GM 350 crate oil burner

[8door]

I purchased a new 350 290hp crate built in Mexico.
After about 500 miles it began to use oil...... not a little ........a LOT.
About every 100 would need a full quart to fill it then consume that. I figured after another 500 or so the engine should be broken in... nope still oil out the exhaust.
Before firing I did all the spec things , pumped up the lifters and system by priming, ran 20 min at 2k to break in the cam, changed out the break in oil and filter watched the pressure and temp etc etc.
Ran nice smooth power overall ran very well except the oil.
After 1500 or so I pulled the rockers all 8 exhaust valve seals were shot.
The warranty is 100,00 mile or three years. but I bought the engine five years ago stored it in the factory packaging in my garage, so no did not contact GM. Whats the point.
I replaced all with Viton seals.... we will see........
Just wanted to let you all know to be aware of Mexico GM.
I do like my "American" built C10.

[geezer#99]

Sounds more like a blown intake gasket. On the underside at the ports.
Did you install the intake?

[MARKDTN]

Have you changed the PCV? That is a lot of oil use. Can you tell by the plugs if it is 1 cylinder or many that is getting oil? Compression on each?

[special-K]

Intake gasket leak or cracked intake

[8door]

New intake manifold, new PVC, all plugs clean.
All new top parts installed, only old stuff are Rams Horns, and alternator.
The start ups, hot or cold produced oil ( blue ) smoke . Lead me to suspect
exhaust seal leaks. Like I said all exhaust valve seals were defective.
Since those have been installed, there is no smoke after about 50 miles or so.
PS I will check compression.

[71tahoe]

Sounds more like the seals just broke down after 5 inert years and then they snapped like an old rubber band when you started using it. I don't think it would have made much difference where it was manufactured since they would have used the same quality valve seals.

[gvw5400]

For what it's worth , Do you have Aftermarket Valve covers?
Once I bought a 80 suburban with a 350. It had M/T valve covers and used 1 QT. oil
every 200 miles. I swapped them out for a pair of stock covers because I liked the look better. My oil use dropped to 1QT every 2800 miles!
Stock GM oil separators are that much better than a aftermarket tin shield.
All the Best, Dirk

[CaptRMW]

Originally Posted by gvw5400

For what it's worth , Do you have Aftermarket Valve covers?
Once I bought a 80 suburban with a 350. It had M/T valve covers and used 1 QT. oil
every 200 miles. I swapped them out for a pair of stock covers because I liked the look better. My oil use dropped to 1QT every 2800 miles!
Stock GM oil separators are that much better than a aftermarket tin shield.
All the Best, Dirk

Dirk is right on about the tin oil shield on some aftermarket valve covers including some by Edelbrock. GM didn't put the step baffles in the stock covers simply to get rid of some extra metal they had and if yours do not have step baffles you have most likely found the problem. Step baffles prevent the PCV valve from sucking the oil into the intake and depositing it on your intake valves in the form of carbon..

[CaptRMW]

8 door you can easily check your baffle by connecting the PCV to the carb with a piece of clear vinyl tubing and run your engine at 1500 rpm while watching for oil trekking up the tubing. I had the same oil consumption problem 20 years ago on a 350 engine while running a set of Edelbrock Elite valve covers with the tin cover over the PCV hole . My engine was losing power to the point it wouldn't pull the sheets off the bed so I pulled the heads and the intake valves had so much carbon on them that they could not draw a decent air fuel charge to make the engine run normally. After a few calls to the head engineer at Edelbrock and some very compelling evidence I sent my valve covers to Edelbrock and was sent a set of chrome stamped steel valve covers free of charge which had step baffles. My question to Edelbrock was why would you put step baffles on the stamped steel valve covers you make if a flat piece of tin would have been just as good. No admittance of fault of course..

[8door]

Originally Posted by 8door

New intake manifold, new PVC, all plugs clean.
All new top parts installed, only old stuff are Rams Horns, and alternator.
The start ups, hot or cold produced oil ( blue ) smoke . Lead me to suspect
exhaust seal leaks. Like I said all exhaust valve seals were defective.
Since those have been installed, there is no smoke after about 50 miles or so.
PS I will check compression.

Update : Another 100 miles....... Zero Oil use. As of today.
There have been some internet conversations about Mexico
installation wrong cam , resulting in contact of the keepers with valve seals.
I am contacting GM to verify this.

[8door]

Originally Posted by 8door

Update : Another 100 miles....... Zero Oil use. As of today.
There have been some internet conversations about Mexico cam
installation was wrong, resulting in contact of the keepers with valve seals.
I am contacting GM to verify this.

Questions regarding valve covers, mine are the stock covers that came
with crate engine.