Re: [AMC-list] failed 195.6 OHV oil pump....

[tom jennings <tomj@xxxxxxx>]

On Tue, Jul 6, 2010 at 8:48 AM, Sandwich Maker <adh@xxxxxxxxxxxxxxxxx> wrote:

> how about shallow v-grooves spiraling in under the gear end, to help
> pull oil in?

Well last night I spent some time with the modded pump I removed. I
excruciatingly checked the parallelism of the cover plate to the
inside base (I'd milled and filed it to reduce the clearance). It was
clean and I used my Starrett caliper (it has the depth tool on it's
butt).

I could find no error greater than half a thousandth. So it wasn't my
machining. So I looked at some used covers I have, and they all have
very (very) light scoring. I think I simply made it too tight, and
like Frank says, gears grew (with temperature) or it simply pressed
through the oil film, through unevenness or whatever.

But the lesson with the stock pump is, the factory clearances are
fine. 40psi at idle, 60 above 1500 is more than enough. At 1500 the
relief valve is dumping oil into the pan; the pump pushing harder than
that is doing no good.

My custom cover is undamaged, I just resurfaced it on a ground steel
plate with wet-or-dry in 15 minutes.

I'm going to drive with the stock pump for a week or two, I'm sick of
working on it for now! The full-flow portion of this mod never caused
any problems, other than my hose hassles, which I could have avoided
by buying the custom hoses at the start.


I realized too, to plug the stock pump outlet all I need is a steel
"gasket" missing that one hole, under an unmodified pump. It can be
very thin because there's the same pressure on both sides of it. The
one possible drawback is that it shims the pump drive gear out the
combined thickness, but I have a clean block, camshaft and pump with
which I can check gear mesh. Then you can do the full-flow conversion
with zero modifications to the pump or motor. And with the engine in
the car!

* stock pump is plenty of volume for this engine, I proved that much!
* steel gasket plugs stock pump outlet
* custom cover provides new pump outlet
* one particular flare fitting is best on the new cover ($8, I have part number)
* hex socket screws for the pump cover (clearance issue)
* two $10 custom hoses
* "remote filter kit" for Wix 1374 filter
* some brass fittings
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