MTFCA Forum

I have a block that the wrist pin has damaged the cylinder. Does anybody have any experience with this? Did it work out to sleeve just one cylinder or did you have to do them in pairs since there so close together? It is already 40 over and I would like to stay with that. The other cylinders still have hash marks in them.

Just the one can easily be done.

I have done it in my shop 100's of times on Model T blocks over the past 50 years with no issues. Send me an email to kprus@zoominternet to discuss.

FWIW, if the car was not burning oil before, it won't after. That said, I'd never leave damage like that on a rebuild for anyone else, but knowing that the car didn't burn oil, and it was my car, if it was a fresh-up and the babitt was staying in place, I'd consider leaving it alone. These things can have damage from wrist pins that looks fearful and run fine and not even lose measurable compression between cylinders. I'm running such a car now, and both it and I are very happy. On the other hand, If it is a full-on rebuild, you might as well fix it with a sleeve.

This is after a light hone

I lean toward Scott's thinking.
That looks insignificant. How wide is it. Ring gaps are .018+

You should check all the other too.
Few years ago the pins were not made right, too long. I have not seen that lately, but you may an older set of pistons.
I still check each set I install.

The rest were okay, this engine was built in 1989. The pins in all of them seem to be long to me. I have a new set coming.

I'm also with Scott. On a national tour in 2004 we had occasion to replace ahead gasket for a participant, and this revealed a far deeper score in one bore. The owner didn't know about it, wasn't concerned about oil burning etc with the car, so it went back together so he could finish the rally. Fast forward 14 years and many tours later, and that cylinder will be repaired when the transmission is rebuilt.

Allan from down under.

What was the bore size before honing? That will make a better determination on whether or not you need to sleeve the engine. You have a low oversize bore, you should be able rough bore it out the damage to clean it up then bore and then hone to the proper size for the next oversized piston size that's available, You'll have to bore the remaining three to the same size. Like Kevin, my Mid-Atlantic shop sleeves engines all the time, as/when needed.

TT

Something that wasn't uncommon back in the day of keeping an engine a runner was just fix what's broke, I've come across many an engine with just one or two cylinders bored. Ford Canada supplied single buy pistons and rings in .1.2.3.4.5.10.15.20.25.30.33.35.40 and 45 thou O,S

Like Scott C I say run it! Many years ago, a very good friend reworked a model T engine that had had a bent rod which wore a wrist pin in a lot deeper than that! We were wanting to get his car together for a meet that weekend, so after a few moments of consideration, put it together with the score and a good rod. The car ran so great the score was left in for several years and lots meets.
We checked the compression once, found no significant difference.

If that isn't good enough? Through a long bizarre set of circumstances, I reworked a modern V8 for the 1965 Ford pickup I drove for work for seventeen years. Circumstances forced me to delay the work, then forced a rush job on the motor. When I got into it, with all the parts I was planning to replace and needing to get it done ASAP, I discovered some cylinder damage in one cylinder, the other seven looked excellent and standard. To get it sleeved, or bore one or all would have cost money and time I didn't have to spare. So I put that engine together with one scored cylinder.
Care to guess how many miles I got out of that engine? With NO work beyond tune-up and oil changes? Never pulled the head. Never pulled the manifolds, or the pan.
No, guess again.
Higher.
The actual truth is I cannot say how many miles that engine went. The speedometer and odometer drive gear wore out and failed almost two years before I retired the pickup. I was averaging about 30,000 miles per year! I had run the engine for over ten years at that rate, and the odometer claimed 325,000 on the engine when the odometer quit. Plus the 50,000 or more after the odometer quit.
I may take short cuts occasionally. But I think I know how to put an engine together to last! And some minor scoring in one cylinder usually doesn't hurt all that much.
Oh, the engine was getting tired by then. But it still ran smooth. And I swear those numbers are accurate!

If the score doesn't extend up toward the top of the bore too far, it probably won't cause trouble. A score that extends into the upper bore can cause very hot gases at very high pressure to leak past the compression rings, which can cause problems, such as ring breakage or erosion of the ring groove behind the ring. Scores further down the bore do not cause these conditions since blowby past the rings at the score will be minimal and the gases will be at a much lower pressure and temperature. As for oil burning, a single scratch low in the bore in one cylinder isn't likely to pass much oil. Serious oil burning is usually due to worn rings combined with worn ring lands or scoring in the upper part of the bore(s).

I had a Chrysler 413 B engine that had a score much worse then that in one cylinder; I replaced the broken rings and put it back together. It ran just fine for several years until I sold it. I did tell the new owner about it. It burned a quart of oil in 1,000 miles. My other Mopar B engine - a 383, also burned 1 quart in 1,000 miles. I called Chrysler and they said that a quart in 1,000 miles was within spec. for the B engines.