For various clearance and space reasons, I'm looking into setting up a wet sump with an external oil pump. Pickup would be welded through the pan. My engine of choice (Chrysler 3.6) routes oil up through the block, out the top (in the filter housing), then back into the block, so I'm already blessed with a hole for the oil to go back into the engine.
I'd like to use a crank-mounted pump, and I see the LS/Mods/Hemis/some others use them, so I know they're available. I would fabricate an exceedingly sturdy mounting frame for the pump to bolt on the engine, keeping it in alignment. I would then either machine up a custom pulley with a pump drive, or some kind of snout extension to drive the pump.
The crux of the question: can these normally-internally-mounted crank driven pumps be mounted outside of the engine? I assume they're lubricated by the oil itself, and I assume they're sealed (otherwise they wouldn't build pressure). Is this viable?
seems possible, but often the ports of an oil pump when internal to the engine are just like a hole in the plate it mounts against or something. So I predict a lot of fabrication just to make the oil pump housing and oil ports. Then you have to figure out port sizes, shaft seals, etc, reengineering a lot of stuff.
Here's an oil pump that came up first on google images that shows sort of what I am referring to.
Then again, if you think one (or maybe two?) motorcycle oil pumps would be enough, they are generally already setup with a shaft to drive them and seals and ports. Also they are sickeningly cheap on ebay. In fact, if you want it I've got a 2009 cbr600rr pump that is basically new that I will give you if you think you can use it.
Example from ebay right now:
I don't mind reengineering some of that. This would be in alternative to converting to a rear-mount rack in a miata chassis, so I wouldn't have to make new steering arms/deal with all of that jazz. I'd rather use the factory Miata stuff
Seems like an accessory drive pump would be easier? Concentric gerotor pumps have to be mounted pretty precisely and re-engineering an engine to support that would be a real challenge.
Some automotive engines, like BMW inline sixes from the 90s and 00s, use a chain driven pump that might work. Most pumps like this use a pressure regulator that vents outside the pump casing back into the pan, so rerouting that could be a challenge.
Motorcycles often run quite low oil pressures and volumes compared to cars. Not sure how well that would work, or how many pumps you would need.
I'm sure there is a good reason, but why not use the pressure stage from a dry sump pump?
The biggest issue would be that oil pumps built to run inside the engine pay no attention to sealing. If oil leaks past the drive shaft or through the mating surfaces, well, it just goes into the oil pan so who cares.
I did see where someone used a small block Chevy oil pump to make a dry sump pump for a Subaru Justy engine, but I don't recall how he dealt with sealing.
Chrysler RB style oil pump?
Buy some used circle track dry sump parts. They're usually set up to run with a cog belt off of a crank mounted mandrel, and they are sealed with AN inlet and outlet ports. You could run just one pressure section or get fancy with suction stages.
+1 for used circle track bits.
Also I always thought an electrically driven oil pump would be an awesome idea...no worries about blowing up the pump at high engine RPMs, can easily build oil pressure before cranking, could do fancy things like vary pressure based on multiple maps and delay factors, could even detect engine wear algorithmically ...you would have to worry about the electric motor failing, but you wouldn't have to worry about the belt failing, which is occasionally an issue with dry sumps.
MGB's are notorious for shelling the oil pump driveshaft at high rpm. Some use sacrificial bronze pump gears to save the cam, others switch to a belt driven pump designed for external use on a wet sump engine.
https://www.petersonfluidsys.com/pump_wetsump.html#specs
