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MG MGB Technical - Oil Pan Anti-Surge Baffle Position?

I am getting ready to weld an anti-surge baffle into a stock oil pan for my 1980 MGB. This prevents the oil pickup from losing contact with the oil as the oil is pushed to one side of the pan when cornering hard.

My car was originally built for dual-purpose use (street and track). It will see most time on the street, but I do expect to use it for autocrossing.

Soon after the motor was built, the car had experienced brief oil starvation due to oil moving away from the oil pickup at a high speed sweeping turn at the track. Upon teardown, it turned out that only one rod bearing was out of spec, although all plain bearings were replaced.

Since I'll be using race tires for autocrossing, I don't want to take any chances with oil surge, so I'll be adding a baffle.

The Special Tuning Manual shows a drawing of the baffle and it also describes a modification to increase the depth of the oil pan by 1-inch in order to increase oil capacity so that during racing, the level does not drop too low.

I am very vigilant regarding oil level, so i felt that the last paragraph of the "Engine oil sump" section in the Special Tuning Manual applies. It states that "For short circuits, where oil levels may not drop, the standard depth of sump should be found satisfactory, but the surge baffle should be made up and fitted as illustrated."

I have a question about the proper position of the baffle in the stock depth pan. The Special Tuning Manual shows a 2.25" height above the bottom of the modified (1" deeper than stock) pan.

So, using the baffle in the stock pan, should the distance from the bottom of the stock pan be 1.25" (since I'm not increasing the depth of the pan), or should it remain at 2.25" from the bottom? It seems that 1.25" from the bottom of the pan to the bottom of the baffle is rather shallow, but I don't know how far down the oil pickup sits.

If it remains at 2.25", the baffle would be below the level of the shallow portion of the oil pan that gives clearance for the crossmember. Assuming the crank doesn't bottom out in the shallow section of the pan, I assume that it shouldn't hit the baffle plate. I'm not sure whether at 2.25" would the oil still be able to flow away from the pickup?

Any thoughts on the 1.25" vs. 2.25" palcement of the baffle?

Thanks,
Dave
sliedavs

Dave,

Your post is very timely. Last night I was making a cardboard template for such a baffle.

I had been going to put my baffle almost in line with the shallow section. I see that I may be wrong.

When working out where to put the hole in the baffle I turned the block over and fitted the pump body and pick up so I could take measurements. Having read your post I realise that I should have measured the verticle offset between the block bottom flange and the pick up. Such a measurement could then be used to establish the correct verticle location for the baffle.

Don't forget the dip stick hole!

What are you making your baffle out of? I would have used aluminium but I don't have any scrap big enough. So I am using 0.8mm galv steel sheet. I am not welding it in. Instead I am welding on brackets and bolting the baffle to them.

David
David Witham

I too am about to make up a baffle - the Cambridge Motorsport ally sump has the baffle level with the shallow ledge - but I can't see the point of putting the baffle higher than the static oil level in the sump, since any higher than that would leave an air space above the oil that would allow the oil to surge up to the plate.
Chris at Octarine Services

David,
I'm using steel sheet metal that is approximately 0.50" thick.


Chris,
I agree with you reasoning regarding placing the baffle at or near the oil level.

I measured that the "MAX" mark on the dipstick is located at 2.875" above the floor when I hold the dipstick in the proper position alongside the engine. The lowest point (closest to the ground)of the shllow section of the oil pan is about 3" above the ground. Therefore I reason that the baffle should be mounted roughly in line with the low point of the shallow section.

Any differing opinions?
sliedavs

I have only seen pictures of the Cambridge Motorsport cast sump. As I tell my children don't touch what you cant afford.

I think the baffle should have a slight "V" or curve to it. This will encourage oil on the baffle to drain towards the hole in the middle.

David
David Witham

1) Plug the sump and, using a bubble level, make it level on both its logitudinal and lateral axis.
2) Fill the sump with the appropriate amount of oil that you normally have after a fresh oil change.
3) Scribe each corner of the interior of the sump at the level of the oil.
4) Drain the sump and clean it.
5) Place the sump baffle at the height of the scribed corners and weld it in.
Steve S.

The top of the baffle should be level with the top plate of the oil pump pick-up. This way, you get a fairly good seal and the oil cannot surge up out of the hole in the baffle around the oil pick-up. Measure from the block bottom face to the pick-up plate and then position the baffle this distance down from the top of the sump. It should be slightly lower than the shallow section of the sump.

My pan has a baffle that was installed by an MGB race engine builder and that is where he put it. It was essentially fabricated to the shape and dimensions shown in the MGB tuning manual. He slightly, and I mean very slightly, dished the baffle so that any oil on top will tend to drain to the pump pick-up. Also, he put in weep holes at the corners of the baffle to allow oil to drain down during hard cornering. And lastly, don't forget the hole for the dipstick.

Sliedavs, I hope you meant that you are using steel that is 0.05" thick and not one half inch. 16 guage steel is fine for the baffle. And when welding in the baffle, you do not need a continuous weld. Short stitch welds spaced about 1 inch apart work just fine. The baffle does not have to be oil tight, it just has to restrict large flow of the oil away from the oil pick-up.
Ron Kluwe

This thread was discussed between 09/03/2004 and 10/03/2004

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