What the heck is going on in the oil pan?

[mbrunson427]

Jay, I'm not sure if it's the same episode of engine masters that you referenced, but on one of the episodes they do an oil pan test. They picked up 22 horse on an 818 horse engine by changing to the below pan. That pan is wide and has a screen for windage. Steve Brule actually made the comment that the pan is good enough that a dry sump doesn't really outperform it. When testing it they had the same pressure issue you're having and cited oil aeration as the culprit. They actually removed oil to solve it in their case (but of course not all situations are the same). With a 7 quart pan they got all the way down to 5 quarts before making the aeration go away. 

https://www.moroso.com/catalog/product/view/id/5804/s/chevrolet-big-block20376/

Not saying I know anything about stuff, but just regurgitating the information that they gave.

[Nightmist66]

I think Barry is on to something also with the shape of the pickup.
Maybe a modified OEM style.

Stay tuned.....


I feel a good alternative to the dry sump route is an accusump. I installed one on mine mostly for the ability to pre-oil the engine every time. But, the other thing it will do is keep the oil pressure fairly stable should you run the pickup dry for whatever reason and give you a small window of safety. I can't see any downside to an accusump.

[cammerfe]

I have used an Accusump for more than 20 years on my FE engines. I do it for the pre-oiling that's, therefore, simple---just use one of the available electric valves. Watch the oil pressure gauge while turning the engine with the starter. When the oil pressure just noses over, flip the ignition on.

KS

[babybolt]

Priceless - "my dyno junkie friend Royce"

[Royce]

That would be an accurate statement ... I just love that S--t. Nothing like seeing an engine straining and bellowing and watch the needles fly past 800 hp...I am sure I will be back for the next round...

[Royce]

As long as Jay does not hang the Dyno Monkey moniker on me...

[gregaba]

Ok guys
I am a little slow in the brain department but after looking at the link I have a question.
I am not that familar with the BBC but what difference is there in using the 168 tooth flywheel?
How would a flywheel interfer with a oil pan?
Thanks
Greg

[JERICOGTX]

As long as Jay does not hang the Dyno Monkey moniker on me...

He does now!!! LOL.

Jay, do you have a picture of the oil pump?

[Joey120373]

Ok guys
I am a little slow in the brain department but after looking at the link I have a question.
I am not that familar with the BBC but what difference is there in using the 168 tooth flywheel?
How would a flywheel interfer with a oil pan?
Thanks
Greg

I don't know for sure, but me thinks its the starter that might foul the pan ? Smaller flywheel diameter puts the starter closer to the pan?

[allrightmike]

   Is it possible the reason for more oil pressure without the vacuum pump is that the vacuum increases the size of the air bubbles that the oil pump must compress before it can actually pump oil?

[MRadke]

Assuming everything is working correctly, and there are no air bubbles, there should be less oil pressure when using the vacuum pump.  You need to think of the oil pump as a pressure adder, meaning that at a given flow and passage size and rpm, it will add x pressure to oil that is at atmospheric pressure.  If the oil is in vacuum, the pump is starting with a negative pressure value and adding to that.

[cammerfe]

Another benefit to a dry sump, not mentioned above is that the engine itself is more compact. I've owned several, but don't have one at hand right now. But memory serves that it's not unlikely that a dry sump pan only adds about six inches to the bottom of an engine assembly. That makes possible mounting the engine lower, or having more ground clearance or some combination of the two. If it's not convenient to place all the extras in the engine compartment, put the can in the trunk. You'll pay for the hose but the whole approach makes for neatness and may even contribute to fore-'n'-aft weight distribution. Use a smaller suitcase when you go on trips.

Another issue, albeit not a really big deal, is just what was mentioned above---there's no need for a vacuum pump. It certainly cleans up the front of the engine.

KS

[oldiron.fe]

                                                                                                                                                               i think most readers know oil pans/pickups  can cause problems if not correct-correct pans help good oil psi.--- i have built or added to pans from early 60s to now--NEVER lost a bearing --ran a built 427 center 66/67 before the nam.-- what worked-- scraper length of pan 1inch on pass side   about 2inch flat extended over back of sump-- -- BIGGEST NOTE 1g of force to sump with rounded bottom will let oil climb 3/4 inches to side or rear -- FIX sawsall off bottom rounded part of pan NEW all bottom with sides no rounds  -- about 88 degree angle will keep much oil from climbing--most race pans are built about this way--GOOD scraper will fit .010 or less to counterweight/rod bolts! use screen type tray-never smooth metal tray-use only with screen above ( directional type ) tray--tray should have scraper on driver side-- some hi/rev overseas tests show 8/10% hp+!! when you bounce 7000 rpm oil off hard non directed surface--look again at jays pictures  i believe BEST current wet sump has good scraper/proper screen/proper tray--2x accumulator look-Rays top t-bolt good scraper/screen/tray combination about 300$-- +accumulator set-up
                     

[galaxiex]

I think a *deep* pan is an all-around win. 

I was discussing this with Jay last night and made the comment that I've never seen this kind of pressure drops in the past, even with the exact same oil pan, pickup, oil, at 7000-7500 rpm.  However, I can't make a direct apples/apples comparison because the engines that were in that situation did not have vacuum pumps.  However, the engines that did have vacuum pumps also did not see an oil pressure drop at high rpm.

The only differences I can think of are these:

1.  I do not use windage trays.
2. I restrict oil to the lifters.

To echo one of Doug's points, I think there's an advantage to keeping oil off the crank, and this may reflect my #2 point.  The less oil that's rolling off of the cam/lifters, the less that falls onto the crankshaft. 

It would be nice to see a test without the windage tray to see what the difference would be.

As mentioned, a different oil type/viscosity may add a difference as well.

Hi Brent,


How much restriction do you use, (orifice size) and do you put the restriction in the 2 rear off-shoot passages from the main galley?


I was thinking .090 orifice.

Are the restrictions for solids only, or hyd lifters as well?

Thanks!