compression test question

[sherms_gsx_tank]

ok so my car is smoking. blue smoke and it smells like oil and im losing oil so its obviously burning oil so i was reading in the other threads about that and i keep hearing that i should do a compression test and i know that im suppose to have a 7.5 to 1 and my question is if its lower on all 4 should i change the head gasket or what thanks a lot and sorry if some of you have to repeat your answer to me but i never read the answer in the other threads

 

[-silencer-]

Compression test will reveal the psi of each cylinder - not the compression ratio. You want all 4 cylinders to be within a few psi of each other and be able to sustain that psi. If a cylinder builds psi then fades after you stop turning the crank, put a capful of oil right in the spark plug hole to oil the rings and try again. If it's still fading it's showing a leak and you should perform a leakdown test.

If all 4 cylinders are below 133 psi, you've got a worn engine. It's up to you if you'd want to rebuild the engine with some overbored cylinders - at that point I'd go ahead and get some high quality pistons, rods, head gasket, valves, valve springs & retainers.

 

[sherms_gsx_tank]

ok thanks i was prolly going to rebuild it if it was bad. my uncle will be doing the test with me and hes been a mechanic for 20 years. and he use to work on dsm's too soo. but if i do the test and the internal life is still good what should i do then i just want to know before i get into it. and if i do have to rebuild it whats the most i can bore it out to

 

[-silencer-]

ok thanks i was prolly going to rebuild it if it was bad. my uncle will be doing the test with me and hes been a mechanic for 20 years. and he use to work on dsm's too soo. but if i do the test and the internal life is still good what should i do then i just want to know before i get into it. and if i do have to rebuild it whats the most i can bore it out to

If he's a mechanic let him do it with you - much easier to make sure you're doing everything right if you've got free help. If the engine is fine (preferably 145+ compression on all cylinders with a max difference around 5) then go ahead with replacing all of the following to ensure you don't have to do any of them again for awhile (this list is overkill for most purposes but I'd rather just get it all done at once):

spark plugs & wires [I'd go with NGK plugs & MSD wires]
all belts & pulleys and timing tensioner [ALL OEM]
all hoses (radiator, vacuum, brake, clutch, steering..)
all filters (air, oil, fuel..) [can upgrade to K&N FIPK air filter here]
all fluids (oil, cooling, transmission, brake, clutch, steering..)
brake pads

While you've got the belts off the car, replace these two:
oil pump
water pump

If you don't want to do everything here and just want the car running for now, just check the hoses, belts, and brake pads and replace if needed. Then just replace the spark plugs & wires, all filters and fluids.

Check for any signs of leaking gaskets - compression/leakdown tests, pressure test intake & exhaust.

If you rebore the engine, I wouldn't do as much as possible. I'd just bore as little as possible to go to the next piston size (.020" usually). If something happens down the line it'd be nice to have some room to go to .040".

 

[sherms_gsx_tank]

ok so i didnt get to do a compression test cause my uncle hurt his foot and my dad is still under doctors orders to not do crap. and i didnt want to do it alone but i did change my oil while i was down there (cant pass up a chance to do that with the lift its soo easy with that baby) and i put in that restore crap (www.restoreusa.com) and everything runs soo much better. theres practically no smoke the clutch engages smoother and the under car thump that happens in 1st and 2nd when ever i get on it is now gone. not to mention all the power is back. so i highly recommend it.

 

[Coup D E'Tat]

You really don't believe that all of those problems were solved from some miracle lube, do you?

 

[-silencer-]

You really don't believe that all of those problems were solved from some miracle lube, do you?

I'm in agreement here.. band-aids don't fix rings & gaskets..

 

[ZenTurbo]

To compression test get auto up to opearting temp.
Remove spark plugs.
Pull MPI relay from fusebox next to battery.
Attach compression tester into the threaded area spark plug resided
have friend turn motor over six times while you read the value on the gauge. 150-160psi on all 4 cylinders is optimal
150 or lower.Possible premature ring wear or high mileage
130 or lower. Yuh jus ain't usin yer turboh car right.
Put er bricks and drop the motor and take it to the machine shop.

 

[ddavisaf]

Wow....
Lets start over people.
Service limit on 1g's is 125.

First and easiest thing you need to do is pull your lower intercooler pipe and check for oil. That would indicate a bad turbo. Might not need to do a compression test. If there is no oil there, then it is either one of two things. Bad piston rings, or bad valve seals. Then you'll want to do a compression test.

 

[sherms_gsx_tank]

no i dont think that stuff fixed all that thats impossible but it did help and thats all i want concidering ill be rebuilding the engine in dec. but ill check the ic pipes for oil and i was going to replace then engine when i rebuilt the engine thanks for the help

 

[sherms_gsx_tank]

Wow....
Lets start over people.
Service limit on 1g's is 125.

First and easiest thing you need to do is pull your lower intercooler pipe and check for oil. That would indicate a bad turbo. Might not need to do a compression test. If there is no oil there, then it is either one of two things. Bad piston rings, or bad valve seals. Then you'll want to do a compression test.

ok so i took off my lower ic pipe and i did find oil coated the whole inside of the pipe and there were little puddles so im going to guess that its a bad turbo. and i do have 122 thousand on my car with original turbo. so i guess im going to replace it. anybody disagree with that before i spend money.

 

[ddavisaf]

Did oil pour out or was there just a coat of oil on the pipe?

 

[sherms_gsx_tank]

well i removed the pipe up were it connected to the turbo not were it connected to the ic should i disconnect it there? but oil coated the pipe and puddled up on the steal pipe that connects directly to the turbo (were there is a groove for it to sit in)

 

[ddavisaf]

Then it sounds like the seals, if they are in fact bad, are BARELY leaking.
Every bad turbo seal I've seen absolutely dumps oil into the LICP. So, I think you're actually okay.
Your PCV and valve cover vent, are they routed to the stock locations? PCV to intake manny, valve cover vent to intake pipe?

Did you ever get a chance to run that compression test? If so what were the numbers?

Can you see any oil leaking from any of the runners on the exhaust manifold?
Pull your spark plugs and see if there is any oil covering the tips of them?

 

[sherms_gsx_tank]

no i never got a chance to check my compression. ill prolly do that in a couple of weeks when i go to change my struts but ill hopefully check all of those things you said a little later today i have other stuff to do right now ill tell you if any of those are bad.