Smoke at idle

[GOT JCE]

A friend has a GN that has had the motor recently rebuilt. Rebuilt heads, all new lifters,springs,valves,cam,pushrods,and crank. Reused the stock pistons and rings. The car runs beautiful except for a smoking problem about 30 seconds after startup. Car smokes unless it is under a load. Blue smoke. Checked the turbo and it is fine. New PCV and EGR. No oil in intercooler. I am thinking leaky intake gasket or rings. But why no smoke under a load? Will a compression test find a sticking oil control ring? He is ready to trade his car for a mustang!!!Please help!:biggrin:

 

[dr_frankenstein]

did you hone the bore and install the old pistons rings?

A.j.

 

[GOT JCE]

Smoke

He left the pistons in the cylinders when the crank was recut with new bearings.So no on the hone and rings.

 

[IrvJr]

Has happened to me after both motor rebuilds. Small break material gets in the turbo and cause an oil leak to the exhaust side. After you shut the motor off oil drains down into the exhaust side of the turbo and after you start it and the exhaust heats up you get the smoke.

 

[GOT JCE]

smoke

But why would it not smoke under a load. When you are sitting in the car reving the motor it will smoke.But put it in gear and get on it and nothing.

 

[IrvJr]

Mine did it at start up because the oil leaks down and puddled up and after that burned off the leak wasnt big enough to keep it smoking all the time. As for why it wont smoke under load, maybe it does but you are pushing out alot more exhaust and it dissipates it some. Maybe.

 

[dr_frankenstein]

you didnt happen to dunk the pistons/rings in oil or STP or anything like that when assembling?

A.j.

 

[Junior Samples]

valve guides/umbrellas

 

[GOT JCE]

Smoke

Pistons and rings were never taken out. Was told the cyl walls looked perfect so no need to re ring it. If it were the valve seals wouldn't it smoke all the time?

 

[Junior Samples]

Pistons and rings were never taken out. Was told the cyl walls looked perfect so no need to re ring it. If it were the valve seals wouldn't it smoke all the time?

oil in heads while running then when its shut off, they leak down, start up...puff

 

[Powder]

Is the new cam a roller?* If so, is it a high enough lift to require cutting the exhaust guides down and installing positive type seals and aftermarket exhaust valves?* The heads on my recent build were done in this manner but several of the seals would slip off and allowed oil to be pulled through the guides, especially under high vacuum siatuations like at idle.* Changed to a better quality seal and so far no more smoke.* Might be your problem.MH