blue smoke only when I open it up?

[vette 53]

blue smoke only when I open it up? running better but when I open it up, to the floor I see blue smoke from the rear,,does anyone know what it could be?
I have new ecm,injectors,dist redone, new plugs and new wires,,new fuel fitler,,etc,,,,
tinming seems to be right,, about 6 degrees,,

 

[vette 53]

okay I think that oil is leaking on to the exhast when I open it up, not sure but could be gasket around dist. does anyone else have any ideas....please reply

 

[jmccloud]

Oil puff when opened up

It's likely the oil pressure sending unit (behind the distributor) or a rocker cover leaking. Either would send oil down the bell housing onto the exhaust.
Really difficult to see back there. If you could get it up on a lift, you could see better.

 

[vette 53]

thank you for your reply,, will check that

 

[blu88]

If you don't find any oil leakage, may want to run a compression check. Could be bad piston rings on one or more cylinders.

 

[vette 53]

thanks will do,, but you would think if that was the case it would be blue smoke always,,right?

 

[blu88]

No, not necessarily, could just be getting blow by when you really stomp it. If the rings were letting a lot of compression by, you would see some blue smoke when you remove the oil filler cap while just idling.

 

[blu88]

I forgot to mention one other thing, check your PCV valve as it can also cause pressure build up in the crankcase. Take it out, shake it and see if it rattles freely.

 

[vette 53]

yes it rattles freely,, already checked that thank you,,,

 

[JimBobC4]

yes it rattles freely,, already checked that thank you,,,

Worn valve guides can cause this as well. The oil leaks past the valve into the cylinder. Its sucked in from the intake stroke of the piston.

However this is usually accompanied by a poof of blue smoke on startups.

Try and have a buddy rev the motor in park or nuetral or whatever with you looking at the pipes. Does it smoke when first revved ? Does it smoke after the RPMS are going down ?

A cracked oil ring and few other nasty things can cause this as well. I think a compression check is needed.

 

[blu88]

JimBob's right on the mark. Old school rule of thumb, if it smokes on start up, check top end, usually valve guides. If it smokes under strain, check the bottom end, usually rings.

 

[vette 53]

Thanks guys,,,

 

[vette 53]

okay put in new dist,,complete, and no more blue smoke and runs great,,seems the dist, when it was rebuild was not done right and it has been causeing all the problems, but now I can just enjoy driving my vette,, thanks guys for your upport,,,