Lot's of air pissing past the piston rings. I only honed the cylinders...I never bored them which may explain all of the air leaking past the rings. I also ground the gap in the rings by hand. The rings were installed "as-is" but would bind up when they could not compress enough.
I'm going to order new rings and minimize the ring gap. If that does not work then I will have to make custom pistons (cast iron this time).
Also, I need a good source for custom fuel & water tanks for the Quadricycle.
Thanks...more coming soon.
Hi Chris
What did you set the ring gap to? I doubt a new set of rings and/or new pistons will solve the problem.
New rings are made to run in
round bores that are also
parallel. OK, not precisely round or parallel, but within acceptable tolerances.
As a rough guide, you will get away with bores up to say 0.005" out of round which is a bit like starting with the bores of a well worn engine. Much more and you start to get blow-by because the new round rings don't seat in the bore properly.
You might get away with the bore up to 0.010" out of parallel, but the rings and pistons won't be happy. Better if it is also within 0.005". The above is considered
very rough engineering when it comes to internal combustion engine practice. Luckily this is a slow revving engine...
As for ring gap, about 0.004" per inch of bore diameter will be ok. The ends of the rings should be carefully filed square to give the correct gap when the ring is placed in the bore.
But first, you need to measure the bores. If you are using a telescopic gauge and micrometer, you need to take 4 measurements working around the bore 45deg at a time. Write everything down. This will give you a fair (approx) indication of the roundness of the bores. Start just inside the ends of the cylinders.
Then measure at a point further down the bore, say where the water jacket weld is on the outside. And also at the crankshaft end of the bore. It's hard to imagine the cylinders being near round if they weren't bored and honed
after the water jackets were welded on...
Regards, RossG
radial1951
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