hey I ran a compression test on the car today cylinders 1,2, & 4 were at 90 at idle and 150 at high rpm. now # 3 cylinder held absoutly no compression. now just to make shure im right #1 if the head gasket was leaking i would have lower compression in 2 & 4 correct?? ok now theroy #2 lets say that the person who put the pistons in didnt put the rings on correctly and aligned the gaps up instead of staggering them. if the rings were aligned than the cylinder would hold no compression am i correct on that?? and option #3 the valves in # 3 are jacked. I just would like some advice before i tear off the head and oil pan tto rip out the pistons to fix the rings. if its the valves im going to just pull the motor and replace it with a stroked B16 that i have. thank you for your inputs in advance.I finaly got the problems fixed that the shop messed up but the motor is still holding back after 4,000 rpm so I did a compression test and this is what i found. also does anyone know the equasion to figure out what compression pistons I have?? there supposed to be 8.5:1 but i want to be shure thats what theyre at so i dont grenade the motor when i put on he turbo. ok thanks again all.
Critter >:^)

 

2 adjacent cylinders showing bad compression numbers signifies a bad headgasket. 2 & 4 aren't even next to each other, so they have no effect on this; only adjacent cylinders. If the rings are aligned, it would still hold compression because only the first ring contributes to compression. The rest scrape the oil off the cylinder wall to prevent it from being burned. It would hold some compression this way but I would think that it would burn tons of oil. The reasons why it had no compression is either A) broken ring lands/cracked piston/cracked cylinder walls or B) you have stuck valves. Bad or aligned rings will still hold compression, so I think it may have to do with the valves or ring lands. For compression calculator, go to www.c-speedracing.com.

 

Compression test "at idle" & then "at high rpm"... How did you do that compression test??

 

i plugged in the compresson tester and started the car. my buddy read the gauge, than i pressed on the gas and let the car run up untill the engine started to struggle and than we shut her down.

 

ok shmoo ummm so do you think its worth the time to take the motor apart?? can i tell if a valve is stuck without taking off the head? and thank you for the compression calculator. i ran low compression in this motor so i could add more boost but with #3 not firing off I cant put the turbo on. another question if my timing was off enough would that cause the whole no compression thing?? like i said before the shop i took it to to have the car tuned ran my cam timing 180 out i thought i had it fixed but now isee that thats not the case. the car runs good with alot of power but boggs a little arround 4-4800 rpm than vtec kicks in and things even out the car kicks hard when vtec hits and everything runs smooth. so could this be timing or shuld i just pull the head?? or is it deffenatly somthing to do with a cracked piston or wall or rings??

 

Not with the engine running!

You're supposed to warm up the engine completely, shut it off, & disable fuel & spark. Remove all 4 spark plugs & put the gauge in one of the plug holes.

Hold the throttle wide-open & crank the starter for maybe 8 revolutions or until the gauge quits rising. Again in each of the other plug holes.

But... it's probably not gonna change the issue of having NO compression in one of them.

 

ohh woops well now i know how to properly do the compression test. im just going to throw in the other motor and stroke the old one and go all out with it itll be my extra untill i blow my first one or get sick of it. thanks for all the advice Im gonna go get started on the swapp ill let you all know how things go.