Compression Test Results/white smoke

[DsM KiD4]

ok so my car is letting white smoke out the exhaust and through my valve cover breather.
my compression test readings are (110 75 150 150). could a bad headgasket cause my compression to be this bad? also... i did not take my car out and drive it before the test because it was blocked in my driveway. but i did let it idle for 30 minutes with an occasional rev of the motor. so this means i need a new bottom end then?...any help is appreciated, thanks in advance

 

[blacktsi95]

sounds like a head gasket. white smoke is your coolant burning off. change it out and then do another check. but before you do another check, take the car for a drive and get on it a good bit. then park it and do your test. that should yield you the best results. 150 is good but your one cylinder of only 110 concerns me. i think maybe cause its next to the cylinder with the bad gasket that that maybe why. im guessing a fracture on its seal as well. after your check, if its still at like 110 and the rest are at 150, your rings are probably getting worn down on that one. your bottom end is fine though. if you wanted, you could drop the pan when you do the hg and rehone the cylinders and drop some new rings in it. some new bearings would work well too.

 

[dsmdragon]

sounds like a head gasket. white smoke is your coolant burning off. change it out and then do another check. but before you do another check, take the car for a drive and get on it a good bit. then park it and do your test. that should yield you the best results. 150 is good but your one cylinder of only 110 concerns me. i think maybe cause its next to the cylinder with the bad gasket that that maybe why. im guessing a fracture on its seal as well. after your check, if its still at like 110 and the rest are at 150, your rings are probably getting worn down on that one. your bottom end is fine though. if you wanted, you could drop the pan when you do the hg and rehone the cylinders and drop some new rings in it. some new bearings would work well too.

This is the best adivce I've seen about this problem.... Yea your headgasket sounds coked, and probably on cyl. 2 which is afeccting cyl. 1 as well. Make sure you check the rings/pistons when you take the head off. You might do something to them but is not so likely to cuase a problem.

 

[DsM KiD4]

150 is good but your one cylinder of only 110 concerns me. i think maybe cause its next to the cylinder with the bad gasket that that maybe why. im guessing a fracture on its seal as well. after your check, if its still at like 110 and the rest are at 150, your rings are probably getting worn down on that one.

My compression is [ 110 - 75 - 150 - 150 ]

i think you accidently misunderstood my first post on my compression...

the last time i had the head retorqued, i had a shop do it with new arp head bolts and a 4layer metal head gasket i bought from extreme psi. THEshop torqued the arp head bolts to the minimum requiremnet on the paper that comes in the box. Ibelieve it was 94-104lbs of torque but im not 100% sure. Is it a possibility that the head is rising off the block if it was not torqued enough?

 

[fwdeclipse]

Wow dude you got me confused. Nowhere in your first post did you say you already replaced the gasket. He was saying the cylinder that is 110 is also probably because of the gasket and if you change it and that one stays low and the other one that was 75 went back up then you could just rering that cylinder. How long ago did someone do your gasket?

 

[DsM KiD4]

in my first post i asked if the low compression could be due to a bad headgasket. because like i stated in my 2nd post, the shop torqued the head bolts to the minimum spec on the arp instructions. when they torqued the bolts , they used a 4 layer metal head gasket as well. this was less than 100miles ago. so u think its a possibilty of a bad gasket or poorly torqued head bolts?

 

[DirtyBirdRacing]

in my first post i asked if the low compression could be due to a bad headgasket. because like i stated in my 2nd post, the shop torqued the head bolts to the minimum spec on the arp instructions. when they torqued the bolts , they used a 4 layer metal head gasket as well. this was less than 100miles ago. so u think its a possibilty of a bad gasket or poorly torqued head bolts?

In your original post you stated that you had smoke coming out of the breather. Becasue of this and the low compression on cylinder two I would suspect that might have a pretty bad blow by problem. To check this option out, pour a cap full of oil down the sparkplug hole for cylinder #2 and then check the compression. If it goes up a good amount you are definetly suffering from blow by and also might have a head gasket problem. I would try this "cap of oil" method on cylinders 1 and 2 actually. If they come upto spec then you should suspect blow by. But, like was stated before since the two low compression cylinders are close to each other I would definelty not rule out a bad head gasket or improperly torqued head gasket.

Did you make sure the block and head surfaces were both flat and clear of imperfections when you installed the new head gasket?

Also when you install a head gasket I believe that a certain amount of miles after the installation you are suppsoe to retorquge the head bolts, but I am unsure about the amount of miles or engine run time before you should do this.

Sorry for the essay.

Bill

 

[DsM KiD4]

Did you make sure the block and head surfaces were both flat and clear of imperfections when you installed the new head gasket?

Also when you install a head gasket I believe that a certain amount of miles after the installation you are suppsoe to retorquge the head bolts, but I am unsure about the amount of miles or engine run time before you should do this.

Sorry for the essay.

Bill

when i pulled the head off last time, i had it hottanked and resurfaced. i didnt resurface the block.

i never heard of having to retorq head bolts after a break in, but can anyone confirm that?

i guess ill compression test it again "wet", and go from there. ill post the results later tonite.

 

[DirtyBirdRacing]

when i pulled the head off last time, i had it hottanked and resurfaced. i didnt resurface the block.

i never heard of having to retorq head bolts after a break in, but can anyone confirm that?

i guess ill compression test it again "wet", and go from there. ill post the results later tonite.

OK that is good that you got the head machined, but did you make sure to scrape the block and then "sand it" to make sure it is good. I'm sure you did I was just making sure. The sanding method is described in this thread:

http://www.dsmtuners.com/forums/showthread.php?t=266980

Good luck with the wet test.

Bill

 

[Xit40]

A compression test is a good place to start, but what would really help you determine the origin of your problem is a leak down test. You already got crappy compression test results so why do the same test again (unless you did it with a cold engine). Yeah it's probably the head gasket, but who knows. The leak down test will help you isolate the problem. Look here and here for how to build a leak down tester and use one. Hope this helps.

 

[DsM KiD4]

if i do a "wet" test and it brings the compression back up to reasonable specs, that means my piston rings are goin out....so does that eliminate the problem being the headgasket?

 

[Xit40]

Yeah you have a probably blowby problem (emphasis on PROBABLY). That doesn't explain where the white smoke is coming from though. I would do the leak down test to try and figure out where the white smoke is coming from. Does your car push any coolant into the overflow bottle? Is there any wetness around the head gasket seal? If so you probably have a head gasket problem.

 

[DsM KiD4]

no it does not pump coolant to the overflow bottle.No it didnt appear to be wet around the headgasket.

 

[DsM KiD4]

ok when i originally posted, i wrote down results in the wrong order... from left to right,
the results are as follows: 150 150 75 110. today when i wet tested cylinder #2, the compression moved up to about 120. This Means my rings are bad? or could it be a bad headgasket? Im going to pull the head off right now to further investigate, but what do u all think it might be? Remember, i have alot of smoke coming out the exhaust and valve cover breather. i also seem to have crankcase pressure because oil is always leaking out from underneath my oil cap (already replaced w/new cap, still leaks). so im guessing i might have a bad headgasket and bad blow by? any thoughts?