Topic: Burning oil!
in Forum: C3 Engines
ineresting topic
Love to hera more abuote avoiding oil over the whole engine from my brethers, Heard that some use cocke bottles for collecting oil from the crankhousevent.
Does any body have agood idea. My 355 runs about 7000rpm and does on the dragstrip 7.601 on 1/8 mile whit NoS, but boy dose it smoke oil after.
Its called vacuum pulling it over through the baffle. We had an engine that we built three years ago for power tour. 418 cubes with a mild hyd roller, made 500 hp and 500 lb ft and made so much vacuum that it sucked the oil over. At first we thought it was because there were no valve stem seals, but we were burning a quart every 100 miles. When we got to a hotel we added the seals to the valve stems which was interesting because we only had three hours before dark. We looked like a winston cup team.
Anyway that did not fix it. We lived with just putting oil into the engine during our gas stops. After we got back we pulled the engine, put it on the dyno and so we could observe it under load. There was no power drop so we knew it had something else going on. The first thing we did was install a clear pvc tube from the pcv valve to the intake port and sure enough when we started it up you could see it starting to suck oil up through this line.
What we did to correct it was put on a set of Circle track valve covers that have the tall breather stacks on it. Solved the problem, but they looked out of place on our 32 3 window street rod.
Might want to give that a try, but you are correct that the blue smoke is more prevelant during decel and during idle.
As far as that drag engine, a dry sump system or an accumulator will help. You can also vent the breathers straight to the header collectors. This causes any excess oil to be blown out the exhaust rather then sucked through the engine and burned in the cylinders.

You can also try a different calibration PCV valve. Get one that pulls less volume, and you may be able to compensate for it a bit. Be sure you valve covers have the baffle in them. Some do not when supplied by aftermarket. The good ones do. Yours does have it, but is it correct?
There is more vacuum at decell than at any other time, so it is more likely to pull oil at that time. If your problem was valve seals, it would not show oil in the valve and PCV line. If it was due to rings, you would have excessive blow by, and the problem would likely be worse durning acelleration, when there is greater cylinder pressure creating more blowby.
The PCV must be connected to a vacuum source to operate anywhere near properly. Manifold vacuum is the point of normal operation.
Connecting to the headers works very well due to exhaust vacuum pulses, but you will still be consuming oil. It won't be burning in the engine, but folks behind you will hate getting the oil drops from you exhaust on their windsheild. If you don't mind adding some oil, it works well. EPA hates it.
I would start with After Shark's suggestion.
Tumarr,
I am having exactly the same problem. I tried a couple of different PCV valves that I was told were "correct." with no luck. My motor is a stock 327/300 - PCV on left side, vent on the right - Stock painted steel valve covers.
Not gearing down at stops has helped a little, but I'm still getting a mouthful of smoke @ some red lights.
I'll try another PCV with different calibration.............Again.
Anthony
Uh Oh! I thought all PCV's were the same. I put a new one on as soon as I bought the car and not sure if it is correct. Seems like I am burning alot of oil too but still checking on that. Just something else to look at. If it is sucking oil, do I ask for a "weaker" PCV at NAPA?
Thanks
Neil