I tried searching, i really have

[iliketocrash]

I've tried searching on google about how to do a compression check and all i find are people and articles talking about having one done and crap, no how to. I did find one that tells me how to do a "dynamic compression check" but it wasn't all to descriptive and overall didn't help me. I tried searching Nico but coulding find anything. There was even a thread where the title asked "how to test compression" but no one answered it. I tried to narrow my search by attempting to search for the exact phrase "how to check compression" but everytime i did the search it just found things that had "how", "to", "check" and "compression" but in no particular order! i tried using the AND stuff and just putting the entire phrase in parentheses but i don't get anything. Someone please help! I'm goin nuts. I've got the tool and my brother and my dad know how but neither have time to show me, (its been a month since they both said they'd help) but nothing! So please, i beg, please someone tell me or link me to something that will help me do a compression check and a leak down test. I'd really appreciate it. Sorry about the long *** rant but really... i'm goin nuts.

[andrave]

lets see, IIRC, you take the spark plugs out one cyl at a time (and I believe you unplug injectors too) and crank engine over a few times.

[Wreckless]

Get a Compression test kit at any autozone or Checker or whatever auto parts store you fancy. It should resemble a pressure gauge on a line that is threaded into a spark plug hole.Drive your car around until its FULLY warmed up.Then park it and pull all of your spark plugs, taking care not to let anything fall into the motor, start with one cylinder thread it in tight as hand tight can be to ensure a good seal, and crank the motor with the starter until the gauge isnt rising in pressure anymore, then move onto the next cylinder, etc. until you are done. Anything less than 130 pounds of pressure is something to worry about. Having a buddy help makes this a lot easier too.

[themadscientist]

Don't forget to disable the fuel system so you don't flood the cylinders with fuel and wash the oil off the cylinder walls, pulling the relay and starting the car till it dies works. Also ensure that the throttle is held wide open otherwise you will get incorrect readings. besides the readings as they relate to spec pay attention to how they relate to each other; one out of whack or two neighboring cylinders posting low figures is bad juju, they should be close to each other whatever they are.

[float_6969]

As per the FSMwarm up the car to NOTpull the fuse in the relay box by the batteryStart the car and let it run till it diesCrank over a couple more timesremove all spark plugsinsert tester in to #1 cylnderDepress throttle and crank engine untill pressure stablizesrecord resultrepeat with other 3 cylndersIf any ONE cylnder pressure is low add a SMALL amount of oil to the cylnder and retest. If the compression improves, then the rings may be bad. If it doesn't improve, it may be a bad valve seat. If any 2 adjacent cylnders are low, there may be a leak in the headgasket. All cylnders should be withing 14psi of eachother. No cylnder should be less than 140psi. Hope that helps!

[iliketocrash]

well i need to do the compression check to my front clip that i got... so i guess i need to find myself a fuel pump and a bucket of gasoline. thanks for all your help guys.

[slw240sx]

you can try it cold, but make sure the motor has oil in it, even if its coastal 98cent crap. .. .

also my compression test was 135.135.130.130 then i added some oil to the cylinder hole. 175.170.~.~ didnt need to see tha rest i now my rings are blown and i have the beater comming very soon so its motor buildin time. now see my latest thread TMS and the rest of you and help me out some! Dee i need your advice man.

[iliketocrash]

couldn't you just put in new rings and maybe bearings while your at it and be good to go? or do you really want to dump all that money into building up the engine?

[slw240sx]

i want to dump all my money into the motor, then onto the suspension and rollcage then i will go wreck it

[iliketocrash]

i want to dump all my money into the motor, then onto the suspension and rollcage then i will go wreck it

hey, that's how i do things too! so far i've wrecked my '84 200sx then my 91' 240sx hb and then my '94 mitsu eclipse gsx. So i'm hoping the third was the last.

[float_6969]

Anyone know how much difference it would make if the motor isn't warmed up? I tested the compressoin in my clip last night, but I had no way to warm it up. Mine came out to 143.147.147.145, but like I said, that was cold. Anybody think it will increase once it's warmed up?

[slw240sx]

maybe 3- 5psi, those numbers arnt too bad, mines in at 130, factory manual sayd lowest usealble number is 142

[float_6969]

Yea, I looked at the FSM, I was just hoping for higher #'s. From what I could see down through the sparkplugs, the pistons have alot of Carbon on them. I may rebuild this motor. Hmmm...