Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties UL Oil Pump

UL Oil Pump

Post Sun Jan 01, 2006 2:42 pm

Posts: 801
Location: Planet Earth
First question
Is there any advantage in using the later rather than the early oil pump? Other than having the extra by pass passage in the early pump.

Has anyone played around with using a stronger pressure regulating spring? Either a stronger spring or by shimming the stock one?


Post Sun Jan 01, 2006 4:55 pm

Posts: 614
Location: Roxboro, North Carolina, U.S.A.

Jim -

I use a multi-weight synthetic. And, as long as I register pressure, along with return to the tank, I see no real advantage of one over the other. Which is to say, I'm really giving an answer to your second question. I start out with the factory setting on the pressure regulator. And, only tweak it up when the engine is hot, so that the oil pressure light stays off at a moderately fast idle. Then, I don't touch it any more. Never seen the advantage of a stronger spring. If the engine is worn to the point that you can't get what you need out of the stock spring, it's time for a rebuild.


Post Tue Jan 03, 2006 6:38 pm

Posts: 148
Location: Dorothy, NJ. USA

the early and late are the same, the one in the middle has the wierd slinger thingy to limit excess oil delivery at higher speeds. now that oil control rings have improved along with cylinder boring technology getting rounder I feel that the little slinger thingy is just something extra to go wrong, but mine has not in 30+ years, but if it does I'll put in an older or newer one 'cause I got em. They look smoother too! Honest!

Post Thu Jan 05, 2006 8:06 am

One more time: there are 3 pumps.

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