Oil Consumption with full Engine Specs

[CowBoyRoy81]

Hello all....understand that I will pull the intake manifold off this weekend to see if I've got a leak and oil is getting sucked in. Also will inspect plugs to see if it's limited to one cylinder, but I did this a little while ago and don't remember a specific spark plug being worse off.

I'm going through an excessive amount of oil. Definitely going into the engine. Zero drops of anything on the ground and the exhaust tips have nasty black soot, more than there should be even if she were a diesel. When I get on it she does smoke a little, but nothing at idle

I have researched and want to post my specs/history because maybe I damaged the valve seals? Ultimately is there a chance I damaged the valve train? I read that too much lift with too much of the head being shaved could damage the lifters? Also with .040 removed off the heads and nothing removed off the intake could I have created a passage for oil to be sucked into the intake?

Engine 1: original 1971 318 with 1970's LA heads shaved .040 of the cylinder face and milled to 2.02/1.88 valve sizes. Installed a Cam with I believe .292/.292 & .501/.501. Had some issues which I thought was too much Cam so I installed a 268/272 & .460/.480. but ultimately the 318 was replaced with engine #2. Ran Edelbrock Performer intake w/650DP

Engine 2 (current engine): 1974 360 bored .030 and about 5k miles. Same heads and smaller Cam. Only the shortblock was replaced.

Any help appreciated!

 

[Alaskan_TA]

Rebuilt engines in both cases?

If so, what oil did you run for the break in period on each one?

 

[CowBoyRoy81]

Rebuilt engines in both cases?

If so, what oil did you run for the break in period on each one?

318 was 60k mile survivor. 360 rebuilt shortblock. Forgot the exact weight but did use zinc additive. Oil weight would have been based on the small block mopar bible I've got from before the internet

 

[furrystump]

You may have a vacuum leak. Get spray bottle with water. Spray intake with engine running see if idle changes. If it is leaking into the valley it might not change the idle.

 

[Rat Bastid]

Make sure you aren’t pulling oil through the PCV system.

 

[Professor Fate]

^^^Exactly. How are you venting the crankcase? PCV with breather (preferably vented to the air cleaner) on opposite side? Are your valve covers baffled beneath the pcv and breather?

 

[Garrett Ellison]

.030 is getting right on the edge of how much you can mill off the heads and not run into problems with an un-milled intake when factory tolerance stack-up isn't working against you. You really should have the intake milled at .040 even if it's not the immediate problem.

 

[K.O. SWINGER]

So I'd put a new set of plugs in it put about 50 mi with some good load burse on it and read the plugs that should let you know if it's an individual cylinder/gasket leak or if you have problems throughout the system . Also you might want to get the motor up to operating temperature

 

[CowBoyRoy81]

^^^Exactly. How are you venting the crankcase? PCV with breather (preferably vented to the air cleaner) on opposite side? Are your valve covers baffled beneath the pcv and breather?

Mopar Performance valve covers, baffles both sides. PCV on one side and breather on the other. Not a PCV issue

 

[CowBoyRoy81]

.030 is getting right on the edge of how much you can mill off the heads and not run into problems with an un-milled intake when factory tolerance stack-up isn't working against you. You really should have the intake milled at .040 even if it's not the immediate problem.

I fully understand what you mean, everytime i take the intake of its a chore to put back on. I'll mill it when it comes off for inspection

 

[Professor Fate]

.030 is getting right on the edge of how much you can mill off the heads and not run into problems with an un-milled intake when factory tolerance stack-up isn't working against you. You really should have the intake milled at .040 even if it's not the immediate problem.

Alternatively, you could have the heads milled on the intake face; that way you're not "married" to that particular intake. Future intake swaps can be done without needing to have the new intake milled, and the old intake can be sold or used on a different engine that may not have had the heads milled.
A quick search turned up the numbers .0123 off the intake surface for every .010 off the head, but you may want to confirm that...

 

[Alaskan_TA]

318 was 60k mile survivor. 360 rebuilt shortblock. Forgot the exact weight but did use zinc additive. Oil weight would have been based on the small block mopar bible I've got from before the internet

Synthetic or normal for break in ?

 

[AJ/FormS]

STOP!
You do not have to take the intake off to find a valley leak!
It's way easier than that; Simply flip the PCV out of the Grommet and seal the hole. Then take the breather out of the other side. With the engine idling, put your hand on the open cover and attempt to seal it. If your hand gets sucked on, badaboom you got a valley leak.
but if you get a pressure build-up, then no valley leak
unless
your engine is creating excessive amounts of blow-by, that is negating the valley leak, but that would be crazy.
Excessive blow-by is obvious; with the PCV defeated smoke will be belching out of the other cover.
Your breather must be OPEN, and breathing in BOTH directions. At WOT, lots of engines make more blow-by than the PCV can deal with.That is even normal. But that pressure has to get out of the engine before it blows something else out, like the rear Cam-plug! That would suck. Backwards thru the breather is normal.
If the engine is burning oil, it will be easy to spot on the back of the exhaust valves.
If your engine is running rich; the gas will wash the oil off the cylinder walls, and it will be burned or flushed out into the headers. In the meantime, look for damaged skirts, worn-out rings, hard starting due to lack of cylinder pressure, and gas in the oil.
With a long-period cam, the intake manifold will get sooted up inside the ports.
Many an engine has been ruined by running rich.
Many an oil-burner was cured by cleaning up the carb.
And finally, late ignition timing will allow the hot expanding and still-burning gasses, Plus some only partially burned gasses, to chase the piston down to the bottom, and burn the oil right off the cylinder walls.