Hey, I just built this 350, and have put around 2000 miles on it. About a week ago, I started getting blue smoke out the tailpipes again. I know this is expected on a new motor for the rings to seat, but I have been through that already, or so I thought. The heads were just reworked, so I know nothing is wrong with them. The smoke only occurs after the engine has warmed up, but is fine at start up. I am running the new 87-later heads, with the adapter kit to run the old style valve covers, and it looks to me like the adapter is not sealing well, but this still woulnd't explain the oil in my combustion chamber. I have narrowed it down to two things; crankcase ventilation and piston rings, and am really hoping that it is the former. I am running a PCV from my passenger valve cover to the carb, and running a standard breather on the other side. What do you guys think the problem is?

 

Try retorquing your intake manifold bolts.

 

After re-reading your post and thinking about it a little more, I have a couple of more things to add.

1st, the only time you should expect to see blue smoke on a properly rebuilt engine is while the assembly lube is burning off the cylinders. Lubricating oil getting past not-yet-seated rings should not put enough oil in the combustion mix to create blue smoke.

2nd, I wouldn't assume your heads are not the source. Plenty of us have seen something done wrong to be suspecious of everything until proven not-guilty.

Finally, when I first rebuilt the 396 that is now in the '57, it seemed fine at first, while I was running in the cam and the first trip around the block, at least. When I took it out on the road for the second time, I left a mighty cloud of blue smoke behind me and used a quart of oil in 50 miles. The problem turned out to be the Weiand Action+ manifold I had put on during the rebuild. It had been improperly machined, wasn't sealing the intake ports in the lifter valley area, and sucked oil into the intake stream when engine speed got up. I thought I had wasted a $2000 rebuild by putting it together wrong, and was sure relieved when I found out I could blame someone else!

 

The thing is im pretty sure the rings have already seated. It is my daily driver, and the engine has a good 5 weeks on it. When you replied telling me to retorque my manifold, you brought that to my attention which I had over looked. I have been having trouble fitting intakes on my heads because I am running a set of old vortec style heads, and about .030 was taken off the block. I removed the intake and found oil in the runners, so I think that was the source of my problem. I have a nice hi-rise I wanted to use, so I bolted that up only to find I over-torqued my heater hose fitting, and cracked the water passage. I took that off, and put my weiand stealth back on, and upon tightening down the thermostat housing I broke a bolt. So...just my luck, I am without a car for the weekend. I work at a machine shop, so I'll get it straightened out on Monday...really sucks though.

Thanks for your replies, really appreciate it.

 

Your problem is probably the Vortec heads. You need a Vortec specific manifold to fit the Vortec heads. The intake ports are a different shape and don't line up correctly with conventional intakes. Which intake gasket did you use, conventional or Vortec? Also, the Vortec's only use 4 intake bolts per side, but a conventional uses 6 per side. If you just left out the middle bolts, then your intake isn't sealing to the block.

If you took .030" off the head mating surface, then they should have taken some off the top of the block, so the intake will line up correctly. To rule out the rings, I would do a compression check on all cylinders. Good luck.

 

These heads aren't the ne L31 vortec heads, they are the vortec heads from the late 80s that were on TBI trucks, so they do have 6 bolt holes on the intake side.

I didn't take .030" off the head mating surface, I took it off the top of the block, to attain a deck clearance of zero.

I am gonna try and run a compression test this week, and see how it turns up.

I fixed my weiand stealth intake, and bolted it up again, and still no luck. Smoke from tailpipes again. I'm almost certain it is the rings now. My next easy fix is to play around with the crankcase ventilation. I know i'm not pulling a lot of vacuum with the race cam I have in there.

 

If they are from a late 80's truck, then I don't think they are Vortec heads. They were just 305 or 350 truck heads. I don't think they had Vortes heads until the mid-90's. Hopefully the problem isn't the rings. A compression check might tell you what cylinder(s) are to blame. It still sucks that your new engine is burning oil. I am hoping to fire up the engine in my truck soon. I rebuilt it myself, and I am anxious to see how much power I can squeeze out of it. I didn't go too wild since it will be my daily driver, then I can park my Monte SS to work on it. Good luck.

 

I know what you mean...I'm a high school student, and this is my only car. Thats ok...I have to show up the mustang guys at school.

I'm almost positive that they are the gen I vortec heads...i'll look into it though. It sucks that it just started burning this oil all of a sudden. I am hoping I can figuree this out without pulling this thing out AGAIN.