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Old 06-21-2021, 06:16 PM   #19
Benson
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Join Date: May 2010
Posts: 2,579
Default Re: model b engine cm gear

My stock B engine was rebuilt in 1989 with 20,000 miles on it now.

Oil pressure with hot engine has always been 2 lbs at idle with 20 W50 and 8 at 45 mph to 10 at 65.

The oil pump was rebuilt to Ford specs for Model B oil pumps.

There is a difference between A and B oil pumps

The B pump from the factory was modified for more volume.

I have posted this information in the past and was told by "experts" that there is no difference between A and B and that I did not know what I was talking about.

The differences are spelled out in Nov 1932 service bulletins with specific warnings to NOT use certain parts from A pump in the B pump.

The large hole (5/16ths as I remember) in front of the galley MUST not be reduced in size. Doing so will starve the rod bearings of oil.

The purpose of the changes to the oil pump volume are to insure that enough oil is delivered to the dipper tray for the rod bearings.

The stock Model A engine gets horsepower at 2200 the B at 2800 RPM so more volume is needed to keep dipper tray from running low on oil.

Last edited by Benson; 06-22-2021 at 04:10 PM. Reason: spelling and text errors
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