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Re: Sumps again

To: "Neil Cotty" <neilc@apphosting.com>
Subject: Re: Sumps again
From: Barney Gaylord <barneymg@ntsource.com>
Date: Mon, 21 Aug 2000 16:27:02 -0500
At 10:47 PM 8/21/2000 +1000, Neil Cotty wrote:
>Urgh,

Believe me Neil, I understand.

>.... I have a 1600 Mk1 block. This sump, the sump .... does not fit over
the oil pump strainer and the sump does not lay flat on the block. In fact
there is a good mm or two clearance in the centre part of the sump. ....

Someone has obviously been doing some offroading.  You need to bang the
bottom of the sump out flat again, or get a better one.

>Looking in the Moss catalog there are two types of strainers (and oil
pumps), a flat based one, and a round style like on the MGB. Which should I
have on my motor?

Take the flat based one and see how far you can throw it!

The early 1500's had the flat based oil strainer with the side port, and an
oil pump with a vertical pickup and right angle entry port.  At engine
number GB46342 (still during 1500 production) this was changed to the bowl
shaped strainer with top port, and oil pump with the angled pickup, which
is the same as used on the 3-maim MGB motors.  The earlier type oil pump is
generally no longer available, which is just as well.  The later one can be
(and should be) used in its place along with the newer type strainer.  It
is possible to fit either oil pump bottom cover and pickup to the pump, but
please do not refit the earlier type of pickup to a new oil pump.

The earlier style oil pickup is a lot more restrictive than the later one.
I have a couple of badly scored crankshafts and a few sets of totally
demolished rod bearings to demonstrate the point.  After a bit of tinkering
I have determined the displacement of the oil pump.  It will pump about 0.8
quart of oil per second at 6000 rpm engine speed, and it only has
atmospheric pressure to push that much oil up through the screen and pickup
ports.  I can tell you from personal experience that when it tries to move
56 quarts of oil per minute at 7000 RPM the earlier type oil pump will
cavitate, and both the oil pressure and the oil flow will instantly drop to
zero.  Just a few seconds later, with no oil flow to provide cooling of the
bearings, the oil film breaks down and the white metal on the face of the
rod bearings melts and flows out the sides of the journal like hot wax.
After that the copper and steel backing materials in the bearing shell
quickly wreak halvoc with the (previously) smooth bearing journal on the
cankshaft.  Thank you, I feel much better now.

>Should the strainer touch the bottom of the sump? I should think not - ? ....

No, but it's okay if they come pretty close together.  You need about 1/8
inch of clearance between the pickup pipe and the pan, and the screen can
occupy some of that space.

>Soo what do I do, do I have to find another Mk1 sump

If you can beat the bottom out flat, and get the top flange flat enough to
seal the gasket, and it doesn't develope any cracks in the process, you can
continue to use that sump.  If the dents and wrinkles bother your sense of
beauty, then you might want to look for another one.

>or is my problem in the type of strainer/oil pump I'm using?!?

As mentioned above, ditch the early style oil pickup and use the later
style parts.

>Not to mention the sump gasket in the gasket set is so way off it's not
funny, had to cut it out and enlarge the holes.

The 3-main and 5-main engines use different oil pumps with different
gaskets which are not interchangeable.  The MGB 3-main engine uses the same
oil pump and gasket as the MGA.

Barney Gaylord
1958 MGA with an attitude
    http://www.ntsource.com/~barneymg


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