SR20det redtop compression

[silversr]

I just ordered a longblock from jrautoparts and did a compression check, at first it was in the below 100 in all cyl but then I dropped a cap full of oil in it my numbers were 1.150 2nd 3rd and 4th cylinder were like at 128 to 130 psi, is this a bad sign? I don't think there should be that big of a difference in compression right?

[opponheimer]

Thats unusually low, oil will give u a higher reading.. The fact that the other cylinders are consistent and one is higher isn't terrible. I'll bet you 20 bucks that if you were to run that motor for a while, and test it under hot condition the number would be higher + more even.

Also did you have the throttle wide open when you were doing the testing? You need to.

[silversr]

I didn't open the throttle because I didn't think that would make a difference but I guess I'll do that tomorrow, I just bolted up the tranny and starter and thats how I did the test, the motor wasn't in the car.

[Realnez]

i got my sr block and did a compression test when it came. It was like

175 175 175 150

Put the motor in and ran it (runs so mint) and the compression even'd it self out. You get weird readings because most places put oil into the cylinders to keep it from seizing. Try throwing it in and running it, then do a comrpession.

[silversr]

I'm just going to replace the headgasket and have the head cleaned up a little bit, I hope it helps out a little because the only turbo I have is the gt2871r don't have the stock setup anymore.

[JDMClifford]

should be at 180 across all 4. put a dab of oil in every spark plug hole. then use some old spark plugs and burn the oil out when your done checking the compression. or go out and puy new plugs if you dont save your old plugs, whitch i dont know why you would.

[silversr]

180 seems a bit high, How would I burn off the oil if the engine isn't in the car?. I've been doing some research for the past 4hrs and people said that I have to have the engine warmed up, open the throttle(some say that I don't), put a little oil in the cylinders etc.. Well heres a pic of the valve train, looks pretty bad doesn't it?
http://i115.photobucket.com/albums/n290/blu24d/DSC00218.jpg

[lazierhobo]

honestly man, that thing looks pretty gross. could use an all around good cleaning.

[silversr]

I did another compression check again with the throttle open and it didn't do much, my numbers are 130,120,120,127, I don't know what to do now, the numbers seem real low to me.

[nrg]

your numbers are fine for being a cold motor. Putting oil in the cylinders to check will just comfirm if you have bad rings. get the head hottanked while you're at it.

[opponheimer]

Dude listen, the motor I had in my old coupe read 138 142 150 135 and it ran like a dream. I never replaced HG or anything. Actually ran a 12.90s on slicks.. But if you do replace headgasket. Get some arp headstuds and have your head checked and or resurfaced..

[Johny5]

Dude listen, the motor I had in my old coupe read 138 142 150 135 and it ran like a dream.....

http://grr.xoc.net/boxster/articles/f40.jpg

[silversr]

^ Haha, ran like a dream ha? I hope thats not your car burning LOL. but yeah I will go ahead and replace the headgasket and have the head worked on. I just wouldn't feel comfortable with the head looking like that.Thanks