Re: [AMC-list] 195.6 ohv engine build, always takes longer and costs more...

[Frank Swygert <farna@xxxxxxx>]

Wait a minute... since you blocked the oil return in the 65 pump you only have the bypass in the main oil gallery. The one in the pump cover no longer has a place to dump excess oil pressure, which would have gone back to the pan. I don't think that's a problem. There can only be as much pressure in the system as it will hold, so it won't hold more than 70 psi. Pressure might go up a little more due to the limitation of flow through the bypass, but I doubt the oil filter will ever see more than 75 psi, which should be fine. Or am I confused about how the cover bypass valve works? I have a 65 pump, but it's still on the 65 L-head in the 65 American. 

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Date: Mon, 22 Feb 2010 11:49:37 -0800
From: tom jennings <tomj@xxxxxxx>

I figured out how to put the 65 oil pump on the early block. I've set aside
the 63 pump mods; it's all worked out and machined, the problem is, it
leaves  the pressure bypass AFTER the filter, so in really cold weather the
pump will jam cold thick oil into the filter which could burst it or shear
the pin, worst-case. Since I have no idea how high pressure would want to go
w/o a bypass, I'm not doing it. This has got to work 100% first time every
time, I don't have a research budget.

But the 65 pump has the bypass in the cover. The problem with that pump is,
the block casting was changed to accomodate it; they milled a passageway in
the pump that is closed by a flat in the block. But the fix turned out to be
easy: I milled the floor of the cast passageway flat, and made a circular
plug that fits into it, when assembled on the block it seals the passageway
to the main gallery. Its easy to see in photos.

Now I have TWO pressure bypasses (one after, one before). I'll stiffen up
the "after" one with a spacer under the spring (raise the pressure to
something useless) so I don't have to worry about it being less pressure
than the other and leaking off oil from the main gallery. I think that's
more reliable than a kludge to seal it.




--
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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