I just tested my zc sohc for compression the number 3 cylinder was down 15psi the others were all about even around 170 or 175 can't remember which.

I do get a little blow by after boosting I can see it coming out of the breather on my catch can, but it doesn't use much oil really. The thing I am worried about is my turbo, if there is excessive crankcase pressure then the turbo's oil drain may not be able to drain, which can cause the turbo to crap out, my turbo is ballbearing and has had the inside of the housing ported out to stop oil from sitting in a ridge, but yeah I don't want to blow the turbo should I be worried?????

 

Come on some one knows something...

 

check your leakdown %'s on each cylinder, it will tell you more of whats up with your engine.

 

I am almost positive its the ring on number 3 but its not that bad it is only down 15 psi, surely someone has been in this situation before...

 

if the ringlands are cracked, the only thing that will happen is that the motor will destroy itself over time.

you wont hurt your turbocharger unless parts of the piston come flying out the exhaust side.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lazerus &raquo;</TD></TR><TR><TD CLASS="quote">if the ringlands are cracked, the only thing that will happen is that the motor will destroy itself over time.

you wont hurt your turbocharger unless parts of the piston come flying out the exhaust side.</TD></TR></TABLE>

yea correct. My old d16 did the same thing. Started with 15psi down...in a month it was 100psi down. Most likely you cracked a piston. If you have smoke coming outa the crank case breather..its a sure sign.

Personally if i were you..id pull the head and replace the bad piston with a new one and a new ring before you damage the side wall with the broke one. Although it also depends on the miles on your motor. Too many miles and getting a new ring to seal is a bitch. It took my motor 3000 miles to finally get a new ring seated correctly....it was a high milage wonder motor.

liam

 

Thanks guys yeah its a pretty high milage motor I am also pretty sure the number 3 cylinder has been down for a while (4 months) I did change to a much thicker oil though. Its not really getting any worse at the moment so you think I will be OK as far as excessive crankcase pressure not allowing my turbo to drain???? I'll monitor the compression but if it stays only 15psi down will I be alright. Thanks

 

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