fresh rebuild/smokes after startup

[jeremey thomas]

just got finished rebuilding a 306 and upon startup it started smoking shortley after it started to idle.idle quality is good,oil pressure is good,air fuel is slightly lean as i noticed for some reason the oxygen sensor wires on the drivers side is broke.water temp is fine.engine is stock except for f cam and exhaust.any help would be appreciated.

 

[jeremey thomas]

come on guys i need help

just rebuilt my 306, but after it has run a few minutes it starts some white smoke from the exhaust.oil pressure is good,air fuel guage shows slightly lean,possibly due to bad oxygen sensor,water temp is fine.engine has no miles yet but i let it idle for about 10 minutes.the longer it ran the worse it smoked is this normal.engine consists of stock intake, heads, f-303 cam,bbk longtubes,h-pipe,mac mufflers and 2 1/2 tips.i have edelbrock aluminum heads and intake but do not want to install until short block has a few break in miles on it.

 

[bill302]

white smoke is coolant entering combustion chamber right...what did you do to the heads....did you take them to the machine shop to be checked for flatness,rebuild or what....

 

[bill302]

need more info....new head bolts torqued properly head gaskets on right i have seen people put them on backwards.... you problem is with the heads or intake gasket or head or intake themselves...by your description....just my opinion ....anyone else...

 

[TheBocSez]

A few other things could be that when you rebuild the engine, you oil the cylinders when installing the pistons. May just need some time to burn off the oil.

I had the same thing happen when I installed my new engine. Within a few miles, no more smoke.

I also had a smoking issue when I changed my intake. Problem was a poor seal at the lower intake. I replaced the lower intake gasket, used a non hardening sealant between the head and gasket, and used 4 studs to guide the intake down straight. Torqued everything down and no more oil leak.

Could be drawing oil into the intake though the PCV valve. Check where the hose connects from the valve to the intake and look for oil.

Just a few things to check. Good luck.

 

[jeremey thomas]

its quite possible,however idid check oil frequently and it looked good.if i was getting water into combustion chamber would it make oil milky

 

[jeremey thomas]

thanks for your reply. a gentleman told me to cote my cylinder walls with pb blaster since it was going to be a couple of weeks before i put it together.could this be a sample of what you are explaining

 

[bill302]

depends where the leakage is occuring i have seen head and intake leaks that put water in the oil and or oil in the water and i have seen it where there was no oil or water signs just loss of coolantwith no signs of leaking and just white exhaust...but one way to tell is a compression test of the cooling system....it could be the pb blaster but the only way to clean it from the system is to drive it....

 

[bill302]

white smoke is coolant entering combustion chamber right...what did you do to the heads....did you take them to the machine shop to be checked for flatness,rebuild or what....

what did you do to the heads.....

 

[TheUser]

if it's a bad gasket, I'd bet you'd overheat in a hurry. Sounds like the PB blaster to me. Maybe you got some oil or junk on your exhaust and it's burning off.

 

[MustangGT92]

i'm gonna say its a head gasket.....sound like water is getting in the combustion chamber somehow... check all your hoses and the gasket on your egr spacer and make sure water is not getting in that way.....

 

[R2D2]

put the gasket on backwards?