soulassasincc Posted July 3, 2008 Report Share Posted July 3, 2008 hey what is compression supposed to read per cylinder? im checkin it to make sure its all workin great and dont know wat the comp ratio is on our motor? Link to comment Share on other sites More sharing options...
Chad Posted July 3, 2008 Report Share Posted July 3, 2008 Stock motor, with stock 7.0:1 pistons, throttle plate full open, all spark plugs removed, engine warm, minimum 5 cranks per test: 140 is perfect, 135 is normal on a great running car 130 is good 125 is fair and quite common 120 is a bit low and shoudl be watched with any mods used 115 and low, but some have driven compression long term with out problems 110 and lower is pull it appart before you completely destroy it. I belive an 8.0:1 motor tests out about 13 PSI higher on average. Link to comment Share on other sites More sharing options...
vbrad511 Posted July 3, 2008 Report Share Posted July 3, 2008 I've been running about 95 across the board for quite a while now. She starts every time, smokes a little, but sure doesn't have the juice she used to have. Just gotta get the other motor in it one of these days. Link to comment Share on other sites More sharing options...
Indiana Posted July 3, 2008 Report Share Posted July 3, 2008 (edited) different gauges different readings Brandons car is higher than stock CR it runs about 165 give or take a few psi I'm sure some are higher than that, he's about at 8.4:1 Edited July 3, 2008 by Indiana Link to comment Share on other sites More sharing options...
shift1313 Posted July 3, 2008 Report Share Posted July 3, 2008 my motor on a stock rebuild stock CR cold was 135psi across the board so id say chads numbers are on the money Link to comment Share on other sites More sharing options...
soulassasincc Posted July 3, 2008 Author Report Share Posted July 3, 2008 thnx Link to comment Share on other sites More sharing options...
Wolf87Conquest Posted July 4, 2008 Report Share Posted July 4, 2008 Along with what numbers you get...it's important that they be witin 10% of each other...they are, you are good to go....if not, the engine will need a rebuild. Link to comment Share on other sites More sharing options...
boostandmuscle Posted July 5, 2008 Report Share Posted July 5, 2008 Along with what numbers you get...it's important that they be witin 10% of each other...they are, you are good to go....if not, the engine will need a rebuild. depends on alot of factors throughout the motor though.. is there something wrong with the valves? head gasket? head warped/cracked, piston rings s*** in one cylinder?? etc... theres alot of issues.. ive taking so many dsm's that i cant even count and replaced 1-2 valves or just one set of piston rings and it put it back to normal just fine .. just depends on hwo mechanicaly inclined a person is and what they are capable of doing Link to comment Share on other sites More sharing options...
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