Technical > Matt Shaff's Engine Shop

Looses oil pressure

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Guido:
I have a Dart little m block 400 Cid fresh build with a melling 10550st high volume oil pump and a 7qt pan. When I make a 1/4 mile pass it looses oil pressure the last hundred feet or so and after I let off it comes back. I go through the traps at 7800 rpm could it be sucking the pan dry?

denverflatheader:
Guido - you know what happens to your oil pressure when the car is moving to WOT.  Try it in the pits stationary and rpm up to 7800rpm and hold it there a few seconds to see if oil pressure drops off.  If it does, then you need to explore where the oil is sitting (i.e. valley or heads) and how to improve the restriction so it flows down faster to the oil pan. 

I'm guessing if it holds oil pressure constant at 7800rpm when stationary, then the issue is probably more related to your oil pan design.  Alan

JEFF/21C:
denverflatheader is most likely right, bad pan design,oil level to close to the crankshaft,or lack of oil control and if oil drains back from the top end and you have a good windage tray and oil pick-up placement and design. I've had problems with pans in the past.

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