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Reply to "Building a faux cam Carrera track car"

Stan Galat posted:

David,

I know that your have a dry sump system-- converted from a wet-sump system, and I'm 99.9% sure that the conversion was done by Ron L. after he had the engine built, installed, and running. That's why there's a dipstick on the engine-- because the dipstick tube was already there, and putting a dipstick in it is a decent way to keep from puking oil out the hole. Here's what I did with mine:

Blank-off

I think I finally understand the confusion. I believe you want to know why there's a level in the sump, as it can't bleed backwards that quickly (it's not overnight, it's "right now").

I've got one big question-- does your oil pump look like this?

CB Dry Sump

^^^ A CB dry-sump pump is only about 1-1/2" thick. ^^^

Or does it look more like this:

AutoCraft Dry Sump

^^^ An AutoCraft or Buck-Pack pump ^^^ sticks much further away from the case-- like about 3- 4" out to the face of the pump.

The pumps we are talking about are "2-stage" pumps-- they are 2 separate pumps in the same housing*. With both of the pumps above, there is a "scavenge" pump, and a "pressure" pump. The scavenge pump sucks the oil out of the engine and puts it into the reservoir, the pressure pump sucks it out of the reservoir and puts it back in the engine bearings. The oil can be filtered and cooled in either system, but almost everybody (except me) does it in the scavenge circuit.

The scavenge pump will always be bigger than the pressure pump, because the whole goal is to keep the sump dry ("dry sump", get it?).

As you can see from the thickness of the pumps, the impellers on the AutoCraft pump are a lot bigger than those on the CB pump. A LOT bigger.

Why? Well... packaging. The big drawback to a nice, big dry-sump pump is two things

*FWIW, AutoCraft (and Moroso, and a lot of other people) make multi-stage pumps with many scavenge circuits pulling from a lot of different places (valve-covers, etc.), all dumping back in the reservoir. They're really, really funky looking and are typically belt-driven.

The deeper you go into this stuff, the cooler it gets. Good luck. If you decide to go to a bigger pump, get out your wallet-- it's goes pretty sideways, pretty fast.

Thanks for all that, Stan. My pump is more like the CB Perfromance example you showed above. Here's two pics. The second pic (from the rear) has a very dirty finned surface and two rows of lettering and only part of the bottom row is legible....last three digits might be HES. 

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Images (2)
  • Oil pump bottom view
  • Oil pump rear view
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