I am just looking for some advice.
A 1912 engine arrived Sunday, the owner said "It smoke and eat oil" and " the motor has been done 6 or 7 year ago and had never real power".
This morning I took it apart cleaned it and took some photos of the pistons and cylinders.
I put the pistons without rings up side down in the cylinders and measured the distance between cylinder and the piston, best was 0.20mm(0.008") and worst was 0.30mm (0.0118"). I Did the measurements at piston pin and at the camshaft side.
I know the block need new pistons but I wonder what oversize should I take?? Now the pistons are 0.020" over.
It is the first time I am working on a 1912 (March) engine. The brass screws to block the magnets on the fly wheel are secured with a safety wire is this the way it should be done in 1912? Should the screws be replaced while the engine is open? Are these the same as the later screws?
The rivets of the brake drum are a little loose. Can they be tied or should I replace them ?
The piston pin on the worst piston come over the piston core when moving it from one side to the other. Is this normal??
One of the pistons show there was something between the piston and the cylinder but I couldn't find any think. The piston was in cylinder 3 . The worst cylinder is number 1.
Thanks for your advice??
Sounds like it may need to be rebored for a new set of pistons.
Go to the next size rebore that would be just enough to even the cylinders up. Maybe no more than .040.
"The rivets of the brake drum are a little loose. Can they be tied or should I replace them?"
Tightening will not last. They need to be replaced.
I would replace the brass magneto screws and peen them, as per usual.
The ring gaps should never line up, if that is the way the piston came out. I notice that one of the triple gear pins has been hot.
Andre, I would have the machinist test bore the worst bore for .040" oversize pistons. If it cleans up at .040" then that will be the way to go. Should it need to go to .060" to clean up, I would have the block sleeved back to standard, and give the old girl a new lease on life. 1912 blocks are scarce, and a set of sleeves is good insurance.
Others will have different opinions.
Allan from down under.
Ring do rotate in service. I took apart one engine I had put together and 3 of the 4 pistons had the top rings with slots in close proximity to to each other. And I KNOW they were not that way when I put it together.
RE pin sticking out side ^, Unless the thrust on the rods is very worn it should keep the pin centered in the pistons. Of course if the rear main thrust is also really really worn that could change things some.
Sounds like a complete rebuild is need. Seems you got a few issues that are best solved by restoring the engine and transmission.
I think you need a new or reground camshaft to solve the " never had any power complaint." A good cam is the key to many engine power issues.
An engine with a worn cam can be revived somewhat by setting the valves by the K R Wilson valve timing method but will the engine will have noisy valves.