Hey I did a compression test on my stock 01 ls and for cylinder 1 it read 200, cylinder 2 was 170, cylinder 3 was 180, and cylinder 4 was 190. Is this a good reading for a stock ls or is there something wrong? Thanks

 

You want all of your compression numbers to be close to the same, your lowest being 170 and your highest being 200 meaning you had a gap of 30psi between those cylinders which isnt usually good, but your auto manual should tell you what the maximum gap should be, I dont know off the top of my head.

However your compression numbers are pretty nice though.

Before you start modding it, Id start with a head gasket/ timing belt kit and your numbers should improve. unless of course its not just a wearing gasket causing the pressure gap, but with numbers close to 200 I doubt your problem is in the rings.

Just adding a head gasket to my car brought all of my cylinders to even compression numbers (use arp head studs)


EDIT: How long did you try to crank for each cylinder? 5 seconds? 10? Did you stay consistent across all 4 cylinders? It is important that you test each cylinder for the same amount of time.

 

Well my cars automatic so I'm not going to do any mods to the motor.. Also the time to change my timing belt and water pump are coming up should I just replace the headgasket then?

 

Well if I had my timing belt off I would go ahead and do the head gasket. But remember what I said, you might not have a problem. Check with a service manual (you can find one and read it at the auto parts store) and see what the maximum range between cylinders should be in psi for your engine.

Also did you try each cylinder for the same amount of time? if you hit 200psi trying to crank for 10 seconds and then 170 psi trying to crank for 5 seconds you might not have a problem, just need a retest. Any cylinder can build pressure if you keep trying to crank it for long enough just try and crank for 5 seconds on each cylinder if you redo it.

 

Well what I did was hear the motor click 6 times and I did this two times and still came up with 170.

 

Ok then you must have correct numbers. Do a search on how much gap is within spec between cylinders. I am sure it is more than 30psi.

 

Anyone else?

 

If your just searching for an excuse to rebuild your engine you shouldn't be building on it. Usually those builds end up unfinished.

 

I'm not im just looking for an accurate answer

 

I gave you one, your question was "Is this a good reading for a stock LS" and since you have a 30 psi gap max that is probably not a good reading. Because most engines only take a maximum of 14 psi gap between cylinders. You probably havent even searched, because just typing "b18 compression gap" in google the first link i found said that 20 psi was the max allowed between cylinders. So to get technical that means your engines compression is out of spec.

If you buy a $20 Repair manual it will tell you most of this stuff, and walk you through how to repair it

 

Thanks a lot

 

Sounds ok...yeah memorybox is right...within about 30 of each other should be just fine.

 

Well at school they told us it shouldn't be more then 15psi difference...But 200psi on a LS doesn't sound right to me, unless you read it wrong, have P30 or PR3 pistons in there, or it has tons of carbon build up on the combustion camber, and piston head. You should be around 175-185 psi.

 

There is a guide on team-integra.net that shows max expected psi per cylinder, some higher than 200 on some engines. All engines are different, my supra only could take 15psi per cylinders but bseries can take almost 30 psi

http://www.team-integra.net/forum/di...g+Common+Topic

 

http://www.team-integra.net/sections...ArticleID=1086



Sounds to me like you're right on the limits, you should be fine I would assume.