300zx TT gives blue smoke from exhaust

[Oestergaard]

Hello.
My 1990 300 zx TT has begun to make blue (and bad smelling) smoke from the left exhaust pipe, at idle speed. The car has run 235.000 km. Recently I have installed new valve stem seals, and new hyd. lifters. That was a quite big job. Unfortunately the car is still making blue smoke.
I suspect the turbos to be worn.
Question: Has anyone had a similar problem, or know what could be wrong. I think it would probably be the turbos and not worn pistonrings, since the engine is running smoothly at idle.
Finest regards, Michael, Denmark.

 

[evtech]

My turbo smoked real bad at first run up mid this year, I had fitted a full service kit and it felt 'all nice', (i was well happy) so I stripped it again and cleaned all parts, took a couple of measuments and found that the turbo shaft had been ground minus 10thou at a previous factory rebuild.

Gave up and sent it to BTN Turbos for crack testing and rebuild, lucky that cause the shaft had 3 cracks through it at near 70%.

Now blows sweet and sounds crisp, and smoke has gone at idle, still get a little bit when blowing but this winters re-ring should sort that.

There is not much allowance (tolerance) in the turbo for 'wear' before it starts to allow blow-by, the main failure is the tiny spring labrinth seals between gas housings and the oil supply area for the plain bushes/bearings.

Regards

Nigel

 

[Gio]

try this http://www.300zx.co.uk/tech/SmokeDiag.htm

also, have you changed the PCV valves yet? If not, try this to eliminate turbos as the problem http://zhome.com/ZCMnL/PICS/pcvValve/pcvValve.html

http://www.ttzd.com/tech/pcvtech.html

 

[Oestergaard]

Blue smoke from ex. pipe

Hi.
First of all THANKS for helping with suggestions to my problem. I forgot to mention that the smoke appeared after I built a stainless ex system with hi flow cats and straight through mufflers. JWT says that the turbos could leak oil if there is no backpressure. Still I will put new pcv valves on, and perhaps upgrade the turbos to sport 500 from JWT.
Thank you both for helping .
Hope I can help you back sometime.
Michael Oestergaard, Denmark

 

[Gio]

JWT says that the turbos could leak oil if there is no backpressure.

Although I am not mechanical, that is what "everyone knows" about our turbos. It has happened so many times after people de-cat, it may even be true.
[famous last words]My Z has 225,000km and once started to smoke but after replacing all the PCV stuff it seems to be OK now [/flw].
My guess would be that if you are only getting smoke from one bank it would be more likely to be the turbo on that side - however, if you haven't done the PCV valves before, you'll need to do them anyway even with new turbos so you might as well try it to see if it helps.

 

[jimmer]

you can check the pcv valves by removing them and giving them each a shake by your ear.if it rattles then the ball inside is moving correctly and doing its job.

 

[Oestergaard]

Great thanks to Nigel, Gio, and Jimmer. I'll check the valves, and see what that gives me.
Finest regards, Michael

 

[Oestergaard]

Hello again.
I'd just checked both PCV's, and they are fine with no dirt inside. They are a little wet with oil, and they rattle when being shaked. The lead air through the one way and are closed the other way.
I guess I'd better find some $ for that Sport 500 turbo upgrade from JWT...
Attached pics of both PCV's.
Regards, Michael