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Better worn piston longevity using skirt buttons ?

That engine sounds exactly my YJ right before I had to replace the piston. It started sounding like crap on the way home and was blowing smoke out the oil cap. The wrist pin had seized and gouged the cylinder with identical galling on the piston skirt you see in the video. You can see his wrist pin is seized as the rod isn't moving and the rod is discolored. The bad piston was .04 smaller in diameter than the good ones - a badly overheated piston will end up smaller after it cools down. I replaced the piston, honed the hell out of the cylinder wall and all was good for another 30k miles until I sold it.

Funny to note that the factory put half the rings on upside down.

It really sounds like a piston to me too. I am lucky so far that there is no blow by. I just put a quart of Marvel Mystery Oil in to see if that makes any changes. My SO thinks it's quieter. That piston noise in the rear is still prevalent.

I'll do a compression check here soon. Also, as soon as I repair my exhaust analyzer, I'll check to see if the head gasket is leaking combustion gasses into the cooling system.
 
In my 13 years with my 292,000 mile Wagonner, 87, (had 224,000 on the odo when I bought it), it made that noise a few times (maybe 3), in the very cold start up days here, but makes very little noise now. If it had been a serious piston issue, it would have persisted and gotten worse.

Mine was mostly noisy sticking lifters. And some noticeable wear in the valve train parts.
 
In my 13 years with my 292,000 mile Wagonner, 87, (had 224,000 on the odo when I bought it), it made that noise a few times (maybe 3), in the very cold start up days here, but makes very little noise now. If it had been a serious piston issue, it would have persisted and gotten worse.

Mine was mostly noisy sticking lifters. And some noticeable wear in the valve train parts.

I'd much prefer that the problems be in the valve train. Simpler to fix for me. But if I'm lucky, the engine will have a heavily worn piston skirt that I can add buttons too.
 
I'd much prefer that the problems be in the valve train. Simpler to fix for me. But if I'm lucky, the engine will have a heavily worn piston skirt that I can add buttons too.

Instead of experimenting, why not just replace the piston? A single piston is cheaper than the teflon rod you found.

I could see maybe on a racing engine that gets rebuilt after each race, but I wouldn't expect those buttons to last very long in a daily driver. Also ptfe expands about 6x as much as aluminum per degree temp difference. You'd need more clearance when cold.
 
I could see maybe on a racing engine that gets rebuilt after each race, but I wouldn't expect those buttons to last very long in a daily driver. Also ptfe expands about 6x as much as aluminum per degree temp difference. You'd need more clearance when cold.
It wont last long and is going to turn into a gooey teflon mess in his oil system.
But its his motor.
 
Don't forget that the skirts have to be machined. You would have to really watch getting the piston to piston balance screwed up.
 
Don't forget that the skirts have to be machined. You would have to really watch getting the piston to piston balance screwed up.

Not only this, but I'd think that the machining process on an already worn/weakened skirt would invite premature catastrophic failure.

These engines run for a long time noisy. Noisy pulling into the driveway beats quiet getting towed home....every time.
 
These engines run for a long time noisy. Noisy pulling into the driveway beats quiet getting towed home....every time.
+1

Totally agree, my last xj ran for 40k miles with a cracked skirt making plenty of noise before finally coughing out the piston.

My $.02... fix it right, or don't take it apart.
 
Did a dry, cold, compression test today. Total spread was 13 psi, which is around 10%. Not terrible for almost 200k miles.

1 135
2 126
3 131
4 126
5 122
6 132
 
Instead of experimenting, why not just replace the piston? A single piston is cheaper than the teflon rod you found.

I could see maybe on a racing engine that gets rebuilt after each race, but I wouldn't expect those buttons to last very long in a daily driver. Also ptfe expands about 6x as much as aluminum per degree temp difference. You'd need more clearance when cold.

I was in R & D for decades. Experimentation is normal for me.

The 500 degree teflon is only $15. I'm not opposed to putting in a new to me, used piston. But that would be a second choice.

The fellow's buttoned pistons that are inspiring me, have 400k miles on them, so far. If I got 5% of that mileage on a quiet modified piston, I'd be happy that the experiment proved the concept.
 
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Whew! Then I must be on the right track! ;)


It's not like this has never been done with success. I'm just skeptical whether it's worth trying on a piston that's likely already damaged. Do post back after you start tearing down. I'm curious what you find and how the experiment goes.
 
As long as you go in eyes wide open, let us know how it turns out.
 
It's not like this has never been done with success. I'm just skeptical whether it's worth trying on a piston that's likely already damaged. Do post back after you start tearing down. I'm curious what you find and how the experiment goes.

Who ?? Where ?? I only found one guy online doing buttons with new pistons. If you know of someone doing it with used pistons, I'd like to talk to them.

It does depend on how damaged the piston(s) is. If it's not cracked up to the rings I think buttons will hold up well.
 
Who ?? Where ?? I only found one guy online doing buttons with new pistons. If you know of someone doing it with used pistons, I'd like to talk to them.

It does depend on how damaged the piston(s) is. If it's not cracked up to the rings I think buttons will hold up well.

I didn't find anyone retrofitting used or damaged pistons.

I was doing a little googling and found posts about guys talking about drag racers using them when they oversized the bore to let them run the original pistons. The buttons took up the slack and helped with the aluminum piston expanding faster than the bore.

I think I saw the one you were looking at where hes said he had 400k on the engine and it got rebuild every 150k (kilometers no miles).
 
I didn't find anyone retrofitting used or damaged pistons.

I was doing a little googling and found posts about guys talking about drag racers using them when they oversized the bore to let them run the original pistons. The buttons took up the slack and helped with the aluminum piston expanding faster than the bore.

I think I saw the one you were looking at where hes said he had 400k on the engine and it got rebuild every 150k (kilometers no miles).
The drag race motors they are using those in are a whole different breed and have some crazy expansion going on.

As for using them in a new motor. If its built to tolerances there should be no reason to increase drag and heat.

At least the op recognizes its an experiment and some degree of failure isn't going to be tremendously dissapointing.
 
I didn't find anyone retrofitting used or damaged pistons.

I was doing a little googling and found posts about guys talking about drag racers using them when they oversized the bore to let them run the original pistons. The buttons took up the slack and helped with the aluminum piston expanding faster than the bore.

I think I saw the one you were looking at where hes said he had 400k on the engine and it got rebuild every 150k (kilometers no miles).

Thanks for making the effort.

New heads every 150k. That's a stout motor. 400k on the buttons shows the utility of buttons for street usage.

Using buttons on pistons in an over sized bore showed me how they stabilized the pistons in the bores.

Going to get a few more things done on the jeep while I await the arrival of the teflon. I've worked out mentally the order of making one button so I don't waste material. 8 buttons per piston is a lot of buttons, and a lot of piston fitting to the bore. Gotta find my ridge reamer too.
 
None of us (to my knowledge) have tried suicide either.

But I have used many things like duct tape with good results. Good luck

I saw your posts on the Snapon forum. How has your mt2500 treated you? I want one for this renix jeep and my old dodge truck. Can you use the bi-directional feature for the Renix jeeps?
 
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