An incredible amount of blue smoke...

[Bowtie]

This really sucks, have been building the car for four years and finally ready for final inspections. Bought a "rebuilt" 1975 Chevy 350 (I need a smog engine to get it road legal in Sweden). The engine runs fine but is burning oil on the right side (an incredible amount of blue smoke is generated from the right exhaust pipe under acceleration or load).

The engine builder has "no idea" of what might be wrong and I have no idea either! My guess is that it has to be the rings or maybe the valves (any other possible cause?). It just sucks in this stage of the build! I guess that I have to make a comp test on the right side, then remove the head for a general inspection and check the valves, then drop the pan and start pulling the pistons…

Any thoughts or advices before I start to get my hands dirty (again)?

[wilf]

Very sad to hear this, but it could be something as simple as a PCV valve pulling oil out of a valve cover.

First thing is to do a comp test, that will tell you a great deal about where to look next.

Take the plugs out of the affected bank - you should be able to see which cylinder has a problem. Hate to say this, but my money is on either a mis-labelled piston, (i.e. it is not what it pretends to be) or bust rings.

Is the engine builder going to stand by his work?

[Bowtie]

Originally Posted by wilf leek

...could be something as simple as a PCV valve pulling oil out of a valve cover

Thanks for your encouragement Wilf, how would I verify if that is the case or not?

Originally Posted by wilf leek

Hate to say this, but my money is on either a mis-labelled piston, (i.e. it is not what it pretends to be) or bust rings.

Just my thought...

Originally Posted by wilf leek

Is the engine builder going to stand by his work?

Don't think so, bought the engine four years ago (and put it away until this day). I'll better do it my self this time (got it cheap anyway, guess you get what you pay for)...

[Bowtie]

Originally Posted by wilf leek

Very sad to hear this, but it could be something as simple as a PCV valve pulling oil out of a valve cover.

Oups... Forgot to tell you that the PCV valves not even connected (no PCV valves or breathers on valve covers yet, just holes at the moment)...

[Purple AK]

Originally Posted by Bowtie

Thanks for your encouragement Wilf, how would I verify if that is the case or not?

Robert. You could try running it with the PCV valve disconnected from the carb (with the port blocked) That would confirm either way. Has the rocker cover got a baffle under the PCV take off? Lack of one could cause the problem. However it seems unlikely if its only smoking on one bank
Good Luck

[Purple AK]

Forget that then

[mylesdw]

My logic says that if it was valve guides the smoke would be worse at light load when the high vacuum would pull oil down the guides. That leaves pistons I'm afraid and the compression test seems like the way to go. I have driven V8s with worn bores and broken rings and they still don't smoke much so I'm wondering if the oil rings in one (or more) have been wrongly installed; it is very easily done. Did it smoke as soon as you ran it or has it got worse?

[Clive]

Originally Posted by mylesdw

My logic says that if it was valve guides the smoke would be worse at light load when the high vacuum would pull oil down the guides. That leaves pistons I'm afraid and the compression test seems like the way to go. I have driven V8s with worn bores and broken rings and they still don't smoke much so I'm wondering if the oil rings in one (or more) have been wrongly installed; it is very easily done. Did it smoke as soon as you ran it or has it got worse?

As a general rule of thumb, smoke under power suspect pistons/rings. Smoke on the over-run, suspect valve guides.
Clive

[Clarkson]

Check your intake manifold gaskets,could be pulling oil in via the intake!

[Purple AK]

Originally Posted by d clarkson

Check your intake manifold gaskets,could be pulling oil in via the intake!

Good Call Dave :thumb: