Oil Pump Test

T

Tubby

Senior Member
I have recently purchased a 1939 Deluxe. I have yet to start the engine and have removed the pan for cleaning. I have removed the oil pump. Is there some way to test it off the car before reinstallation?
 
If it was me, I would install one of the 49 - 53 pumps with the proper pickup. All readily available. Otherwise do a forum search for the test procedure.
 
So many times a fellow will ask a question on repairing a part and he gets all kinds of advice but not an answer to his question.

Why buy a new pump ($140+) when you can test yours. Pumps are long lasting and yours is probably good. GM has published a test procedure so send him (GM) a pm and I am sure you will get an answer. He is a very helpful guy.
 
If you go through the process of inspecting and measuring the components against the specs, then there should be no need to test it.
 
Yes, it can be tested but requires a special jig to hold and capture the output.

The most important reason for testing is to identify pressure regular valve performance and value. Although such a test might not expose the actual pressure potential in engines of pre-1948 design.

I agree with Flatjack--the 8BA style pump is a step up from the older pumps.
 
JWL said:
Yes, it can be tested but requires a special jig to hold and capture the output.

The most important reason for testing is to identify pressure regular valve performance and value. Although such a test might not expose the actual pressure potential in engines of pre-1948 design.

I agree with Flatjack--the 8BA style pump is a step up from the older pumps.
Click to expand...

JWL You have to test and see the results of the pumps. There is no problem
with the early pumps, they will put out close to 100 lbs. One thing about the early pumps is they don't have the pressure valve which is GOOD. The pressure valve serves no purpose with the valley valve, it served as
a problem on a lot of engines I have seen with oil pressure problems.
The spring gets weak and the pump bypasses oil dropping pressure and
not supplying enough oil to the engine. The pressure can be adjusted in
the front bypass by shimming the spring, spinning the engine with 12 volts
with the spark plugs removed and a mechanical gauge. The pressure you
get spinning with 12 volts will be the pressure in the 40 MPH range. I
set them at 50 to 55 lbs by the thickness of the shim. G.M.
 
I will assume it is a 39/41 A engine, these engines do not have a rear seal, just what we in the paper industry called a lambryth seal--really just a set of slingers that push the oil back to the drain in the rear main bearing area. we have had a lot of trouble building these engines and putting in an 80 lb pump--too much volumn. test the pump and re-install!!!
 
As some of you know, I am going through a similar situation with a '51 Merc I am resurrecting. Compression is good and the bearings/journals also look good. I removed the old pump, checked the clearances (they were good), and the check valve (also looked good), and compared the "feel" of the pump against a new one; it also seemed good. Rather than go to the messy procedure of setting up test fittings, etc. for the pump. I just installed a known good pump and bolted everything back together. However, then came a time crunch, and I didn't have time to check the oil pressure again after I got the engine back on the test stand, when it was time to leave for 6 months in Florida. (Trust me, I need the break after the summer I've had.) If you can wait until May, I'll let you all know what happened.

I know this is maddening to do to you guys, but the point was to tell you that I don't think there is any way of determining if a pump is good or not without actually running it, whether in a test fixture or an engine. Sorry.
 
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Here is how I test my pumps.
 

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That is an interesting arrangement and should work great. My test fixture is one I fabricated from steel and allows me to do tests inside a 5 gallon bucket. I use 10-30 oil with a gauge and ball valve at the output. The torque is controlled by a brace with a hole through which the upper 1/2" drill handle is located. The pump slides into a housing and mounts to a flange in the same manner as it would mount in a block.

I have tested dozens of pumps both for me and others and found it is difficult to exceed the performance of the old, stock, 8BA pumps if they are not worn slam out.(South Georgia expression)
 
Back in the early 90's when I started rebuilding engines for sale I used Mellings new pumps. I had to replace several because of low oil pressure. These pumps had a number of problems that I hope have been corrected by the manufacture. However, I've never used an aftermarket pump since. I have JWL test the stock cleaned original. Lately I just clean them and inspect for end play and reinstall. And yes, the original early pump works very well and not having a relief valve is aplus in my opinion as this is the cause of heat in the oil. Placing the relief valve at the end of the oil supply line insures the engine of better oil flow and less heat. JMO
 
Flatjack9....that is awesome. Where do you guys get the time to put together these contraptions? I must be working too much. ;)
 
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