Piston ring fried?

[rhdude]

Ok, replaced my blown stock motor with a junkyard motor... motor had 36k on it, heads were rebuilt. Finnaly got it in and running correctly... and went to do Emissions testing.

During the 180sec test at 2700rpm, about 90sec in, my car started blowing whiteish/blueish smoke out of the exhaust, and continued to do this the rest of the test.

The mechanic and I talked for a few minutes, he and I came to the conclusion that it *could* be a cracked piston ring...

He said to do a dry, then wet compression test, and if it looses compression after the wet compression test, then the ring is fried? Is that right?

Anyway, I'm going to do the tests tonight to see whats up.

If it is the piston ring, how do I replace it? I've pulled the heads before.. thats not problem. But do I have to split the block to get the piston out? I believe you don't, but just making sure. So if anyone has links or directions for a piston install, it'd be alot of help...

Thanks,
Brian

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[Wedge]

Sounds familiar.

You don't need to crack the block open in order to pull the pistons. You do however need a Subaru specific tool to remove the pins. (But I think some people have done it without that tool)
As for the compression test, all you do is pour some oil into the sparkplug hole, and test compression. If it's more than a dry test, then most likely it is rings.
(I do believe that you have to crack the block in order to change the rods though.)

-Vic

[rhdude]

thanks man!

also, do you think it could be the valve seals?

or something as simple at the PCV system? I remember Larry Ganz saying something about cars with the crankcase vents hooked back into the intake with the IAC line tee'd, then he has seen cars smoke ALOT... thats how I have my lines run, but never have had it smoke like this before... should I just try replacing the PCV valve and rerouting the lines before I do anything major?
someone told me it could be that as well, cause the crankcase vents could be pressurized and push oil through the valve seals....

[inpreza kid]

are you running the stock 98RS headgasket? it might be your headgasket...

[Wedge]

2 things.

1-Check your oil for signs of coolant. Or check your coolant for signs of oil. (If any of that is positive, then it is a headgasket)

2-Check those crankcase vacuum lines for signs of oil. There should NOT be excessive oil there, if the hose goes back into your intake pipe, check the turbo for a small oil puddle. This is a sign of blowby, goes back to rings.

[rhdude]

Originally posted by inpreza kid
are you running the stock 98RS headgasket? it might be your headgasket...

I've been there, done that with the headgaskets... this motor has the new 4piece metal gaskets... car does not overheat at all... coolant levels do not drop at all...


ok, if I was burning oil, my oil level will go down right? cause I'm not loosing any...
a friend came over today and said the smoke does not look blue... does not smell like oil or coolant... it only occurs about 60sec. after revving constantly at 2700rpm.... This is really confusing both of us... does'nt seem to be oil or coolant... almost like something in the PCV system... we check and cleaned the PCV valve (I am getting a new one tommorow).. checked and cleaned the EGR valve... checked all vacuum lines.. and I am running some fuel system cleaner...