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**rusty nut garage** · 03-12-2009, 06:00 AM

I've rebuilt 3 of these in the past and haven't had to mill the pump body but yours may have greater wear. I'm not sure how many different pump rebuild vendors are making these kits. I know that at least one of the kits I used had mellings shrink wrap on it the others if memory serves were unmarked.
Having said all that I don't see a problem with milling the pump body to decrease the overall endplay of the gears.
Russ

quote:Originally posted by Pinchbolt

Hi, everyone; I've been looking through the archives here for the answer, so my question isn't redundant. But, it may be unique. I am rebuilding my 289, that had been sitting partially disassembled for awhile. It hadn't had any serious trauma, that I can see. On the first order of business, since new oil pumps are not readily available, reconditioning the old one was the only option. I bought a kit from an individual in the LA area who adertises in TW. It contained just a bottom plate, and pair of gears. Here is the situation: The old gears are past the outside limits of clearance, with .008 endplay, and .006 side clearance. The LS gearset has .013 end clearance, but the side clearance is within limits. By that, I mean a .004 feeler gage can be inserted, but an .005 can't be inserted. I measured the length of the gears with a mic, and the difference between the length of the gears is even greater. The original gears are 1.499, and the replacements are +/-1.493. The drive gear measures half a thousanth difference from one side to the other! Now, in case you notice a discrepancy in the clearance vs the overall length of the gears, there is a chamfer on the OEM gears, that the LS gears don't have. Plus, an unworn area in the pump body that creates a ridge.I tried to chamfer the new gears slightly to address this issue, but it didn't quite take care of it. I've been sitting here, thinking that maybe I'll take the pump body over to a local machine shop, have them mill say .005 off of the pump body, and set the drive gear in the pump body and lay it on a piece of glass with 220 grit and wd40, and true it up. Or, What? Buy the Melling Oil Pump Kit, and start over? On the whole, I don't mind having to figure things out for myself; but don't care to reinvent the wheel. That, is why I'm troubling you folks. What do you think? Anyone been there before?

Russ Shop Foreman "Rusty Nut Garage"
53 2R6 289 5SpdOD (driver)
57 SH (project)
60 Lark VIII 2dr sd (driver)

**PackardV8** · 03-12-2009, 06:49 AM

FWIW,

1. If your pump body is sufficiently worn to have a ridge inside, it should be replaced. Stude V8 oil pumps are relatively plentiful and inexpensive. Before spending bucks to take yours to a machine shop, which usually has a minimum charge, find another pump to compare with yours. Does anyone on this forum have a V8 oil pump apart who could measure gear height, body depth for this poster? Does anyone have a better pump body to sell him?

2. If you choose to repair yours and make the LS gears fit, the cast iron pump body can be cut .005" by hand with aluminum oxide paper on a flat surface and a bit of time and patience.

3. The Melling kit is probably less expensive than the machine shop charge.

thnx, jack vines

PackardV8

**Mike Van Veghten** · 03-12-2009, 08:15 AM

I can say for fact that the shop time in the milling operation won't be cheap. Unless you know the guy running the mill and are good friends..!
There is no good/easy way of holding that pump.
I asked a shop to do some work for me in making the interior of the pump into a big oval rather than the strange shape that it is to help increase the efficiency of the pump. He had it for a week or so...called me and said he didn't have time to do the work. BUT..upon carefull inspection, I found vice marks all over it..!
And we even talked about some sort of holding fixture. Oh well...I hand ground those little tips away.

Mike

**Pinchbolt** · 03-14-2009, 12:24 AM

Thanks for your responses, all. The machine shop I had in mind milled a pair of Mopar exhaust manifold flanges back in 91, and redrilled a set of axle flanges for me in 1996. They call themselves "Economy Machine", and lived up to their name. It isn't that I haven't considered using sandpaper on a sheet of glass to reduce clearance on my oil pump. Just that my previous experience as as machinest and then as an Autobody Tech tells Me that taking a .005 or more cut on the cast iron pump flange using a hand method like this might not be feasible. It might not be square. OTHOH, I figured that the pump body could be bolted to the mill table thorough the hole for the pump drive gear. The flange for the pump output ports would square it. Just to be sure, a couple of blocks could be put on the table to support it, as well. Then, flycut it. Hey--I'm NOT going to hire an attorney to do it, so it shouldn't take months and $1000 of dollars to get the job done. Tell you what though: I have some sheets of Emery cloth, and flat glass,, and will work with them a bit, and see how long it takes to remove just a couple .001 clearance. Thing is, after doing some more study, I am not so sure it is necessary to be a fanatic about end play. See, the Buick people have an oil pump setup that really is the weak link. That one is an engine design that is the Mickey Dee motor; Billions served, almost. It is external, and remotely located in the aluminum timing cover housing. The gears are way smaller than our beloved Studes. . And, case in point: so are the gears in the small-block chevy pump.Puny, by comparison. My observation leads me to believe that it appears the submerged, large gear Studebaker pump is part of a high volume,(yet) low pressure system, can tolerant some wear, and still do its' job, by virtue of some overkill engineering, there. Meanwhile, I've read that a Buick engineer maintains that It is the gear tooth-to-pump-wall clearance that is critical; whereas end play can deviate considerably, and not be a problem. Those Buicks use a gasket on the bottom plate, where Studes do not. Guess the stdebaker designers were not terribly concerned about a little leakage, either. That said, I will cautiously sand my pump body flange awhile to decrease clearance, using the prescribed methods, and hopefully save a trip to Economy Machine. Will let you know how it turns out.

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