Compreesion test

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S

smooth_criminal

Senior Member
Well i took the day off of work so i could figrue out what was going on with my car. Well i did a compression test and heres the results.

Cyl 1. 190
cyl 2. 70
Cyl 3. 180
Cyl 4. 195

So this means my rings are shot right? So now it's time to buy new pistons and rings right? Let me know what brand / model i should go with. I should buy rods while i'm at it.

I'm looking for a daily driver with 250 Whp.
B18b1
18g greddy kit
 
is it already running the turbo or not yet?

the low compression could be 3 possible things...

1. is your rings
2. is your valves
and 3. is your head gasket...

the easiest way to check is to put the motor at TDC and do a leakdown test, which basically means just putting air into the combustion chamber to pressurize it...

the pressurized air will be leaking from somewhere...
you wanna take the oil filler cap off, if the ait is coming out of there then its your rings... if the air is coming out of the intake then its your intake valves, and the same for the exhaust...

if you don't see anything from these three locations then it could possibly be your headgasket, then you wanna check your oil for any coolant and vice versa...

are you sure you got a good reading on cyl #2?
thats a really huge diffrence, and i;m guessing that there is a problem that caused it... if you are already boosted i would seriously look into your fuel supply before running this motor again...

edit: and if it is rings you're prob gonna want more than just pistons and rings... like rebuilding the whole bottom end, bored, honed, possibly sleeved but not necessary for 250whp...
def get the cylinders checked out by someone who builds engines...
 
Originally posted by reckedracing@Apr 18 2005, 12:48 PM
is it already running the turbo or not yet?

the low compression could be 3 possible things...

1. is your rings
2. is your valves
and 3. is your head gasket...

the easiest way to check is to put the motor at TDC and do a leakdown test, which basically means just putting air into the combustion chamber to pressurize it...

the pressurized air will be leaking from somewhere...
you wanna take the oil filler cap off, if the ait is coming out of there then its your rings... if the air is coming out of the intake then its your intake valves, and the same for the exhaust...

if you don't see anything from these three locations then it could possibly be your headgasket, then you wanna check your oil for any coolant and vice versa...

are you sure you got a good reading on cyl #2?
thats a really huge diffrence, and i;m guessing that there is a problem that caused it... if you are already boosted i would seriously look into your fuel supply before running this motor again...

edit: and if it is rings you're prob gonna want more than just pistons and rings... like rebuilding the whole bottom end, bored, honed, possibly sleeved but not necessary for 250whp...
def get the cylinders checked out by someone who builds engines...
[post=488314]Quoted post[/post]​
Click to expand...



Yeah it's already boosted. And your right i'm when i tyook the plugs out there were all white. I tested number 2 , 3 times so i'm thinking it was a good reading.
As for fuel i'm running rc310 injectors with a blue box. (I know shittly)
 
damn

thats sucks dude...

thats sucks real bad...

sounds to me like you rocked that motor...
damn, that fucking sucks...

did you get the injectors new?
did plug from cyl #2 look any diffrent from the rest?
you can try putting oil in the cylinder and doing another compression test... if it blows higher then its most likely your rings... oil helps boost the compression psi...

hopefully you just burned a couple valves or something...
that would be a lot cheaper than going into the bottom end...
 
Heres the deal, 96lx 4dr with b18b1 swap greddy 18g turbo kit with fmic. running rc 310's and the shitty ass greddy blue box. I'm throwing codes(miss firing in cyl.1,3 and 4)(not second?) I changed the plugs to NGK Brk7e gapped them at .3. Took the car out and the codes were gone for 5 min then they came right back. Checked the plugs and they were white ass shit. So i bought new ones. Check the coil it was fine. The wire, cap and rotor are new. Put the new plugs in started it up it was idleing for 3 min and the codes came back.
1. Waht should i check next?
2. What could it be?
Click to expand...


what codes are you throwing?
do you have an upgraded intank fuel pump?

what do you mean by misfiring?

how long did you run it with the blue box and shit?
did you know the compression of the motor before you put the turbo on it?

did you just buy this car? or was that someone else?
 
don't order shit until you rip it apart.

ordering new pistons when you have a cracked sleeve isn't going to get you anywhere...
 
Originally posted by reckedracing@Apr 18 2005, 01:11 PM
Heres the deal, 96lx 4dr with b18b1 swap greddy 18g turbo kit with fmic. running rc 310's and the shitty ass greddy blue box. I'm throwing codes(miss firing in cyl.1,3 and 4)(not second?) I changed the plugs to NGK Brk7e gapped them at .3. Took the car out and the codes were gone for 5 min then they came right back. Checked the plugs and they were white ass shit. So i bought new ones. Check the coil it was fine. The wire, cap and rotor are new. Put the new plugs in started it up it was idleing for 3 min and the codes came back.
1. Waht should i check next?
2. What could it be?
Click to expand...


what codes are you throwing?
do you have an upgraded intank fuel pump?

what do you mean by misfiring?

how long did you run it with the blue box and shit?
did you know the compression of the motor before you put the turbo on it?

did you just buy this car? or was that someone else?
[post=488326]Quoted post[/post]​
Click to expand...

1, Codes 71 , 73 and 74
2, No
4, I'm not 100% sure thats what the codes read mis firing in cyl 1 , 3 and 4. I'm guessing they mean detonation

5, About 3 weeks
6, Nope
7, I've had this car for about 3 year, Just swapped the motor in 2 months ago everythign was running 100% Put the turbo on like 2 / 3 weeks ago.
 
Originally posted by reckedracing@Apr 18 2005, 01:09 PM
you can try putting oil in the cylinder and doing another compression test... if it blows higher then its most likely your rings... oil helps boost the compression psi...

[post=488324]Quoted post[/post]​
Click to expand...



Just did this and the read was 150 so it jumped up does that mean it's my bottom and not the head right.
 
sounds like its not a valve issue...

ok, have you warmed the motor up to normal operating temp and then pulled a comp test?

be careful, it will be hot
lol
 
Originally posted by reckedracing@Apr 18 2005, 02:43 PM
sounds like its not a valve issue...

ok, have you warmed the motor up to normal operating temp and then pulled a comp test?

be careful, it will be hot
lol
[post=488385]Quoted post[/post]​
Click to expand...


No not yet, I've going to go running for like an hours. I'll do the test when i get back..
 
yea sounds like rings to me if oil in the cylinder bumped it up that much
 
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