Upshur's opposed twin engine

[Gordon]

If you don't tell your son that you are feeling better maybe he will keep on mowing the lawn.

 

[Ghosty]

Brian,
It's good to see you on the mend. Don't try and do too much too soon or you will be back at the start again.
As Gordon has said, don't tell the son, maybe he will keep helping out.
Cheers
Andrew

 

[Brian Rupnow]

It seems to want to rain here every darned day, about mid afternoon. Can't cut the grass when it's wet or it all clogs up the mower deck. My good wife has asked me to show her how to run the garden tractor-----Tomorrow should be an interesting day.

 

[Brian Rupnow]

Felt really good today. Weather forecast is calling for rain every day for the next week. I decided to hobble out and start the lawn tractor myself---soon as I did it started to rain again. Cut the lawn anyways. Probably I felt better today than I have since the operation. My back is giving me Hell tonight, but the lawn looks good!!!

 

[Sparky_SC]

Nice picture ! I know you are feeling much better BUT no rodeo style riding the mower! ( with one hand in the air) Both hands on the wheel !

 

[Ghosty]

Brian,
It's always good to get out and do a bit after having work done on the body. Great picture.
Cheers
Andrew

 

[GreenTwin]

Looking good Brian !
Great to see you active again.
.

 

[Steamchick]

Welcome back to the land of the more-or-less able bodied older folk, and the younger fitter folk too! Doesn't matter how fit you are in this hobby. Just having your brain to support us is good! But looking forward to your next project as well.
Keep taking anti- inflammatories or whatever.
K2

 

[Brian Rupnow]

Today, five weeks after my surgery, I spent half a day working in my shop. It felt wonderful!!! As Jason had pointed out in an earlier post, the rocker arms weren't aligned very well with the end of the valves. This was a relatively simple fix, requiring two new rocker arm support posts to be machined with a 0.031" offset in them. This took me far longer than I had anticipated, but they are finished and they do look better.

 

[Ghosty]

Brian,
It's good to see you back machining parts again, take it easy or you could be back where you started.
Cheers
Andrew

 

[Steamchick]

Welcome back Brian. Take it easy, small steps at a time. (Short hours in the workshop). A healing body take a lot of the body's energy and resources, so rest is really necessary - hence the phrase "R n R". - "Rest and recuperation.".
K2

 

[SteamChEng]

That's great news, Brian! Welcome back to the shop! I'm glad you are feeling better and getting active again.

 

[Brian Rupnow]

Okay---It's 4:12 and I am officially whipped!! However---today I drilled and tapped both pistons for a wrist pin retaining grub screw. I machined the top and the bottom of the 4 crankcase plates while they were assembled to ensure a flat plane surface for gasketing. I Loctited the crankshaft gear to the crankshaft---it will get drilled tomorrow when the Loctite dries for a 1/16" cross pin which will be Loctited in place. I added the Viton o-rings to the pistons and re-assembled them into the cylinders.(this included machining a tapered lead in tool to compress the o-rings so that they weren't cut while the pistons were installed into the cylinders.) The cams have been mounted on the camshaft but are not yet Loctited in place.

 

[Brian Rupnow]

Today I finished the re-assembly, but due to changes in my flywheel placement, my filler spout for the gas tank would no longer fit. I thought about making new pieces, even designed a couple, but thought, Jeez, that will be a lot of work.--Then I thought--"I wonder if I can heat up the existing filler spout with the torch and bend it 50 degrees". So--out to the main garage I went, fired up the oxy-acetylene and proceeded to do exactly that. The results were great!!! After cleaning off the oxidization with a wire wheel in my lathe, and a goodly dose of J.B. weld on the threads, the gas tank filler now misses the flywheel and is also clear of the exhaust. I'm happy, happy, happy!!!

 

[Brian Rupnow]

Every thing I did this morning turned to crap!!! You can see by the pictures that my cam lobes stick out a fair long ways from the center of the camshaft (as per Upshur plans). As the crankshaft turns, the con rods have to be able to pass under the lobe of the cams. One did, one didn't---and I don't know why. They should have both cleared. Anyhow, I kept grinding and filing away on the rod that didn't clear (there's not a lot of room there) and by the time I was finished, I had buggered up both the con rod and the cap.---POOP!!! Now I will have to remake that con-rod and cap.

 

[Jasonb]

Have you timed the engine, quite likely they clear if they are positioned correctly relative to when the big ends come up.

EDIT

Adding up the sizes they should just clear anyway.

Crank throw 0.359
half Big End 0.328
Cam Lift 0.239

Total 0.926"

Distance between crankshaft and camshaft 0.937"

 

[Gordon]

I am not sure what the problem is with your engine but when I built that engine I found that if the cam hit the connecting rod the valve timing was wrong.

 

[Brian Rupnow]

I haven't timed the engine yet. I don't know if when the engine is timed the cam will be in a position to be hit by the con rod or not. I'd rather be safe than sorry, and it is supposed to clear anyways.

 

[Jasonb]

Can't you double check with your CAD, should be possible to simulate the 2:1 gears and turn the engine over on the screen. It will show what part you made differently or if it is just the timing which from Gordon's post it seems to be.

 

[Gordon]

This is from the original Upshur drawing. It hits if the timing is wrong.