Engine Problems

[cadmanof50s]

Sorry for such a long post....

I have a 68 with a 327 engine. Although it is not the engine that this car left the factory with, it is a Camaro engine (build date is Oct. 13, 1967)..my car appears to have been assembled in March of 1968.
When I purchased the car it had a Holley 457S style carb and an aluminum Holley intake (neither is correct..but functional).
I acquired the car in the early summer and ran it almost daily until September. It ran very well at first but after a week or two I noticed that it  started using oil and this became progressively worst. I did not see any oil leaks under the engine..I assumed it was burning it.
By the end of September the car was backfiring, losing power and even stalling. I pulled the plugs out and 6 out of 8 were so badly fouled that the end of the plug looked like one black mass of oil and soot. Attached  picture shows one of the better plugs.
I decided to have the engine rebuilt because it was (to me) obvious that the engine was burning  oil. Once the engine was apart we saw some wear on the rings but not enough to create the mess that we were seeing on the plugs..

When I was taking the engine apart, I noticed that the intake manifold bolts were barely finger tight. If I'm not mistaken these should have been torqued down to about 35 ft-lbs. or so.
If the intake was not bolted down properly, is it possible that it was taking in oil (and air) from the valley under the intake? Could this have been the cause of the oil burning?

Two other things I noticed.
1. The engine timing when I first got the car was ridiculously advanced....like 18 degrees. I brought it back down to about 6 degrees..
2. Unlike other V8s I have worked with, this car would not ping. ..no matter what the timing was set for. (I know pinging is a bad thing and should be avoided....BUT if the timing was far enough advanced this engine should ping. It didn't...I don't get it.

Could these two issues have anything to do with the oil burning?

Vic

[JohnZ]

Heavy oil fouling like that is usually the result of either failed valve stem seals or oil ingestion from the lifter valley into the intake ports due to bad intake manifold gasket sealing. In either case, you should see heavy black deposits on the back side of the intake valves.

[cadmanof50s]

Thanks John.

I think you may have confirmed my suspesion that an improperlly torqued intake manifold was the culprit.
I still have to check the valve stem seals..

Sad part about it is, it just cost me a whole engine rebuild (where it probably didn't need it).

Vic

[hotrod68]

  For my 2 cents, backing the timing down to 6 degrees (I assume at the balancer) seems a little drastic. Those old 327s loved around 10-12 degrees initial. They idled better, had better throttle response, and pulled more idle vacuum. As long as they didn't ping or start hard that was the way to go. If it was a 2bbl engine or 250hp 4bbl originally it didn't have a lot of compression anyway, which is probably why it didn't knock with you. At 6 degrees, I would imagine it was an unresponsive slug.

[cadmanof50s]

hotrod,

right on both points. It was originally a 2 bbl. And it become more sluggish when set to 6 degree....I was just following the shop manual.

But I will defintely set it higher once I get it back together.

Thanks!!

Vic