cracked91

I was having major fouling issues with 2 of my cylinders, with the spark plugs drenched in oil. Both cylinders were heli-coiled as well as 1 other, so I found a set of heads and am replacing them. But should I replace the piston rings when I do? The whole truck only had 95k on it, I don't know how the P.O. killed the motor so quickly. And if I do, how much extra work is that going to be for me? Any help would be much appreciated. Thanks.

874runnersr5

Well if your going to be doing the rings, youll need the cylinders honed.. at this point the crank isnt much more work to remove and then your right next to a full on rebuild..

MuddfreaksOffroad

like he said, you prob dont have to do the rings, you should do a compression check on all cylinders first, if you have no low pressure then your rings are fine. IF so ya replace them but if your doing that u might as well get the whole rebuild kit and do it all. Cuz you have to get the new heads refaced ( or checkd to see if they are warped ) and you also would have to hone the cylinders. so id do it all. OR go get a USED low mile engine???

MuddfreaksOffroad

also in order to get the pistons out you have to drop the oil pan to access the caps which since your there take out the crank check it over have it cleaned. lol AND if you have the money throw in some larger cams haha jp jp.

cracked91

But does the fouling mean the rings are probably bad?

budro

No. The oil could be coming in from the valve stems as well. The bottom end on the 3vze is usually gonna be good for a ridiculous amount of mile. I'd say for 250k+ pending being ran without oil or something like that, but if you have the time on your hands and the know-how then yeah why not. I am not entirely sure you can find out if your oil rings are bad with a compression test though it is not a bad place to start because if your compression rings are bad then that oil ring is bad too.

betelnut

Problem is, if the cylinders are all full of oil, that'll disguise bad rings on a compression check, make the reading higher than it would be if the rings weren't all gummed up with oil.

Comes down to a gamble: do the bottom end with the top end, and risk rebuilding the bottom needlessly, or do the top end only, and risk having to redo the cylinder head R&R if the bottom end's bad. Budro is right that the bottom end is pretty tough. If it were me, I'd just do the top end. If the bottom end really is bad, which is unlikely, then you've already learned how to pull the cylinder heads, and the bolts are already unfrozen, so it'll be fast.

MuddfreaksOffroad

or what you could do is plan on a top end rebuild and while your at it take the lower end in your local shop ask them if they can look it over to see if it needs rebuilt. Idk they might charge you but some places will do that for free.