Should I hone the cylinder and replace rings?

[asu4me]

I removed 2 cylinders for a camshaft inspection on my 1900 hr O360. The pistons were removed from the cylinders so the piston ring positions will no longer be the same if I were to install the cylinders with the same rings. Oil consumption was about a quart per 7-8 hours.

Should I expect higher oil consumption or likely plug fouling problems if I were to install the cylinder/piston with the rings not being in the same postion as before?

Fly it and watch it, or hone and replace rings now?

Jerry Kosirog
Mesa,AZ
RV-7A Firewall Forward

[rvbuilder2002]

Do you mean the piston ring gaps wont be in the same position, or you removed the rings from the pistons so they wont be on the same Cyl?

It is well proven that the ring gaps don't stay in the same positions... the rings often rotate on the piston, in operation, so that shouldn't be a concern.

Not to say the original rings wont still work if they stay in the same locations on each piston, and they go back in the same cyl they were originally, but it is standard practice to install new rings and hone the cyl.

It is a huge amount of work to remove and install 2 cyl once you have done the baffling, etc. Honing, plus new rings is not that expensive compared to the work involved (if you are paying for shop rate labor anyway).
If you are willing to gamble, and don't care about having to do it all over again if oil consumption is high, you could give it a try... but personally I wouldnt.

[asu4me]

Gaps won't be in same position. Rings will stay on same piston and installed in same cylinder as removed from. The gaps locations will be close, but not exactly in the same position.

Jerry Kosirog
Mesa, AZ

[rhill]

I'd plan on doing all 4 cylinders, Hone and re ring
rhill

[rvbuilder2002]

Originally Posted by asu4me

Gaps won't be in same position. Rings will stay on same piston and installed in same cylinder as removed from. The gaps locations will be close, but not exactly in the same position.

Jerry Kosirog
Mesa, AZ

Gaps don't matter. The rings rotate during operation so they never stay in one place anyway.
The big question is if you are willing to do the whole thing over again, if your gamble doesn't work out.

[rocketbob]

Why did you have to look at the cam?

[hgerhardt]

The rings are supposed to rotate as the engine runs. That's how they're designed. Reassemble it and don't worry about it.

Maybe you're thinking about 2-stroke engines. Some of them have small anti-rotation dowel pins in the ring grooves to prevent rotation, so that the ring ends don't end up in the side port of the cylinder.

Heinrich

[asu4me]

Rocketbob.. to answer your question about why I inspected the camshaft.. I bought a higher time engine removed from a Cherokee 180 that has been sitting longer than I thought it would be before mounting on the -7 I am working on.

Jerry Kosirog
Mesa, AZ

[rocketbob]

ok makes sense. In that case I would just put it back together and build on!

It is not a problem taking the cylinder off and putting it back on.

[asu4me]

Yes, but the pistons were removed from the cylinders. The concern is now I will have big time oil consumption and maybe plug fouling since the cylinder-piston-rings interface has been upset