Clemson Vette

ok this isnt on my vette but i am hopin that u guys will help out a vette brother. my dad bought a restored 1972 chevy pickup with a 400 bigblock in it. runs real well for a truck and has gobs of torque. but there is one prob with it. at complete random it will smoke like a freight train. mostly on a startup but not every one. after a min or two it'll stop and be fine. the guy he bought it from said he rebuilt it. so what do yall think? are rings not seated? does it need to just break in? What all are my options? please list em all and what i need to do to fix it. thanks so much in advance.

Stuart.

Corvette Kid

I'd guess valve guides and seals. Probably not a thorough rebuild.

autotech

more than likely - valve guide seals...

Clemson Vette

oh let me add that there is absolutely no pattern as to when it does this. it can be on startup but can be anytime. does it when it's cold and hot. and does it more on one side than the other, it has dual exhaust. under heavy load both smoke good bit, but passenger side is aweful. it doesnt use too much oil considerin its a big block. i appreciat the help guys, keep the ideas comin. oh and should we get some of that lucas oil stabilizer that is super thick? or is that a bad thing?

Clemson Vette

any other ideas on what it could be? tia

Stuart

clemsonvette

how much consuption are we talking about here?

BBA

If it only does it on starts, it would definitely be valve guide seals. With bad valve guide seals, during some cold starts, the oil has already drained down out of the chambers and wont smoke, but on hot starts after sitting for about 20 minutes to an hour or more it will smoke, but only for a few minutes.

Does it have a TH350 trans? If so, if it smokes pure white smoke...it's the shift modulator diaphragm leaking (sucks trans fluid into the intake) This would happen mostly at startup but can also happen at random while driving.