I did a compression test today to see where my motor is at. Unfortunetly the numbers were hard to read on the gauge and my buddy is blind, i should have looked instead of cranking the motor.

#1 was about 160
#2 was about 185-190 the first time, the second time it was about 175
#3 was around 160
#4 was around 160

So any s2k specialist know if those numbers sound about right? And if the difference on the one cylinder is alright. My buddy said its fine if its within 10% of the other numbers. But i wanted to check with you guys also.

And i don't think the plugs have ever been changed, the car has about 69xxx miles on it, and they looked like they all had equal and regular wear, i plan on changing them anyways within the next couple weeks when i have spare time and cash.

What plugs would you recommend? ngks right? but irdium or twin prong, i think the 4 prong bosches are prolly not that effective anyways.

Thanks

 

FYI: cylinder 1 is at the front of the car; cylinder 4 is nearest the firewall. It matters when adjusting valves.

 

thanks! edit and fixed it

 

Variation among cylinders is probably more important than the pressure itself. One question, did you hold the throttle wide open (gas pedal to the floor) while testing? Failure to do so is a common mistake and will give you low, but consistent, readings.

 

nope, i had it in neutral and held in the clutch and pressed the engine start button for around 7 cranks. didn't touch the throttle

 

You should have the throttle to the floor when doing a compression test.

 

Correct. I should have stated that failure to hold it wide open is a common mistake. I'll edit that post to avoid any confusion.

 

I believe you have to remove all sparkplugs from the cylinders not being tested, and drop oil in all of them, for a better seal, just a few drops each.

 

You only put oil if you get a low number. If it reads higher with oil you have a worn ring.

 

thats what ive heard. Also i heard you don't need to give it throttle