Modifying oil pump.

Chris Haynes

Chris Haynes

Well-known member
I have read the instructions on how to increase the flow of a stock oil pump. I am limited of doing this myself because I don't have a milling machine. Is there anyone who does the work on these pumps?
 
One option is to buy an aftermarket oil pump. Below is a photo of the one on my car. Two little threaded holes have to be added to the block. I turned the photo 180 degrees to make it easier to read the name on the oil pump. I read the name as Specialty Motor Cams.



481989
 

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I have seen stock pumps that were modified to increase flow by means of enlarging the inlet and outlet ports but have to wonder why greater flow is necessary in an unpressurized engine that already has excess volume spilling down the overflow pipe and over the camshaft gear.
 
Not shure, but I suspect Chris is trying to perform the modification recommended for use in the new Burtz block for pressurizing the oil flow to all bearing surfaces, thus the desire for more flow.

I too, would like to make that modification with hand tools if someone has proved it can be safely executed
 
nkaminar, ursus, and Russ/40

Chris Haynes is building one of the “New Engines” with 17 pressure-fed bearings.

The new engine utilizes a dog clamp to hold the oil pump in place and the added holes are not required. The Specialty Motor Cams (Stipe) oil pump delivers too much volume with resulting high oil pressure. There are several ways of reducing the volume and/or pressure as described in the “Builders Guide”.
 
This is premature in my build, but related to the pump issues of this thread. I purchased the suggested 60lb spring to hold the pump/distributor drive bearing in place. Curious how others have put that spring in place. It is one tuff squeeze to get that spring home. How did you do it.
 
Terry's concern about high oil pressure is the stress on the gears driving the oil pump. He has a point. My pump puts out 50 psi for the pressure lubrication on my main bearings. My rods are lubed with the scoops. I am going to try and install a regulator to reduce the pressure. I think all modern oil pumps have a means to dump excessive oil pressure.
 
H & H Antique In La Crecenta, CA sells an oil pump with enlarged inlet and outlet. I was just wondering if anyone has used it. One of the guys in our Model A Club has had a couple of engines rebuilt by H & H and I’m going to ask him if he has used one.

David Serrano
 
Jim Brierly discusses modifying a 59A V8;oil pump in his book.
The limitation of the model a pump is gear size, the V8 pump has larger gears & more flow.
Increased pressure leads to more oil pushing out.
The stock model a pump is adequate if not turning high rpm, not sure about the flow requirement of the new engine?
 
The "flow requirement" for the new motor should be less than for the stock Model "A".
Since the manual has instructions on using an "A" pump with modifications, it is adequately sized

The Ford V8 pumps have a longer gear-set which equates to more volume for same diameter of gears. One advantage of the V8 pump design is the pressure relief re-circulates the oil back into the inlet side of the pump. This also reduces the amount of flow rather than dumping the excess off into the sump.

I believe the main concern about the amount of pressure the pump produces is the fact that the original pump drive was never intended to drive a pressure application, only a transfer pump. Terry has mentioned in the manual the spring used to retain the pump drive, this is an indicator that excessive pressure is being produced.

Opinions will vary on the subject about how much pressure is necessary but remember that the original engine had only gravity feeding the mains, the new bearings are not that much different than the original (length and diameter of the "B"). Before you say it, the "B" motor did not have true pressure system, it was directed oil, not pressurized. The galley had a large hole dumping to the front of the motor.

Just a few observations, J

FWIW, I have had 95 psi show on a new race motor with external pump and not cause leakage. But reduced to 60-70 for operation.
 
You can do the modifications with a hand drill or a drill press and a die grinder.
Its not as nice as doing it with a mill, but who's going to see it.
There are several articles on how to do this and what is should look like you just have
to search. GO SLOW
 
Chris Haynes said:
I have read the instructions on how to increase the flow of a stock oil pump. I am limited of doing this myself because I don't have a milling machine. Is there anyone who does the work on these pumps?
Click to expand...

when you make the comment about the milling machine, what is the modification that needs a milling machine? tighter clearance somewhere?
or what are they suggesting.

interested to know what they are milling off.

thanks
ou
 
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