Oil pump Old or new Melling

[luvmyclassics]

I was planning on re-using my old oil pump on my rebuild. I have not taken the pump apart for inspection. It was just soaked in solvent as part of the cleaning process.

I am considering purchasing a new Melling M-19 in place of the old pump but have read some comments that were not so favorable.

Any guidance is appreciated.

[JM 35 Sedan]

I have M-19 op's in two of my Flathead engines. Both work well and one has 30k miles with no problems. Let's hear some recent unfavorable comments from the folks having problems. Sometimes myths are perpetuated by "alternate facts" or maybe one bad experience someone heard about years and years ago.

[Seth Swoboda]

I have never installed a used oil pump on a rebuild simply because I don't want to take the chance of a problem having spent some $3000+ at a machine shop. I too have used the M-19 no problems thus far.

[Ol' Ron]

Back in the day when I was building these engiines, I had to replace several Mellings pumps. In talking to the source, I was tolsd the send them back for replacement. When dissasembling the pumps I found several problems with them. Most were in the relief valv area. This was written up by several people in the business and did hit several publications. I ASS U Me they have fixe the problem. However I've never used one of their Flathead pumps or their rebuild kits. I stick with the f Stock Ford unit. I just don't trust them.

[Lawrie]

I had a small problem with one on an engine I built last year,it would take a little time(5 secs) to start to build oil press after shutting down,turned out to be a not good seated relieve valve,an easy fix,but a pain as the eng was assembled before I found it.
after fixing it makes good press straight on start up.
Lawrie

[drolston]

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With my 59A/B rods knocking before the rebuild, the gauge gave me 15 PSI at idle and 30 PSI at speed, hot. That seemed "not broke", so I stayed with the original pump. The pump was taken apart for inspection and cleaned. We did have to replace the bushing on gear that connects the pump gear to the cam gear. On the first run on the engine stand, oil pressure held near 80 PSI at speed, hot. After a few hours of break-in and about 30 miles on the road, I get 40 PSI at idle and 55 PSI at speed, cold. All of the preceding on a mechanical gauge, and Valvoline VR1 50/20 racing oil (for the high zinc content).

So if your pump was working okay prior to tear down, I would stay with the known quantity.

[Overkill-F1]

I plan on making a device out of PVC pipe to pressure test my new Melling pump before I install it.
Seems like a good thing to make sure it is working like it should.
...Terry

[cas3]

take the bottom cover off, and if the gears have been touching the sides of the cavity, its shot. if not, i'd run it

[tubman]

Originally Posted by drolston

With my 59A/B rods knocking before the rebuild, the gauge gave me 15 PSI at idle and 30 PSI at speed, hot. That seemed "not broke", so I stayed with the original pump. The pump was taken apart for inspection and cleaned. We did have to replace the bushing on gear that connects the pump gear to the cam gear. On the first run on the engine stand, oil pressure held near 80 PSI at speed, hot. After a few hours of break-in and about 30 miles on the road, I get 40 PSI at idle and 55 PSI at speed, cold. All of the preceding on a mechanical gauge, and Valvoline VR1 50/20 racing oil (for the high zinc content).

So if your pump was working okay prior to tear down, I would stay with the known quantity.

The only other thing I can add is to stay away from "High-Volume" pumps unless you are working on a race only engine and have a lot of experience and really know what you're doing. The factory engineers really DID know their stuff!

[flatjack9]

I always use an original pump and test each one in the test rig I built. I can test flow rate and relief pressure.

[19Fordy]

flatjack9: That is a very neat set up. Well done.

[flatjack9]

Thanks, I certainly had too much time on my hands at one time.

[Binx]

I have a Melling from the 1980s that isn't machined right and literally drops into the block so compare (mic) the ford pump to the melling if you go that route. If you want to rebuild the ford pump with a kit, only use a genuine melling kit. There are others cheaper but reportedly cause gear binding.

Lonnie

[Ol' Ron]

A Melling's kit??

[Dak Rat]

I would like to know more about a "Mellings Kit" as well. Have a few original pumps that could use one.

[GOSFAST]

Originally Posted by Dak Rat

I would like to know more about a "Mellings Kit" as well. Have a few original pumps that could use one.

The Melling kit part number is K-19, should have all the necessary pieces to make a pump like new.

In all my years of using the Melling M-19's I've never gotten a "bad" one, ever! Somewhere along the line they may have had a batch go out with an issue but I've never experienced it first-hand!

Thanks, Gary in N.Y.

P.S. The kit will work ONLY with the M-19 pumps, no others, this according to Melling!

[JWL]

I have seen several defective Melling pumps. I would NEVER install a pump without verifying correct sealing diameters and output characteristics. I have seen undersize turns, eccentric relief valve seats, angle cut relief valve seats, "stuck" relief valves and oversized bushing diameters.

[fordscript]

I don't know if I have ever seen a Melling oil pump. Anyone got a pic, or a description explaining the difference?

[Ol' Ron]

There isn't any differance. They are a Ford copy, made in china.or were. I find the originals are OK for the most part, but you have to check them out.

[luvmyclassics]

What is the best way to check and test an oil pump?