bmr89 Posted June 14, 2011 Share Posted June 14, 2011 Alright guys, i searched the forum for a few hours and couldn't find anyone that posted cylinder compression numbers for their L24s with E88 heads. Today checked all cylinders and this is the outcome. Front Engine 1- 110 psi 2- 118 psi 3- 119 psi 4- 110 psi 5- 119 psi 6- 120 psi Rear Engine I thought these numbers were really low and cant find the specs on where i should be compression wise. i have flat top pistons i checked, so i know i should be stock cp ratios. Could my valve seals all be shot? because it burns about a quart of oil every 3-4 weeks and is a daily driver. could the headgasket be leaking oil into the cylinder? Im just trying to narrow it down with opinions before i tear into her to find out for sure. It runs great still just burns oil and doest quite feel like it has the amount of hp it should have. Anyone with specs would be greatly appreciated. Thanks, Brandon Quote Link to comment Share on other sites More sharing options...
bradyzq Posted June 14, 2011 Share Posted June 14, 2011 Alright guys, i searched the forum for a few hours and couldn't find anyone that posted cylinder compression numbers for their L24s with E88 heads. Today checked all cylinders and this is the outcome. Front Engine 1- 110 psi 2- 118 psi 3- 119 psi 4- 110 psi 5- 119 psi 6- 120 psi Rear Engine I thought these numbers were really low and cant find the specs on where i should be compression wise. i have flat top pistons i checked, so i know i should be stock cp ratios. Could my valve seals all be shot? because it burns about a quart of oil every 3-4 weeks and is a daily driver. could the headgasket be leaking oil into the cylinder? Im just trying to narrow it down with opinions before i tear into her to find out for sure. It runs great still just burns oil and doest quite feel like it has the amount of hp it should have. Anyone with specs would be greatly appreciated. Thanks, Brandon It should be 170-185psi. Check cam timing/timing chain slack, maybe? The numbers are pretty even, so it may just be worn out. Quote Link to comment Share on other sites More sharing options...
neotech84 Posted June 14, 2011 Share Posted June 14, 2011 Did you do a wet test?? 1 and 4 are your lows. Pour some oil in there and see if the numbers improve. If not then all you are looking for is consistency, its not a pissing contest! Quote Link to comment Share on other sites More sharing options...
bmr89 Posted June 14, 2011 Author Share Posted June 14, 2011 yeah i havent checked the timing chain slack or anything like that and i havent done a wet test either, but if the valve seals are bad could that cause this low of compression readings? Supposively this engine had a rebuild 50k ago, so im trying to figure out if its the rings or the head thats an issue. If this helps, cylinder 4s spark plug is ALWAYS getting gunked up with a thick oily build up on it really bad, i have to remove it and clean it like once a week or 2. i dont think its a timing issue though, it starts and idles fine, and revs through the power band like it should, if the chain were to be stretched or worn, what side effects would i see? Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 14, 2011 Share Posted June 14, 2011 What kind/brand of compression pressure tester are you using and are you using the adapter that some of them come with? The adapters add volume to the chamber and will give a low number. I got 180 without, and 120 with the adapter. I also got about 135 with a different tester, the kind with the rubber nozzle you hold against the spark plug hole. There is a lot of variability in testing tools. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 14, 2011 Share Posted June 14, 2011 8.3% Variance between cylinders? In spec...move on...next! Quote Link to comment Share on other sites More sharing options...
bmr89 Posted June 15, 2011 Author Share Posted June 15, 2011 Newzed- im not sure what brand of tester it was but it had a 1 foot long rubber hose attached to it, makes sense it adds volume so it would have lower numbers with that tube being on there. so if the compression is correct, then maybe a headgasket issue letting oil leak from a galley into the cylinder 4? thats the only spark plug that looks horrible every time, the rest look great. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 15, 2011 Share Posted June 15, 2011 An oil control ring will not show up on a compression test. Neither will a leaking valve seal. Put one heat range hotter plug in there and hope it burns it off... You can buy a lot of oil for what it will cost to 'fix' what is nothing more than an annoyance. I went for years swapping plugs 5 & 6 in my car as #5 would oil foul. Put it in #6 and it cleaned right up. One day, after extended pounding at 17psi trying my best to kill the engine...the oil fouling stopped and so did my smoking on decel. The ring unstuck. It happens. Don't obsess on this one, move on! Quote Link to comment Share on other sites More sharing options...
bmr89 Posted June 15, 2011 Author Share Posted June 15, 2011 haha alright tony yeah i plan to just drive it while i build my l28 turbo on the side, then complete the swap all at once, engine, tranny etc.. Thank you all for your input! Quote Link to comment Share on other sites More sharing options...
z-ya Posted June 17, 2011 Share Posted June 17, 2011 If you need some hotter plugs I've got boxes of BPR4ES-11 and BP5ES-11. I'll never use them. Quote Link to comment Share on other sites More sharing options...
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