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Old 08-13-2009, 09:32 AM
mitchc mitchc is offline
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Can you provide some more engine info. What heads, intake, valve covers. Have you had the heads off? If so what did the pistons look like. If you have a clean out side edge on the pistons that would indicate oil coming from the rings. What does the exhaust ports look like. dry or wet with oil.

I just went thru this with a friends 32 he built a 350 and had a oil problem on the right side and we could not find it. new rings, new .003 over valves in the heads new viton seals, etc. nothing helped. we noticed that #8 exhaust port was wet with oil so we check the exhaust valve and it was good. We put a diffrent set of heads on and the problem went away. I think there was a crack in the head down around the short inside bolt and it was getting into the exhaust.



Quote:
Originally Posted by y2k600f4
I'll try not to go into much detail but as some of you may recall I am having the same oil consumption issues on my recent SBC 383 10.5:1 rebuild as I did prior to the rebuild and for the 1st 500 miles I was averaging 1 qt +++ oil useage. The car has been with the builder for 2.5 weeks and it has just had been one ordeal after the other and seems like unrelated items keep braking including a recently replaced lower speedometer cable that failed by melting on exhaust, dipstick tube breaking at block etc (moved to make room for wires). Anyway here is a recap of the items already troubleshooted by the builder.

1. Compression test (185 exactly in all cylinders..no cylinder to cylinder variation)
2. leak down test (good)
3. new viton valve seals for 2nd time (previously changed during rebuild) and valve guides within spec (wanted to rule out heads)
3. PCV (suspect); "temporarily" removed and replaced with dual breather setup...believes it was sucking oil due to incorrect/faulty PCV.
4. new plugs (hot) and wires...old plugs were oil fouled with the worst ones on the driver's side (much more evident).

So far a faulty PVC and bad wires (couple cylinders on driver's side were getting minimum spark) were diagnosed and the latest test drive showed ~1/4 qt of oil consumption in 50-60 miles (about 1/2 as before so progress is being made) with smoke during idle eliminated however it seems like when you rev the throttle you get smoke mostly on the driver's side. One plug was pulled on each side after the test drive...the passenger side is showing the start of a good burn pattern and the driver's side showing some slight oil glazing. Also to note that there is baffles in the valve covers and NO oil residue at all in the breathers even after 600 miles or so, which I would expect the breathers to be drenched with oil with that kind of oil consumption if it was an issue with blowby due to rings/cylinders but I could be wrong.

Anyway to get back to the post subject the next item my builder wants to rule out is the intake sucking oil from the galley. I beleive his plans are to back off the rockers to close the valves, remove the carb and construct a custom plate so to pump compressed air in the intake to observe if there is any leaks in the intake gasket causing oil to be sucked up from the lifter galley.

My question wouldn't that issue been evident when the intake was removed previously ? (I had it off prior to rebuild and back of intake valves had no signs of burn oil, they were bone dry and clean); however when the builder dissasembled before rebuild he noticed inside the intake was oily which was evident when he wiped a clean rag in the intake. I know if you see clouds of blue smoke coming out when engine is revved that it is a sign the intake is "puddling" up oil in high vacuum conditions and it`s not being drawn in until it`s revved. If this is the possible case would it also be evident of oil on back of intake valves and associated deposits ?
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