Thread: My 350 sbc is smoking

Tweet

Hey guys, my motor is using a quart of oil every 100 miles..

I ran a compression test and all cylinders read 130-135psi dry..wet they ran 150-155psi..
i changed out the pcv and hose..
adjusted all valves..
there is no oil in the breather cap or air filter..
No oil is dripping on the floor...


Valves seals?

I've always heard as a rule of thumb:

If it smokes on startup then not too bad - bad valve guides.
Smokes pretty much continuously - bad rings or scored cylinder/s.

Because of decent pressure, my guess is there is a scored cylinder/s.

Bert

Originally posted by bgrd
Hey guys, my motor is using a quart of oil every 100 miles..

I ran a compression test and all cylinders read 130-135psi dry..wet they ran 150-155psi..
i changed out the pcv and hose..
adjusted all valves..
there is no oil in the breather cap or air filter..
No oil is dripping on the floor...


Valves seals?

valve seals is about all it could be, i didnt think valve seals would use that much oil though. if the motor is in as good a shape as you just described, it shouldnt be using that much oil. you sure its not a qt. every 1000 miles which wouldnt be bad.

thanks for the info guys...

no it was quart for 100 miles...
smoking continuously, but not real heavy


all plugs were black and oily, after only 100 miles, number 2, and 8 cylinder had some carbon build up on the plugs

Originally posted by bgrd
thanks for the info guys...

no it was quart for 100 miles...
smoking continuously, but not real heavy


all plugs were black and oily, after only 100 miles, number 2, and 8 cylinder had some carbon build up on the plugs

if the rings or a cylinder was bad it would show up in the wet, dry check or blow by out of the breather. 2 and 8 are on the same intake runner so id be looking at that a little closer if the pcv valve is running off of them.

Originally posted by lt1s10
if the rings or a cylinder was bad it would show up in the wet, dry check or blow by out of the breather. 2 and 8 are on the same intake runner so id be looking at that a little closer if the pcv valve is running off of them.

looks like the vac. is sucking the oil into the motor passed the intake gasket or pvc valve.

lt1s10, if it is a vacuum problem, how do i correct?

and may i add, it runs awesome...

Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?

Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??

Thunderbucket Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??

Just gradually over the last 45 days or 300 miles


chevy 37 Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?

No sir, starts smoking right from the start, smokes about the same even after it's warmed up...

Originally posted by bgrd
lt1s10, if it is a vacuum problem, how do i correct?

take the pcv valve out of the valve cover and let it run and see if it stops. if it dont clear up in about 5 min. thats not what it is. you can pull the valve cover and see if the drain holes are stoped up also. it shoulnt be the rings they check to good.

You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.

Originally posted by bgrd
Thunderbucket Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??

Just gradually over the last 45 days or 300 miles


chevy 37 Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?

No sir, starts smoking right from the start, smokes about the same even after it's warmed up...

lt1s10, i will check the pcv valve when i get home this evening, Thanks

Thunderbucket You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.

yes, i over revved twice in the last 30 days, missed second gear... hmmmmm

Originally posted by bgrd
lt1s10, i will check the pcv valve when i get home this evening, Thanks

Thunderbucket You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.

yes, i over revved twice in the last 30 days, missed second gear... hmmmmm

you should have elimated any thing there with the compression check.