New Rings for Old Tractor

[tinsnip]

He's a little reluctant to put a ton of money into the thing since he'll never get it back. So far it's been a labor of love. But he's got it stripped right down to the frame with only the tranny left to dive into. Pistons seem ok and otherwise pretty clean.

It's really my idea to put the new rings in since it seems unlikely it will ever be apart to this degree again in this century. He says he'll live with it if it burns a little oil, I just figure, what the heck, put in the new rings and then have no regrets once it's all re-assembled, shiny and better-than-new.

 

[Spiffy]

Makes sense to me! On those big bores, and the little it sounds like he'll run it; should work out great.

On smaller bores, I've seen new rings give less than impressive results and heard of [take 3rd hand info for what it's worth....potentially very little] it actually making for worse compression loss.

Sound's like he's doing a beautiful job on it! /forums/images/graemlins/cool.gif

 

[tinsnip]

Yeah, he's doing an amazing job. Each and every part has been removed and brought to good-as-new condition. Sheet metal is awesome! Very meticulous. That old JD still comes apart (with a little muscle and liquid wrench) after all this time. Very heavy iron! I'll get him to post some pics when it's done (even though this is technically not an antique tractor site).

Cheers!

 

[3RRL]

</font><font color="blue" class="small">( Yeah, he's doing an amazing job. Each and every part has been removed and brought to good-as-new condition. Sheet metal is awesome! Very meticulous. That old JD still comes apart (with a little muscle and liquid wrench) after all this time. Very heavy iron! I'll get him to post some pics when it's done (even though this is technically not an antique tractor site).)</font>

With that in mind, he should invest in getting the motor in top shape too. It would be a shame to have a super clean tractor with a crappy motor in it. He's almost there anyway.

 

[RoyJackson]

You really need to measure those bores first...or have someone measure them.
The gage to use is called a Dial Bore Gage. It's accurate to .0001". The measurement method 3RRL displayed will work well, but won't show a bell mouth (one end is greater in diameter to the other end) or an out of round (cylinder is ovaled) condition. You need to know that...either condition would probably require reboring the cylinders.

Soundguy had good advice...I hope you heed it.

 

[RobJ]

Since the bore is probably out of round a bit, especially near the bottom where oil wear happens (generally dirty air wear is near the top end), there is another option no one has mentioned. You can buy oversized rings, then file the ends as needed to get the proper ring gap. This gap is in all the manuals. Especially handy when not boring or replacing pistons. Also check the ring landing gap. Another wear spot on the pistons.

 

[tinsnip]

Update:

After reading all the good suggestions in this thread, i decided I had to forgo the surprise and outright ask him what will constitute a correct fit based on his most current measurements. When I questioned him about the bore size, this was his response:

"Found the bore checks I did. Not too bad for 50 years. Worst one measures 5.520, the other one 5.505. New they would be 5.500. (A sheet of paper is .003 thick)."

Based on those measurements, he's still comfortable with the standard ring sizes. He did express some curiosity about what you all would make of the measurements.

Thanks again!

 

[Soundguy]

the one that is .005 out doesn't bother me at all.. could even be an error reading. .. The one that is almost '7' sheets of paper out.. that one would concern me a tad.... How far out are the first set of OS rings?

Soundguy

 

[cp1969]

.010 taper is still quite a bit and will translate into the ring end gap varying by .031" depending upon where the piston is in the bore at any given time.

It usually isn't too hard to rebuild or find replacements for the cylinders. If you do that, and replace the bearings, this old tractor engine will probably be good for another 50 years.

Depends on what you want to do with it. If it's just for occasionally pulling a wagon or something and you don't mind a little bit of oil consumption, replacing just the rings might be the way to go.