Did a compression test tonight, how'd my car do?

[habib_88]

Well tonight we pulled some spark plugs, disconnected the ingition and ECU (fuel system) and did a compression test on my car to see how heathly it was. from left to right (sorry i can't recall what cyclinder # is which) the pressure readings were as follows

180 - 173 - 165 - 180

Now consider, my motor does alot of racing for having 157k on it. And my valves really need a good adjusting (which i'm told can improve the reading) heck i dunno if the valves have ever been adjusted before. And I have minor mods really but that doesn't matter. I was actaully really glad the motor came out ok. Granted the 3rd one over that checked in a 165 is kinda low but i was told its acceptible. I'm gonna get a valve adjustment down the road and give it another shot see if it improves. I was actually really happy to see my motor is pretty heathly for its age...so maybe I won't swap quite yet Anyone else ever do one of these test? (i was told things like head work and cams will usually changed the #'s, so if you've got fairly stock internals i'd love to hear it).

[CRX586]

How much did the test cost?

[habib_88]

It was free my friend has a compression tester hehe

I think autoparts stores have ones you can rent maybe? Or even a garage or dealer could do one for you I think.

[crxlvr]

your third cylinder prolly has a small head gasket leak between it and 2, cuz of the lower numbers, but since the 3 is much lower, you may have blown piston rings in there.

[neonmike22]

I doubt it's a bad ring. I've been behind the car many times and it doesn't smoke at all. When the ring went bad on my charger, it smoked a ton at idle, and when it boosted it'd try to shoot the dipstick out of the tube! The compression on the bad cylinder read like 30psi.

I vote for the valves needing some adjustment.

[Bleebdat]

Habib: If you can get the test done again anytime soon, put a cap full of oil in the cylinders with bad #'s, if the numbers improve with the oil in there, its the rings, if not its either head gasket or valves. Also did you have Wide open Throttle while performing the test, if not numbers can mess up a little there as well.

Im interested to know how or if you relieved the fuel pressure. I was about to do a compression test on my engine the other day, and was going to just disconnect the fuel line from the filter and stick it in a cup. I later decided this wasnt the greatest idea and just didnt do it that day.

[habib_88]

Bleebdat: yea i could do the test again most anytime maybe i'll try that. The car barely ever smokes or eats oil (ok asides from a leaky oil pan gasket but thats besides the point). Also I didn't turn the motor on, I let the starter do the testing. This sounds hellish on the starter but most people don't know how insane my starter is (ask mike). Plus if it ever decides to die I get a new one free (long story). Anywho, I pulled the cap off the distrutor (hence no spark) and pulled the ECU fuse thinking that would kill off the car dumping unnessary fuel in the cyclinders (seemed to work also). If you really wanna kill your fuel PSI take the gas cap off thats the best and easiest way to relieve the fuel PSI. Like I said all those results were from the starter which is pretty damn consistant for the most part. Maybe this week i'll try the oil and report back to you. I have a theory the head gasket could possible have problems (just other little signs) but this well tell me for sure.

[neonmike22]

Habib's starter *is* insane. At the first autocross this season, a new mini pulls up, and as everyone is oogling it, habib's car is like 2 cars over. He starts it up (it makes this funky spaceship sound) and you see everyone look over. It was teh funnie! I'm pretty sure it can take whatever abuse he could dish out too.

Hehe I should be the expert on bad headgaskets. I've had 3 4cyl chryslers over the years!

[CRX586]

Habib, did you beat the mini? Would that care fall into the same category as your car?

[Bleebdat]

Thanks for the info Habib, Ill be doing a comp test today most likely then. Ill post results.

[crxlvr]

doing a comp test, you should only be running off the starter, not the engine. also you should remove all the plugs before you do the test, open the throttle to full open, and then run the test.

[Bleebdat]

OUCH!!!!!

Just got done with my test, the pain is still in me.
Timing Belt
Cylinder-180
Cylinder-30
Cylinder-185
Cylinder-95 double
Distributor

Later today I will do the cap full of oil thing to make sure its my rings, but im almost positive it is without even checking. In essence Im running on 3 cylinders. Once again .