Sudden Oil Consumption
 

I've go around 1300 miles on the engine after a total rebuild and it's suddenly started burning some oil. It's mainly on start-up but starting to notice some smoke at idle now. For the first ~1100 miles, there was no consumption at all... Compression is still strong on all 6 (and even) so I don't think it's rings. What else could be causing this? Thanks as always!

Valve seals and/or guides? Was the head rebuilt also?

It could still be the rings. Just because you have compression doesn't mean you didn't crack an oil ring.

But before you get all willy nilly on it and tear it down, check the PCV system. I have seen systems plug and use oil and I once had a PCV valve come apart internally and the system was sucking the oil out of the engine. I used up 4 quarts of oil in about 120 miles all because of a bad PCV valve. Now, it uses less than a pint between oil changes.

For a quick check of the PCV swap the hose out with a clear rubber hose.
This will show you if the oil is being sucked in.

The home center box stores should have the hose needed.

I narrowed it down to the PCV system on a whole... Since my oil filler tube was messed up I decided to cut it short which initially was letting oil escape past the oil cap and run down the engine. So, I used a stainless steel scouring pad to fill the remainder of the tube in hopes of slowing down the escaping oil. That worked a little too well effectively plugging the tube and not allowing the crank case to breathe. That caused the PCV to suck too hard on the crank case gumming up the valve. I've now taken the steel mesh out of the filler tube and installed a K&N breather cap on the top, cleaned out the PCV and replaced the hose. Initial drive afterward proved to be a lot better. Now I'll change the plugs and hope that the residual oil in the intake burns out fairly quickly. Thanks for the pointers once again... this thing has been a pretty steep learning curve for me!

Just pick up some SS screen and roll your own,

Oil tube splash screen.

I would gladly go that route but I don't have a full length tube anymore...

Unless I'm misunderstanding if you still have the lower section the screen only goes up into the tube just to where you see that small dimple.

????? :confused:

FWIW...
 

... It's about 4.5" from the base of the block up to the top edge.
Then just add the distance from tube stop-rim up to dimple.
If you cut your tube down but are still above dimple you should be good.

You can see in this pic what I'm working with. The only difference now is that I've removed the standard cap and put a K&N breather filter in its place.

So this is in a Chevy II?

If you want a full length stock oil tube, I can send you one for the price of shipping.

Yes it is.

That would be great! PM sent...