Oil pump question on my future motor

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flyfish

flyfish

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Hi all, its been a few years, but I am back rebuilding my race motor. Question I have is should I use the standard Melling 72 or the HV oil pump? My previous 410 had the M72HV pump in it, but I found out after building it that I may not need it and it was a waste of power....so here is the build in question that will be going together in the next few weeks (all parts are on the way except the oil pump).

360 LA block (0.030 over), 4.00 Scat forged crank, Scat I-beams, forged pistons, ~13:1 compression
Ported Edelbrocks, Hughes solid cam 264/268 @ 0.05, Victor intake, home built e85 carb

I don't expect to be revving it past 6500 RPM very often. The previous motor went 10.5's with a small roller cam and 10.8:1 compression, I'm hoping this will do a little better (10.3-10.2).
 
You don't want to waste that 4 hp it takes to drive it.
 
I always use a high volume pump and full groove mains. I may take an extra 4 HP to turn it, but if the rockers are galling the shafts and the pushrods aren't getting oil flow at low RPM's you'll loose way more than 4 hp.
 
We used just the std pump in our 340 for the past 5 seasons and will be using just the std again in our new 416 build,seems just fine
 
I ordered an M72 the other day and a MP high psi spring kit. A HV was almost double the price.
Makes me feel better now lol
scampy said:
We used just the std pump in our 340 for the past 5 seasons and will be using just the std again in our new 416 build,seems just fine
Click to expand...
 
Run the HV pump. Think about what you are saying. A waste of power? What do you think the difference will net you? .002 of a second, while possibly not supplying enough oil.

That wouldn't even be in my wheelhouse of thought.
 
glad the flyfish car is coming back to life :)
 
I always order the M72 and a high pressure spring, also, but I've been told that the high pressure spring is now the standard spring in all their pumps. Not sure on this so I just throw one in. Don't forget to clean it all out and check clearances.

I used a high volume pump on my first Mopar rebuild in 2008. I ran it with valve covers that I cut the top out a bit. I was pretty shocked how the heads just flooded. I think standard vs high pressure is an argument that will always be heated. I personally have never needed the high volume pump.

Someday my bearing clearance may be on the bigger end of OK, and I just might change my mind....
 
I spoke to Melling tech a while back and he said same thing std volume pump has hi psi spring. So there really "isnt" a separate hi psi pump.
Spring kit was $6 thru the Dodge store so I ordered it anyway
Ironmike said:
I always order the M72 and a high pressure spring, also, but I've been told that the high pressure spring is now the standard spring in all their pumps. Not sure on this so I just throw one in. Don't forget to clean it all out and check clearances.

I used a high volume pump on my first Mopar rebuild in 2008. I ran it with valve covers that I cut the top out a bit. I was pretty shocked how the heads just flooded. I think standard vs high pressure is an argument that will always be heated. I personally have never needed the high volume pump.

Someday my bearing clearance may be on the bigger end of OK, and I just might change my mind....
Click to expand...
 
I was surprised at how cheap the MP stuff was at my Dodge store.
Reusable op gasket for $11. Pr of Felpro 1008 HG that come in a set. $68.
We shall see once they come in
Ironmike said:
Yeah. 6 bucks is worth you KNOWING it's in there.
Click to expand...
 
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Somewhere I have an article about a Mopar engineer who did extensive testing on oil flow in small block engines back in the 70s. I have looked for it but haven't found it. When I do I will reproduce it and post the facts he discovered. One fact I clearly remember is that he found that a regular standard volume Mopar oil pump fitted with a non-restrictive pickup tube (1/2" ID or more) would put out more oil than the high volume pump would through the factory (3/8" pipe) pickup tube. Another conclusion I remember was that the standard pump would supply adequate oil for most engines (assuming that clearances were within design spec.) up to about 7,000 RPM. Beyond that he recommended the oiling sytem modifications described in a few threads on this site.
 
And what were the results of the 1/2 inch unrestricted pick up with a Hv pump?
 
Of course it flowed more but I can't remember specifics. That would be his recommendation for loose clearances and/or really high revs along with published oiling system mods. But one of his main findings was in order to acheive higher volume one should start with supply to the pump inlet.
 
The book by the name how to build big inch Mopar small blocks. On page 40 recommended modifications high-volume oil pump should be used on all high performance LA and Magnum engines. With so many places for oil leaks in this system the high volume pump must be used.
On page 38 Engineers tested the volume of oil flow with a stock oil pump then tested it again with a high-volume oil pump. With the stock pick up the high volume pump did not flow any extra oil.
If you read further on into the into the the chapter you learn that the thin wall tubing pick up flows more oil than the standard pickup. Bubba Bubba blah you guys need to get this book if you don't have it it's how to build big inch Mopar small blocks and covers LA and the magnums.

1522552819815561577133.jpg
 
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grimreaper said:
Somewhere I have an article about a Mopar engineer who did extensive testing on oil flow in small block engines back in the 70s. I have looked for it but haven't found it. When I do I will reproduce it and post the facts he discovered. One fact I clearly remember is that he found that a regular standard volume Mopar oil pump fitted with a non-restrictive pickup tube (1/2" ID or more) would put out more oil than the high volume pump would through the factory (3/8" pipe) pickup tube. Another conclusion I remember was that the standard pump would supply adequate oil for most engines (assuming that clearances were within design spec.) up to about 7,000 RPM. Beyond that he recommended the oiling sytem modifications described in a few threads on this site.
Click to expand...


As was posted above, what happens when you put a bigger pickup on the high volume pump?

The article is in one of the Chrysler engine books. I can't remember who did the tests but you can't get a big enough inlet on the pump. They should all have dual inlets.
 
flyfish said:
Hi all, its been a few years, but I am back rebuilding my race motor. Question I have is should I use the standard Melling 72 or the HV oil pump? My previous 410 had the M72HV pump in it, but I found out after building it that I may not need it and it was a waste of power....so here is the build in question that will be going together in the next few weeks (all parts are on the way except the oil pump).

360 LA block (0.030 over), 4.00 Scat forged crank, Scat I-beams, forged pistons, ~13:1 compression
Ported Edelbrocks, Hughes solid cam 264/268 @ 0.05, Victor intake, home built e85 carb

I don't expect to be revving it past 6500 RPM very often. The previous motor went 10.5's with a small roller cam and 10.8:1 compression, I'm hoping this will do a little better (10.3-10.2).
Click to expand...

Read this thread if you haven't already.

Any one interested in the oiling mods I did?
 
Not knocking any author but most guys who pen these "how to" books are not experts as they simply compile the info they get from doing interviews with guys in the business. Often they will get differing opinions on one subject (like oiling systems) and pick the one they think is correct.

I have a friend who has authored dozens of books about collector cars, maintenence on them and such and he can barely change his own oil. Yet he is considered an expert and has sold thousands of books.
 
Dude. Do whatever it takes to get the last .0006 hp you can out of your motor at 7900 Rpm. You will be happy.!
 
I would use the high volume pump. I have bought it from Precision in the past. They blueprint the pump, polish, deburr, etc. to me its good insurance for the small extra charge they have. Well worth it. Makes the Melling a nice piece
 
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