Have an old Veco 50 that has been in storage for many years. It was never run much but now seens to have too much clearance between the rod and crank. Also the wristpin appears to have too much clearance. It seems to have good compression.

How much clearance is too much?

Odell

Some of these had what I would think to be too much clearance from the factory.

Enjoy,

Jim

Odell:

Your Veco was designed in the days of castor oil only. Get a fuel with at least 20% castor and enjoy the engine.

Bill.

New engine clearances were; conrod to crankpin .0015 -.002"; conrod to wristpin .001" + or- .0001"

Thanks for the clearance numbers. Have not measured mine but they appear to be much greater. I can feel and hear the looseness when the engine is turned by hand.
I can look at the crank pin and easily see the relative motion.

Odell

Pull the backplate. Pull the head.

Then rotate the carnk slowly while you hold the piston in one position.

IMO--if you can visibly SEE slop and play in the con-rod bushing; then it's too much.

I had a K&B 48 that I got with a plane I bought from a friend. He told me the engine was a POS. Luckily, it was cheap.

The con-rod had about 1/64" play in it. Engine would run 10 minutes and deadstick. It "knocked" at idle. Didn't matter how fat I tuned the needle.

I have an old Super Tigre S2000 on which you can clearly hear the conrod clicking at idle or when you flip the prop by hand... it has never missed a beat. it doesn't seem to matter that much.

Run your old Veco... if it fails: bummer... if it holds: have fun. There's not much more you can do about except making a new rod, but I don't know if it's worth that much trouble...

up to 0.003" in the lower end of the rod wont matter too much. New fits are 0.0015 ideally, but some engines are still 2, 2.5 or even 3 thousandths.

If the wristpin is that sloppy it will probably ovalise and cause grief before the lower end goes south... I agree. Get some Sig all castpr fuel and fly the thing

AJC