What should I do

[85boostbox]

Going to be tearing into the e3ngine of my GLHT. Has a hurt piston. I am stuck in a snafoo and I really should know better. But I am second guessing myself. Ok heres my problem. Should I just pull the one piston/rod and replace just that bearing and rings. Or should I re-ring/bearing the whole lower end while I am there. I am one of those firm believers that what isnt broke dont fix it. BTW I am doing this with the block staying in the car. I am not dropping the crank out of it. I feel there is no reason too. Car has no knocks/oil pressure problems just low compression on cylinder 3. What do you guys think I should do???

P.S. Car will be going over to T2 status with ported head and intake and exhaust and probably on 16-18PSI with supporting mods. So no high HP application just a fun daily with a little track duty and auto-x.

[raccoon]

Id pull all 4 at least to measure, can you buy rings single? How much of a setback would it be to have to do this twice in a row?

[trannybuster]

did it burn oil, was it noisy, hwo did it run to start with? just serviced an engine that had the rings stuck on the pistins, but the bottom was in such good shape and the bores checked fine that I cleaned the ring grooves, deglazed cylinders then put back together with the same bearings (rod), 6 months later not one issues and it doesnt burn a drop. you can measure everything you need to while its apart....I did rering only because of the ring issue. All the bores can be measured with head off and the single rod/piston pulled you can measure the crank/rod clearance......its condition normally will be indicative of how the rest are

[RoadWarrior222]

Car has no knocks/oil pressure problems just low compression on cylinder 3. What do you guys think I should do???

Check for a bad valve before you go buying pistons

[turbovanman²]

If it ran ok and didn't burn oil, just fix the one cylinder, if it was a bit tired, just fix the one cylinder and rering the rest, its not much more hassle to do with the head off and oil pan off.

[contraption22]

I agree. Pull all 4. Peace of mind.

[zin]

Time saved isn't worth not having the peace of mind that you've got 4 good cylinders sealed up... IMHO.

Mike

[85boostbox]

I completely agree. It smokes once warmed up. It has low compression and you can hear it when it turns over. Skips a beat. Once started you cant tell though until it starts to smoke. I think it has a cracked ringland or a piston. Have to gget the head off to get the real extent of the damage. Also has real bad blow by. Like remove the oil cap or the dipstick and it smokes like a freight train out of it. I think Im just going to rebearing/rering it just for safe keeping. Mains should be perfect due to the fact that the thing has EXCELLENT oil pressure. Hopefully the damage is just limited to a piston.

[zin]

If the oil pressure is good, both the mains and the rod bearings should be OK, sounds like a new set of rings and it'll be in fine shape, assuming nothing more sinister awaits when the head comes off, but based on how you describe it running, I doubt you have any meanies waiting in there.

Mike

[85boostbox]

If it is the rings I would be jumping for joy.

[Lotashelbys]

Im gonna guess its a broken ring-land also. I would pull all 4 if I were you as just yesterday I was pulling a broken piston out of a 2.5 that had low compression in that cyl only. Just to say I did,I pulled the other 3 and 2 more of them had cracks in the ring-lands. Not totally broken off like the low compression cyl but they were broke. Sure glad I looked at all 4 now that I know that. Spend the extra 20 minutes and pull the other 3......

[85boostbox]

But I really have a feeling it is the piston as well.

[85boostbox]

Im gonna guess its a broken ring-land also. I would pull all 4 if I were you as just yesterday I was pulling a broken piston out of a 2.5 that had low compression in that cyl only. Just to say I did,I pulled the other 3 and 2 more of them had cracks in the ring-lands. Not totally broken off like the low compression cyl but they were broke. Sure glad I looked at all 4 now that I know that. Spend the extra 20 minutes and pull the other 3......

Oh yea I have decided to pull all 3. Hopefully no other damage due to these pistons are hard to find.

[85boostbox]

So ended up being cylinder 1. Pictures show the rest of the story. Bearings were PERFECT so I'm just going to do a re-ring/re-bearing.

[85boostbox]

[ajakeski]

Do it all. Why take it apart twice?

[zin]

No bore scoring? ... that's great! New rings and it'll feel like a new engine!

Mike

[turbovanman²]

Honestly, if the bearings look fine with no wear, reuse them. I do it all the time, saves money as bearings aren't a wear item unless you detonate alot or ran it out of oil.

[85boostbox]

Honestly, if the bearings look fine with no wear, reuse them. I do it all the time, saves money as bearings aren't a wear item unless you detonate alot or ran it out of oil.

I would do that but it is just a piece of mind with me. And no bore scoring. Still has cross thatching.

[turbovanman²]

I would do that but it is just a piece of mind with me. And no bore scoring. Still has cross thatching.

Yeah, some can't reuse them, lol, I have no issues doing that,