I just put a new XE268 cam in and finished adjusting my valves. When at idle if you rev the car smoke comes out and if you drive the car down the street and give it gas smoke comes out. I did a compression test just for piece of mind and it came out good. It doesn't smoke on startup so I don't thing it would be the valve stems (and my heads are new). Only thing I could come up with is that my intake gasket is leaking down low and sucking oil in. Is there an easy way to check this or am I just up the creek? I used the new style gm intake gaskets that pace told me use. They seem like they're made of some sort of black plastic and they cost like 40 bucks a pair. Any help would be great.

 

my car dose the same thing so if you get an answer then ill have an answer aswell

so far ive been told
intake gasket leak
bad piston rings
bad valve seals

my car dosnt smoke on start up but only when at mid-high rpm under load
and my compression test was fine aswell
its just annoying when driveing at night if i happen to pass someone on the freeway just to see a tone of smoke blow out the tail pipes

 

I'm going to go ahead a yank the intake and we'll see whats up. I used the gm performance gaskets last time, but I'm going to get some felpro's this time. I've always had good luck with them, but I decided to use the manufacturers suggested gasket. I'll post a reply here with what I find in the lifter valley.

 

How many miles on the trans????

I had/have a problem with blowing smoke only under hard accel n such in my V8 auto car.

Check your tranny fluid level.

The vacuum modulator on th trans that control low speed shift points can go bad and the car will suck trans fluid up the vacuum line only during hard load.
[Gov controls WOT shifts] The vac mod will still operate almost normal. Only real notice will be the odd smoke when your on it and trans fluid going low. [My new vac adjustable vac mod showd up yersterday.]

 

I have a 700R4 and it doesn't have a vacuum mod it runs off a throttle valve cable. The trans does have a lot of miles on it and eventually I want to put in a t56 and sell my trans for whatever I can get for it. I still think its the intake gasket so I bought one last night, but I have to wait for the weather to cooperate.

 

Please let us know what you find. I'm having a similar problem.

 

Could be a bad PVC system / crank case vent.

Under hard load your blowing more then gasses into your engine.
That is if you have your PVC system venting into the engine like stock.

If it was the intake leaking you would have problems getting it timed right. It would want tons of advance, well more then normal.

Though maybe your just a bit rich when on it hard and thats why?
To much fuel, not enough air but only at WOT.

 

My PVC system has a breather on the pass side valve cover, then the PVC valve on the driver side with the hose connected to the PVC connection on the carb. There shouldn't be any issues with it because its all new. I finished the gasket change and it would seem to have to solved the problem. I won't say it has yet because right now I'm in the middle of getting timed right and all that. As soon as I finish up I'll fill everyone in. It looks like the issue was mainly my fault. This time I cleaned the heads as clean as they'll ever get and since I had the intake off I port matched the gaskets and intake. Last time I didn't do any of this so thats probably why I had issues from the start. I should be done timing it shortly. Thanks for the advice and help.

 

Having issues trying to get it started. Had it running for a while and then it died on me and now its acting like it needs fuel. I'll have to mess with it tomorrow because I have to go to work now. I still think the new gasket solved my problem but I'll have to get it running and then I'll make a test run with it to be sure.

 

I have this problem . I only have a pcv sucking and the other side was a breather/oil cap . It got so much oil spewing out of it after a few years I just put an oil cap on it not thinking about crank case breathing . Now under full throttle sometimes I get small clouds of blue behind the car . I now drilled holes in each valve cover and connected it to my homemade dual snorkel air cleaner . Ill post a pic , im pretty sure my problem will be solved after im finished .