Oil fouled plugs, eating oil

[panteramatt]

I changed the oil in my 74 and all of a sudden it ate like 3 quarts in a few miles, never did before. Changed it to rotella t 15w40 with a little lucas oil stabilizer and it still eats oil. No smoke at all and compression is 150 on all cylinders give or take 5 psi. Almost all plugs are oil fouled and not old. It has a holley sniper on it. What should I look for? I also just put new bronco script valve covers on and ran the passenger breather straight to the sniper where it was vented to atmosphere before. Could that be the issue? No major oil leaks and coolant is clean.







All reactions:
99

 

[Broncobowsher]

Proper baffling in the valve cover is my first go to. If oil is splashed at the PCV, it will suck it up and burn it through the engine. And since this started as soon as you put new valve covers on, hard to be anything else.

Valve cover and crankcase venting issues.

 

[panteramatt]

The valve cover has a baffle in it though but Im not running a pcv just an elbow from the valve cover to the sniper

 

[Broncobowsher]

Need that PCV valve to throttle the suction. Right now you have unlimited pull everything possible through the valve cover into the engine.

 

[panteramatt]

Will it hurt anything to remove it from the sniper and just put a filter on the valve cover?

 

[Johnnyb]

Will it hurt anything to remove it from the sniper and just put a filter on the valve cover?

I tried venting (instead of PCV) and eventually decided to install a proper PCV. Helps vent the motor and keeps engine smells out of the cab and in the exhaust.
-JB

 

[Broncobowsher]

PCV is not a part, it is a system. Fresh air in one side, picks up blowby and moisture as it passes through the engine, and goes through the PCV valve as it gets sucked into the engine to be burned.

It replaced the old road draft system where there was still a fresh air inlet to the engine, but the blowby was drafted out with a tube that just vented into the air passing under the car. This went away in the early 60's.

The PCV system did a couple of good things. Enviromental of burning the unburned fuel vapors that were in the crankcase was one. The bigger one was it really helped the engines run much longer. The PCV system actively vented the crankcase. This kept the inside of the engine much cleaner. Engines last longer.

Race cars typically don't have a PCV system. They just run vented breathers. They don't care. Race engines are short lived. There will be damage in other ways before lack of active ventilation is a problem.

So just putting a filter on it, isn't really a good long term answer. Work on getting a functional PCV system going. From the right PCV valve to baffles that are effective at keeping splash away from the PCV valve.

 

[73azbronco]

Poor poor race engines...