Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

BBC oil restrictors

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Kevin Johnson
HotPass
HotPass
Posts: 9028
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: BBC oil restrictors

Post by Kevin Johnson »

Belgian1979 wrote: Sat Jul 04, 2020 10:45 am 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>
yves a.jpg
You do not have the required permissions to view the files attached to this post.
Belgian1979
Guru
Guru
Posts: 4059
Joined: Sat Mar 26, 2011 11:34 am
Location: Belgium - Koersel

Re: BBC oil restrictors

Post by Belgian1979 »

Kevin Johnson wrote: Sat Jul 04, 2020 5:43 pm
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
Unbelievable that you kept all of that Kevin. I remember that one. The graph shows the straight line up to about 900-1000 rpm and then the bypass starts to have effect.
I remember that you could potentially block the internal passage and have the pump return the oil to the pan. I don't remember anymore why I didn't go this route, but probably due to some side effect.
Kevin Johnson
HotPass
HotPass
Posts: 9028
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: BBC oil restrictors

Post by Kevin Johnson »

Belgian1979 wrote: Sun Jul 05, 2020 7:41 am ....
Unbelievable that you kept all of that Kevin. I remember that one. The graph shows the straight line up to about 900-1000 rpm and then the bypass starts to have effect.
I remember that you could potentially block the internal passage and have the pump return the oil to the pan. I don't remember anymore why I didn't go this route, but probably due to some side effect.
One side effect of the internally by-passed oil being churned is that it pulverizes any entrained bubbles into smaller bubbles. Smaller bubbles go into solution in the pump (higher pressure) more felicitously. This means the oil delivered to the bearing is more "solid."
70MC
Pro
Pro
Posts: 302
Joined: Thu Oct 07, 2004 1:12 am
Location: Austintown, Oh.

Re: BBC oil restrictors

Post by 70MC »

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.
The tray in my pan fits tight to the edge of my pan on the down stroke side of the pan, with the exception of the small kick out the pan has to clear large strokes. I took a ball peen hammer to the tray and made it fit tight at the kick out. The gap was small, about .040 to .060. I took pick of my pan, how do I download them?
A bad day of racing is better than a good day of work
70MC
Pro
Pro
Posts: 302
Joined: Thu Oct 07, 2004 1:12 am
Location: Austintown, Oh.

Re: BBC oil restrictors

Post by 70MC »

One of the things I would like to add to this pan is a trap door, but I called every major pan company and none of them will sell a trap door. I found aluminum trap doors for aluminum pans, but mine is metal.
Can anyone help with finding one?
A bad day of racing is better than a good day of work
User avatar
MadBill
HotPass
HotPass
Posts: 14758
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: BBC oil restrictors

Post by MadBill »

70MC wrote: Thu Jul 09, 2020 6:07 pm One of the things I would like to add to this pan is a trap door, but I called every major pan company and none of them will sell a trap door. I found aluminum trap doors for aluminum pans, but mine is metal.
Can anyone help with finding one?
Could you use an aluminum door and bolt the hinge to the pan?
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
Kevin Johnson
HotPass
HotPass
Posts: 9028
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: BBC oil restrictors

Post by Kevin Johnson »

70MC wrote: Thu Jul 09, 2020 6:07 pm One of the things I would like to add to this pan is a trap door, but I called every major pan company and none of them will sell a trap door. I found aluminum trap doors for aluminum pans, but mine is metal.
Can anyone help with finding one?
I considered purchasing small prefab hinges for trap doors but with at least hundreds of different trap doors that was impractical.

I buy dozens of lengths of brake line and 1/8" steel rod that nests in the ID. Bend short sections of the rod using a brake. Be sure to use an insert for the brake that has a rounded edge to avoid creating a stress raiser. Trim the brake line to the length of the door and carefully MIG it to the top edge of the door. Drill holes in the bulkhead on either side of the trap door for the other end of the bent rod sections. MIG or TIG the backside extending section of rod.

So you will need to make a cardboard template of the bulkhead and door. Small sections of sheet steel can be found in hardware stores.

You can see examples of the doors in this video:

https://youtu.be/arb5quRCkKA
Belgian1979
Guru
Guru
Posts: 4059
Joined: Sat Mar 26, 2011 11:34 am
Location: Belgium - Koersel

Re: BBC oil restrictors

Post by Belgian1979 »

70MC wrote: Thu Jul 09, 2020 6:07 pm One of the things I would like to add to this pan is a trap door, but I called every major pan company and none of them will sell a trap door. I found aluminum trap doors for aluminum pans, but mine is metal.
Can anyone help with finding one?
rivetting it in place?
Kevin Johnson
HotPass
HotPass
Posts: 9028
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: BBC oil restrictors

Post by Kevin Johnson »

Pictures from 70mc:
You do not have the required permissions to view the files attached to this post.
70MC
Pro
Pro
Posts: 302
Joined: Thu Oct 07, 2004 1:12 am
Location: Austintown, Oh.

Re: BBC oil restrictors

Post by 70MC »

Thanks for posting the pictures Kevin.
When I installed this pan, I had to cut the tray to clear the titan pump a small amount on the side near the end of the pan, and I did not like how much the sump was exposed so I added an inch to the tray to cover more of the oil in the sump to help keep windage out.
I called Kevco and they are sending me a trap door. They said they can make it the size I wanted, they made it and mailed it the same day, should be here today. Real nice people to talk to.

I removed the lifter valley screens, more than doubled the length of the return holes in the head and made them about .020 wider, thats as wide as they could be because that is up against the valve cover wall of the head.
I am going to add a fuel pump block off plate with the AN fitting that runs to the valve cover to aid in venting.

I am not going to do the external drain lines. Since I thought there was an issue with the pump, I did not measure the clearance to the firewall before removing the engine to see if there is room for the plumbing, plus I think the rest of the plumbing to the pan will be a nightmare routing around headers and starter, ect.

I do not want to install this engine without being 100% sure I fixed my problem. I still would like to add restrictors to limit a very small amount going to the top of the engine. In the very little I can find on restrictor hole size, It appears that I would drill the restrictor holes to .100 to .125 to do very little restricting?
A bad day of racing is better than a good day of work
Kevin Johnson
HotPass
HotPass
Posts: 9028
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: BBC oil restrictors

Post by Kevin Johnson »

70MC wrote: Wed Jul 15, 2020 9:30 am ...
I am going to add a fuel pump block off plate with the AN fitting that runs to the valve cover to aid in venting.

...
I do not have a BBC core to examine -- on some other engines this area is exposed to direct windage flow and you would be dynamically pressurizing the valve cover volume. Who knows -- maybe that ultimately would be a positive thing BUT is this what you are intending?

If not, then I suggest making a simple interior baffle to block direct flow to your block-off-plate fitting. Maybe it can be integral with the plate itself.

With oil drain passages from the heads, some engines use a side jogging passage to interfere with this flow out of the crankcase and back up to the head.
User avatar
af2
HotPass
HotPass
Posts: 6661
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: BBC oil restrictors

Post by af2 »

The pan with the radius on the left side will make it even worse. the wind-age will pull the oil straight up the straight side of the pan and uncover the pick-up.
GURU is only a name.
Adam
User avatar
af2
HotPass
HotPass
Posts: 6661
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: BBC oil restrictors

Post by af2 »

I had a similar pan that on my 431" would kill the pressure at 6000. I cut that radius out and added a 2" kick-out on the right side under the starter and fixed the problem. I shifted it at 8000 with no drop in pressure. I can see with the stroke you are running the pressure drop would be sooner like it is.
GURU is only a name.
Adam
69chev496
New Member
New Member
Posts: 1
Joined: Tue May 20, 2008 6:50 am
Location:

Re: BBC oil restrictors

Post by 69chev496 »

Let me share my experience. I have a 598 with AFR 335 CNC "S" version heads. I found there was not enough ventilation holes drilled in the heads. What happened is the blow-by escaping the sump into the valve covers to exit the breathers was blocking the oil flow return from the valve covers to the sump and the valve covers were filling with oil during a hard run. This happened under load when the blow by was greater. When the engine returned to idle, the blow by was reduced allowing the oil to return to the sump. I ended up drilling additional holes in the heads to allow ventilation solving my issue. I see the AFR heads were a change you made. Not sure what vintage heads you have. I believe AFR fixed this issue with their newer heads. I can find some pictures if needed.
70MC
Pro
Pro
Posts: 302
Joined: Thu Oct 07, 2004 1:12 am
Location: Austintown, Oh.

Re: BBC oil restrictors

Post by 70MC »

af2 wrote: Wed Jul 15, 2020 10:42 am I had a similar pan that on my 431" would kill the pressure at 6000. I cut that radius out and added a 2" kick-out on the right side under the starter and fixed the problem. I shifted it at 8000 with no drop in pressure. I can see with the stroke you are running the pressure drop would be sooner like it is.
I understand what you're saying.
A bad day of racing is better than a good day of work
Post Reply