What rings to use?

[seahaul]

I have a 184 with lots of blowby, so wanted to install new piston rings. Pistons are marked 0.010 and cylinder bore measures 0.010 overbore. Cannot find 0.010 rings, so should I use standard rings or 0.020 rings and file to get correct end gap?

[tst]

before you buy parts you should measure the cylinders to see if it needs to be bored, .010 rings have not been available for years, standard are to small, .020 do not work well being filed down as they kinda lose there shape being squeezed in

[MiCarl]

To be done correctly the bores need to have six measurements made to check for out of round and taper. After that you can determine what size piston and rings will be needed after it's bored true and round.

Doing it properly takes a lot of practice. I let my machinist take the measurements then tell me which pistons and rings to buy. Then he measures each piston and machines the bore it will go in to an exact match. I do the end gaps at assembly.

[Gary Dotson]

If the bores truly measure well at .010 over, I, in disagreement with Tim, would not hesitate to use .020 over ring, filed to fit. Race engine builders have done this for years. Measure the bores as Carl instructed, if you have a bore gauge. If not, let a machine shop measure them for you.

[tnestell]

If the bores truly measure well at .010 over, I, in disagreement with Tim, would not hesitate to use .020 over ring, filed to fit. Race engine builders have done this for years. Measure the bores as Carl instructed, if you have a bore gauge. If not, let a machine shop measure them for you.

I seem to remember George Willer spoke about using this technique.

[Gary Dotson]

Yes he did but George used it as a band-aid for worm cylinders, with only moderate success.

[SamsFarm]

I know that if I had a tractor with +.010 bores that was within spec (and good pistons too), I would be using the +.020 rings made to fit as already suggested!

[outdoors4evr]

I bought one size bigger rings and filed them to fit. Just make certain there is some gap in the rings (.001-.002) when you are done filing.
They need a little space to expand with heat. The rings will shatter if you file them to fit exactly (no gap).

[ricky racer]

I bought one size bigger rings and filed them to fit. Just make certain there is some gap in the rings (.001-.002) when you are done filing.
They need a little space to expand with heat. The rings will shatter if you file them to fit exactly (no gap).

The end gap should be .011"-.012" each, or as specified by the ring manufacturer. The standard rule of thumb is .004" of end gap per inch of bore. If you're putting new rings in a worn bore, the end gap needs to be measured at the smallest point of the bore (usually at the bores midpoint).
If there's a ridge at the top of the bore, it needs to be removed to reduce the chance of the rings contacting the ridge and breaking the piston or rings.

[Gary Dotson]

All good advice, Ricky!

[seahaul]

Thanks to all for the advice. I think I have a better understanding now.

[outdoors4evr]

Ricky has it right. I had my decimal off.
I was shooting for .010 gap per ring. Most ended up a little loose .010.

[Duner]

I have filed rings to achieve proper end gap. Be sure to check ring at tightest spot.
You don't want them to bind.