Oil pump rebuilder
- Thread starter JHarley
- Start date
3twinridges
Well-known member
I don’t know Harley but man that’s a cool truck in your avatar, what is it?
JB
JB
tubman
Well-known member
I believe that the late model pumps with the helical gears are superior to the early pumps. They will fit into all flatheads, though there are fitment problems with the oil pickup on some models. Seeing that the oil pump is the best lubricated engine component, they seldom go bad. An inspection and a check of the cover clearance (the only published specification I can find) should be adequate. At the same time, a new relief spring should be installed, as the old ones tend to get "tired".
In my experience, just about all late model pumps are good if they look good (no scoring, etc.) and are a better choice than aftermarket pumps.
In my experience, just about all late model pumps are good if they look good (no scoring, etc.) and are a better choice than aftermarket pumps.
rockfla
Well-known member
Yes, IF you use the 8BA style pump, for the 36 you will have to modify the oil pick-up AS well as cut the baffle in the oil pan and remove the cup in the bottom of the pan from the old style oil pump. "IF" you are so interested....I first measured the depth of my pan and made a "go no go" template so once I cut the oil pick up I could measure just how much needed to be removed and cleared everything that it needed to clear. Once I cut the required amount out to the supply side side of the tube, I used that piece that i cut out to TIG weld on the underside of the on the pick up tube side to get the pickup closer to the bottom of the pan/Screen than stock. Once I had the pick up TIG welded up, I made a template of the block where the pump bolts up and used that to mount the oil pump into the pan. That gave me where I needed to cut the baffle to accomadate the large pick-up bell of the tube. Then I cut the baffle and bolted all of into the pan, this also allowed me to make sure I had proper distance between the bottom of the pan and the bottom of the pickup bell. There you have it in a nut shell.
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rockfla
Well-known member
Yes, TerryOH makes a good point for all the "early" blocks using the 8BA to be sure and leave your 50psi oil pressure relief valve in the block.....ALSO as an aside. I use an O-Ring in the groove of the oil pump housing by the flange where it meets the block to seal it off.....It "may not" make any difference BUT it cannot hurt anything either and its assurance oil stays where its intended!!!
KiWinUS
Well-known member
No sure I agree with above. I have a 36LB that has 80lb pump and springs. Has been that way for over 20 years. No leaks or issues.
rockfla
Well-known member
Tony (I agree with you), I think, wouldn't there be a conflict of the stock oil pressure sender most will already have installed (50 psi) AND would the potential of 80psi have issues with the stock gauge as well??? My current engine shows 55psi on a manual gauge I have installed at the block boss just on spinning the starter (haven't run it yet).
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Mac VP
Well-known member
Assuming that there are no leaks elsewhere in the oil supply network, the oil pressure for the entire system will be controlled by the weakest relief spring. The 8BA pumps have built in pressure relief springs rated for 80 psi. The 1932-40 blocks were built with the separate relief having a 50 psi spring. The oil flow will always seek the weakest point to relieve and that would be the stock factory relief with its 50 psi spring. You could theoretically have a 100 psi pump and a 10 psi block pressure relief……the system will always relieve at the 10 psi point.
Ford went with an 80 psi block relief spring in 1941. This was well before the 8BA pumps with their built in 80 psi relief spring. The block rear oil seals were rope instead of the slinger in 1941 so I suspect Ford felt it okay to bump up the system pressure since they were changing to the (improved) rear rope seal setup.
The 32-40 blocks may have worked fine at 80 psi with fresh new rear main bearings, but I’d be a little concerned about rear main leakage at 80 psi with the old style slingers and a worn rear main bearing.
Ford went with an 80 psi block relief spring in 1941. This was well before the 8BA pumps with their built in 80 psi relief spring. The block rear oil seals were rope instead of the slinger in 1941 so I suspect Ford felt it okay to bump up the system pressure since they were changing to the (improved) rear rope seal setup.
The 32-40 blocks may have worked fine at 80 psi with fresh new rear main bearings, but I’d be a little concerned about rear main leakage at 80 psi with the old style slingers and a worn rear main bearing.
tubman
Well-known member
Aren't the 8BA relief springs rated at 55-60 psi? Every good 8BA I've ever had ran around that pressure at highway speeds. I was always under the impression that when everything is in good working order, maximum oil pressure is controlled by the relief spring (hence its name).
