Bringing this one back, my car still smokes after a bottom end rebuild.

When I pulled the motor apart, the rings and bores looked good. Everything spec'd out fine except some pistons have worn wrist pin bores. I put all new pistons and rings in it, as well as new rod and main bearings and bolts.

Last night, I bypassed the PCV to eliminate oil being pulled into the intake from the valve cover and it actually smoked MORE.

Really the only thing left is valve guides unless I am completely missing something here?

To recap I have run it with and without turbos, and after prolonged hot idle or engine brake decel, it puffs smoke when you rev it. I have bypassed both PCV hoses and it still smokes. Actually it smokes more without the intake side PCV unhooked.

What is left besides the head? Anyone have any other ideas because I am out of them...

 

There is another poor soul on SF who is having the same issues I am. He dropped his car off at a shop to diagnose and they are leaning towards valve guides. I am waiting to see what happens with his...

http://www.supraforums.com/forum/sho...ide-of-coupler

 

Your all the sudden low idle, miss and smoke sound like my recent battle with a full tank of bad gas. The oil your finding is different though.

 

Yeah and I have run several tanks of gas through it.

 

I was saying Turbo oil seals, or valve seals.

Blowing rings is not something a heavily over-engineered jz engine is known for doing.

Or any engine built in the last 15-20 years with all the advancements in technology, really.

I hate to say it, but tear it down again and get that head redone.

 

It is not turbo seals or valve seals. Valve guides maybe. Two sets of turbos, and no turbos, it still smokes. Also, two sets of new VSS and it still smokes.

 

Damn Stockhatch you still got smoke Ic. The only thing really left is valve guides I mean how bad did your head look before this? This is bad news I hope you get it worked out soon..

 

I read your post again and I'm really leaning towards the turbos at this point, you did say that there is oil in the turbo inlets as well seems like the front turbo seal. The rear seals are most likely bad as well

 

Nah, I took the turbos off and let the car idle for like 20 minutes to get good and hot and it smoked. I ran it through a few cycles of letting it idle for a few minutes and revving it and it smoked every time even without the turbos on it. I think it smokes faster with the turbos on it because the oil gets hotter faster.

At any rate, I have replaced everything except the valve guides at this point. I don't know for sure that they are the problem, but I don't know what else to do besides rebuild the bottom end again or buy a third set of twins to try lol.

 

I found that the oil in the turbos was coming from the valve covers. Once I vented the passenger side VC to atmosphere, the turbo inlets were clean and dry again.

 

Just for grins, here is a vid of what the car does. It has to be fully up to temp HOT before it wants to smoke. It will sit and idle away with no smoke until you rev it. Then, once it clears, it will take another minute or so of idling to "reload" and smoke again...

http://www.youtube.com/watch?v=TRy3tgcb1Xs

 

have you had the car tuned by a competent tuner?

do you have a catch can?

when you installed the catch can, did you completely remove the pcv system? catch cans are in effect a pcv system, except that they do not allow the oil vapors to seep into the intake. a quality catch can will constantly drain back into the crank case.

 

The car is stock, no need for a tune. Regarding catch can, no I do not have one. I have tried venting the valve covers to atmosphere in effect bypassing the pcv, but it did not help.

 

Could be you have bad mufflers?

 

I suppose I could...