# Webster Build



## simister (Jan 20, 2015)

Guys, I have just started to build the Webster. However, I notice that Brian and Longboy have used Viton O rings instead of normal steel rings. What is the reason that you have used O rings instead of steel?

Do the O rings give a better seal?

Also, does the aluminium flywheel have sufficient weight or is it better to go for cast? . I would prefer to use aluminium if it is heavy enough.

John


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## Blogwitch (Jan 21, 2015)

John,
I can answer both of those questions for you simply.
If you are not going to be running your engine for long periods of time, say just to show people what you have made, then viton is perfectly acceptable. But, if you are going to have it running for hours on end, say at a show, then you are much better of fitting cast iron rings. It is just a case of longevity versus time used. The viton rings wear away much quicker than cast rings would.

What a flywheel does is to store energy produced by the piston/cylinder to enable it to turn over until the next power stroke.
The further away the outside mass of the flywheel is from it's centre of rotation, the more carry over it will have. So your question about using an aluminium flywheel, yes it might work, or it might not have enough inertia to carry over to the next power stroke.
There are ways to get around that problem, drill cross holes in the flywheel rim and either fill them with molten lead or even just Loctite in some steel slugs. Or, if you have room, you could make a steel tyre to go around the flywheel rim, both will have the same effect.

Slug type flywheel (not cross drilled as suggested)







Steel tyred






I hope this helps a little

John


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## bazmak (Jan 21, 2015)

Certainly does blogwitch.Nice flywheels,nice workmanship.Congratulations


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## simister (Jan 21, 2015)

Thanks for your advice. 

Yes, I understand your points.

Do you get any better compression with the Viton O ring?

Would brass slugs on the flywheel give sufficient weight?


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## Blogwitch (Jan 21, 2015)

John,
Viton, if using the correct compression figures for the o-ring to give a good seal, then it will seal perfectly straight away, whereas piston rings usually take a while to 'bed' in, but once bedded in, they will be there for years, whereas viton will wear and you will need to change them when the compression drops to a point the engine won't start. It is the old swings and roundabouts theory.

With regards to the brass or steel slugs. Because they will be heavier than aluminium, yes you will get a better turning force. It also depends on how many you use.
The one I showed with the slugs around the outside were only for a finger engine. Without the slugs, it was difficult to keep it running smoothly, once fitted, the whole machine became much more manageable and it worked a lot better.
If possible, I would always go for the steel tyre, and if done with brass spokes, the looks can't be beaten.

John


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## simister (Jan 21, 2015)

John,

Thanks for your advice. I was going to do the brass slugs. However, I can see the steel tyre would be much heavier. 

I already have the piston rings (Otto), but I noticed on Brian's posts that he used the Viton O ring. As this is my first IC engine, I was thinking that if I am a fraction out of tolerance with the piston fit, the Viton may be a little more forgiving than steel rings. 

John


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## Brian Rupnow (Jan 21, 2015)

After building 9 i.c. engines (which all run well), and fighting to get a proper seal numerous times with cast iron rings, I can firmly state that small diameter pistons with cast rings are a complete and utter pig of a thing to work with. The Viton ring will seal immediately, with no problems. Contrary to what some may say, I have run some of my engines all day at shows with no trouble from the viton rings. The only caveat when running a viton ring, is that you must run at least a 50:1 mix of two cycle or lubricating oil with the fuel, and the engine must not be allowed to overheat.---And--You don't want the cylinder bore to have the typical cross hatched finish that would be suitable for running cast iron rings, because the cross hatching holds minute quantities of oil to lubricate them. When running viton rings, lap the cylinder bore with 600 grit lapping paste and leave it shiny, otherwise it will chew up the viton ring quickly. On a couple of engines I have built for use with cast iron rings (and failed miserably to achieve compression) I have swapped the pistons out for pistons made for a viton ring and ran them. After half an hours running, the viton ring will be worn out, but the inside of the bore will be polished to such an extent that the next viton ring will last forever.---Brian


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## Brian Rupnow (Jan 21, 2015)

Here is a Webster I built to the original plans (and with a viton o-ring). When I couldn't get it to idle slowly enough with the original aluminum flywheel, I made the largest diameter flywheel I could (without changing the bearing support pillars) from brass and made it as wide as I could by moving one of the bearing support pillars out to the maximum that the base would allow. Engine runs marvelously!!!
http://s307.photobucket.com/user/Br...LOWS CARB ON WEBSTER_zpsuvmz22jj.mp4.html?o=5


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## simister (Jan 21, 2015)

HI Brian,

Thanks for your advice and I thought that the o-ring may be more forgiving than cast rings. Do you have a part number of the Viton o-ring that you used or it's dimensions?

The flywheel that you made with the brass slugs looks great.

I have been reading your posts with interest as I go through my build. 


John


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## simister (Jan 21, 2015)

Brian,

I didn't realise that you changed from the brass slugs to all brass. Still looks good.


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## Brian Rupnow (Jan 21, 2015)

All of the o-rings I have used are a "nominal" 1/16" cross section. ---In reality they are .070" cross section. You only need one ring per piston, and the groove should be 0.057" deep x .093" wide. I don't have specific part numbers, and I can't remember what bore the Webster is, but if it has a 1" bore, ask the o-ring supplier for a ring that will have a 1" outer diameter. There is really a 3 part story to my Webster. First, I built it with an aluminum flywheel, as per the original drawings. (which, by the way, are excellent.) Then I wanted it to idle slower, so I drilled the aluminum flywheel and put the brass slugs into it, which helped a lot. Then I had a brain wave about putting a 3 ball governor onto it and turning it into a hit and miss engine, but for that I needed the truly huge flywheel. It "sort of" worked as a hit and miss, but not well enough to keep it that way. I took the 3 ball governor off, but left the huge flywheel.


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## simister (Jan 21, 2015)

Brian,

A company here in Melbourne has suggested the following o-ring.

Viton Part Number BS-O18

Inside diameter .75"
Thickness .07"
Outside Diameter .89"

Temp Range +220 Centigrade.


How does this compare with what you used?

John


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## simister (Jan 21, 2015)

HI Brian,

Our posts have crossed at the same time.

Thanks for that info. The supplier here is very helpful, so I will take the info down next week and have a chat to him.

Did you find that the flywheel with the brass slugs worked ok or should I go for more weight?

I was thinking of either going for Bright Steel, however it is a large diameter to machine. The other option which Blogwitch suggested was to make a steel tyre to go over the aluminium wheel.

John


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## Brian Rupnow (Jan 22, 2015)

That o-ring information looks correct. The engine ran fine with just the brass slugs added to the flywheel. A steel or brass or cast iron "tire" added to the o.d. of the aluminum flywheel would be a great help.----Brian


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## tms6401 (Jan 22, 2015)

I am also watching this build. It is an interesting engine and all of the finished examples seem to run very well.

I might have a go at the cylinder and if that goes OK we will see.

I am following this thread with great interest.

Tom


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## simister (Jan 22, 2015)

Thanks guys for your advice. This forum is a great help to newbies like myself.

I am sure there will be a lot more questions as I progress.

John


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## simister (Jan 24, 2015)

Well, I have finally made a start. I have decided that I am going to use the Viton o-rings for the piston and the dealer for Viton is 5 minutes from my place.  I have left the base plate as a rectangle and not done the  cut out as shown in the drawings. I haven't rounded any of the edges of the cylinder block at this stage.

In the notes on the drawing it suggest .250 drill rod for the camshaft. Is it really necessary to use drill rod or could I use Bright Steel? 

Here are some pics on where it is at the moment.


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## tms6401 (Jan 24, 2015)

I am not an expert by any means, but I would think that bright steel would work. Drill rod does have a smoother finish, and that might make some difference. 

Tom


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## Cogsy (Jan 24, 2015)

You can buy drill rod (or silversteel) from Bohler Metals or Blackwoods. It's not expensive and cuts nicely. I've just started using it for the first time and I'm a huge fan of it now.


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## simister (Jan 24, 2015)

Thanks Tom and Al, 

I have never used drill rod before but it sounds like it is worth using rather than bright steel particularly if it machines to a smoother finish.

I didn't realise that drill rod is silversteel.


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## simister (Jan 26, 2015)

This is the cylinder head frame that I worked on today. All I need to do is tap the thread for the NGK spark plug and bore the recess for it. I won't do that until I receive the plug so I can double check the dimensions and thread. 

I have ordered some drill rod for the cam shaft. I am also going down to the Viton Dealer tomorrow and pick up a few Viton O-rings. 

You will notice on the photo that one of the holes is slightly damaged at the start of the hole (this was the last hole to drill). I was being very careful, however, I had inadvertently knocked the adjustment wheel on the milling machine table. To make sure that it was going to be in the correct position in relation to the other holes, I reversed the piece and drilled it from the other side. This took me about 45 minutes to set up so that it was going to be in the right position.  Anyway, all worked out ok.


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## simister (Jan 26, 2015)

Brian, 
I have been reading to posts on the Webster and I notice that you reamed the bore for the cylinder with a 7/8 chucking reamer. I was going to do it on the lathe with a boring tool. Now, I am not sure what is the best method of getting a good finish and a straight bore. Can you give me some advice on why you went that way?
John


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## Brian Rupnow (Jan 26, 2015)

Simister--When I built the Webster I was very new to this machining game. I had read many posts about the poor finish left by internal boring, the problem with internal tapers induced by boring, and a whole load of possible "fails" caused by boring the cylinder. I thought, "What the heck"---If I buy a reamer, the finish will always be consistent, assuming the same rpm and material and lubricant used, there should be absolutely no induced taper, I won't have to worry about tool flex on long bores---And--If I build a dozen more engines in future (which I pretty well have) the size and finish of my reamed bores is never going to change. I have taken out all of the variables. Now 500 people will immediately jump on me and tell me that boring is better, but I know what worked well and continues to work well for me. I do have a complete set of boring tools now, and a boring head for my mill, but I still use reamers when making cylinder bores.---Brian.


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## simister (Jan 26, 2015)

Thanks for the advice Brian.


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## bmac2 (Jan 26, 2015)

Hi John
Your Webster is looking good. Personally I have to agree with Brian. I have a decent set of boring bars and I do use them a lot but to be honest if Ive got a reamer the right size Ill use it. 
Ill be following along for the ride . . .


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## simister (Jan 27, 2015)

Bob & Brian, 

Thanks  for your input. 

I cannot purchase a 7/8 chucking reamer here in Australia. I have contacted a number of suppliers and they claim they are not available. Can you suggest a company in the US that I can contact where these would be available. I have a US shipping address so it can be on forwarded to to me.

Also, I would require it with a MT2 taper. Should I get a right hand or left hand cut?

Thanks guys.


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## Swifty (Jan 27, 2015)

simister said:


> I cannot purchase a 7/8 chucking reamer here in Australia. I have contacted a number of suppliers and they claim they are not available. Can you suggest a company in the US that I can contact where these would be available. I have a US shipping address so it can be on forwarded to to me.
> 
> Also, I would require it with a MT2 taper. Should I get a right hand or left hand cut?
> 
> Thanks guys.



It will be referred to as being a 7/8" taper shank reamer, chucking reamers always have a straight shank. Should be no problem getting one in Australia, even try Ebay.

Edit. Quite a few straight shank reamers available, but the shank size is also 7/8", look for a taper shank one.http://www.ebay.com.au/itm/size-7-8...66?pt=LH_DefaultDomain_15&hash=item2c769cb692

Paul.


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## Brian Rupnow (Jan 27, 2015)

On those larger reamers, the working end is hardened. The shank is soft and can be turned down with a carbide to fit into a 1/2" or 5/8" tailstock chuck. You can buy through Travers Tool co. inc--they ship internationally.


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## simister (Jan 27, 2015)

Thanks guys. I have managed to pick one up on Ebay with a tapered shank.


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## simister (Jan 27, 2015)

Spark plug arrived today.  "Wow - it is small - very cute" . I checked the threads and finished the cylinder frame completely. Now on to the next piece.


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## simister (Jan 31, 2015)

Does anyone know where I can purchase the intake and exhaust valve springs?

 I have tried a few of the spring dealers here, but whilst they have plenty of compression springs they don't have the specs required for the webster.

Is it that important or could I use a stock compression spring of similar coils and wire?


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## Cogsy (Jan 31, 2015)

You can use any suitable spring, the specs are just a guide. I bought a cheap spring assortment box from the hardware store for about $15 with a mix of compression and tension springs and I've used various sizes on my I.C. engines. I just dig through and try different ones til I get one that works.


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## simister (Feb 1, 2015)

Thanks Al,  That makes it easy. I have box of assorted springs.

JOhn


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## gus (Feb 1, 2015)

Hi John,

No worry.Just like Cogsy,my Webster Engine valve springs came from same box. Engine ran very well.


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## JLeatherman (Feb 1, 2015)

I bought mine from CenturySpring.  They have a $40 minimum order, so I bought springs for the Webster, the Farm Boy (future build), and a few standard sizes I'll find a use for someday to flesh out the order.


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## simister (Feb 1, 2015)

Thanks Guys. I have a box of assorted springs so I will try those. I did have a look at the Century Spring website and thought that they would have to custom make them.

John


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## Brian Rupnow (Feb 1, 2015)

John--In Canada we have two major suppliers of industrial fasteners, Brafasco and Fastenall. They sell nuts, bolts, etcetera, and they both sell a wide assortment of compression springs. I can't remember the name right now, but there is a spring company (probably out of USA) that has a fairly large metal box with about 50 drawers in it full of various little springs in all of these stores. The springs are sold individually for about $2 or $3 each, and are perfect for engines like the Webster. If you have an industrial fastener supplier anywhere near you, that would be the place to look. I have had to wind my own tension springs for governors on hit and miss engines to get exactly what I needed, but never for a valve spring.---Brian


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## simister (Feb 2, 2015)

OK, Thanks Brian, 

We do have some industrial fastener suppliers close by. I will call in as it would be handy to know what is available off the shelf.

I had been calling spring manufacturers and they basically manufacture to order in large quantities. 

I have a box of assorted springs here, so that will probably get me started.


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## gus (Feb 2, 2015)

''Spring Design and Manufacture''  by Tubal Cain is highly recommended for wannabe DIY Spring Makers. Made some with piano wires bought from AeroModel Hobby Shops. Will take a bit of practice to make springs to satisfaction.


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## Swifty (Feb 2, 2015)

I would be happy to have the sweepings off the floor from a spring manufacturer, I'm sure that there would be a lot of small springs lost under benches etc.

Paul.


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## bazmak (Feb 3, 2015)

Hi just a quick comment.I use s/s rod for most pins and shafts.Normal round
is ground to nom - 1 thou.Its tougher and silver solders well.Corrosion free
no cleaning the fiddly bits and its cheap.Works well on crankshafts
Only downside is its tough to machine.Precission ground M/S is more expensive
Just my twopennef


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## deverett (Feb 3, 2015)

bazmak said:


> Hi just a quick comment.I use s/s rod for most pins and shafts.Normal round
> is ground to nom - 1 thou.Its tougher and silver solders well.Corrosion free
> no cleaning the fiddly bits and its cheap.Works well on crankshafts
> Only downside is its tough to machine.Precision ground M/S is more expensive
> Just my twopennef



Depends on the grade of Stainless.  Sounds like you are describing 316.  303 is much easier to machine, but does have less resistance to rusting.

A good source of excellent stainless rods is old printers/photocopiers/scanners.  The older the machine, the more useful bits inside.  In addition to the rods, there are numerous springs, gears several small motors and really old machines will yield ball bearings and/or bronze bushes.  The electronic wizards may be able to make use of some of the electrickery bits as well.

Dave
The Emerald Isle


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## gus (Feb 3, 2015)

Swifty said:


> I would be happy to have the sweepings off the floor from a spring manufacturer, I'm sure that there would be a lot of small springs lost under benches etc.
> 
> Paul.



Its true. Fascinated with their technology with springs flying out .

Whenever Mustad Plant calls for compressor service,my fishy mates were so happy.Only problem was, when hooks are packed and despatched to warehouse,getting choice free hooks not possible.Not even free samples.
 But whatever hooks they are making on their hi speed presses,you can take some.Another problem. Either too big or too small. :wall::rant:


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## gus (Feb 3, 2015)

Next trip to TokyuHands.Will buy a series of spring wire and make springs as per Tubal Cain's Book. Harold Hall has drawings on a spring winding machine.


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## simister (Feb 12, 2015)

I have now finished the frame. Now to start on the cylinder. I have ordered a brake cylinder honing tool to finish the bore. I have also managed to get a drill and reamer through ebay. They are second hand but should do the job.


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## canadianhorsepower (Feb 12, 2015)

is it me or if your cyl head is on the wrong side


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## Swifty (Feb 12, 2015)

That's what I thought at first Luc, but I googled some models and the flywheel sits between the uprights and the cylinder is on the outside.

Paul.


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## Brian Rupnow (Feb 12, 2015)

Looks very good so far.--One nice thing about that design--If you want to go to a real killer flywheel to get low rpm, you can drill 2 mew holes in the base and move that outboard bearing support almost an inch to the outside for a much thicker flywheel.  There is also enough vertical clearance to go to a 3.950" diameter flywheel without removing any material from the top of the baseplate.-Brian


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## simister (Feb 12, 2015)

I have got onto a guy here that can supply material for the flywheel in cast. Hopefully that should have enough weight in it. I was going to machine the inner diameter to keep the weight to the outside.


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## Brian Rupnow (Feb 12, 2015)

You don't really have to machine away any material. It won't make the engine run any better if you do. The reason most cast flywheels had the center relieved was simply to save material for the manufacturer. It is true, the material machined away (if you do so) doesn't have much positive effect on how well the flywheel works if you leave it in place. 95% of the actual flywheel influence on the engine is all in the outer rim. Relieving the center is mostly a cosmetic thing.---Brian


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## vederstein (Feb 13, 2015)

Some time ago a forum member asked about substituting aluminum for cast iron in a flywheel.  After several somewhat ambiguous answers, I replied with an explanation of mass moment of intertia.

You can find the post in this thread:

http://www.homemodelenginemachinist.com/showthread.php?t=23069&highlight=moment+intertia

...Ved.


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## simister (Feb 13, 2015)

Interesting! I wasn't sure about machining the inner of the flywheel. I have often seen the inner machined out and was under the opinion that it was a design requirement. I can see that the larger diameter will give it more inertia. I am going to put the maximum diameter cast iron flywheel that can be fitted. That will be just under 4 " diameter.


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## simister (Feb 15, 2015)

Brian, I have made the crank as per your design with the counter balance. It is all finished and looks fine. However, I never thought at the time but I have made it in Aluminium. I realise now that I can't silver solder it to the crankshaft and will have to loctite it instead.

Do you think this will be a problem or should I make it again in steel?

John


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## Brian Rupnow (Feb 16, 2015)

Aluminum only weighs 1/3 of what steel weighs, so it should never be used for a counterweight. . Aluminum should never be used anywhere on a crankshaft.


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## Jasonb (Feb 16, 2015)

The inner part of the flywheel is often machined away as it improves throttle response as there is less innertia to overcome when the engine changes speed. Thats why you will find lightweight flywheels fitted to improve the performance of car engines.

Not too much of an issue on an engine like this but worth bearing in mind for future projects


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## simister (Feb 16, 2015)

Ok, I thought that might be the case. Anyway good practice - I will make another.


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## simister (Feb 18, 2015)

I finally finished the crank. This is the second one I have made. The first I made in aluminium. I only realised after I finished it that I had used the wrong material. I should of known  that it was going to be useless as a counter weight.  I have now made this one in steel.  Also, as far as I know, I wouldn't have been able to silver solder it to the crankshaft.  I used Brian's design as  it looked quite good - thanks Brian.

John


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## Brian Rupnow (Feb 19, 2015)

Simister--You're not the first person to be caught by that. ---Brian


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## simister (Feb 22, 2015)

Can anyone give me some ideas where to start looking for the spring steel for the rocker arm?


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## Jasonb (Feb 22, 2015)

Piano wire also known as music wire is available from the local RC model shop or online.

J


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## Brian Rupnow (Feb 22, 2015)

simister said:


> Can anyone give me some ideas where to start looking for the spring steel for the rocker arm?


The rewind spring from a chainsaw, lawnmower or weed-eater all are close to the right size and work very well.---Brian


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## Blogwitch (Feb 22, 2015)

Get hold of a piece of the metal banding that is used to fix things to pallets etc.

John


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## simister (Feb 22, 2015)

Thanks Guys, That should be easy enough to get hold of.


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## simister (Feb 26, 2015)

I have finished the connecting rod.  This was a challenge for me to do. I made a rough cut first and finished the ends with a rotary table.


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## simister (Feb 28, 2015)

I am about to start the exhaust cam. I am having some difficulty getting my head around doing this part. Any advice on doing this would be a appreciated. I do have a rotary table.  I have machined the diameter to .712 and reamed the centre hole. 

John


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## gus (Feb 28, 2015)

Hi John,
The Con Rod very well done and profiled. I did a lousy job with mine and had to file and manual finished to remove flaws. The DIY RT was not well made and did chattered. However a new RT was made and no more chatter with subsequent con-rods.


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## Brian Rupnow (Feb 28, 2015)

see post #139 here.--Brian
http://www.homemodelenginemachinist.com/showthread.php?t=7687&page=14


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## simister (Mar 1, 2015)

Thanks  Brian, Looks fairly straight forward. The finished result of the exhaust cam looks very good.
I will post my attempt when finished.

Gus, I also had to do some filing to clean up some machining marks on the con rod.


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## simister (Mar 1, 2015)

Well, I finished the exhaust cam today. I followed Brian's post in the procedure.   I scribed the required diameters and tangent lines on the cam. I machined some mild steel with a spigot to take the cam, I then tapped a thread to take a cap screw to hold the cam in place. I was now able to hold the cam and have some sanding guide lines.  I then used the belt sander to follow the shape. It is not perfect but the dimensions are as required, so, I am hoping it will work ok. 

I also machined the cam gear to take the cam.


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## simister (Mar 20, 2015)

I have finally finished the cylinder. I have honed the cylinder with a brake hone and it looks  fairly good. However, I have been reading some other posts since I honed and I am now not sure if I should of lapped it with a lapping tool. I am going to use the Viton o-rings on the piston. I am quite pleased with the way it turned out. I notice on the plans that is says not to polish the bore as the fine grooves help to hold the oil.


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## werowance (Mar 20, 2015)

it is my understanding that honing is done for engines with rings in order to do 2 things, 1 is oil control and the other is to make the ring rotate or spin.
the scratches help hold oil on the walls of the cylinder and the cross hatch pattern I have been told (others more learned than I should correct me here) will cause the ring to spin on the piston as well.

lapping is for example a 2 stroke engine that has no rings. like the rc aircraft engine I am working on so the cylinder is slick and smooth because there is no ring and the piston must fit almost perfect to the cylinder.


edit - I know the Webster plans call for rings so I would say you should hone it.  if you are subbing an oring for rings then I would not do a course hone job because it might wear out the rubber ring quicker.


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## simister (Mar 20, 2015)

werowance said:


> it is my understanding that honing is done for engines with rings in order to do 2 things, 1 is oil control and the other is to make the ring rotate or spin.
> the scratches help hold oil on the walls of the cylinder and the cross hatch pattern I have been told (others more learned than I should correct me here) will cause the ring to spin on the piston as well.
> 
> lapping is for example a 2 stroke engine that has no rings. like the rc aircraft engine I am working on so the cylinder is slick and smooth because there is no ring and the piston must fit almost perfect to the cylinder.
> ...



Ok, that all makes good sense. The bore looks to be smooth, maybe, slightly scratched but extremely minor.

Thanks for your advice.

John


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## Cogsy (Mar 20, 2015)

I've only ever used cast iron rings and always go for the honed finish. However, Brian Rupnow uses viton orings and he always laps the bore to a very fine finish or the orings wear very fast. If you search for one of his builds (like the rupnow hit and miss engine) there should be some nice pics of the finish on his bores.


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## Blogwitch (Mar 21, 2015)

Sim,
You have done the right thing with the bore, honing puts the fine scratches on the cylinder walls, allowing the metal rings to bed in nicely with the bore, but I don't know how well the viton ring will stand up to rubbing against the roughish surface left by the hone.
Maybe you should have lapped it after all, as that should give a highly polished bore, usually associated with steam or air driven engines that don't usually have a running in period.

John


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## crankshafter (Mar 21, 2015)

John.
I have Vitonrings on my Webster and on my Hoglet. I have lapped cyl.on both. They'r runnig great, and have no lack of compression after many houers.
Btw. I just come in from my shop after running them. Usualy start's on first flick;D

Best reg
CS


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## simister (Mar 21, 2015)

Ok, it looks like I need to get the bore smoother if I am going to use Viton O-rings.  I have a brake honing tool which has fine grinding pads on each leg. What is the best way to lap the bore?  Can I make a lapping tool to do this job?


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## gus (Mar 21, 2015)

crankshafter said:


> John.
> I have Vitonrings on my Webster and on my Hoglet. I have lapped cyl.on both. They'r runnig great, and have no lack of compression after many houers.
> Btw. I just come in from my shop after running them. Usualy start's on first flick;D
> 
> ...



Hi Crankshafter,

Long time no see your posts. Now in the midst building the Howell V-2 which will require 16 spur gears for timing and oil pump. 16 spur gears to cut tooth by tooth will take some time.

Trust all is well at home.


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## Brian Rupnow (Mar 22, 2015)

Simister--Just go ahead and use a viton ring with the bore the way it is now. After half an hour the o-ring will be worn out, but the bore will be polished smooth. Then pull the piston and change the o-ring for a new one.---Brian


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## simister (Mar 22, 2015)

Brian Rupnow said:


> Simister--Just go ahead and use a viton ring with the bore the way it is now. After half an hour the o-ring will be worn out, but the bore will be polished smooth. Then pull the piston and change the o-ring for a new one.---Brian



Thanks Brian, I have already purchased extra O-rings as spares.


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## simister (Apr 6, 2015)

I have now machined the groove for the viton o-ring. I was concerned about going to deep with the groove and having to make a new piston. So I crept up on the depth and kept trying the o-ring. Like Brian, the width is a fraction wider than I would of liked but I think it will still be OK. It is very tight to move in and out. I am expecting it to loosen up with some wear. 

Brian, I read in your post that you also experienced the same tightness. Did you find that it loosened up much with some running in? I am in the dark how tight this piston should be. If I machine it so it moves freely, I may find that it is too loose after running in and have no compression.

John


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## Brian Rupnow (Apr 6, 2015)

Let it run tight, but be sure and use lots of oil in the fuel during the first hour of running. About 20 parts naptha to 1 part 2 cycle engine  oil. Once it has been run in, back off to 40 parts naptha to one part 2 cycle oil.


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## simister (Apr 6, 2015)

Thanks Brian, I have a quite a lot to do before I get to the stage of running the engine. I actually think that it is too tight too run the way it is. I may need to gently take off just a few 000's more.


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## Longboy (Apr 6, 2015)

If you can detect by hand the piston with ring sticking in bore, Webster isn't gonna like it.  Your O-ring with a proper width piston groove will rotate within the groove. To check the depth of the groove, place piston into cylinder with O-ring on.....if it doesn't go, the O-ring is above the surface circumference of the piston. Deepen the groove another 2-3 thousandths and try it again till its right!


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## simister (Apr 7, 2015)

I have now taken a few thousandths off and I think it is now OK. It runs in the cylinder by hand without shuddering.  If I put the palm of my hand over one end of the cylinder and with the other hand slowly withdraw the piston there is quite a lot of suction. Likewise when I compress the piston I can feel the spring in it as the air compresses. 

So, hopefully it is ok.


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## Mechanicboy (Apr 8, 2015)

Blogwitch said:


> Sim,
> You have done the right thing with the bore, honing puts the fine scratches on the cylinder walls, allowing the metal rings to bed in nicely with the bore,
> John



This is near correct, we must have fine scratches in bore to save oil in the pockets and improve lubricating on piston ring. Same too with lapped piston/sleeve. The blank mirror surface in bore is bad to keep oil on place and make more worned piston ring/sleeve. Before running in the engine, the surface has "mountains" and after running in is done, the surface has "plateau mountains" with oil in "valleys". Crosshoning will be 45-60 degree in the bore.

The Webster engine do not have the oil controlled piston ring due there is not closed crank case with oil inside. Also it has 2 compression ring on piston. 

I prefer piston ring instead O-ring in gas engine.


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## Blogwitch (Apr 8, 2015)

MB,
I didn't mention oil retention because it had been made in previous posts.

John
I do know you are well on your way with this engine and should have mentioned earlier, unhardened silver steel (drill rod) should not be used on small engines that will produce any moisture, and all small i/c engines do to some extent, as well as ones running on air or steam. It might look ok for a while, but once it gets put away on a shelf for any length of time, you will most probably have corrosion showing where you have used the silver steel. I refurbished a lot of engines for other people, all types, air, steam and i/c, and came across this problem with many of them. Invariably I fitted ground stainless rod as replacements and no further problems were reported. In the UK ground stainless can be obtained in smaller sizes from RS.

With regards to types of fuel. For many years I run on what the late, great, Bob Shores came up with. He used pump gasoline with 10% WD40 added for running in, then when run in, he swapped over to 5% WD40. About half a pint of the 10% was enough for running in, you wouldn't want to mix up too much. 
I found it perfect for my i/c engines, and even though a bit of oil comes out of the exhaust, I have never had a fouled plug and any residue carbon that builds up in the cylinder head just wipes off with a cloth.
Just to confuse you a little, this is a friends Webster running using a Minimag magneto that I built as the prototype to try out whether the plans were OK and to test if it would all run. This proves that it does, and does make the engine a little different from the rest. This mag will be used on a R&B engine when I get around to building it.

[ame]https://www.youtube.com/watch?v=8r9ivpUR0T8&list=UUbmnXOvtxx1wUp4fFjFLsfA&index=4[/ame]

John


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## kquiggle (Apr 9, 2015)

John - 

That's a very timely tip on not using unhardened drill rod. I'm working on the valve block for my Webster right now, and was thinking about using drill rod for the valves - I'll switch to stainless steel instead.

Thanks again.


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## Blogwitch (Apr 9, 2015)

Hi K,

Stainless is usually the recommended material for valves on these small engines anyway.

I could never bring myself to use drill rod for items associated with fairly high temperatures such as inside a cylinder, as it needs heat to harden it. I always wondered if it could become too brittle in use and snap. Maybe not, but the thought was always in the back of my mind.

John


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## simister (Apr 9, 2015)

Blogwitch said:


> MB,
> I didn't mention oil retention because it had been made in previous posts.
> 
> John
> ...



They are great tips - thank you. 

I was wondering about the fuel mix. In Australia that would be unleaded fuel with a WD40 mix? Would it be preferable to use the higher octance fuel or not.

John


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## Blogwitch (Apr 9, 2015)

Bob Shores just stated pump gas (or so I thought), so I always used unleaded, and it worked just fine in my little engines.
Buying a gallon would be way too much usually as you may well know, gasoline deteriorates with age, so maybe a quart would be the max mix for a lot of running.
I have never tried it, but they now reckon this 'green' gasoline for garden motor powered machines is the way to go, in that doesn't 'go off' like normal petrol, plus it doesn't have that awful petrol smell. I do use the green spirits based version for running Stirling engines with a wick burner, and that has no smell at all.
But anyway, after reading Bob's old post again, for reasons unknown to myself, I used gasoline instead of Coleman fuel as recommended by Bob in these tips on here (although old, they are well worth reading)

http://www.floridaame.org/Tips.htm

I also noticed that Bob used to use drill rod for his valves, but even so, I would still use stainless for mine.
What would the world be like if we all used and did the same things all the same way?

But it all still works fine for me.

John


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## simister (Apr 11, 2015)

Thanks John,

I will just use the standard un-leaded with the WD40. I am still quite away off finishing the engine. I have now fitted the piston in the cylinder and it showing quite good compression.


John


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## simister (Apr 17, 2015)

Well, I am slowly getting there. I finally finished the piston, crankshaft and crank. I silver soldered the crank, pin and shaft from 3 separate pieces which seemed to work ok.  When I first set it up I found the shaft was binding in the bearings. I took a a few thou off the crankshaft with some fine emery and it is now running freely.

I can now turn it over with a battery drill and it seems to have good compression and I can hear the suction from the inlet as the piston retracts. 

I have now received the cast iron ready to make the flywheel.  The plan has an option to add three .750 holes to the flywheel. I would like to do this for looks, but was wondering if it is better to leave and have the advantage of the slightly extra weight. Would this be a consideration or not make much difference?

John


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## Swifty (Apr 17, 2015)

Hi John. Drilling the holes in the flywheel just for looks is no problem. Most of the momentum of the flywheel comes from the outside, you may have seen flywheels with aluminium centres with shrunk on outer steel rims, or flywheels with spokes.

Paul.


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## kquiggle (Apr 17, 2015)

Looking good! Where did you get the cast iron for your flywheel?


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## simister (Apr 17, 2015)

kquiggle said:


> Looking good! Where did you get the cast iron for your flywheel?



Thanks Paul, in that case I will drill the holes, as I think it gives it a little more character. 


Kquiggle, I got the cast from the link below (around A$26). The problem is that postage may be the killer if it is sent to the US. If you send Bob (owner) an email, you will find him very helpful. If you have any problems, let me know and I can give him a call for you.

John


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## simister (Apr 17, 2015)

Hi Kquiggle,

ooop's forgot to put the link in. Here it is.

http://www.minitech.com.au/


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## kquiggle (Apr 17, 2015)

Thanks John - always looking for new suppliers, but Down Under is a bit of a stretch for me - I should have noted your location.


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## simister (May 1, 2015)

I am in the midst of machining the cast iron fly wheel. I am not sure how it is secured to the crankshaft. I was going to put a set screw in the hub but I am  having difficulty getting the short drill bit into position, because of the width of the chuck. Any clues on this would be a help.

John


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## kquiggle (May 2, 2015)

John - roll pins.

The following is from the last page of the plans (sorry for the all-caps, it's from the original - underline by me):
EXHAUST VALVE TIMING IS SET BY ROTATING
 CRANKSHAFT COUNTERCLOCKWISE TO ABOUT 15
 BEFORE BOTTOM DEAD CENTER. ROTATE FLYWHEEL (AND
 CAM GEAR) UNTIL THE EXHAUST VALVE JUST STARTS
 TO LIFT, AS SHOWN. CLAMP / LOCK IN PLACE,
 THEN DRILL FOR, AND INSTALL ROLL PINS.
​However, I have read other builds where set screws were used, as you are planning. I am thinking of using set screws myself for my build, and I may also install them at a slight angle to the vertical to enable access for drilling. Another option is to make a long-reach drill bit by installing a drill bit in a longer piece of rod (and a similar long-reach tap to go with it).

I have seen other builds where the angled set screw idea is used but I have not read any discussion as to whether this method has any drawbacks or not. 

If I decide to go with setscrews, I will install two at a 90*°* angle to each other, and maybe mill a couple of small flats as well if I see any slippage.


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## Longboy (May 2, 2015)

Set screws are marginal for flywheel to crank security in a gas engine. The constant hammering of the power stroke of single cylinder engines rocks the flywheel ( the heaviest item mounted) back and forth on the crankshaft where the cup points of a pair of set screws just doesn't have the contact area to resist. Another reason.... set screws will gall the crankshaft if loose at  the edge of the set screw flats in crankshaft when trying to "cure" the loose problem. If you ever have to remove the flywheel for servicing or troubleshooting the engine you can scar the hub bore to the point where flywheel never runs true and wobbles from now on upon reassembly.  Roll pin or keyway the flywheel here.Thm:


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## Brian Rupnow (May 2, 2015)

When I built my Webster, it was my first internal combustion engine. I found it VERY scary to drill a hole thru the extended hub on the flywheel and thru the crankshaft.--What if I got it wrong??? Fortunately I followed the instructions exactly, and everything come out okay----but it was quite unnerving. Longboy is right in what he is saying.--If you look on page #27 of this link, you will see that I actually built a fixture to ensure that everything was positioned correctly before I drilled the hole. There is also a detail drawing of the fixture I made and used.-Brian
http://www.homemodelenginemachinist.com/showthread.php?t=7687&page=27


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## simister (May 2, 2015)

OK, Thanks guys. The roll pin seems to be the way to go. Correct me if I am wrong, so, I should not drill the hub/shaft until the final assembly so I can get the timing adjusted correctly?

Brian, how did you manage to drill the extended hub of the flywheel, given that it is very close to the wheel itself. Kquiggle suggested a drill rod extension, which seems like a good idea. I would be interested in any other ideas that may work.

John


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## Brian Rupnow (May 2, 2015)

simister said:


> OK, Thanks guys. The roll pin seems to be the way to go. Correct me if I am wrong, so, I should not drill the hub/shaft until the final assembly so I can get the timing adjusted correctly?
> 
> Brian, how did you manage to drill the extended hub of the flywheel, given that it is very close to the wheel itself. Kquiggle suggested a drill rod extension, which seems like a good idea. I would be interested in any other ideas that may work.
> 
> John


Simister--Look in the link I posted. it's all in there. I used the "longest skinniest drill-bit in the world".---Brian


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## simister (May 2, 2015)

Thanks Brian, Yes, got it now.  Also, the design for holding the flywheel looks like the go for accurate drilling.
John


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## Longboy (May 3, 2015)

simister said:


> OK, Thanks guys. The roll pin seems to be the way to go. Correct me if I am wrong, so, I should not drill the hub/shaft until the final assembly so I can get the timing adjusted correctly?
> John


 The timing gear ( my engine) is independent of the flywheel on crankshaft so its placement has no effect setting the timing. What I would do is drill for a 3/32nd roll pin in flywheel hub. Mock up your crank with all components (crank throw, timing gear, flywheel, points cam trigger and starter drive) in the frame bearings. Then you can slide shift the flywheel between the timing gear and ignition side bearing in frame to your satisfaction. With a transfer punch thru the drilled hub, mark the crank to drill for the pin then. Upon final assembly you know where the flywheel's fixed position is and you can still get a hex key down to the timing gear to set timing too. I used purchased timing gears with set screwed hubs for my Webster.


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## simister (May 4, 2015)

Longboy said:


> The timing gear ( my engine) is independent of the flywheel on crankshaft so its placement has no effect setting the timing. What I would do is drill for a 3/32nd roll pin in flywheel hub. Mock up your crank with all components (crank throw, timing gear, flywheel, points cam trigger and starter drive) in the frame bearings. Then you can slide shift the flywheel between the timing gear and ignition side bearing in frame to your satisfaction. With a transfer punch thru the drilled hub, mark the crank to drill for the pin then. Upon final assembly you know where the flywheel's fixed position is and you can still get a hex key down to the timing gear to set timing too. I used purchased timing gears with set screwed hubs for my Webster.



The only problem is that I have loctitited the drive gear to the flywheel. My drive gear did not come with a set screw. I am not sure if I can do what you suggested, now that the drive gear is fixed to the flywheel.

John


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## Longboy (May 4, 2015)

That Loctite bond can be broken with heat and separated from the flywheel again. Looking at the Webster plans, if you are using the SDP gear per plan, I see has a .188 hub length.....that's enough to drill and tap for a #6 set screw.


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## simister (May 5, 2015)

I think there is enough room for a set screw. Ok, sounds good - I will separate and drill it.  This method seems to allow more adjustment and little more forgiving than fixing the flywheel/drive gear to the shaft.


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## Swifty (May 6, 2015)

If there was no boss on the gear for a set screw, you could always put a small one in a tooth gap. Just make sure that the screw doesn't protrude into the tooth gap. We're only making models with very little load on the gears, so a screw in the teeth will not make any difference.

Paul.


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## simister (May 6, 2015)

Thanks Paul. I think there will be enough room on the boss for the set screw.


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## Longboy (May 6, 2015)

Also John,with hub less spur gears, you can make a press fit hub with set screw. If you find it impossible to drill your flywheel hub for a pin because it doesn't extend out far enough.... the same solution. You can bore the existing flywheel hub to receive.... let say a 5/8 in. Dia. brass or CR round with a flange to seat square in your flywheel. When installed, you would chuck the flywheel up in the lathe to run true , then you drill/ ream the replacement hub to crankshaft diameter. On my new "SUPER H" twin, an overhanging crank engine, the flywheel is CR steel round with a pressed in hub drilled for a roll pin.


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## simister (May 6, 2015)

Ok, that is a good tip. However, I think I will have enough meat on the flywheel hub to drill and fit the roll pin. I will be removing the drive gear and setting it up on the weekend. I will post the result when done.

Thanks for all your advice.

John


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## simister (May 7, 2015)

I removed the drive gear from the flywheel. After applying some heat it came away easily. I didn't have enough room on the hub of the drive gear to drill a hole for a set screw. So I drilled through the teeth gap as suggested and tapped for a grub set screw. This sits below the teeth and the gear runs smoothly.  

Next is to drill and fit the roll pin to the flywheel.

John


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## Swifty (May 7, 2015)

Glad you found a solution, members tossing ideas around is great.

Paul.


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## simister (May 24, 2015)

I have now set the drive gear up independent of the flywheel. Here is a photo of the flywheel before I removed the drive gear. Now to start on the valve block. 
John


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## simister (Jul 23, 2015)

I have finally got back into the shop to do some more work on the Webster. I have completed the valve block and it seems to be working ok. The engine so far seems to have good compression, however, I have nothing to compare with, so I am not sure. When I try to spin the flywheel it bounces back quite vigorously. If I squirt some compressed air in through the inlet port it throws the piston back with a lot of force. 

As this is my first attempt I am not sure what to expect. Although I am happy with the compression, and on the surface it appears that it will be quite sufficient.  However, when I insert compressed air into the inlet port there is some seepage of air through the closed exhaust port/valve. It is also the same if I inject air through the exhaust port - the inlet port has seepage. 

I have re done these valves and inserts twice to try an eliminate any leakage, but I still get some.  Am I expecting too much for this to be a complete air tight seal?

I have not completed the tappet at this stage.

John


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## bmac2 (Jul 23, 2015)

Hi John
Ive read 100s of threads on IC engines but Ive only built 1 so Im no expert. What I can say about mine, and what Ive read is that it is almost imposable to get the valves in these small engines to seal completely before they run. My Webster had what I thought was good compression and the valves where seating as good as I felt they were going to get but the difference after the first couple of pops was very noticeable. Please note Im saying _pops_ not minutes of run time. 
It sounds like you have a good solid build there and Im sure its well on its way for making smoke and noise. Thm:


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## simister (Jul 24, 2015)

Thanks Bob, Well, that's encouraging. It seems to have a fair amount of compression. I am looking forward to some smoke and noise, but I have a way to go yet.

John


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## gus (Jul 24, 2015)

John,

No worries. The Webster is a very forgiving engine to build. The outboard valve block was a bit strange to me but as long as you lap the valves and seats properly, the engine will start but will need some timing adjustment.A good indication is when you get some pops and smoky exhaust,you are about there. Some plus and minus tuning will get your engine up and running. No worry about engine not starting and run on day 1 or day 2. On day3 mine decided to start and run. A good job on the carb is required. I cheated and bought an OS Carb. Subsequently I did master the black art of making good carbs and tuning.  Good Luck . Now worries. The Nemett Lynx was a bit tough to make and get going. Rupnow Hit&Miss engine was hard to get the hitting and missing. Good Luck. Now doing the Howell V-2 Engine. Will take another 2 more months minimum to to complete. Very Unforgiving.


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## gus (Jul 24, 2015)

John,
Your engine looks good and sure beat mine.


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## simister (Jul 25, 2015)

Thanks Gus, yes, I have cheated as well and have a OS carby to fit. I have reduced the spring tension on the inlet valve and it now snorts when I rotate the flywheel.

I started with the Webster as my first. I will attempt something a little more complicated after this. This is a big learning curve for me.

John


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## simister (Sep 8, 2015)

The points and ignition cam are now complete.  I had some trouble with the valves not sealing properly. I have re-done them and they are a lot better but not 100%. Although, I feel that they should be OK. I have a reasonably good amount of compression and when I spin the flywheel there is a distinctive snort from the intake valve. I can't see it opening but I guess it only has to move a few thou to intake the mixture.

Anyway, now onto the carby and exhaust. Getting there slowly as I have been up in Queensland for 6 weeks getting away from cold Melbourne.

John


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## gus (Sep 9, 2015)

Hi John,

This a "Rolls-Royce Engine equivalent. Very well presented. Dying to see the video.


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## kquiggle (Sep 9, 2015)

Your engine is looking good. I have only made a little progress on my own build, but hope to get back to work on it soon. Keep posting - I need the inspiration!


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## simister (Sep 9, 2015)

Thanks Guys.


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## simister (Sep 19, 2015)

I am about to start building the fuel tank. Is there any special considerations that I should be aware of? for eg. height of the tank, fuel level in relation to carby.

Does the fuel level need to be higher than the carby intake, so as to enable a gravity feed?

I was going to build it in brass.

Thanks John


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## Brian Rupnow (Sep 19, 2015)

Tank height is based on the following:--When completely full, the top of the fuel level in the tank should ideally be 1/4" below the centerline of the carburetor main air passage. This is based on the fact that the fuel bleed hole in the spray bar is essentially on the center of the carburetor air passage, and you don't want the fuel to gravity feed and "puddle" in the carb, nor run out onto your test bench and start a fire.---Brian


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## simister (Sep 19, 2015)

Thanks Brian


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## chucketn (Sep 19, 2015)

John, could you take another picture of your Webster and put something in the frame for a size reference? BTW, I'm following closely, as the Webster will be my next build.

Chuck


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## simister (Sep 20, 2015)

Hi Chuck,

Here is a photo with an apple for reference. I hope this helps.

Regards, John


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## chucketn (Sep 20, 2015)

Thanks, John. Helps to put it into perspective.

Chuck


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## simister (Nov 28, 2015)

Well it is finally coming near completion. I thinks I have made the fuel tank way too large.  I am not familiar with the screw adjustments and settings on the Carby. There is a needle valve screw and two adjustable screws on the side. Any help on making the initial adjustments on these screws would be appreciated.

Also, what is the preferred fuel for this engine? I have seen that some people are using unleaded fuel and WD40 and others Coleman lantern fuel. 

Thanks John


----------



## Mechanicboy (Nov 29, 2015)

simister said:


> Also, what is the proffered fuel for this engine? I have seen that some people are using unleaded fuel and WD40 and others Coleman lantern fuel.



I has same engine as you, my the engine is running at unleaded petrol (95 octane) and 5W-30 motoroil. Also no problem.


----------



## Swifty (Nov 29, 2015)

On my Rupnow engine I use shellite (Coleman fuel) with a small amount of 2 stroke oil added.

Paul.


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## simister (Nov 29, 2015)

Thanks guys. When you say you add a small amount of 2 stroke oil to shellite and 5w-30 to unleaded. - what percentage would that be. 

Is shellite and coleman lantern fuel one of the same?

Regards, John


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## Brian Rupnow (Nov 29, 2015)

I think you would be quite safe at a 30:1 mix--possibly even 40:1.  I'm not sure about shellite, but Coleman fuel is basically Naptha gas in a fancy can. The nice thing about burning Naptha is that it has very little odour. Pump gasoline works but it stinks when it burns.---Brian


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## Mechanicboy (Nov 29, 2015)

simister said:


> Thanks guys. When you say you add a small amount of 2 stroke oil to shellite and 5w-30 to unleaded. - what percentage would that be.
> 
> Regards, John



My engine ran at pure unleaded petrol direct into the engine, while the oil came into the cylinder via oilcup with adjusting screw for oil amount. There is not sign of abnormal abration, compression is still good.


----------



## 10K Pete (Nov 29, 2015)

Jens, where in the cylinder does the oil go? On the piston skirt? I'm curious
because I would like to avoid mixing oil with the gas. No special reason
other than I associate gas/oil mix with chainsaws and that means work.

Pete


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## Swifty (Nov 30, 2015)

simister said:


> Thanks guys. When you say you add a small amount of 2 stroke oil to shellite and 5w-30 to unleaded. - what percentage would that be.
> 
> Is shellite and coleman lantern fuel one of the same?
> 
> Regards, John



According to my research, they are both about the same. As far as oil ratio goes, as others have mentioned, 30:1 to 40:1 ratio is fine.

Paul.


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## deverett (Nov 30, 2015)

Bob shores used to advocate 10% WD40 into petrol or Coleman's fuel for running in the engine and 5% thereafter.

I've always found this a strange mixture, because I'm not aware of any lubricating properties of WD40.
http://www.floridaame.org/  Under Tips & Links.  Bob Shores, tip no.10.

Dave
The Emerald Isle


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## Longboy (Nov 30, 2015)

On the model airplane carburetor, start with the fuel mix needle at 1.5 turns open. The horizontal screw under the throttle arm sets the idle speed as a closed throttle stop. The screw in the center of throttle arm into the carb body sets the needle withdraw from the mixture tube as you open the throttle arm. Sight down the barrel to see its position as you open/ close arm. With all three of your hands...Spin Webster over, prime and release with finger tip and adjust mixture as the number of "hits" indicates.


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## simister (Nov 30, 2015)

Thanks guys for all your advise on Fuel mixture.

Also, thanks Longboy on the carby settings. At least I will now have a starting point and I can experiment with settings later.

John


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## simister (Dec 3, 2015)

I have fitted the carby. However, I am not sure if I put it in upside down, as I saw another on You tube the other way around. I have the main thumb screw to the bottom with the fuel feed also from the bottom. My last photo should show how I have installed it.

I have tried to start the engine but with no luck. 

I have  set the exhaust valve timing so that it just starts to open about 20 degrees before the piston reaches its most outward part of the stroke. I have done all these settings from the plans and all being viewed from the fuel tank side of the engine.

I have set the cam so the the points are closed and just about to open at 15 degrees before TDC.

I have compression.

When I spin the flywheel I can see the fuel being sucked up the fuel line.

I am not sure if the spray bar in the carby should protrude into the throat slightly or be flush with the throat.

The plug doesn't appear to be saturated in fuel. 

I don't know how to check and what to look for to see if the carby is set correctly.

Any help on this please.

John


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## Longboy (Dec 4, 2015)

Your carb position is fine. They work in any degree position. Prime to flood the engine, see if fuel is drawing into cylinder and a wet plug. You can remove plug and dribble some fuel in there. You may be able to check the draw through on the removed carb with a rubber tiped blow-off nozzle on the bore of carb with air pressure very low...if you get wet from the manifold side, you have fuel flow. Set your spark right at TDC and make sure the exhaust valve is closed just before TDC.  What do you use to turn the engine over?    Dave


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## simister (Dec 4, 2015)

Hi Dave,

OK, I will give that a try. I have been turning it over with a battery drill fitting (anti clockwise). The spark plug appears to be getting fuel through to it. I was told that the spray bar should be half way into the throat, but mine is just protruding into the throat. So if I set the spark at TDC, are you saying that the exhaust valve should be open as the piston is moving from BDC to TDC?

Thanks John


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## Brian Rupnow (Dec 4, 2015)

This engine will run either direction, depending on how you set up the valve timing. As the piston is moving from top dead center towards bottom dead center, set the exhaust valve to just start to feel the effect of the cam when the piston is 1/8" before bottom dead center. Once the piston has reached bottom dead center and started back up in the cylinder, that will be your exhaust stroke. Since the points run off the crankshaft, you will get spark both at the top of the exhaust stroke and at the top of the compression stroke. I can't remember now if the cam on this engine has any overlap on the power stroke or not, but it doesn't really matter. Time it to fire at top dead center. You can always adjust the timing after you get the engine running.


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## Longboy (Dec 4, 2015)

simister said:


> Hi Dave,
> 
> OK, I will give that a try. I have been turning it over with a battery drill fitting (anti clockwise). The spark plug appears to be getting fuel through to it. I was told that the spray bar should be half way into the throat, but mine is just protruding into the throat. So if I set the spark at TDC, are you saying that the exhaust valve should be open as the piston is moving from BDC to TDC?
> 
> Thanks John


Yes...during the exhaust stroke. The ex. valve should be closed coming up to TDC so the in. valve gets a full draw on the intake down stroke. Ignition should happen near TDC, the top of compression stroke. Looking at my Webster crankshaft from the con rod side, the exhaust valve by clock face timing is open at 1 and closed by 9. Regardless of carb setting, if you know you have a fueled cylinder and compression and spark...Webster should show some pops!   Dave.


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## simister (Dec 5, 2015)

OK, I think the problem is that I am not getting fuel into the cylinder. I took the spark plug off and blew it out with some compressed air. Next, I started turning it over with the drill, and when I put my finger over the carby intake,  I could see fuel started flowing through the fuel line. I could see the intake valve opening and closing but only a very small amount. As I continued, the fuel started dripping out of the exhaust valve through the valve stems. I then took the plug out and it appeared dry. It certainly was not dripping with fuel, as I tried to flood it on purpose to see if fuel was getting through. The fuel is sucking through the lines but I don't think it is entering the cylinder. I put a lighter spring on the inlet valve but with no improvement. I am fairly sure the problem is fuel. If I blow some compressed air into the carby intake I can feel it come through the spark plug hole. So it appears there is no blockage between  the valve block and the cylinder. I am not sure what checks to do next to pin point the problem. Would you think that the compression is sufficient given that it is sucking fuel through the lines?

John


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## Mechanicboy (Dec 5, 2015)

Engine need to run:

1. Good compression--> Check there is no leakage in valve, gasket and cylinder/piston (not too large gap of piston ring in cylinder).

2. Good spark from sparkplug--> Check all connections, contact breaker and battery is in order.

3. Right timing of ignition--> Set a ignition timing between 2.5 and 5 degree before TDC as start point. 

4. Fuel tank in same level as in carburator (not flooding from tank to carburator, let the engine suck the fuel into engine). If problem to suck the fuel into carburator--> can be caused by too hard inlet valve spring and replace with a softer inlet valve spring.

5. Right fuel/air ratio--> The engine running as petrol engine need less amount of fuel than engine running on methanol due high energy value in fuel. Also adjust less petrol than methanol in same engine. 1.5 turn turns of fuel mix needle is maybe too much for me since i has engine running with fuel mix needle at 0.5-1 turns since my engine is running on petrol.

6. Too much oil from oil cup on cylinder can give fouled spark plug, be careful to adjust a amount of oil into cylinder with adjusting screw. Can you see there is oil in cylinder while the engine is running--> amount of oil is correct. Also not too much oil out of exhaust, little smoke is ok.


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## simister (Dec 5, 2015)

I deliberately tried to flood the engine by holding my finger over the air intake and cranking with an electric drill. I could see the fuel moving through the fuel line. It then started ripping through the exhaust port valve as it was flooded with fuel. Then, when I took the spark plug out it was fairly dry - I would of thought it to be dripping with fuel but this was not the case.  There is enough suction on the piston to suck the fuel up the line but it doesn't appear to be getting into the cylinder.  John


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## Mechanicboy (Dec 5, 2015)

simister said:


> I deliberately tried to flood the engine by holding my finger over the air intake and cranking with an electric drill. I could see the fuel moving through the fuel line. It then started ripping through the exhaust port valve as it was flooded with fuel. Then, when I took the spark plug out it was fairly dry - I would of thought it to be dripping with fuel but this was not the case.  There is enough suction on the piston to suck the fuel up the line but it doesn't appear to be getting into the cylinder.  John



Flooded fuel out of exhaust without starting the engine ---> Check the spark is there on sparkplug and check ignition timing is set to 2.5 - 5 degree TDC. Also the egnine is not startet up due lack of spark from sparkplug or the ignition timing is too late after TDC. 

You had the finger on carburator and the engine is sucking the fuel into engine---> Replace the stiff intake valve spring with a soft intake valve spring. Stiff intake valve spring will make difficult to start the engine since vacuum in the cylinder is not strong enough to open the intake valve and suck fuelmix into the cylinder.


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## simister (Dec 5, 2015)

Jens,  Correct me if I am wrong, but if the fuel was being sucked up the fuel line, wouldn't that indicate that the inlet valve spring was not too stiff? Or, are you saying that it may be opening enough to suck it into the valve block but not into the cylinder?

John


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## Mechanicboy (Dec 5, 2015)

If the engine can suck fuel, the spring is ok.  The problem is igniting the fuelmix.  Check the ignition equipment.  If ok,  close fuel from tank. Then give some drops of fuel into carburator and start up.  If engine is starting up and running a short time, ignition is ok---> turn the fuel mix up 1/4 each time you are trying to start up engine until the engine is running with correct fuelmix.


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## simister (Dec 5, 2015)

Ok, I will try that in  the morning. Actually, I have got a small perfume atomizer spray, which can spray a very fine mist. Do you think that may be better to try than some drops of fuel?

John


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## Mechanicboy (Dec 5, 2015)

simister said:


> Ok, I will try that in  the morning. Actually, I have got a small perfume atomizer spray, which can spray a very fine mist. Do you think that may be better to try than some drops of fuel?
> 
> John




Yes,  you can do it..  Later in this day i can make a movie how do it with the engine then you can learn out how do check and start up engine.


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## Mechanicboy (Dec 5, 2015)

Here is my engine in these movies.. The text is wrote there..

[ame="http://www.youtube.com/watch?v=LD5lRiQ_SL8"]http://www.youtube.com/watch?v=LD5lRiQ_SL8[/ame]

[ame="http://www.youtube.com/watch?v=o1dNPdmGxSE"]http://www.youtube.com/watch?v=o1dNPdmGxSE[/ame]


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## simister (Dec 5, 2015)

Thanks Jens for the videos - a great help. I have sprayed the inlet of the carby with fuel and still with no luck on firing. So, next I purposely turned the engine over while I sprayed a lot of fuel into the carby. I did this to test if the fuel was getting through to the cylinder. When, I removed the spark plug it was dry. I would of expected it to be dripping with fuel and totally flooded. I am now convinced the issue is fuel. I do have suction from the piston but the fuel is not getting into the cylinder. 

Tomorrow, I will remove the valve block and investigate why. I feel sure now that there is a blockage between the carby and the cylinder.

I will update the post when I have pulled it apart.

Thanks guys for all you help so far. However, I am not there yet, but it is now narrowing down.

John


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## Brian Rupnow (Dec 5, 2015)

Simister--There is a trick involved here. If you block the carb inlet with your finger and turn the engine over, it will always pull fuel up the fuel line because of direct suction as long as the inlet valve and spring are functioning. However, for the engine to run in a normal manner without being choked by your finger, the vacuum created to suck the fuel up from the tank is created by venturi effect. This is essentially a low pressure area created in the carburetor by a narrowing of the air passage into the carburetor, or a restriction caused by something protruding into the air passage. As the air flows past the restriction, it creates a low pressure area and that is what sucks up the fuel under normal conditions. Did you use a gasket when you mounted the carburetor? If so, did you cut out the hole in the center of the gasket to let the air pass thru? If your ignition timing is remotely close, and you have good compression, then suck up a bit of fuel in an eye-dropper, remove the sparkplug, and squirt it into the cylinder, then quickly put the sparkplug back in, put the coil wire on, and spin the engine.  If it doesn't at least "pop" or try to start, then the problem may very well be in your ignition system.---Brian


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## Mechanicboy (Dec 6, 2015)

I can see you has OS carburator. I has same carburator in my OS 10FP engines. Spraybar in my engines is in mid position to create vacuum and make easy to adjust and start up engine. Can you move the spraybar into the carburator to mid position as i am showing your photo of your carburator.


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## simister (Dec 6, 2015)

Thanks Brian for the tip. However, I have found a blockage in the valve block and now it is clear. There is now fuel going into the combustion chamber as the engine cranks over.

Now, I have managed to get it to fire and then stop. Whilst cranking the engine,  it is firing and the cylinder is getting quite hot, but will only run by itself for a couple of seconds.  I have checked the timing of the spark and the exhaust valve timing and they are correct. I think the problem is a leaky exhaust valve. When I remove the valve block and put my finger over the inlet there is good springy compression when I rotate the flywheel. However, when I re fit the valve block the compression is much less. With the valve block removed I injected some compressed air into the block and there is leakage through the exhaust valve. The inlet valve seems fine with only  a small amount of air leaking. So, I think before I go any further I should fix this issue. I am not sure if I will have to remake the valve and guide, or if it can be ground with some abrasive paste.

John


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## simister (Dec 6, 2015)

Jens,

Yes, I can move the spray bar higher. I will now change it to mid position.

John


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## Cogsy (Dec 6, 2015)

You could try lapping the valve into it's seat with some toothpaste as abrasive. Do it by hand and only rotate the valve backwards and forwards (don't spin it) for a while, then change it say 90-120 degrees and do it again. A few minutes repeating this procedure is all that's needed to achieve a reasonable seal in most cases. Pressure from combustion will seal it properly in short order once the engine is running.


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## 10K Pete (Dec 6, 2015)

What was the blockage!!!???? Gotta know. And yes, use a fine abrasive,
not auto valve compound as it's way too coarse.

What was blocking the intake? Can't leave that issue just hanging!
:shrug:th_wwp

Pete


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## Brian Rupnow (Dec 6, 2015)

Before you tear everything apart, start cutting 1/2 coils at a time off your intake valve spring. If your engine fires at all---if you can get it to run for two minutes even, then the exhaust valve will probably seal itself.


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## Longboy (Dec 6, 2015)

...if you had a few seconds of running, there is no valve leakage unless the adjustment screw has no gap. I use a flat blade needle file across the valve face chucked in the lathe if it looks galled from cutting under a magnifier. Brass valve seats seem to cut smooth every time. Good to hear you got a response from Webster!


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## simister (Dec 6, 2015)

Ok, I will give all your suggestions a try and report back.

Well Pete, you wanted to know what the blockage was. I am embarrassed to say that I forgot to drill the hole through the side of the cylinder to match the valve block inlet. So, as you can see I had no hope of it going. Amazingly, it was still sucking fuel up the fuel line. There was a very tiny gap for the air to seep through. I knew that I had to spot it when the block and  cylinder were finished. However, it was a nice surprise to find something obvious. 

I am getting close - just a few small fixes to go.

John


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## 10K Pete (Dec 6, 2015)

Thanks for the info on the blockage, John. I'd laugh but I ruined a bearing
on a pump once by failing to drill the oil hole thru the new bearing bushing. One of those forehead slapping moments!!

Keep in coming, I'm interested as I have a H&M in the planning stages.

Pete


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## simister (Dec 7, 2015)

Pete, I know the feeling - I felt exactly the same. 

John


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## simister (Dec 8, 2015)

Mixed Success today. Very pleased with the results - "She Runs"

I managed to start the engine today and after adjusting the mixture,  got it to run for about 5 minutes. Later in the day I ran it again twice, each time  for about 5 minutes.

Here is the Problem:

The engine progressivly got harder and harder to start. I realised that I had lost a lot of compression. I pulled the engine down and found there was plenty of compression in the cylinder - Ah! - the problem must be in the valve block as I had previously suspected. I removed the valve block and found that the exhaust valve was leaking again.  I pulled it apart and lapped the valve with toothpaste. I then reassembled the valve block and the exhaust valve was still leaking.
The valve seat looks very good, but I am suspect about the valve. 

So tomorrow I will make another valve, unless anyone has got a better idea.

Is there any way to test that the valve is sealing in the valve seat without having to reassemble the block each time. This existing valve appeared to be sealing ok until I put it back together.

Anyway, I am still very satisfied that the engine runs. 

John


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## 10K Pete (Dec 8, 2015)

Do a blow-down test. Put the piston at TDC firing, lock the crank, and 
put some air in thru the spark plug hole. I use an adaptor made from an
old spark plug body, gutted, with a male air fitting welded in. Put in 40,
50, 60 pounds and listen at the intake and the exhaust. I use a short length
of tubing like a stethascope and put the far end right into either manifold.
If one of 'em is leaking you'll hear it!!

When you lap a valve, you should see a lapped ring all around the valve
face and all around the seat. If you don't see a complete ring, it's not seated.

Pete


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## simister (Dec 8, 2015)

Thanks Pete,

Yes I have done blow test. I did it a different way, but with the same effect. The exhaust valve is definitely leaking.  I need to check if it is the valve guide or the valve that is the problem.

John


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## simister (Dec 8, 2015)

Update: 

I have just removed the valve guide from the block. I fitted it in some clear hose (very tight fit). Submerged it under water with the valve inserted into the guide. I then blew as hard as I could through the tube and there were just a few small  bubbles.

I really don't think I could improve on this valve seal.

I then had a look around the guide and found carbon buildup under the valve guide and on the inside of the block. I have attached some photos and it looks like the loctite didn't go right around the guide and has left an air gap.

I think this may be the problem.

Any thoughts?

John


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## Cogsy (Dec 8, 2015)

I was going to comment that it's very unusual for a valve to get worse at sealing after the engine begins running on it's own. I think you're probably right about the outside of the guide leaking instead. At least you've heard it run - that should keep you motivated while you fix it.


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## simister (Dec 8, 2015)

It certainly has renewed my motivation now I know it can run. 
Just a few fixes to go.

Is there any special Loctite that I should be using on the valve guide?

I have used a permanent high strength thread locker. However, I have some Loctite 609 which is a retaining compound of medium strength.


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## Cogsy (Dec 8, 2015)

I've never built a Webster so I'm not sure what the design of the valve guides is like, but for slip in guides/cages, I use Loctite 635 which is a slip fit Loctite. The various grades of Loctite have differing strengths, but also differing requirements about thickness of the film. It is possible to misuse them by applying one that is designed for use in large gap applications (like threadlockers) in a close fitting application, or vice versa, and you may not get the bond strength you think you should.


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## Brian Rupnow (Dec 8, 2015)

You should lap in two stages--First with 320 grit, then with 600 grit. Toothpaste isn't really good enough for what you are doing.--Voice of experience!!!


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## Mechanicboy (Dec 8, 2015)

simister said:


> It certainly has renewed my motivation now I know it can run.
> Just a few fixes to go.
> 
> Is there any special Loctite that I should be using on the valve guide?
> ...



Use Locktite 638, it is good to fasten the sloppy parts up to 0.25 mm/0.0098 inc clearance and keep temperature up to 180 degree celsius/356 degree Fahrenheit. 

I prefer light press fit to mount the bronce sleeve for valve into valve block + locktite on groove in valve block to keep gas tight.


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## Brian Rupnow (Dec 8, 2015)

No Loctite will stand up to the temperature that is seen in an air cooled cylinder head. If you have built the webster to the original design and the valve block is actually situated on the outside of the cylinder, the guides are held in place by a ring around the inside end that keep them from flying out under combustion pressure. However the shoulder above the ring must be a very very good fit into the valve body, and use some loctite too.


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## Mechanicboy (Dec 8, 2015)

Brian Rupnow said:


> You should lap in two stages--First with 320 grit, then with 600 grit. Toothpaste isn't really good enough for what you are doing.--Voice of experience!!!



I used the lapping paste (fine paste) for valve in automotive cars where i am working as car mechanic when i lapped the valves in Webster engine, it can not hurt the valve/seat. 

If doubt about the paste is too coarse, you can mix the grinding paste in kerosene to a thinn paste and apply on valve and grind valve in both ways (rotate valve in both ways) until you feel there is not more grinding under work. Then wash the valve/valveblock and examine---> Correct lapped valve ---> Dull ring around valveseats. 

Under running-in the engine will improve the valves and last long time.

Tooth paste is not a grinding paste for metal, if case the tooth paste was a gringing paste then your tooth will be grinded away for a long time since when you was a young children.


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## Mechanicboy (Dec 8, 2015)

Brian Rupnow said:


> No Loctite will stand up to the temperature that is seen in an air cooled cylinder head. If you have built the webster to the original design and the valve block is actually situated on the outside of the cylinder, the guides are held in place by a ring around the inside end that keep them from flying out under combustion pressure. However the shoulder above the ring must be a very very good fit into the valve body, and use some loctite too.



Correct, my Webster engine is watercooled..


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## Brian Rupnow (Dec 8, 2015)

Thinning the lapping paste with more liquid does not reduce the grain size of the lapping compound. Automotive valve grinding compound is far too course. When I built my first engine I used automotive valve grinding compound, and it feels like a load of rocks compared to a proper lapping compound.


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## Longboy (Dec 8, 2015)

The vinyl tubing around the valve guide to check leakage a great idea John. I use ordinary 5 minute epoxy setting the guides into the heads of my engines with no issues. All are air cooled. 

I think using toothpaste for a lap compound is too far fetched reasoning for what one wants to accomplish. Its doesn't cut brass and certainly not a steel valve. If it did, you wouldn't use it for oral care then.

I have tried some diamond lap. It is expensive, probably did some work against a model engine valve and seat in a clean up effort not ordinarily needed. Making a new valve in an hour anyway.... a more economical approach. I think you are on top of it discovering the guide is not totally sealed into the valve block!


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## simister (Dec 8, 2015)

All noted on the toothpaste as a "no go".  However, I believe the valve and seat are ok - there appears to be a good seal there.

The interesting point is that initially I put a small amount of oil in the back of the cylinder to lubricate the ring. Now, when I first turned the flywheel by hand, I had good compression, and then after a dozen or more swings on the flywheel, the compression dropped away until there was none at all. When I put the oil in the cylinder again there was compression. Now I know that this is not a lack of compression in the cylinder, because if I remove the valve block there is good compression in the cylinder all the time.

What I think is happening, is the oil is making its way in the valve block and lodging between the valve guide and block and giving a temporary seal. When this is eventually pushed out from between the guide and the block the compression is lost.

I think the proof of this is the carbon that was lodged in that gap between the guide and the block. 

Anyway, today I will seal it up and give it another try.

John


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## 10K Pete (Dec 8, 2015)

I think your analysis is good, especially in light of the carbon in the crack.

Pete


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## Cogsy (Dec 8, 2015)

I agree that toothpaste isn't for removal of lots of material, it's more of a 'polish' I guess, but it certainly is abrasive with normal toothpaste composed of at least 50% abrasive material including such types as "aluminum hydroxide (Al(OH)3), calcium carbonate (CaCO3), various calcium hydrogen phosphates, various silicas and zeolites, and hydroxyapatite (Ca5(PO4)3OH)" - [from Wikipedia].

I have some diamond lapping pastes in various grades that I use if I need more material removal, but normally to lap valves in I only ever need to use toothpaste YMMV.


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## Swifty (Dec 8, 2015)

Diamond paste in various grits is available in syringes, 13 assorted for $25 Australian on eBay. Will last for years. 

Paul.


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## deverett (Dec 9, 2015)

Swifty said:


> Diamond paste in various grits is available in syringes, 13 assorted for $25 Australian on eBay. *Will last for years*.
> 
> Paul.



Yes.  Remember the old advert: Diamonds are forever.  If using diamond paste, make sure you wash the surfaces _Thoroughly_ afterwards.  Some have even gone so far as to suggest using ultrasonic cleaners.

Dave
The Emerald Isle


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## bmac2 (Dec 9, 2015)

Hi Simister th_wwp
I think your spot on with the valve guide. I actually had a similar problem on my Webster. Id go with Jens (Mechanicboy) suggestion and try the Loctite 638. I have an oscillating engine that I _have_ (once or twice) run on steam and thats all thats holding the head on.:hDe:


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## simister (Dec 10, 2015)

Thanks Bob,

Well, I have sealed the valve guide with loctite as suggested. I now have good compression - so hopefully that problem is nailed.

The engine now starts and runs very nicely. However, it runs for a while and then there is a knocking sound. it sounds like the piston is hitting the top of the head. I have checked all the clearances and can't see where it is knocking.

I then thought it may be pre-ignition, as I had the spark advanced to about 5 degrees BTDC. I then advanced it to fire at TDC and the knocking was still there. Then I thought this could be detonation due to the engine getting too hot and causing pre-ignition way before TDC.

Has anyone else experienced this problem with the Webster?

Bob, shortly I am going to do a video and post it up on the forum. 

Regards, John


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## Brian Rupnow (Dec 10, 2015)

Check and see that the set screw over the key in the flywheel hasn't come lose. that will give a very definite and hard to track down knock.---Brian


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## simister (Dec 11, 2015)

Brian, I checked  the set screw and it is tight.


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## Mechanicboy (Dec 11, 2015)

Check engineparts in case there is sloppery fit between moving parts.


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## Brian Rupnow (Dec 11, 2015)

Check side to side clearance at the big and of your con-rod. If you have exessive free movement there, the rod will move side to side with a strange knock every time the engine fires. Likewise, check for endplay in the crankshaft itself.


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## simister (Dec 12, 2015)

I have pulled it all down again, and gone through all the parts to check for any movement. I found that there is a very small side to side movement on the wrist pin at the piston end of the con-rod. It is very small but as you say Brian, that may be enough to cause the knocking. I will re-make the con-rod bush for a tighter fit.


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## Longboy (Dec 12, 2015)

If you have a few thousandths lateral thrust clearance in the rod ends, you will want to keep that clearance so the rod floats sideways some on the pin. These little engines are sensitive to friction binding of such. This would not be the source of the described pounding or knock in the rod assemble anyway. That would happen if the bearings/ bushings are undersized to the pins.

If the rod slides side to side at a 90deg. relation to the pin that is fine. However if the rod slides and bends/cocks off the 90deg...its a bad bearing or pin fit.


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## Brian Rupnow (Dec 12, 2015)

I don't think side to side clearance at the piston end of the rod will make noise. However, at the journal end of the rod, it definitely will. The most common source I have found for "Knocks" are loose set screws over the key in the flywheel, or undersized key in the flywheel allowing some rotational "slop". It is almost impossible to keep the centerline of the con rod journal perfectly parallel to the centerline of the crankshaft on these small engines. The result is that as the crankshaft turns thru a full 360 degrees, the rod will attempt to slide from side to side to accommodate this misalignment.


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## Brian Rupnow (Dec 12, 2015)

Another source of "knock" on the Webster is that long valve rocker. I found that the torsion spring as shown in the original Webster plans allowed the rocker arm to "float" part of the time, and it would produce a rattling, knocking sound. I solved this issue by using a 1/4" wide piece of rewind spring from an old chainsaw, doubling it over and securing it on one side of the rocker arm pivot. This keeps the rocker arm under spring pressure at all times, and got rid of the noise.


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## simister (Dec 12, 2015)

Thanks guys. I have lateral movement along the wrist pin. However, I think there could be too much slop as the con-rod has some movement off the 90 degrees, as Longboy pointed out. 

Brian, I also used chainsaw spring for the rocker arm from your original suggestion and it is very firm.

There is no movement in the flywheel as it is secured with a roll pin and is very tight. I do the timing adjustment from a set screw in the small timing gear.

I will re fit a new bushing in the small end of the con-rod and see how that goes.

It is a process of elimination.

John


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## simister (Dec 17, 2015)

Well it is finally up and running.  I found that the knocking was caused by the small end of the con-rod, hitting the  inside of the cylinder when the engine fired. The clearance was only a few thou and I couldn't see how close it was. It was just by chance after putting some pressure on the con-rod that I felt it touching the back of the cylinder. I rounded off the radius of the small-end and that fixed the knocking problem. 

Then when I started the engine it ran for a few minutes and stopped. On investigation I noticed that the 3 mm roll pin I had used to fix the flywheel to the crankshaft had sheared. I re-bored it and have now increased the size  to 4mm. - I hope that is now strong enough.

I have used a rubber band to stop the throttle from advancing to full. I will have to make something to keep it in place.

It now needs a clean up and some final tweaking.

This forum has been an enormous help in getting the engine up and running. This is my first petrol engine and a big learning curve  - thanks guys.

Here is a link to the video.


https://drive.google.com/file/d/0B3DfwczDMNaeaUllR1ZxVlpkRHM/view?ts=56724c59

 John


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## GailInNM (Dec 17, 2015)

Congratulations John.  You have a fine runner.  
Thanks for letting us ride along with your build.
Gail in NM


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## simister (Dec 17, 2015)

Thanks Gail,


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## Brian Rupnow (Dec 17, 2015)

Congratulations John--I knew you'd get there.---Brian


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## 10K Pete (Dec 17, 2015)

Very nice!! That's a great runner, and I love the sound of the exhaust. Is the 'muffler' the one on the drawings?

Pete


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## canadianhorsepower (Dec 17, 2015)

Very nice job  Thm:Thm:

love the spark plug CAP    Rof}Rof}Rof}


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## simister (Dec 17, 2015)

Thanks guys. 

Yes, Pete, it is the same muffler as the drawings.


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## bmac2 (Dec 18, 2015)

Congratulations John th_wav
Youve got a good runner there. Thats actually pretty go throttle response for a Webster. Ive been following along from the start and its sure nice to see. I wish Id thought of that spark plug cap . . . wouldnt have tasered myself so many times trying to adjust the carb.


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## simister (Dec 18, 2015)

HI Bob,

I still managed to taser myself with the plug. I have now fitted a proper insulated plug.

John


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## Longboy (Dec 18, 2015)

Yes! Good job John on troubleshooting the start up issues. We'll have Brian send you a check for a job well done!  On one of the second hand carburetors on an engine I used had the same loose throttle problem. I used a light smear of 5 minute epoxy mixed about 1: 1/2 and put it on the barrel and turned back and forth as it dried to a soft sticky. Enough to open and close by hand but engine vibs don't move it any more.Thm:    Dave


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## simister (Dec 18, 2015)

Thanks Dave,  today I made a throttle handle with a friction screw joined to the carby, and it works quite well. I got the idea from one of Brian's posts where he did a similar thing. The epoxy idea also sounds like a good solution.

John


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## gus (Dec 18, 2015)

Hi John,

A MasterPiece by a MasterCraftsMan. I am very impressed with the hand start. Your Webster beat mine hands down.


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## simister (Dec 18, 2015)

Thanks Gus, There are plenty of imperfections when you look closer. I am just happy that it runs.

I will post a photo of the throttle mod later today.

John


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## simister (Dec 19, 2015)

This is the modification that I did as a throttle friction control. I got the idea from Brian's post.  Works well Brian,

John


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## Brian Rupnow (Dec 19, 2015)

AhHa--the old "Casey Jones throttle trick"!!! It does work well. I was afraid to try the two part epoxy trick on my carburetor, as I was afraid it might glue everything up solid.  I never thought to mention the con-rod hitting the side of the cylinder where is exits through the bottom of the cylinder as a possible source of "engine knock", although it has happened to me too. In my case it was easily solved by rounding the edges of a rectangular or square con rod to give that tiny bit of clearance needed. That is a tricky one, because when modeling it in 3D cad, if you take a cross section view on the center of the con rod it will show a clearance. It doesn't take into account that the cylinder curves upward on each side of the centerline and fouls the lower corners of the rod. ---Brian


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## pkastagehand (Dec 19, 2015)

Brian Rupnow said:


> . That is a tricky one, because when modeling it in 3D cad, if you take a cross section view on the center of the con rod it will show a clearance. It doesn't take into account that the cylinder curves upward on each side of the centerline and fouls the lower corners of the rod. ---Brian



Should be able to move the section view off center to near edge of con rod?  Seems like most CADs will let you take a section wherever you want?  (Not that I have a ton of 3D CAD experience and none at all with Solidworks; if that's what you're using.)

Paul


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## Brian Rupnow (Dec 19, 2015)

pkastagehand said:


> Should be able to move the section view off center to near edge of con rod?  Seems like most CADs will let you take a section wherever you want?  (Not that I have a ton of 3D CAD experience and none at all with Solidworks; if that's what you're using.)
> 
> Paul


Yes, I could do that---If I had thought of it---


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## pkastagehand (Dec 19, 2015)

Brian Rupnow said:


> Yes, I could do that---If I had thought of it---



Yes, of course; Hindsight is an exact science.


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## simister (Dec 19, 2015)

" the old Casey Jones throttle". I used to watch that series when I was a kid.

How long can the Webster run before overheating?

What are the symptoms and end result from running the Webster too long, apart from it getting very hot?

After I have run it for a short time it seems to get very hot.  Being only air cooled it must have some limitation.

John


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## Brian Rupnow (Dec 19, 2015)

If it gets too hot, it will gradually slow down and stop because of increased binding between the cylinder and the piston. If you are running cast iron rings, it may or may not "unseize" when it cools off. If you are running a Viton o-ring on the piston, then overheating is not a good thing, because apparently Viton releases some really horrible acid when it overheats and melts. I have been repeatedly warned by various doom criers that if any of my engines get THAT hot, that the melted o-ring acid will eat off my fingertips "right down to the bone!!!"---I'm not sure that I believe them, but I try and run some kind of cooling fan on my engines now.----OR---maybe nothing will happen. A lot depends on the clearances in the engine, the speed it is ran at, and the ability of the fins to radiate heat away as it builds up. The longest I have ever ran my Webster is about half an hour.


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## Cogsy (Dec 19, 2015)

Brian Rupnow said:


> I have been repeatedly warned by various doom criers that if any of my engines get THAT hot, that the melted o-ring acid will eat off my fingertips "right down to the bone!!!"---I'm not sure that I believe them


 
Viton o-rings are rated for applications around 400F and there would be a significant safety factor as well, so the chances of one melting or catching fire in a small engine would be very slim I imagine. 

However, when they do melt or catch fire they decompose into hydrogen fluoride. On contact with moisture or skin this becomes hydrofluoric acid - which boils at room temperature, dissolves corneas! and burns really badly. Check the picture of burnt fingers at the bottom of this link.

So it looks like everyone is right, they do work in engines and they will cause you severe injuries if they fail catastrophically.


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## Longboy (Dec 20, 2015)

Its unlikely that one would have any overheating on an air cooled model engine like Webster or others of similar types that are demonstrated in a fast idle condition even during one after another tankful runs. I have been all around my engines with an infrared thermo gun and at the cylinder head spark plug area the temps are hottest at around 270 Degs in a Tucson July day inside the garage. No issues but it gets hot enough to where WD40 smoke rises out of the exhaust valve guides. Enough radiator draws the heat from the cyl. heads and I am ready to call it a day after a tank or two in summertime here!

 On those fractional  displacement model airplane engines running 5 figure RPM's, they generate lots of heat. Overheating is abated not through radiator size per se, but massive airflow across the finning by prop wash.

As has happened to me, lack of proper lubrication in the fuel mix would be the #1 reason for hot engine stall and since the model is not usually under a heavy throttle load will just stop running without any damage to  metal or plumbing o-rings.


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## simister (Dec 20, 2015)

Ok, that explains a lot. This engine has stopped after 10 or so minutes of running. It may be that there is not enough lubrication in the fuel mix. I will give that a try and post the result.

I am also using Viton-O-rings. I took them out today for inspection and there was no noticeable wear in comparison with a new one I have on hand. So, they seem to be coping very well.

John


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## gus (Dec 20, 2015)

Cogsy said:


> Viton o-rings are rated for applications around 400F and there would be a significant safety factor as well, so the chances of one melting or catching fire in a small engine would be very slim I imagine.
> 
> However, when they do melt or catch fire they decompose into hydrogen fluoride. On contact with moisture or skin this becomes hydrofluoric acid - which boils at room temperature, dissolves corneas! and burns really badly. Check the picture of burnt fingers at the bottom of this link.
> 
> So it looks like everyone is right, they do work in engines and they will cause you severe injuries if they fail catastrophically.




Hi Al,

Thanks  for warning and advice.  I have no idea that Viton when subjected to prolonged hi temperature can be so hazardous. Will stick with C.I. Rings.Have no desire to worsen my eye sight with ''Glaucoma Right Eye''.. No worry. Permanent eye drops kept Glaucoma at bay.


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## Mechanicboy (Dec 20, 2015)

gus said:


> Hi Al,
> 
> Thanks  for warning and advice.  I have no idea that Viton when subjected to prolonged hi temperature can be so hazardous. Will stick with C.I. Rings.Have no desire to worsen my eye sight with ''Glaucoma Right Eye''.. No worry. Permanent eye drops kept Glaucoma at bay.



Same here i prefer cast iron piston ring due hi temperature. Never tried Viton ring in combustion engine, steam engine only.


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## simister (Dec 21, 2015)

I found that the spring on the intake valve was not strong enough. I replaced it with one that has two extra coils and it runs fine. I recognized the problem because I noticed small puffs of blue smoke coming out of the carby intake on the exhaust stroke. With the longer and stronger spring that has now stopped.

What is the most efficient way of setting up the ignition?  I am currently using a motorbike battery with a car coil. Has anyone found another or better way of setting this up? 

John


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## Longboy (Dec 21, 2015)

I see this listed in EBAY/AU.  Seems to be a new product will little Ebay sales now. I use a 3V vintage model engine coil with a pair of "C" batteries. They come up on Ebay every month. Coils from small gas engines like Briggs & Stratton  or a gas string trimmer are small and convenient sized too.  
http://www.ebay.com.au/itm/Spark-pl...056900?hash=item43e738a0c4:g:9pgAAOSwys5WVxNT


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## simister (Dec 22, 2015)

That unit off Ebay looks quite good. I wasn't sure if you could use a coil out of a brush-cutter or motor mower that was run by a magneto. I have seen a lot of Briggs & Stratton coils but they look like they require a magneto to run. 

John


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## Cogsy (Dec 22, 2015)

The switch that unit uses to actuate is a simple microswitch commonly used for limit switches. I bought a bunch of similar switches and was going to use one on the ignition of my Rupnow Hit and Miss instead of a hall sensor but I wasn't sure how fast such a switch could cycle and how many cycles it would perform before failing. I still have doubts about how durable the switch would be, and how may RPM it could sustain so I hope whoever developed this ignition has tested it and they are up to the task.


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## Longboy (Dec 22, 2015)

simister said:


> That unit off Ebay looks quite good. I wasn't sure if you could use a coil out of a brush-cutter or motor mower that was run by a magneto. I have seen a lot of Briggs & Stratton coils but they look like they require a magneto to run.
> 
> John


Ya, I guess thats true ..... with their coils wrapped around the flywheels. Motor bike coils next best bet.


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## kquiggle (Dec 23, 2015)

This discussion about ignition systems is much appreciated - there is a lot of info around on Webster building, but very little detail on the ignition system(s) used. 

I have seen at least one other build which used an electronic (Hall sensor) system. Nothing wrong with that, but my own goal in building my own Webster is to keep things as "mechanical" as possible - so points, coil, etc.


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## Brian Rupnow (Dec 23, 2015)

I have used both the auto ignition points and coil and battery, and the "modern" hall effect sensor and ignition pack with 4 small dry cell batteries. If you already have some kind of battery, either car or motorcycle, then the points/coil/condenser costs about $80.00 and is great for home use but not very portable because of the large battery required. That system is virtually "foolproof". The electronic ignition with Hall sensor , switch, and battery pack is over $100, is very compact and portable and is rather fragile. If you should test a sparkplug without having it properly grounded, then it blows the Hall sensor which is the heart of the system and quite expensive to replace. I have many engines, so I built a "power box" which is basically an automotive coil with wire leads and a ground strap mounted in a box. Each of my engines have their own points and condenser, with plug in wire leads (about a $30 cost). That way I only have to buy one of the 12 volt coils (at over $50 each.) Of course, it means I can only run one engine at a time.----Brian


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## 10K Pete (Dec 23, 2015)

Here is some interesting info on ignitions:

http://www.oldengineshed.com/ignitor.html

http://www.homemodelenginemachinist.com/showthread.php?t=17198

http://www.eldensengines.com/Otherstuff/LT Scope Pictures/LT Scope Pictures.html

http://www.old-engine.com/magign.htm

Pete


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## simister (Dec 23, 2015)

Thanks Brian for the info. I figured that the simple car battery and coil is probably the way to go. I already have that set up. I will now fit it up in a box with terminals, switches etc.

Also, Thanks Pete for those links. I will have a look through those before I finally decide, but, I think at this stage I will keep the method I am already using - nice and simple.

Regards John


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## simister (Dec 28, 2015)

Can anyone suggest another i/c engine to build? Brian originally suggested I build the Webster, and this was good advice for a beginner. 

I would like to build another engine as a step progression from the Webster.

Regards John.


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## Cogsy (Dec 28, 2015)

My first I.C. was an Upshur farm engine, which I think is about the same complexity as a Webster, then I built the Rupnow Hit and Miss. It's a little more difficult but runs well and has a cool set of flyballs swinging around. Brian's design and build thread is http://www.homemodelenginemachinist.com/showthread.php?t=21176

My finished version is here http://www.homemodelenginemachinist.com/showthread.php?t=23431 - although I had it running a lot nicer after that video was taken (I don't know why the pictures won't display, I haven't moved them).


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## simister (Dec 28, 2015)

The hit and miss looks really interesting. Did you have any problem getting parts?

I am not that familiar with the operation of the "hit & miss" so it would be a big learning curve.

Your video looks great. 

John


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## Brian Rupnow (Dec 28, 2015)

Simister--Although my engine was fun to build, it did require some special mitre gears and was a badly balanced engine. The next logical progression after the Webster would be the Kerzel hit and miss engine. It too is an engine built totally from bar stock, and the plans are (or at least were) a free download from the internet. The "hit and miss" mechnism that controls the exhaust valve opening/closing is a bit complex, but if you can build the Webster, then you can definitely build the Kerzel.----The engine itself is  a quite simple water cooled single cylinder engine.---Brian  (I have a build thread on it as well.)
http://www.homemodelenginemachinist.com/showthread.php?t=10091


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## Cogsy (Dec 28, 2015)

The engine is a bit out of balance, I would like to get it back and try my hand at drilling a few well placed holes in the flywheels to see if I could make a difference.

As for the parts, the bearings are off the shelf and cheap to buy, the valve springs I used came in a $8 200 part assortment from a hardware store and the only things I had to think about for a while was the mitre gears. In the end I pulled apart a $10 right angle drill attachment and the gears in that were almost spot on the correct size.

For another option, the Upshur farm engine plans give you 4 options to build for $10 + $3 postage - 2 horizontal and 2 vertical. They can all be built hit and miss as well and the plans are very easy to follow. The website is http://upshurengineworks.com/ .


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## simister (Dec 29, 2015)

Thanks Brian and Cogsy,

I will have a look at the Kerzel and the Upshur. 

Do either of these days engines involve building your own gears or carby?  With the Webster I purchased the gears and carby as I was not confident enough at this stage to build my own.

John


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## Brian Rupnow (Dec 29, 2015)

Just about all i.c. engines I know of have some form of carburetor. All but the Philip Duclos gearless have gears, unless they are a two cycle with no cam shaft. As a generalization, most of these engines will run with a purchased model airplane carburetor if you don't want to build your own carburetor. If you are going to seriously get involved with i.c. engines, then you should buy a set of gearcutters.


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## Cogsy (Dec 29, 2015)

The carby isn't something to be too concerned about, especially with a hit and miss model that doesn't have a throttle. I felt the same as you but both my engines ran better with my home built carbies than my RC carbies.

For both the Rupnow and Upshur engines I used a simple home made 'hob' to cut the gears. If you've got a rotary table / dividing head acceptable gears are fairly simple to make. Full info on making your own hobs is at this link.


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## Blogwitch (Dec 30, 2015)

Just a little reminder about alternative ignition systems.

A few years ago I built the prototype of the 'Minimag' (now renamed as the 'Falcon') to prove it's new concept, after the Minimag was updated with new types of magnets. A fairly easy build, and it works perfectly.

http://minimagneto.co.uk/Products.php

This is a video of my Minimag (Falcon) running a Webster to prove it's concept and show that it can be run by a small engine. My Minimag is destined to run a full sized R&B engine.

It can be swapped over to different engines very easily, so even though fairly expensive initially, it pays for itself in the long run and of course, no batteries required at all. For multi cylinder, just swap over the easily made cam with more lobes on it. A fully self contained ignition system.

[ame]https://www.youtube.com/watch?v=8r9ivpUR0T8[/ame]

The same Webster engine using standard type ignition system.

[ame]https://www.youtube.com/watch?v=jeRE8SoxStU[/ame]

If anyone is interested, I do have a PDF that shows exactly all the machining sequences for building a Minimag magneto.


John


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## Jyman (Dec 30, 2015)

Hey blogwitch,

I would love to see the pdf of it

Jon


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## simister (Dec 30, 2015)

Ok, this will be a new learning curve. I have a rotary table, so, would it be advisable to purchase a set of indexing plates? 

I had a look at the link for the hob also. It is all a little confusing until I learn some more about it.

John


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## Cogsy (Dec 30, 2015)

simister said:


> Ok, this will be a new learning curve. I have a rotary table, so, would it be advisable to purchase a set of indexing plates?
> 
> I had a look at the link for the hob also. It is all a little confusing until I learn some more about it.
> 
> John


 
Oops, I always assume having a rotary table implies indexing ability. You will need to be able to index so some plates would be a good investment.

The link I gave is sort of mid-way through the understanding process of the hob but shows the thing you're going to build. If you have a look at the site map on the right of the hob page, have a look at the section marked gear cutting. The involute page gives all sorts of background data, but the 'how it works' page really makes things clear.

BTW - The little 'flats' on the gears smooth out quickly as they bed in when running.


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## Blogwitch (Dec 30, 2015)

Jyman,

Here are the PDF's.

No plans are included as they are copyrighted, it just shows how I made every part of the magneto, but there are a few techniques in there that can be used on other things.


John 

View attachment Building_Minimag_Prototype_Part1.pdf


View attachment Building_Minimag_Prototype_Part2.pdf


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## simister (Dec 30, 2015)

Cogsy, that link explain it well.  

Is it worth buying an indexing head or is a rotary table with indexing plates just as good?

John


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## Cogsy (Dec 30, 2015)

I've only got a dividing head so I don't really know. I assume that as long as you can make the appropriate divisions and hold the blank steady then a rotary table should be fine.


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## simister (Dec 31, 2015)

Ok,  that's fine. I will get some dividing  plates and stick with the rotary table.

Thanks guys for your advice.

I have been doing a lot of googling on cutting gears and now feel more confident to make my own.

John


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## Brian Rupnow (Dec 31, 2015)

A rotary table with indexing plates is what I use for cutting gears. I have mounted a 3 jaw chuck on my rotary table, and the whole set-up works excellent. If you do buy a rotary table, make sure that you get one with two finished surfaces to mount against your mill table. That will let you use it with the output shaft either horizontal (as you would use it for gear cutting) or vertical for use when drilling a circular hole pattern  from above with the spindle chuck.


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## simister (Dec 31, 2015)

Thanks Brian,

I already have a rotary table. It can be mounted vertical and horizontal. All I need are some indexing plates.

John


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## VallejoSpeedway2 (Jan 17, 2016)

Where can I print some free Webster engine plans?

Steve


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## Brian Rupnow (Jan 17, 2016)

VallejoSpeedway2 said:


> Where can I print some free Webster engine plans?
> 
> Steve


email me at [email protected]


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## canadianhorsepower (Jan 17, 2016)

http://www.john-tom.com/html/ICEngines.html

webster and many more enjoy


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## kquiggle (Jan 18, 2016)

You can find links to Webster plans at the link below, as well as links to a lot of other Webster related information.

Go to the link below and scroll all the way down to the bottom of the page:

https://sites.google.com/site/lagadoacademy/machining---lathes-mills-etc/build---webster-engine


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