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Old 02-07-18, 11:04
David Herbert David Herbert is offline
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Join Date: Mar 2010
Location: Ayrshire, Scotland - previously Suffolk
Posts: 547
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Colin,
The pick up assembly is purely a device designed to give the pump a pool of oil to draw from. The critical part of designing the intake to the pump is that there is oil there under all possible circumstances. In a tank this is more critical when the vehicle is going uphill as the engine will usually be at full throttle then whereas downhill it will usually be coasting so much less bearing load. Side slopes are a mid condition and flat usually easy to provide for. As I said before I think it is very important that you increase the oil capacity as much as is practical to prevent the oil overheating. It is not an option to use a car sump even if it was shallow enough to fit over the cross tube as you will boil the oil if you ever do any more than just potter about. Also loading onto a truck will let the pickup run dry as cars are not designed to be on that kind of slope. Remember that these tanks pitch badly both forwards and backwards in addition to the gradient.

Most relatively modern engines have the pipe from the pump going straight to the lowest point of the sump with a simple wire mesh strainer on the end and a tin shroud over that so that there only needs to be about 1/2" of oil to cover the intake. The CMP pickup is just a rather complicated version of that. Also modern oils have additives to reduce the foaming that wartime oils did not have. The CMP pickup would have been intended to try to separate air from the oil but that function is just not required any more.

You can have the pipe to the pump at any angle but the shorter it is the better. It is critical that it does not vibrate as it will vey quickly fall off ! It is also necessary that there is some sort of mesh to stop lose bits of rubbish being sucked in. Other than that it is just a matter of arranging things so that there is as much chance as possible of there being oil covering the end of the suction pipe. Sheet metal baffles that reduce the movement of the oil away from the pickup on slopes but still collect it from above can usually be designed and can be welded to the inside of the sump or fixed to the pickup as in what you have.

Not rocket science but just need some thought. Have fun !

David

PS: Colin posts much faster than me so I had not seen his solution when I wrote the above. I would put a horizontal baffle in the sump at the same hight as the new section and carrying on the line of the new section to almost the pickup. This would trap oil below it on uphill slopes but allow it to drain into the lower part of the sump on the flat. As it is you only have the capacity of the pickup assembly available when you are on an uphill slope and the oil has gone to the other end of the sump. The problem is that having reversed the engine the pickup is at the wrong end of the sump though I do agree that having the drain over the access hole in the floor is a good thing so the deep end of the sump needs to be where it is.

Last edited by David Herbert; 02-07-18 at 11:40.
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