Modifying oil pump.

[Chris Haynes]

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?

[nkaminar]

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.

[ursus]

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.

[Russ/40]

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

[Terry Burtz, Calif]

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”.

[Jim Brierley]

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I have modified stock pumps without special tools, just go slow and be careful.

[Russ/40]

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.

[Russ/40]

Originally Posted by Jim Brierley

I have modified stock pumps without special tools, just go slow and be careful.

Jim, did you use a drill press and drill, or did you grind it out freehand with a burr?

[Jim Brierley]

Drill press, then smoothed the area with a die grinder.

[nkaminar]

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.

[California Travieso]

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

[Bob C]

Here's a link to the pump. http://handhantique.com/oil/oil.html

[Chris Haynes]

I am curious if the H&H pump meets Terry's specifications.

[duke36]

Isn't Specialty Motor the Stipes shock guys? Quality stuff.

[CA Victoria]

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?

[johnneilson]

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.

[Dodge]

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

[old ugly]

Originally Posted by Chris Haynes

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?

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

[Bob C]

Originally Posted by old ugly

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

Here is a link to the modifications. http://www.modelaengine.com/doubling...-oil-pump.html

[old ugly]

Originally Posted by Bob C

Here is a link to the modifications. http://www.modelaengine.com/doubling...-oil-pump.html

thank you




ou

[Lawrie]

You cant increase the flow of the A pump just by opening up the holes or reducing the shaft diameter.
If you could we would only need one size of pumps, but with different size holes
Lawrie

[old ugly]

on an original engine. i am wondering why the need to modify the pump for higher flow? if the original pump with the narrower shaft is use it will fill/overfill the oil gallery which is all that is needed to oil the engine. this is why there is a oil drainback tube to take care of excess oil.
on a pressure fed engine different story.

i am wonder why the need? i see lots of discussion on oil pumps.

[daren007]

Five million Model A’s left the factory without this modification.

[Bob C]

Originally Posted by daren007

Five million Model A’s left the factory without this modification.

But they didn't have a Burtz engine in them.

[CA Victoria]

For grins and giggles I built a test fixture and tested three pump configurations. At 660 rpm i measured the time it took to pump 1 gallon of 15/30 oil at room temp; I obtained the following results:
Stock Model A Pump with 1/2” shaft - 84 seconds
Model A Pump with shaft turned to 3/8 dia - 60 seconds
59a V8 Pump modified for Model A - 38 seconds.

Albeit I’m not a NASA sanctioned test facility I resolved the debate in my mind as to the direction I was following. The pressure produced by either pump is quite worthy, the v8 pump can be easily regulated to 30 pounds. A thanks to Jim Brierley for the wealth of information in his book and taking time to answer my questions.

[old ugly]

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Originally Posted by Bob C

But they didn't have a Burtz engine in them.

but for a stock engine they must supply enough oil

or is there a problem?

[Bob C]

No problem for a stock Model A but this thread started as a question of
modifying a stock oil pump for use in the new Burtz engine.

[Terry Burtz, Calif]

You cant increase the flow of the A pump just by opening up the holes or reducing the shaft diameter.
If you could we would only need one size of pumps, but with different size holes
Lawrie

Stock Model A oil pumps have a small inlet window to the gears. When the intake window is enlarged to expose more gear area, the output volume increases. Larger passages have nothing to do with volume, but they will provide less friction.




on an original engine. i am wondering why the need to modify the pump for higher flow? if the original pump with the narrower shaft is use it will fill/overfill the oil gallery which is all that is needed to oil the engine. this is why there is a oil drainback tube to take care of excess oil.
on a pressure fed engine different story.

i am wonder why the need? i see lots of discussion on oil pumps.
__________________
old ugly

but for a stock engine they must supply enough oil

or is there a problem?
__________________
old ugly

A stock Model A engine does not need a modified oil pump.
People posting on this thread are not discussing a stock Model A engine.

[RickInVA]

I was taught a few things years ago I would like to throw out here and see what you think. The study of fluid flow in physics, or hydro dynamics, has some basic rules when a positive placement pump is used. The volume of the fluid flow is determined by rpm and is fixed. You can change the speed of the flow, and the fluid pressure, by the size of the openings it flows through. A small opening and the fluid flows faster to maintain the fixed volume. A wider opening will cause the fluid to flow slower. Think of a river, the volume is the river is the same even though it goes faster where the river is narrow and slower where it is wider, but the gallons per minute remains the same. The gear pump delivers a constant volume because it is a positive displacement pump and fluids are not compressable. By changing the openings in the pump you are changing the speed of flow and the pressure but not the total volume. If you want more volume you need to speed up the pump or get a pump with biggger gears. My two cents.

[old ugly]

Originally Posted by Chris Haynes

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?

Originally Posted by Bob C

No problem for a stock Model A but this thread started as a question of
modifying a stock oil pump for use in the new Burtz engine.

i don't see a Burtz engine being mentioned here by the OP.

is he building a pressured oiling system? i guess i am not reading between the lines.

[saxman657]

Originally Posted by Russ/40

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

I spoke with Specialty Motor Cams this morning. There is a lighter spring that can be inserted in place of the internal "green" spring that will reduce oil pressure from a max of 50psi to approximate 8psi at idle and 18psi at 2200rpm: McMaster-Carr spring #9657K153. This is a 2" compression spring with a .313OD. Cost for a pk of 12 is $9.31. Much cheaper and easier to install than a pressure relief valve -- and for those ordering a Stipe pump for your Burtz engine, request the lighter spring for lower pressure, and this is what they will install in their oil pump.

[Chris Haynes]

Originally Posted by old ugly

i don't see a Burtz engine being mentioned here by the OP.

Although I didn't specify Burtz it is for one.

[McMimmcs]

I am sure you have read post number 5 from Terry, correct?

[old ugly]

Originally Posted by McMimmcs

I am sure you have read post number 5 from Terry, correct?

yes but at the time i read it Terry, didn't translate to Burtz for me.

then i got thinking why does he need to modify an oil pump to that extent.

sorry

[nkaminar]

If anyone is using the oil pump from Specialty Motor Cams and want to reduce the pressure by installing a lighter spring for the pressure relief valve, I have a bunch and will send you one, no charge. I bought some from McMaster Carr on advice from Stripe Machine Company. The minimum order is 12. I will use one and maybe one for a spare. The part number from McMaster Carr is 9657K153, Compression Spring 2" long by 0.313 OD. If you want one send me a PM with your mailing address.

[fr33777]

I would like one. [email protected]