SBC oil pump recommedation

[Mike Taylor 3601]

melling M-55A is heavier casting, m55 and m55hv have lighter castings,some things that will break pump are cavitation most of time pickup too close or far away from pan,or oil getting away from pickup or lack of oil, out of balance or vibration from driveline, oil pump shaft rubbing block some blocks need hole opened up or shaft that is undercut, some dart blocks need drilling for clearance around oil pump shaft.
Mike Taylor 3601

[Mike Pearson]

Originally Posted by Mike Taylor 3601

melling M-55A is heavier casting, m55 and m55hv have lighter castings,some things that will break pump are cavitation most of time pickup too close or far away from pan,or oil getting away from pickup or lack of oil, out of balance or vibration from driveline, oil pump shaft rubbing block some blocks need hole opened up or shaft that is undercut, some dart blocks need drilling for clearance around oil pump shaft.
Mike Taylor 3601

I think mine was one of the lighter castings. It was in the engine when I bought it. Thanks for the tips I will check for clearance. I think the shaft is one of the undercut type. I will change that too.

[joespanova]

I have both castings in my shop and the diff is very obvious. I believe mine is a Moroso version of the HV55 , which at the time of purchase was the heavier casting. That being said , I had a bypass spring break last year costing me a new block in the process as it threw a rod from no oil pressure and yours truly didnt have a low pressure warning light...I do now

[Mike Pearson]

Originally Posted by joespanova

I have both castings in my shop and the diff is very obvious. I believe mine is a Moroso version of the HV55 , which at the time of purchase was the heavier casting. That being said , I had a bypass spring break last year costing me a new block in the process as it threw a rod from no oil pressure and yours truly didnt have a low pressure warning light...I do now

I will have a warning light from now on. Right up front and center. Nothing is fail safe.

[Alan Roehrich]

The base pump, the Melling M55, is a very weak casting, they will break just putting a stock Melling pick up in. This has been a problem for years, and has only gotten worse. I have a standing deal with the warehouse I buy my parts from that not even a stock rebuild gets an M55. Minimum is an M55A, which is a higher pressure pump.

The M55HV is also a different casting, although I have stopped using high volume pumps for most engines. It has seen changes over the years, it was pretty robust, then they took strength out several years ago, then, after failures and complaints, they went back to the old stronger casting.

At one point, even the high pressure and high volume Melling pumps were using cheaper powdered metal gears, and the gears failed. Now they say only the stock replacement budget pumps get those gears. Supposedly, the test for those gears is to mark them with a Sharpie, if the mark disappears, they are powdered metal gears, and should not be used in performance engines.

Melling has a Select line, those seem to do fairly well, they are held to tighter tolerances, use better castings, and better gears. They have several versions for small and big block Chevy applications.

Melling also has a new helical gear pump for the small block Chevy, it is supposed to have less drag, a smoother pressure curve, and less pulse variation. I have not tried one yet, I may. It looks good in testing.

I used the Moroso pumps for a while, as they were built to tighter tolerances than the Melling pumps, although Melling makes the base pump.

Schumann was making their pumps based on the old DynaGear castings, and using the nodular iron used for rear end housings. However, the last Schumann pump I got did not look as good as the older pumps. I have not bought one since, I switched to the cast steel Clay Valley Racing pump, and that is what all race engines now get.

[Mike Pearson]

Originally Posted by Alan Roehrich

The base pump, the Melling M55, is a very weak casting, they will break just putting a stock Melling pick up in. This has been a problem for years, and has only gotten worse. I have a standing deal with the warehouse I buy my parts from that not even a stock rebuild gets an M55. Minimum is an M55A, which is a higher pressure pump.

The M55HV is also a different casting, although I have stopped using high volume pumps for most engines. It has seen changes over the years, it was pretty robust, then they took strength out several years ago, then, after failures and complaints, they went back to the old stronger casting.

At one point, even the high pressure and high volume Melling pumps were using cheaper powdered metal gears, and the gears failed. Now they say only the stock replacement budget pumps get those gears. Supposedly, the test for those gears is to mark them with a Sharpie, if the mark disappears, they are powdered metal gears, and should not be used in performance engines.

Melling has a Select line, those seem to do fairly well, they are held to tighter tolerances, use better castings, and better gears. They have several versions for small and big block Chevy applications.

Melling also has a new helical gear pump for the small block Chevy, it is supposed to have less drag, a smoother pressure curve, and less pulse variation. I have not tried one yet, I may. It looks good in testing.

I used the Moroso pumps for a while, as they were built to tighter tolerances than the Melling pumps, although Melling makes the base pump.

Schumann was making their pumps based on the old DynaGear castings, and using the nodular iron used for rear end housings. However, the last Schumann pump I got did not look as good as the older pumps. I have not bought one since, I switched to the cast steel Clay Valley Racing pump, and that is what all race engines now get.

Good info Alan. Have you tried a Moroso billet pump in any of the engines.

[Alan Roehrich]

Mike, I have not. If I were going to buy a billet pump, I'd probably buy either a Clay Valley Racing pump or a Titan.

[Dan Timberlake]

Please post some pictures of the broken pump, showing the location of the break, and also the "fracture surface."

[Lyn Smith]

Was going to buy a Moroso 22101,but it looks like it is just a glorified m55 mellings???Has m 55 casting on it.Isnt the m55 the pump the one with housing breakage problems?

[Mike Pearson]

Originally Posted by Lyn Smith

Was going to buy a Moroso 22101,but it looks like it is just a glorified m55 mellings???Has m 55 casting on it.Isnt the m55 the pump the one with housing breakage problems?

Yes. that is what broke in my engine. I went with the billet Moroso pump. I have been happy with it so far. One thing I did after that deal was to put an idiot light in the car. Its hard to watch the gauges as you are racing.