How is the oil return from the heads, and valley?

 

It is returned through the stock head and block passages. Hoping my test will show if I have a return problem.

 

What engine block are you using Bill??

 

Are you using a baffle or gasket already? Can you add washers to space the pick-up were it bolts to the pump?

 

It is a dart block,and the measurement includes the gasket thickness.

The oil pump I has the pickup welded on, I really don't want to start prying on it to get it to move.

I filled the pan with oil and ran the oil pump for about 5 minutes. Oil level only dropped approximately 1/2 quart. I pulled a valve cover off while I ran it. Oil volume in the valve cover seems pretty modest. Just a steady trickle off of each rocker. Granted I was only running the pump at half the speed I will see at the track. Even if the observed volume doubled, I still wouldn't be worried about it.

 

I had considered drilling and tapping large drain holes in back lower corner of my heads for a drain back to oil pan. I believe it has to get a pretty good puddle of oil in there before it starts draining back into pan and the holes are rather small so even when they do start returning oil it is not very fast. You also have to consider that there is a lot of air coming up through those same holes the oil is trying to go down through and that may slow it down some. I have good oil pressure all the way down the track but when I hit brakes it will drop quickly. So yes baffling inside could be better but volume of oil in the pan is low at that time or it would not happen. I called AFR and they said on my heads there is no water at that location and it would help get the oil back down in pan. I also think a lot of oil is getting trapped up in lifter valley. Putting drain back hoses in back of heads would eliminate much of that problem. I run 8 quarts in my system and I bet at end of run there is less than 2 quarts in pan.
I agree with you I would not feel comfortable depending on accumulator to keep oil pressure all way down track. Come up with a better solution and the accumulator only if there is some strange issue as a safety.

 

The standard pump may eliminate much of your problem and give you more power to. As long as you have enough volume and pressure anything more is lost power and harder to control oil.

 

Bill, have you seen the new Melling (ST) “Shark Tooth” pumps??

 

I see in your sig that you are at 1.29 60', around 2.2 G's average. To the oil in your pan, that's like having your engine tilted up in front appx 65 degrees. Add the degrees from the wheelie in your avtar, the oil in your pan will be about 80 degrees from level in that first 60' or so. I'd want the pickup as far back as possible under those conditions.

When you imagine the engine operating WOT with the nose tilted up 80 degrees, it's easy to see that very little oil is going to return from the front of the lifter valley. Do everything you can to make sure the oil return paths are free flowing from the rear. The front returns are important too, but instead of returning oil, they become a path for crankcase pressure to reach the top of the engine

 

Those sharktooth pumps look pretty slick.

I put the same pump I had in the motor before I had the rebuild so I know its more than adequate. Dart doesn't recommend a high volume pumps with their priority main oiling system.

I really find it hard to believe that oil is getting stuck in the valve covers. If anything, I believe the excess oil draining back is becoming aerated as it drains back through the crank.

I have filled my motor up with oil without the valve covers on and it gets rid of it pretty quick. Also consider, Typical sbc move around 8-10 gallons of oil per minute. So your moving a gallon of oil every 6 seconds. So my car moves a gallon of oil in the course of a 6 second pass. So out of the gallon, to me it would be reasonable to believe the majority of the oil is going to the mains. So that leaves less than two quarts going to the valve covers. So starting with 7 quarts in the pan, you still have 3 quarts in the pan assuming that no oil drains back to the sump. I really don't see oil getting stuck in the top of the motor being my issue.

 

Agreed on the standard volume pump for the Dart blocks. My second rebuild on my SHP this year I had the re-builder replace the standard volume pump that had the Stefs pickup welded on and use the Melling 10552 that is only 10% more volume than the standard pump. I’ve read that Carl Hinkson use this same pump in many of his builds and wanted to try it.

I use a Stefs 6qt pan w/ filter and the shop used a Kevko pick-up for the new pump. The first build of the engine by a different shop had me using my accusump as I still had oil pressure loss at 140 in the shutdown. With the new rebuild I no longer had oil pressure problems in the shutdown no matter how hard I used the brakes. I didn’t used the accusump after this, so I drained the accusump and cable tied the manual valve closed on it for the 2016 season. I didn’t do the installation , but the shop that replaced the pump said the original pick-up was set to the correct depth. The Stefs pick-up was an upside down funnel and the Kevko is a box style.

 

On a BBC, M77HV pump, if you put 3 quarts in the stock style pan, fill the oil filter before you screw it on and prelube it with a drill driven tool, it will go off suction in less than a minute. At 4 quarts it takes a little longer, but same result. At 5 quarts it will hold pressure. Where is all that oil at if the pump can empty the pan?

3 quart accusump is good insurance.

 

I think you'll be fine.

 

To be clear I meant pump baffle between the maincap & pump. And pump gasket. http://www.summitracing.com/parts/mil-32500/overview/year/1977/make/chevrolet/model/corvette

 

I don't have that baffle, but the windage tray goes back there. I would have to cut the windage tray to make something like that fit.

 

I don't have the exact answer but I believe 1/2" is to much and highly suggest you contact both the oil pan manufacturer and oil pump manufacturer. Too much pan to pick-up clearance can lead to a "eddy" (just like what you see in a river or stream) and will lead to a pressure loss. Too tight and the pick-up will be inefficient. I'm pretty sure the clearance is 1/4" to 3/8" but do not take my word on that. All I'm saying is you need to consult with an expert on this. I'm 98% sure 1/2" is too much.

 

You can calculate the clearance by measuring the internal pan depth and measuring the distance from the block's pan rails to pickup bottom. The difference between the two measurements will provide the pickup to pan clearance. Gaskets will add some additional clearance. Here are some recommended pickup to pan clearances: Ford Pans- 5/16-3/8 inch (.312-.375) Chevy Pans- 5/16-3/8 inch (.312-.375) All Others 5/16-3/8 inch (.312-.375). Deep sump pan pickups are submerged deeper into the oil are less sensitive to clearances. Deep sumps may have clearance up to a 1/2 inch.
Taken from the canton website

 

Per moroso in the oil pan instructions, with the deep pan, they recommend between 3/16 and 1/2 inch. So I am with manufacturers recommendation, just curious if I should tighten it up. I think the pick up location now is alot more ideal now.

 

I made my own baffle like BOOT referred to above using 1/8" thick aluminum, sandwiched by a copper gasket on both sides. That would tighten up your pickup to pan clearance close to 1/8" over the stamped steel Moroso/Milodon baffle alone, closer to 3/16" over a pump with no gasket & no baffle. Since you are wheel standing, you could make the aluminum baffle to fit closely to your pan to control the oil climbing on acceleration. Also, what weight oil are you running? Of course a thinner oil will return to the pan more quickly if your pressures will allow it. I don't know if your engine stand test is indicative of the levels in a hot, running engine since your oil is cold on the stand & the rotating assembly is in a static condition.

 

Forgot to add that I did have to make longer pump alignment studs for the rear main cap. Also I did assure that I still had adequate engagement of the distributor shaft to oil pump shaft since the pump was sitting further down in the engine.

 

Not sure what shape the end of your pickup is but, you could always modify the end by welding a skirt on the side of it (all the way around it) to reach down that additional .250" for the more desired clearance. The 1/2" you have now is the outside limit of spec, that 1/4" could be the diff between burping on the top end.... or not?


I'd take 5 or 10 min and tweak it while you're there