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Discussion Starter · #1 ·
I've known for a while that Melling has been using PM gears in their regular oil pumps, but I thought they used billet in their Select series. I called Melling tech to ask some other stuff, and I thought just double-check on the gears in p/n 10778...... and the guy said they're PM. I searched around on the net and read that Milodon's pumps use billet gears. I just called them today, and the guy said "I believe it has PM gears" (p/n 18760).

Does anyone use non-PM gears in oil pumps anymore? Are today's PM gears alot better than just a few years ago? What's the deal?

Am I worrying about nothing? The thought of a shattered oil pump gear is quite disturbing.
 

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Discussion Starter · #3 ·
Which Melling pumps have billet gears? They make several for BBCs: M77, M77HV, 10770, 10778, 10778C, and apparently a few billet-housing pumps (I'm looking for a cast-housing pump). If any of the P/Ns I listed have billet gears, then George, their tech guy, must not have gotten the memo.
 

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For all looking I e-mailed Melling tech last year, they have NOT used billet gears in any pump they produce for more than two years. All the pump companies use the same PM gears except three that I know of, Moroso only the gerotor pump, Titan, and CVR. CVR has a billet aluminum pump with billet gears, and recently released a cast steel pump with billet gears and a bolt on pickup. I have had the billet aluminum pump apart, it is very well made. For a Chevy, the above are the only pumps I will use when building anything serious. Competition Products sells CVR, not sure if you can buy direct.
http://www.cvrproducts.com/
 

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Sorry man, I ment Milidon, That why I when with theirs in my small block, 1 year ago. I just went to their site, you might want to call first. I see they no longer have it listed they may have changed it.
 

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Are you worrying about nothing. Yes and No. PM or Powdered Metal can be an awesome way to process and forge material. You can get killet grain flows and densitys. The strength and ductility can actualy exceed that of a normal forging.

I think aot of guys here PM and they think of the difference between Forged pistons Cast pistons and Hyperutectics.

Not really a fiar comparison but I have seen that illogical line drawn a few times.

With Powder Metal products it is all about the process" Sintered' Sintered Forged" etc. There are literally dozens of ways for a product to be powerdered metal. Then you can have cold, hot forginging post shapping. The list just goes on and on.

You can also have alloys like 4340 or 8010 or 1051 or doezens of other combinations of steel.

So PM really means nothing.

Comparing to a billet gear though I would take a well designed PM Hot forged part out of 4340 over a billet anyday. Grain density and uniformity will be substantially improved over a billet part if the process and engineering is right.

So if you do the reasearch you will find they can be comparable process's. The reason for PM over billet would be reduced machineing steps. You can get a PM part very close to net shape from the beggining. With a bilet or standard forgining you are going to have more machining steps. Hence more $$$$ in machining.


So I am sure that is why Melling etc are using PM gears.

Are billets gears better ? As I stated above that is extremly iffy. If the process is properly engineered most likely not or the difference is not tangiably meaningful. You will need a minmum hardness in the gear to prevent wear and deflection. That is going to setup a situation for a brittle gear.

The reason for other companies running billet gears maybe that they cannot afford to manufacture PM gears. It is exspensive to setup a PM production facility. .


I've known for a while that Melling has been using PM gears in their regular oil pumps, but I thought they used billet in their Select series. I called Melling tech to ask some other stuff, and I thought just double-check on the gears in p/n 10778...... and the guy said they're PM. I searched around on the net and read that Milodon's pumps use billet gears. I just called them today, and the guy said "I believe it has PM gears" (p/n 18760).

Does anyone use non-PM gears in oil pumps anymore? Are today's PM gears alot better than just a few years ago? What's the deal?

Am I worrying about nothing? The thought of a shattered oil pump gear is quite disturbing.
 

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While I agree that PM CAN be strong, companies like Melling would not change over if they were more expensive. Just look at the castings used on the newer M55 pumps and compare them to the earlier ones we have all used for years. It tells you on the box, do not use with solid motor mounts. It does not give me any confidence on the new gears. And since they supply most of the companies with components, Speed Pro, Milodon, Moroso, Engine Pro, you get the same gears in all of them. There are posts on ST on this issue and a couple of them that have had PM gear failure. All it takes is a contaminant to get in during the manufacturing and you have your failure point. Or cheap material used.

http://speedtalk.com/forum/viewtopic.php?t=7382
 

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PM gear would be cheaper. Once the investment in tooling was made your net shape forging process would drastically reduce machining.





While I agree that PM CAN be strong, companies like Melling would not change over if they were more expensive. Just look at the castings used on the newer M55 pumps and compare them to the earlier ones we have all used for years. It tells you on the box, do not use with solid motor mounts. It does not give me any confidence on the new gears. And since they supply most of the companies with components, Speed Pro, Milodon, Moroso, Engine Pro, you get the same gears in all of them. There are posts on ST on this issue and a couple of them that have had PM gear failure. All it takes is a contaminant to get in during the manufacturing and you have your failure point. Or cheap material used.

http://speedtalk.com/forum/viewtopic.php?t=7382
 

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Discussion Starter · #9 ·
Sorry man, I ment Milidon, That why I when with theirs in my small block, 1 year ago. I just went to their site, you might want to call first. I see they no longer have it listed they may have changed it.
Yeah, I called Milodon yesterday, and the guy said PM. :(

You can get killer grain flows and densitys...
You will need a minmum hardness in the gear to prevent wear and deflection. That is going to setup a situation for a brittle gear.
My understanding was that PM parts have no grain structure at all. ???
I also thought that they're more brittle than regular forged parts, which makes them not sound like the best choice for oil pump gears. I severely doubt anybody uses PM gears in transmissions or rearends.
 
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