Miles in Florida

I have had a comp XE-R 224/224 0.581/0.581 114LSA cam with Rev 1116 dual valve springs for about two years. About 2 months ago I was driving from Michigan to Florida, and a valve spring broke. The cylinder with the broken spring didn't hold compression (I assumed because of a bent valve), so I took the head off and sure enough, there was a smiley face staring out of the piston at me Wasn't really deep, I've seen people post pics of valve cutouts bigger than that, so I was still hoping for the best.

I had the head cleaned up (valve and valve guide replaced), and the guy who did it said to check if the rings are okay by pouring a 50/50 mixture of mineral spirits and transmission fluid into each cylinder, and waiting 5-6 hours to see if it drained any quicker out of the cylinder with the piston that got smacked by a valve. I've done so, and within 30 minutes, the 0.5" of fluid is gone from that cylinder, but no others.

Is this test legitimate? Is there any chance the rings are okay, or is this pretty definitive? Anything else I can do to see if the rings on that cyl. are okay besides tearing the motor down? I have no reason to think this test isn't reliable other than (perhaps irrational) hope...

I'm not gonna fix it myself if the rings are shot, I'll either pull the engine and take it to a shop, or maybe buy a long-block and install it myself.

Thanks,
Miles in Florida
(used to be Miles in Michigan)

Redlinez

iTrader: (5)

Sounds legit to me. Mine broke two valve springs in the last 7 months, but I guess I got lucky. Losing fluid in that cylinder and not the others sounds like an accurate assumption that cylinder ring is done. If you have the money, get you a built short block and heads of your choice, since you pulled your heads off. Save some money and do it yourself. That sucks BTW>

Miles in Florida

Don't know why I said "dinged pistons" in the subject, it is just the one piston.

Car is a 99 C5, stock heads. Only engine mods were cam, Rev 1116 valve springs, matching spring seats from Andy at A&A, TI retainers, chromemoly pushrods, dual roller timing chain, ported oil pump, long tube headers, and ls6 intake manifold and PCV system.

- Miles

ZR2877

How many miles were on the springs when the one broke?

Louis

iTrader: (7)

I dont see how tapping the piston has any relation to the sealing of the rings.

Buff and deburr that piston and put it back together

Missed shifts with 8500 overrevs with nasty dings in the pistons still resulted in 180-190 cranking compression if you want real world data

coop5885

iTrader: (2)

why wouldnt you just do a leak down test to see if the rings are OK? Alot less time consuming. And you wont have to put anything in your motor.

Miles in Florida

I don't either, but the crazy old coot who's been building engines since before I was born and who fixed up my head, was very specific about using a 50/50 mixture of mineral spirits and transmission fluid to check for if the rings are still good after the valve hitting the piston. And then when I did it, the fluid only drained out of the one that the valve hit the piston on, and it drained within a half hour. Same thing when I took the head off and coolant got everywhere. The other 3 cylinders had coolant in them for days (until I sucked it out with a shop vac), the other one the coolant drained past the rings in a matter of hours. Hence my post here, because I'd really like to believe my heads are okay.

Miles in Florida

I tried using compressed air to hold up the valve so I could get the spring off before I pulled the head, and the valve wouldn't stay up, which I assumed was because the valve wasn't seating right. So now I've already got the head off, and was told that the mineral spirits/tranny fluid will tell me if the rings are good, before I put it all back together. If it passed this test I would have put the head back on and then done a compression test, but since it failed it I want advice on if it's conclusive proof the rings are bad on that cylinder, or if I should put it back together and see what happens.

Thanks,
Miles

Redlinez

iTrader: (5)

Sounds like the heads are fine, you had him repair those right? I wouldn't put that engine back together from the sounds of it. You might want to contact one of the sponsors to the right, I would think that piston needs to come out.

LSonederfull

I would clean and assemble motor , leak test cylinder with rockers off affected cylinder. Readings around 10% are fine, as for mineral spirit test this could be wrong because if rings were lined up to each other cylinder would fail that test when ring seal is actually fine, understand?