Coke Posted May 22, 2012 Report Share Posted May 22, 2012 As the title describes. I lost compression in cylinders 1,2,3....4 was fine. 1. 802. 1103. 1254. 135 I pulled the head and decided to do a head gasket job. Just got the new one on, torqued down with ARP studs this time around (bolts before) and now the compression numbers are lowish, across the board, right around 95 across. I then decided to do a wet test on cylinder #1 with 3 squirts of oil into the cylinder. I turned it over with the tester installed, and it bumped up to 120psi. Does this sound like a ring and/or piston issue? Or is it simply because the oil is displacing space inside the cylinder? I'm beginning to assume the worst....I'm going to need new rings and/or pistons. The cylinder walls are fine from what I could tell, looking at #2 and #3 (engine was set at TDC). No scoars or scratching going on. Real smooth like it should be. What should I do from here? Thank you! Justin Link to comment Share on other sites More sharing options...
Komeuppance Posted May 22, 2012 Report Share Posted May 22, 2012 Do a leakdown test before you pull it apart. If oil helped the compression, it's in the pistons/rings. My vote is still a busted ring land. -Robert Link to comment Share on other sites More sharing options...
RobH Posted May 22, 2012 Report Share Posted May 22, 2012 def ring related if your compression went up with oil if it were valve related oil would do nothing for it my bet is a leak down test will show air out the oil fill Link to comment Share on other sites More sharing options...
scott87star Posted May 22, 2012 Report Share Posted May 22, 2012 Or is it simply because the oil is displacing space inside the cylinder? What planet are you from? Stop trying to talk yourself out of the obvious, its time for a rebuild. 1 Link to comment Share on other sites More sharing options...
ESIrType? Posted May 22, 2012 Report Share Posted May 22, 2012 Cough cough...leak down test. Well on the bright side if you need rings PF is over a month away. Shawn Link to comment Share on other sites More sharing options...
Coke Posted May 22, 2012 Author Report Share Posted May 22, 2012 What planet are you from? Stop trying to talk yourself out of the obvious, its time for a rebuild. Excuse me, there is no need for the rude comments. This is a Virtual Mechanic topic. There may be a such thing as stupid questions, but what I said doesn't seem TOO far fetched. Give me a break. Like you've never said something that someone else might have found to be stupid. Getting back on track...I don't have, or have access to a leak-down tester. I feel that I've already located the problem anyway, with the wet test. This pretty much confirms the pistons and rings are going to come out. At this point, I'll just buy Wiseco 8:1's and be done with it all. Sending a PM to Dad tonight. Link to comment Share on other sites More sharing options...
StarquestRescue Posted May 22, 2012 Report Share Posted May 22, 2012 http://www.ebay.com/sch/i.html?_nkw=leak+down+tester A leak down tester is a tool that takes some practice to be fully able to interpret the results. Testers vary and there is always some leakage. This is an opportunity to see how your new tester reacts to a sick engine. Then when the engine is healthy again do the test again. This is how a base line for what is good and bad as indicated by one particular gauge on one particular model of engine is established. Link to comment Share on other sites More sharing options...
Chad Posted May 22, 2012 Report Share Posted May 22, 2012 could be valves, bent or burnt. The oil test usualy only works on rings though. Cracked rings are not uncommon on stock motors with above stock boost, or motors that have leaned out regardless of piston/age. Detonation can occur down in the ring groves and will blow upward on the ring lands and destroy them. Seen this in on forged JE's before, was caused by boost spike. Pulled down a few OEM motors with poor compression, all had broken lands and cracked rings. Link to comment Share on other sites More sharing options...
Coke Posted May 22, 2012 Author Report Share Posted May 22, 2012 I'm running stock/original pistons. Rings have about 20,000 miles on them, but they weren't gentle. I'll be forward about that. Link to comment Share on other sites More sharing options...
Chad Posted May 22, 2012 Report Share Posted May 22, 2012 oil in the combustion chamber can cause a diesel effect, so if there was excess blow by and boost, or problems with oiling in the intake from a bad turbo, you can cause an otherwise healty, propperly timed and stoich A/F ratio motor to detonate. Link to comment Share on other sites More sharing options...
Skullzaflare Posted May 22, 2012 Report Share Posted May 22, 2012 just out of curiosity, presuming you have a hydraulic head, have you bled the lifters?i dont see how you would LOOSE all compression in 3 cylinders, and upon pulling the head off and putting back on have low compression.i would attempt a lifter bleeding before going with the worst when you replaced the rings, did you get the block honed? also, long time no chat lol Link to comment Share on other sites More sharing options...
Coke Posted May 22, 2012 Author Report Share Posted May 22, 2012 Of course the block was honed when I replaced the rings last. I have mechanical tappets. Link to comment Share on other sites More sharing options...
Recommended Posts