Fredscott

Gentlemen
I have a nicely built 406. On the pcv system consists of a passenger side pcv which is connected to a recovery tank which in turn is connected to the large vac port on a holley 750...this is the pcv circuit. the recovery tank fills very quickly (2 days, 3/4 qt) so of course I figured bad rings/blow-by. I just did a leak-down test and all cylinders are excellent! this is my wtf situation....could I have too much vacuum on the pcv and am just sucking oil out of the passenger side? the covers are baffled, the plugs are burning as clean as can be....Im confused.
any suggestions would be greatly appreciated.
Thanks!!!

REELAV8R

PVC is normally on the drivers side with vent on the passengers side.
Is there at least a vent on the drivers side valve cover in your set up?

Fredscott

I have a fairly large vent on the drivers side cover. Might this be backwards? does the engine want the pcv on the drivers side? I didn't think it would make a difference, but its easy enough to change!
Thanks

MelWff

the side it is on shouldnt make a difference, Pontiacs have it dead center on the valley cover. I'm unclear why a PCV would be using a recovery tank and also am curious about the valve covers internally if they are contributing to the PCV sucking up too much oil.

gkull

The pvc would have to be sucking up oil splash to get that much in a few days.

I don't believe in even having a PVC with manifold vacuum.

twin breathers are the first best mod. Second is a vacuum pump. Third is dry sump

REELAV8R

If could make a difference. Maybe as simple as one valve cover has better baffle than the other one. The engine does have an air flow direction due to the rotation of the crank.
I'd give it a shot to see what happens.

7T1vette

I also suspect that there is no oil baffle below the pcv valve opening. That would allow the crankcase pressure to blow oil out along with the crankcase vapors. The PO probably had blue smoke coming out the back until installing the recovery tank (to capture all the liquid oil).

Pull that valve cover and, if needed, install some kind of baffle plate that will block splashed oil, but allow vapors to flow around it.

Also, as mentioned, there should be a hose from the other valve cover going up to the [filtered] air cleaner base. That is where fresh air is brought in to purge the crankcase. Without a supply of fresh air, the pcv valve will flow very little. You may also want to flush the pcv valve out with solvent...because of the crud it has probably built up inside it. Then, you can remove the collection tank from the system.

hugie82

It only takes a little mist of oil to be sucked up and fill the recovery tank. Maybe some heavy steel wool inside the breather tube can reduce oil savaging?

Fredscott

Im doing some research on the oil pump...I'm wondering if it is a high volume/high pressure pump with the the road race oil pan. I have to find the receipts that came with the short block....it would be nice if it were that easy.

MelWff

Not sure why you think the oil pump would cause your problem? Did you check the interior of the valve cover as mentioned above?

Fredscott

I did check the baffles...they are intact and in excellent condition. I just researched the purchase of the pump and its an M55 High Volume pump with a big block pick up (?). Seems to me I am getting way too much oil to the top end and this must be why.

7T1vette

With the little drain-back holes in the stock heads, that high-volume pump will FILL the valve covers. Best leave that recovery tank in place until you resolve the excess oil issue. If it were me, I'd stick a stock pump back into the engine.

lionelhutz

A high volume pump won't fill the valve covers. It won't pump any more oil to the top end than a standard pump. Mostly, you just waste HP with a high volume pump by pumping more oil through the pressure bypass.

gkull

When You run a higher vol oil pump smarter people block off the bypass and use higher pressure oil filters. Then you use the oil weight to adjust your pressure.

In stock block motors you restrict the oil to the top end with block restrictors. I used drilled out Morroso block restrictors something like .100 vs the as sold .050.

Another simple choice is restricked pushrods

http://www.jegs.com/p/Comp-Cams/Comp...73464/10002/-1

7T1vette

Hmmm... A "high volume" oil pump that doesn't pump MORE oil.....

Fredscott

I spoke with tech at the manufacturer and they researched the original order. the pump that was ordered to this pan is a high volume pump with a big block pick up. It absolutely does pump more oil to the top end (i.e. "high volume") and it is overcoming the returns on the AFR heads. I cant vouch for what these "smarter people" do, but I'm going back to the stock pump with the correct pick up....this should solve the problem.

gkull

Is this directed at me? if it is, it just show a lack of understanding about things that are wrong with stock block gen 1 chevy motors. I'm not even sure what your statement means.

racers figured out that you needed more oil to the crank and less to top end...... That is where they came up with the cam valley oil restrictors in the back of the block. The restrictors work great in a high rpm only motor. That is why I drilled mine out for less restriction to the top end. My 7500 rpm rev limited 383 also has to idle around town and is only doing 2500 rpm going down the freeway in OD



After market dart and Motown corrected the stock block oiling system with priority oiling to the mains

gkull

For years I ran a pvc with high vol pump in none restricted oil system with AFR heads.

I used tall valve covers and stud girdles. The stud girdles block oil splash to the top of the valve covers and I had no massive loss of oil like you are experiencing.

AFR heads oil return hole is more than enough in size at both ends of the heads. They just don't have a clear oil return channel on the lower side of the heads. So the oil level is above the lower side gasket. I had my heads machined to correct this years later.

Just showing my stud girdle getting starting to set the valves on a new motor

Lt1er

Fred, I'm with gkull on this one. I don't believe that changing the pump will accomplish anything.

I have solid lifters and a hivol melling pump for 15 years now without a problem. My oil pump was setup with shims behind the oil bypass spring. Raising the point where oil will bypass up to about 75 psi. So only on a cold start the oil might bypass never at up to heat thinner oil

The big block pickup might be required to place the screen slightly of the bottom of your Canton pan.

I would not believe 7T1vette on motor related subjects. I've read some of his other posts

lionelhutz

How the hell can a HV pump pump more oil when it has the same pressure as the normal pump?

Now, if it's a high volume and high pressure pump, the oil flow increases due to the higher pressure. But no-one here has posted anything about running a higher pressure.