MGB & GT Forum

problem with new County uprated pump fitment -

referring back to this thread - Oil pump misfit
- - Dave Headley wrote "you can produce more or less pump tipping and you can have block, pump and spindle shaft size variation, which all can effect the binding." - -

all the following discussion is without torquing the pump down - (that will be the next step in checking for spindle bind once i get decent loose fitment)

there is apparently some problem with my new County pump body "bumping something" in the bore or on the flat, to the extent it does not fully bottom or mate with the machined flat in my block, resulting in it being able to be rocked or tipped - and i can feel it "rising" slightly, as if riding over a tiny hump, when i rotate it in place w/o studs - blue dye indicates that it is not contacting all around the flat - (we are looking at maybe .007 tipping clearance on the high side)

I have already done all the Flowspeed recommended pump improvements Flowspeed Pump mods

yes, I have already chamfered the area where the body could contact the slight non-machined ridge on the block flat - that is not the source of the problem (fwiw the County pump body casting is thicker than the Eaton, so this is a definite necessity)

I have also blue-dyed all the other surfaces and carefully measured & inspected the block bores & both pumps' mating collars and fitting depths; also chamfered the block stud holes to assure they were not causing this

- now maybe a gasket stack can fix this, but a single 'thick' gasket does not do it, and it seems it would take a stack of the oem paper gaskets to seal off the inlet port so the pump can't "suck air" (I ordered 10 of 'em from Moss last nite) - AND, stacking up gaskets might only accentuate the spindle binding potential

for comparison, my old Eaton pump fits perfectly flat & does not "bump up" when rotated in place

I have tried both these in 2 different blocks with same results

So what do you Engine Builders do about this????

I have a couple more pump questions, but will confine this query to this single issue (more posts coming)

- pictures - County vs Eaton

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ASE Master Tech 35 yrs
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MGB parts FS & '63 MGB FS
- view pdf on Google docs ..... https://tinyurl.com/MGB-FS-list-06-2022

my car: https://pbase.com/emoze/1963_mgb_

You've certainly invested more effort and heartache into this than most people would have. Hats off to you for that.

With all the issues I've read about County oil pumps, I think I'm going to just rebuild my OE pumps in future with a new gerotor assembly.

http://www.bpnorthwest.com/mg/mgb/engine-main-components/oil-pump-repair-kit-mgb-65-80.html

Are those pumps the same?

What happened to the bore in the oem pump look destroyed? Stacking gaskets to solve a machining problem?

X2-Ben rebuilt one that had 80+K it came out perfect,OP right on the money. Packed the pump and the pressure came right up.

Thanks all - I am going to use my old Eaton pump body -