Nemett Lynx 15 cc 4 Stroke I/C Petrol Engine

[Brian Rupnow]

Gus--I am always surprised how a person can breeze through all of the big engine parts with a fairly low degree of frustration, and at the end of a day have something really impressive to look at. When you get into all of the "fiddly bits" one can work all day, and at the end of the day have a surprisingly small pile of very unsophisticated little parts that makes you think "Gee---Is that all I done today??"---Brian

 

[doubletop]

Looking good Gus. The way you are going you'll get through those fiddly bits OK. The cams and valves are going to be interesting on your setup so spend a bit of time thinking about how you plan to tackle them accurately. Them and the fit of the piston are most important parts of the job. Pete

 

[gus]

Looking good Gus. The way you are going you'll get through those fiddly bits OK. The cams and valves are going to be interesting on your setup so spend a bit of time thinking about how you plan to tackle them accurately. Them and the fit of the piston are most important parts of the job. Pete

Hi Peter,

Thanks for the tip.
By now done two pistons for Webster and Rupnow and they were OK.
But I have no piston rings making experience. This is where I fear to tread.
The cams are so mini. This another fear. I am watching Paul Swifty doing these.Will monkey see, monkey do.

 

[gus]

Disaster struck today at 4:30 pm. After 14 years of drilling and tapping,I broke a tap and it just has to be a M3 Tap and of all the time to happen. Beyond extraction.
So move on and make another cam box.Lesson learnt---------dump M2,M3,M4 taps after 2 years service.M3 and M4 is frequently used.

 

[Swifty]

That's a shame Gus, but it's only a small part and easily replaced. You will make the next one in half the time. I'm already feeling nervous about making the piston rings, I think that I'm worried that I may split them when putting them on the piston, I better make a few spares straight away.

Paul.

 

[Brian Rupnow]

Gus--Make up a solution of Alum salts dissolved in water--as much as you can get to dissolve in it, Put in plastic container and soak aluminum part in it overnight. Keep the solution as warm as you are able without melting the plastic container. Overnight it will dissolve the tap and not hurt the aluminum.---Brian

 

[gus]

That's a shame Gus, but it's only a small part and easily replaced. You will make the next one in half the time. I'm already feeling nervous about making the piston rings, I think that I'm worried that I may split them when putting them on the piston, I better make a few spares straight away.

Paul.

Will need your good advice to make piston rings. Will make a couple more for insurance. The pistons I bought for Webbie and Rupnow engines were quite tough.
We did break some 15mm O.D. piston rings while repairing a 5000 psig compressor.

 

[gus]

Gus--Make up a solution of Alum salts dissolved in water--as much as you can get to dissolve in it, Put in plastic container and soak aluminum part in it overnight. Keep the solution as warm as you are able without melting the plastic container. Overnight it will dissolve the tap and not hurt the aluminum.---Brian

Good advice but Alum is a controlled chemical in Singapore. Need license to buy. I have just finished a blank. Will take about 2 hours to make replacement.
I have moved on.

 

[gus]

Took only 2 1/2 hours to make new Cam-Box but the fitting up wasn't done till 5pm. The slot hole is better looking than the last one. Cam shaft,shaft bearings,breather cap screw etc mounted on Outer-Head.

 

[doubletop]

Guys Don't stress about the rings. You've made the liner Ok and you've cut the fins in the head just combine the two processes and you'll kick yourself how easy the rings are. Breaking them is also easier than you think. I had similar concerns, made the rings to size and parted of 16 of them. Heat treated and gapped 8 and used 2. The rest are spares that will last somebody about 50 years if not longer. Follow Malcolms write up, including the heat treatment jig and you'll be fine. Pete

 

[gus]

Guys Don't stress about the rings. You've made the liner Ok and you've cut the fins in the head just combine the two processes and you'll kick yourself how easy the rings are. Breaking them is also easier than you think. I had similar concerns, made the rings to size and parted of 16 of them. Heat treated and gapped 8 and used 2. The rest are spares that will last somebody about 50 years if not longer. Follow Malcolms write up, including the heat treatment jig and you'll be fine. Pete

Thanks. Peter.

The sub-contract turner who made 3/4'' pistons for our high pressure compressors died five years ago. Just wish he is still around.

OK. Read,comprehend and download into my brains Malcom's method.

In about two weeks will make the P.Rings. Will be fun. Malcom has lotsa surprises for us. By the time we complete and run the Nemett-Lynx Engine,
hopefully Gus becomes 3/4 or fully baked in 4 stroke I.C. Petrol Engines.
Plan to build the Jaguar too.

 

[Brian Rupnow]

Gus--You're right---The cams are very mini. I just checked, and the cam for the Lynx is almost identical to the Jaguar engine. I just made my cams today, and after a bit of hassle they turned out okay, but my goodness, they are small. I suggest you have a read through my post before you start to machine the cams.---Brian

 

[gus]

Gus--You're right---The cams are very mini. I just checked, and the cam for the Lynx is almost identical to the Jaguar engine. I just made my cams today, and after a bit of hassle they turned out okay, but my goodness, they are small. I suggest you have a read through my post before you start to machine the cams.---Brian

Hi Brian,

Thanks. Will monkey see.Monkey do.

Paul succeeded making good looking piston rings.Piston ring making now no longer a black magic art.

My fishy mates decided to take a break to take their '' better halfs'' for Saturday Brunch. Spent whole day cutting/milling the tiiming case and disc. Profiling the Timing Case made possible with the DIY Rotary Table which is not quite completed. Some improvements required to done to take off the back-lash.
Crankshaft keyed with 3 M3 fasteners. Crankshaft now fittted in with a dummy prop chuck. CrankPin Needle Bearings just came in from ArcEuro. Con-Rod and pistons will be next to do.

 

[Swifty]

It's all going well Gus, I'm just about finished with the bottom half on mine, now working my way towards the top. I will probably work on the valves next.

Paul.

 

[gus]

It's all going well Gus, I'm just about finished with the bottom half on mine, now working my way towards the top. I will probably work on the valves next.

Paul.

Needle Bearings just arrived. Next week will be con-rod and piston. Followed by piston rings. Probably valves the week after. The cams will be fun. For now the cams maybe Webster and Rupnow type. I have no DRO. Cutting the cams the ''Malcom'' way just unthinkable w/o DROs. Will cross the bridge when I come to them. Neap Tide tomorrow.Will try the 70' deep rocky structures where good size Groupers lurk. Will be losing fish,line and sinkers. Success means big fish.

 

[gus]

The DIY Harold Hall Boring Head was meant to bore holes from 3/4------1 1/2'' I.D. The Con-Rod big end ''14 mm O.D. needle bearing'' means BH must be modified to bore this I.D. Spent 3 hours brain-storming and came up with ''add on'' adapter. No ''Bush Engineering''.
Trial bore was a success. Will mark out material for Con-Rod. This time will use Height Gage to mark 58.25 mm center-distance on Con-Rod.

 

[gus]

The Con-Rod took time to do. After two days ugrading Boring Head to bore 14mm I.D. Big plus one day(today) make fixture to profile big end and small end of Con-Rod. Will be tomorrow to complete.The Con-Rod required to fixtures.One to bore and the other to profile.

 

[gus]

The Con-Rod looks very simple but with my WW-1 Workshop Technology, it will be very basis skills. Jigs and fixtures required to finish up Con-Rod.
The crankshaft now have a Con-Rod to spin. Made DIY bushing for the big end needle bearing.Quite happy with the fit.Material was Grade 5 Hex Bolt.
Took three days to come this far.:rant:

 

[Swifty]

It's coming along nicely Gus, no work on mine today as we had friends over for most of the day, the friend was my foreman when I had a toolroom, a very nice fellow.

Paul.

 

[gus]

It's coming along nicely Gus, no work on mine today as we had friends over for most of the day, the friend was my foreman when I had a toolroom, a very nice fellow.

Paul.

Will be good to take a break to avoid burnt-outs. After finishing touches to the con-rod and crankshaft,will cut the piston. Then figure out cutting the piston rings and make the heat treatment tooling. I have Mapp Gas Torches.
Will be fun.