Compression Test with out Valve Cover?

[cookmeup272]

Can I do a compression test with the valve cover off and the engine not warmed up?

 

[romeen]

You can do it with the VC off but I don't know why you would want to. Unless the tester itself has a particularly long hose the gauge will probably be sitting on the cams and will get banged around when they spin and could possibly get wedged between the cams and the head with disastrous results. At the very least you'll have oil splattering on the engine.

The motor should be at normal operating temp for accuracy. If the motor is cold the test results will be deceptively low.

 

[Mrdrd_Laser]

My compression numbers were extremely low when I did a compression test without the engine being warm. Back in the day when I was a "nooooob"

 

[cookmeup272]

Yes i know they will be low but im not 100% sure if i want to start the motor atm.

 

[Mrdrd_Laser]

Yes i know they will be low but im not 100% sure if i want to start the motor atm.

What exactly is the reason you have the valve cover off?

 

[cookmeup272]

well i took it off a while ago to see if my head was torqued to spec and decided to swap out valve cover gaskets. The one that i bought that was supposedly for my car didnt fit right. But now i have the right gasket and all is good. Just need to finish up a couple other things before i comp. test it.

 

[fergulus]

Go ahead and put your valve cover on before you worry about it. it will take you but a couple minutes to get it back on, and you will not have to worry about being scared by low compression values. You need to remember that your engine needs to be at operating temperatures to get a good compression test for a reason. Metal expands as it heats up, which creates a better seal and is why you will get your actual compression values warmed up, versus lowered values cold.

 

[DyNamiC]

+1 for putting the valve cover back on. Its a quick job and will save you a HUGE mess of oil everywhere. Even if you need to take it back off its only a few minutes to do so. Its worth it just to be safe.

 

[xioca]

Do a leakdown test.

 

[cookmeup272]

Where is the MPI fuse located? Can i just unplug the injectors prior to performing the compression test?

 

[habitatguy187]

Where is the MPI fuse located? Can i just unplug the injectors prior to performing the compression test?

You could, but it's a lot easier to pull out the mpi relay, it's located on the positive battery terminal.

 

[cookmeup272]

Thats the thing haha the dude before me relocated the battery to behind the passenger seat so I am kind of lost...

 

[cookmeup272]

Ok so from what we read i have compression as follows...

155-cylinder 1
150-cylinder 3
150-cylinder 4
150-cylinder 2

Comments?

 

[rock1t]

Seriously?

 

[cookmeup272]

yes...?

 

[thatblondechik]

You have an 18 year old car with straight "15x" across the board...I wouldn't be complaining.

 

[dsmfa9nutter]

You're good to go. I'm rocking some low 120's with no problems. You're almost at factory fresh specs there.

 

[95fwdtsi18psi]

Wanna trade. 150s all the way across. Throw some of that good luck you have my way please!

 

[Lofty]

You're good to go. I'm rocking some low 120's with no problems. You're almost at factory fresh specs there.

Really? 120?
Your car was still fast when I last rode in it!
Mine was nearly 150 across the board, thanks mitsu!

 

[cookmeup272]

What is factory spec for a 1g? I know 2g's are like 180 IIRC.

 

[dsmfa9nutter]

2.0L turbo in a 1g dsm is 164psi stock. Non-turbo engines are higher.

How to do a Compression Test

Really? 120?
Your car was still fast when I last rode in it!
Mine was nearly 150 across the board, thanks mitsu!

haha Yeah man, that's a stock 130k mile shortblock in there until I get the ross/eagle together.

 

[cookmeup272]

Ok now that the compression is good, what would be the best plugs for my car? I have 4 brand new BPR7ES that i was going to put in my old car. Would the BPR6ES be better? How much of a difference?

 

[dsmfa9nutter]

Not much of a difference, toss them in and go.