excessive oil consumption

[vega_guy_76]

I just rebuilt and installed the engine in my Monza with new rings, bearings, and cam/lifters/timing set. Saturday was the first time I fired the engine and by the time I returned Sunday from the Everett gathering I had put roughly 400 miles on it. In that time the engine burned 5 quarts of oil. It didn't leak a drop, but burned every last bit. Obviously I added oil as it was needed. The engine is a .040 4-bolt main 350. The cylinders still measure 4.040 and were still showing some of the cross-hatch pattern and there was no ridge at the top, so all I did was rehone them myself and install new cast rings on all the pistons. The ring end gaps measured .018-.020 for top and second rings, and were positioned around the piston as the directions called for. I know it's normal for a new engine to burn a little oil, but 5 quarts in 400 miles? Here is a picture of the plugs from the passenger side:

And the driverside (the #5 plug that looks like it was painted black was loose when I pulled it out):


Why would the passenger side appear fine, while the driverside looks terrible? Any suggestions?

Charlie

[DjTy]

looks ok according to this

maybe oil coming in through the heads... are you using umbrella type valve seals?

[vega_guy_76]

I know it's not the heads as the engine before didn't have this problem.

Charlie

[AusRs]

maybe the rings did not seat properly !

[ozzymoose]

Take us thru your run in phase, may help us answer with more accuracy.

What oil did you use?
What you did to run it in for the 1st 300 miles?
How long did it take to run the cam in? ect etc

doh! yeah that too what he said next post down, thanks Mldeolde All this info will help

[mldeolde]

first thing to do is run a compression check. get a guage if you dont have one and check every cylinder and document the readings with cylinder number and compression readings for each. that will tell you a lot and we can go from there.

[mldeolde]

first thing to do is run a compression check. get a guage if you dont have one and check every cylinder and document the readings with cylinder number and compression readings for each. that will tell you a lot and we can go from there.

[ColinOpseth]

I believe an incorrectly working PCV system will also cause a problem like you're experiencing. Recheck your vacuum tubing and PCV valve.

A compression test will give you a good handle on the problem, too.

[Monza Madness]

Almost looks like the oil rings failed.

[starfire383]

Any chance one of the intake gaskets slipped during install?

As mentioned, is the PCV a true pull thru with breather on one side and valve on the other?

Also, crackpot theory here.......
What would happen if the drainback holes in the head weren't open, like if they were clogged with loose silicone from a valve cover. Or if the head gasket drainback holes weren't open. I'm quite sure this exact situation will overwhelm the valve seals with standing oil, leading to what you're seeing.

To me, the fact it's one side of the engine only rules out ring seal problems. Too coincidental that no other cylinders in the other bank are doing it.

[vega_guy_76]

Whatever the problem was, it's going away. Instead of driving the car like an old man I've been running it through hell, and oddly enough in the last 310 miles it has only burned 1 quart of oil. 300 miles ago I poured in some "Smoke Fix" from Schucks.

Take us thru your run in phase, may help us answer with more accuracy.

What oil did you use?
What you did to run it in for the 1st 300 miles?
How long did it take to run the cam in?

I use regular Castrol 10w30.
In the first 300 miles I ran it easy, no fast starts, no excessive revving, no steady speeds.
I ran the engine at a varied RPM of 2500-3000 for about 15 minutes to break the cam in.

I believe an incorrectly working PCV system will also cause a problem like you're experiencing. Recheck your vacuum tubing and PCV valve.

A compression test will give you a good handle on the problem, too.

I am still running the PCV system as the car was set up with when I bought it. Which is one valve in each valve cover, vacuum tubing to a 'T' in front of the carb (carter 600cfm) to the central port on the carb. And an open breather is installed in the driverside valve cover. I will get to the compression test this coming weekend if I have time.

Any chance one of the intake gaskets slipped during install?

Not possible as I watched very closely as I inserted all the bolts for the intake.

Charlie

[mldeolde]

glad to hear that things are starting to look better. really strange if the problem is only on one side. the only thing i can say now is maybe the bore hone was not adequate and the bores were a little loose causeing less pressure on the rings than they would normally have making breakin much loner and more difficult. running it hard may have been just the trick to force the rings to seat due to the increased pressures placed on them. sometimes ddoing the wrong thing can be the right thing to do. scarry thought!!!!!!!!!!!!!!!!!

[ozzymoose]

yeah , they just dont want to seat in a hurry sometimes, give it another oil change with really cheap oil the thinner the better and take it for another fang for another 200 miles or so go a bit hard on her on the way up and cruise back. The slightly thinner oil should help her seat properly if she is a late bloomer, let the rings get into that nice hone you gave it. Then go to your fav oil.
Let us know how she does.--- Moose

[starfire383]

Your PCV system is set up wrong. Those are designed to be a pull thru system that draws vapor from once side to the other. Meaning PCV valve in one valve cover, breather in the other.

Doubt it's the cause, just an FYI. The way you have it now probably isn't effecively scavenging crankcase vapor, so it's gonna pollute the oil faster.

Something for the next owner to worry about