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263 oil pump


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I'm trying to increase my oil pressure.  I have the pan down to replace rear seal so I took the oil pump apart to check specs.  The clearance is good between the top of the pump body and the top of the helical gears.  The book says it should be .004.  One gear is .004 and the other is .005,  However, it had  a gasket between the body and the cover and it measures .009.  The book makes no mention of a gasket or whether the recommended .004 clearance is what it should be when the cover is on.  Obviously my clearance with the cover on and using that gasket is going to be .013 or .014.   So, should I install the cover without a gasket , cut a very thin gasket , or use the gasket that it has now?  Will it work without a gasket?

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  • 2 weeks later...

There is not supposed to be a gasket.  One comes with kits sometimes, and if used it ruins the oil pressure.  Back in 1965 I had to remove the pan and take the gasket out to get the proper oil pressure.  Also, all 1941-53 248/263 engines use the same oil pump.  And to increase oil pressure in 1934-1940 248 and previous engines you should use the later pump.  Gears are 25% larger.

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If that doesn't get you up to 45psi at 45-50 mph, you have other problems.  I also gained 5psi on my other 39 with an overhauled rather than rebuilt engine by switching to Shell Formula 20-50 oil.  Nobody believes me, but I've got eyeballs and can see the gauge.  The blue car runs at 45psi at 45, 15 at idle like it is supossed to.  The other car idles at about 12psi hot and runs at about 35psi hot.  Both have 1941-53 oil pumps with no gaskets.  When the blue car was first rebuilt it would only get 30psi hot until we went back and removed that oil pump gasket.

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Ran the '53 in a long Fourth of July parade today. Carole drove the Buick and I followed in the Model A. Taking that cover gasket out of the oil pump was a great move. Pressure was much improved. Don't have a proper guage on it but the Buick guage runs good in the white area at hot idle. Never came close to that with the gasket in.

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  • 4 weeks later...
Guest Straight eight

Dyna Flash Eight, just in case you overlooked adding an oil supplement for the sliding effect of the tappets on the valves, Shell and most all of the oil producers have changed their formula due to Federal requirements.  It seems our catalitic converters on our modern cars were suffering from premature failure due to the zinc for anti wear qualities.So Uncle Sam had the zinc removed.  Shell has made the Rotella Oils that combat this shortage.  You may inquire from Shell, and they will fill you in. Here is a copy of what they sent to me.


-----Original Message-----
From: shelltechnical-us@shell.com
Sent: Friday, January 11, 2013 2:43 PM
To: alglen@comcast.net
Subject: Re: Fw: 1947 Buick Super Convertible
On Fri, 11 Jan 2013 14:35:49 -0500 you wrote:
All Rotella T Multigrades have 1200 ppm zinc including the T5 oils.
>Attn Keith Perry.
Edited by Straight eight (see edit history)
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