Early Hemi (51) Oil pump drive

Discussion about the Hemi in general.

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jagster
Posts: 4
Joined: Wed Aug 17, 2011 4:16 pm

Early Hemi (51) Oil pump drive

Postby jagster » Thu Aug 18, 2011 11:20 am

Just when I thought I knew most everything about the early hemis, I'm out there about to pre-oil this old lump before trying to start her up after a lot of years of sitting idle (40 years), and I go to pull the intermediate shaft that drives the distributor. No problem. So, I am about to go into the oil pump with my handy hex head 'spinner' and whoa!, different drive dog. And I thought all these small-block originals kept pretty much all the internals the same. Well, there is the big 'slot' on the top of the pump shaft. I am planning on a new pump at some point and need to know if the newer style pump will bolt on the block or if some sort of adaptor is available? I got a piece of half-inch rod, and will make the 'female' slot to get the job done, but that was a surprise. Just thought I'd share this with the group. Ron

DavidBraley
Posts: 163
Joined: Sat Jan 30, 2010 7:40 pm
Location: Fort Collins, Colorado

Re: Early Hemi (51) Oil pump drive

Postby DavidBraley » Fri Aug 19, 2011 12:49 am

You will find that the oil pump drive shaft is just a tad under 1/2". It's 0.486" to be a little closer. It needs to be that size to fit inside the bronze guide bushing. 8)
Horsepower determines how fast you hit the wall. Torque determines the size of the hole you make. Holzwarth's Law

George
Posts: 627
Joined: Wed Aug 25, 2004 4:12 pm
Location: Fl

Re: Early Hemi (51) Oil pump drive

Postby George » Sat Aug 20, 2011 3:42 pm

jagster wrote:Just when I thought I knew most everything about the early hemis, I'm out there about to pre-oil this old lump before trying to start her up after a lot of years of sitting idle (40 years), and I go to pull the intermediate shaft that drives the distributor. No problem. So, I am about to go into the oil pump with my handy hex head 'spinner' and whoa!, different drive dog. And I thought all these small-block originals kept pretty much all the internals the same. Well, there is the big 'slot' on the top of the pump shaft. I am planning on a new pump at some point and need to know if the newer style pump will bolt on the block or if some sort of adaptor is available? I got a piece of half-inch rod, and will make the 'female' slot to get the job done, but that was a surprise. Just thought I'd share this with the group. Ron

there's nothing wrong with the OEM pump, get a rebuilt kit if it needs it. There are adaptor kits for LA pumps, but there are problems with some of them. The LA HV pump only gives a skight increase in flow.


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