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BBC oil restrictors

General engine tech -- Drag Racing to Circle Track

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70MC
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Re: BBC oil restrictors

Post by 70MC »

Racing68 wrote: Wed Jul 01, 2020 4:35 pm I'm using a canton 13-334 with 10778 melling pump and 10-30 oil in my 505 with no issues. Your pan is very similar to the one i'm using but my pickup is only 5/16 from the bottom of the pan. I've never run one that far from the bottom and that could be the issue.
Maybe? But with my issue like it is at such low rpms, I think it is more than that.
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Re: BBC oil restrictors

Post by af2 »

70MC wrote: Thu Jul 02, 2020 9:30 am
af2 wrote: Wed Jul 01, 2020 10:22 am That pan has nothing to stop the oil from going up the sump and starving the pump. The extra clearance to the pan from the pump is making it worse.
Some kind of kick out is better than none in the sump.
I wished it had a trap door. Many many years ago I bought a pan for a 350 that had kickouts on the lower sides of the sump to gain oil volume and ground clearance. My machinist said he did not like that style of pan because it gives the oil more places to go instead of surrounding the pickup.
That is why you want the pick up toward the right side of the kickout.

This is the pan I run on My 403". With yours having a large stroke I would be running one also.
https://www.ebay.com/itm/BB-CHEVY-ALUMI ... 2308490456
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Re: BBC oil restrictors

Post by 70MC »

af2 wrote: Thu Jul 02, 2020 10:03 am
70MC wrote: Thu Jul 02, 2020 9:30 am
af2 wrote: Wed Jul 01, 2020 10:22 am That pan has nothing to stop the oil from going up the sump and starving the pump. The extra clearance to the pan from the pump is making it worse.
Some kind of kick out is better than none in the sump.
I wished it had a trap door. Many many years ago I bought a pan for a 350 that had kickouts on the lower sides of the sump to gain oil volume and ground clearance. My machinist said he did not like that style of pan because it gives the oil more places to go instead of surrounding the pickup.
That is why you want the pick up toward the right side of the kickout.

This is the pan I run on My 403". With yours having a large stroke I would be running one also.
https://www.ebay.com/itm/BB-CHEVY-ALUMI ... 2308490456
I see they have one listed for a Gen VI. I called the number, but it is now a private number a real nice lady informed me. It looks like that add is a few years old. Do you have any updated info for the person that makes those pans?
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Re: BBC oil restrictors

Post by Kevin Johnson »

70MC wrote: Thu Jul 02, 2020 9:12 am ...

Can you help with pics of pans that allow the stream of air to the pickup? And do you have any experience with the Milodon pan I am using Milodon 31185? Actually it is the 31186 which has a dipstick provision.
I do not have direct experience with your pan. The pictures available online are vague.

It is important to note that even if constructed pans have the same part number they MIGHT not be identical due to changes in available cores.

This is from about 6 years ago:

viewtopic.php?t=39927



Yves_1.gif






The tray has a right angle bend to stiffen it. The vertical portion acts like a downstroke scraper. The gap between it and the wall of the pan would allow high speed windage/air to be injected into the reservoir area and force its way through the swinging trap door.

Each case has to be considered separately.

I would spend more time on this but I have WELL over ten thousand images that I would need to manually sort through on many different hard drives in order to try to find the pics that Yves sent me of his pan.
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Re: BBC oil restrictors

Post by af2 »

70MC wrote: Thu Jul 02, 2020 11:12 am

That is why you want the pick up toward the right side of the kickout.

This is the pan I run on My 403". With yours having a large stroke I would be running one also.
https://www.ebay.com/itm/BB-CHEVY-ALUMI ... 2308490456
I see they have one listed for a Gen VI. I called the number, but it is now a private number a real nice lady informed me. It looks like that add is a few years old. Do you have any updated info for the person that makes those pans?
[/quote]
I e-mailed him and will get back when I get his #. I am going to fish in the mountains the next 2 days.
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Re: BBC oil restrictors

Post by Belgian1979 »

Kevin Johnson wrote: Thu Jul 02, 2020 11:12 am
70MC wrote: Thu Jul 02, 2020 9:12 am ...

Can you help with pics of pans that allow the stream of air to the pickup? And do you have any experience with the Milodon pan I am using Milodon 31185? Actually it is the 31186 which has a dipstick provision.
I do not have direct experience with your pan. The pictures available online are vague.

It is important to note that even if constructed pans have the same part number they MIGHT not be identical due to changes in available cores.

This is from about 6 years ago:

viewtopic.php?t=39927




Yves_1.gif







The tray has a right angle bend to stiffen it. The vertical portion acts like a downstroke scraper. The gap between it and the wall of the pan would allow high speed windage/air to be injected into the reservoir area and force its way through the swinging trap door.

Each case has to be considered separately.

I would spend more time on this but I have WELL over ten thousand images that I would need to manually sort through on many different hard drives in order to try to find the pics that Yves sent me of his pan.
I could look but as this is already a long time ago and since then I've changed laptops I'm not very optimistic I still have them.
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Re: BBC oil restrictors

Post by Kevin Johnson »

I found them.
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Re: BBC oil restrictors

Post by Kevin Johnson »

Kevin Johnson wrote: Fri Jul 03, 2020 7:29 am I found them.
I had to immediately leave for some appointments -- did not want Yves to look for them.

Here is a pic of the installed piece of screening.

Yves_2.gif





IMG_2593.JPG
IMG_2596.JPG
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Re: BBC oil restrictors

Post by 70MC »

Thanks Kevin.
I will take a good look at my pan to see what the gap between the pan and tray looks like.
I have never posted pictures on Speedtalk, I would like to show what the inside of my pan looks like, will take pics this weekend.
I am leaving work in a few and can not remember my password to post from my phone. I will post back after the weekend.

Have a nice 4th everyone.
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Re: BBC oil restrictors

Post by Belgian1979 »

Correct, I had to cut the baffle a little to get the pan to fit. Keving also made a screen that closed the gap on the side an something that fit around the pump =D>
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Re: BBC oil restrictors

Post by gmrocket »

Belgian1979 wrote: Tue Jun 30, 2020 2:38 pm
70MC wrote: Tue Jun 30, 2020 1:07 pm I bought a used GM 572 crate motor and changed heads (AFR), cam (solid roller by Jones),lifters (Crower), rocker arms (Crower shaft), oil pump (Titan) and oil pan (Milidon).
I ran the motor with the changes I listed with exception to the oil pump and pan with no problems. I then added the Titan pump and the Milodon pan and immediately had an oil pressure problem. The problem was an oil pressure fluctuation while steady cruising at 55mph, the rpms are around 2500, cant remember exactly. The oil pressure was bouncing from 50-to 60 lbs, and gets worse with rpms.

I sent the pump back to Titan to have inspected since I was sure there was something wrong with it because I ran this motor for a few years and it never had this problem prior to the the pump and pan change.
He found the pump to be in perfect working order and said I am not draining oil back to the pan fast enough and sucking air due to the volume of oil this pump is capable of. That answer surprised me, but I believe him. He is recommending oil restrictors, and doing what I can to ensure oil drain back. I removed the heads to enlarge the drain back holes, removed the valley screens and am seriously considering external drain back lines.

This motor is in a street strip car and may see many miles at hours at a time on the freeway. I have no experience with oil restrictors, or external dran back lines. I see Moroso makes them for the Gen VI Bow Tie motor with a .0625 orifice that can be drilled larger if needed.

I am looking for everyones thoughts on this, and recommendations for the restrictor size and external drains?
Just my .02$.

A pump will pump the maximum it can at a given rpm as it is a positive displacement pump. Always. Most pumps volume vs rpm diagram will show you that it will reach maximum volume at around 1300-1500 rpm. All it will do, when it pumps more volume than the engine needs (which depends on internal clearances) is raise pressure. It will do that until the point when the bypass will open. At that point, all of th excess will be pumped back into the pan. So in principle there is not such thing as sucking the pan dry.

A couple of things could be the problem here:
- incorrect installation of the pump screen versus the pan (not deep enough or too close to the floor of the pan).
- if suction is so strong and the pan has a large surface it could suck up the floor of the pan thereby decreasing the distance to the screen. This can be solved by welding nuts to the screen that prevent the floor from coming too close.
- Incorrect oil level in the pan.
- aeration of the oil due to the crank whipping up the oil and turning it into foam (check if the oil level in the pan is correct and the oil is below the pan baffles.

Long time ago I witnessed a similar problem on mine but it did so at high rpm. The root cause was that I neglected to test the contence of the pan before I mounted it. So I poured in the amount of oil that the manufacturer of the pan said it could contain and I marked the dipstick. I found out that amount of oil would actually make the oil level sit above the baffle of the pan. (courtesy of Kevin Johnson who gave me this advice) I adjusted the oil level to the correct height while measuring the amount of oil. I then remounted the pan, filled it up with the required amount of oil after my test. Remarked the dip stick and never had to look back again.
What do you by ,, when the bypass opens, the excess will be pumped back into the pan?
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Re: BBC oil restrictors

Post by Belgian1979 »

Well, you have valve that is internal to the pump and that limits the maximum pressure that the pump can reach. Above the set pressure the valve opens and the oil returns (either to the pan or in most case to the inlet side)
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Re: BBC oil restrictors

Post by Kevin Johnson »

https://www.titanspeed.com/Titan%20Catalog.pdf

Pages 12-13: All Titan pumps are internally bypassed.
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Re: BBC oil restrictors

Post by gmrocket »

Belgian1979 wrote: Sat Jul 04, 2020 3:08 pm Well, you have valve that is internal to the pump and that limits the maximum pressure that the pump can reach. Above the set pressure the valve opens and the oil returns (either to the pan or in most case to the inlet side)ll
Can you show me a pump that dumps excess bypass pressure into the pan?

Or, like you said, the pressure relief bypasses back into the pump inlet side..
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Re: BBC oil restrictors

Post by Kevin Johnson »

gmrocket wrote: Sat Jul 04, 2020 3:58 pm
Belgian1979 wrote: Sat Jul 04, 2020 3:08 pm Well, you have valve that is internal to the pump and that limits the maximum pressure that the pump can reach. Above the set pressure the valve opens and the oil returns (either to the pan or in most case to the inlet side)ll
Can you show me a pump that dumps excess bypass pressure into the pan?

Or, like you said, the pressure relief bypasses back into the pump inlet side..
There are many oil pumps that eject bypassed oil externally. In SAE 750051, the relative foaming effects of internal versus external relief are discussed for a V8 engine.

(At least some) Schumann pumps have external bypasses.

I think, though, that Yves is referring to the bypassed oil backing down the intake inlet (the object of the energy savings by Schumann). Melling sent him a chart:
Yves_Melling_graph.jpg
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