, then strip most of the outer steel shroud off the high tension lead, back to where you couldn't see it anymore under the base. Then I attached a wire from what was left of the steel shroud to the bottom of the engine for earthing. It worked just fine, the only reason I did it was the plug cap didn't match my sparkplug and the thick cable looked way out of scale on my engine.


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## gus (Sep 8, 2014)

Hi Paul And Cogsy.

Thanks for the info.  I have two sets for both 1/4'' and 10 mm plugs with the spark cap. I saw the spring clips. 
Plywood Box to hold the RCELX is about ready and now putting on a last coat of Lacquer for  protection from my grimy hands. The top cover will be hinged. Still shooting for startup this Friday 12th.


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## doubletop (Sep 8, 2014)

gus said:


> SOS  SOS  SOS
> 
> Hi Paul,
> The electronic ignition must be earthed. ............t.



Don't panic; the reason you need the system earthed is you'll fry the CDI if you try to make sparks without a plug connected. The screen on the plug lead will be adequate to make the circuit, however, as belt and braces either clamp the outer screen to the engine with a metal P clip or solder a flying lead to the screen, put a tag on the other end and clamp it under one of the mounting screws.

How is the compression looking? from Brian's experience with O rings vs CI rings and me spending a week or so getting mine to run, compression is the key.

Pete


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## gus (Sep 9, 2014)

doubletop said:


> Don't panic; the reason you need the system earthed is you'll fry the CDI if you try to make sparks without a plug connected. The screen on the plug lead will be adequate to make the circuit, however, as belt and braces either clamp the outer screen to the engine with a metal P clip or solder a flying lead to the screen, put a tag on the other end and clamp it under one of the mounting screws.
> 
> How is the compression looking? from Brian's experience with O rings vs CI rings and me spending a week or so getting mine to run, compression is the key.
> Will soldier earth wire to cable screen.
> ...



Compression looks OK. Will decide using temperary base or permanent to spin engine. May may a spark plug test jig with earth to just to look at the sparks.


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## gus (Sep 9, 2014)

Gus down with mild flu but terrible sore throat. The M.I.C. sore throat powder works. Overnite the sore throat should go away. Will prep for engine startup.
Chest for RCELX done and fixed. Been fun.
Good news. I found the spark plug spring clips.


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## Swifty (Sep 9, 2014)

Gus, I hope that you get over that touch of flu quickly, I'm getting anxious to see your Lynx running.

Paul.


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## gus (Sep 9, 2014)

Swifty said:


> Gus, I hope that you get over that touch of flu quickly, I'm getting anxious to see your Lynx running.
> 
> Paul.



Hi Paul,

Thanks.
Gus now a lame duck and too lethargic to work in the machineshop. No more ice cold drinks on a very hot day. Sore throat gone with the M.I.C. Throat Spray but slight cough fixed by some Thailand Lozenges and it works.

*New Engine---R&B Engine from Model Engineer  MAg no.4489 22 Aug -----4 Sept Issue.*
Very challenging engine for Paul and Gus and others but I am about to give up-------Castings.  But I am thinking of using aluminium bar stocks to fabricate the base and frame. The crankshaft machining featured in this issue scares me but the step by step made it possible. Will wait for the next few issues to decide.The engine is not H&M. The oil wells look very unique. Was topping these during my engineering trainee days at Metal Box,Singapore on the can body maker which slams out 400 tin cans per minute and after three years Gus's left ear is half deaf.:rant:


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## Jasonb (Sep 10, 2014)

Thats quite a big engine Gus - 12" flywheels so you may not be able to get it all on your machines they are a two man lift. Also quite  an effort to turn over, you will need something like my SDS+ drill seen here on a friends engine, no cordless drills on these!!






They are also known to be difficult to get running, maybe something smaller like a Wyvern or Centaur if you want a throttle governed engine.

J


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## gus (Sep 10, 2014)

Hi Jason.

Thanks for the kind advice. I had no idea it was that big.
I give up. 12'' flywheels. My balcony machineshop will collapse. OK other engines. I still have the ''Bolero'' and the '' Firefly'' to dig out from the dust and finish same now that I have picked up the necessary skills on honing and the fuel jet needle. After the Nemett-Lynx will be DIY a long list toolings.
Over the last three years HMEM members have taught me many skills.


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