L69 rebuild - 100 miles on it. Just started smoking oil smoke out of the oil dipstick tube and valve cover breather cap. Why? Some of my other motors I've built have smoked a bit at first during breakin, but never this much... a friend says that it is normal but I don't think so. Smoke increases under load. Any ideas?

I'm guessing the rings haven't seated yet... right? Just kind of funny how it started smoking all of a sudden.

That may not be a very good sign...

It is possible to have blowby from exhaust valve guides, but it's rarely enough to be noticeable. The only other thing that would cause that is a broken ring.

Check your PCV system, make sure it's working right. If there's plenty of suction getting through the PCV valve, and even with it hooked up it still puffs smoke out of the crankcase, your motor may not be long for the world. I would certainly not run it until that is fixed because if a ring is FUBAR it can tear up the cyl wall, and then you'd have to bore it to fix it. Not fun at this point. Disassembly and all that is not fun, but a return to the machine shop and purchasing more pistons is even less fun.

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"So many Mustangs, so little time..."
ICON Motorsports

hrm. Here is what I have now:

Edelbrock 600 cfm carb. I have the left vacuum going to the distrib advance, the right vacuum blocked off. The middle PCV outlet goes through brand new tubing to a PCV valve on the right valve cover from a 2.8 that I had lying around. This PCV valve is from autozone and is approximately 500 miles old.

I have a breather cap on the left valve cover.

Everything seems to be fine. Is that PCV setup ok? If not what should I do?

Is there any way I can test to see if the PCV system IS in fact at fault?

thanks,
Matt "not a PCV expert by an means" 84TA

If you pull the valve out and hold it in its normal installed position, does it suck fairly hard?

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"So many Mustangs, so little time..."
ICON Motorsports

I don't understand what you're asking me to try

Pull the valve out, and put my finger over the hole in the valve cover? Or pull the hose off the valve and see if it sucks?