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#3
06-04-2002, 09:25 AM
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"Witchdoctor" George Hanks gave a VERY imformative tech talk about oil pump differences at the PSN's. All Pontiac oil pumps are the same volume pump. Difference in volume comes from having different ratio drive gears. THe replacement pumps are the same volume as any other. Different pressure is a direct result of the spring pressure in the relief valve. You can shim up a stock pump with washers for added pressure but 60 psi is sufficient.
Stock oil pumps come in 40-45 psi(2bbl motors), 55-60 psi(4bbl) and 80 psi(SD-455) |
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#5
06-04-2002, 01:10 PM
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Okay,thanks rocky,but my question is still not answered. You gave the diff in volume,and how to change it for stock pumps. I am putting a high PRESSURE melling pump on my poncho. it clearly states on the pump that it is high pressure,not high volume,and wants you to know that. Mykee,disregard you!
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#7
06-04-2002, 05:24 PM
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You would think that higher pressure would make it move faster but it's not the case when looking at fluid pressure in this sense. It can only move a specific amount by how large the gears are and how fast they spin(engine rpm). The pressure relief valve dictates how much pressure the system will build. Kind of like your raditator, you need to watch what psi cap you have on and that will monitor pressure but you STILL have the same volume moving throughout the motor by the water pump. Like the oil pump, the water pump and cap work together.
What pump did you buy? What's the number on it? 60 psi Melling pump is adequate. 80 psi is ove kill and was only used in the extreme loose tolerance SD-455. On a tighter fit motor, 80 psi can enduce bearing wash which is when is the pressure does not allow a film of oil to properly coat the bearing surfaces and journals. |
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#8
06-04-2002, 05:29 PM
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okay,makes more sense now,thanks. heres the pump I ordered,melling.
Protect your engine with 20 to 25 percent more oil volume. MEL-M54DS Pontiac: 265-455, high pressure oil pump Protect your engine with more oil pressure. This Melling high pressure oil pump gives you the additional pressure you need for your performance application. Melling performance oil pumps are built using a proprietary casting process which yields maximum performance and reliability. Every Melling oil pump is completely pressure tested, including idle and bybass pressure, before it leaves the factory. High pressure pump not high volume. Includes pickup with larger than stock 3/4 in. tube (stock tube is 5/8 in.). $26.95 |
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#9
06-04-2002, 05:30 PM
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Pressure and volume are two different things.
Volume would be the amount of fluid it can pump over a specified time frame (for example - fuel pumps are rated in gph - gallons per hour). Pressure would be measured in psi (of course) and just tells you how "forceful" the flow of the fluid is. Pressure is also affected by any restrictions (or lack thereof) in the lubricating system. Obviously you would need a sufficient amount of pressure to keep the rod and main bearings floating on oil. 10-psi for every 1000 rpm is generally the accepted "ballpark" figure. A high volume pump in a Pontiac with a stock pan is not a real good idea, as it could suck the pan dry under a WOT 1/4 mile pass. The readily available pumps on the market (such as the Melling) provide a sufficient volume for street/strip Pontiacs, and in most cases, an all out race Pontiac.
__________________
Just a blind squirrel looking for a nut. |
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#10
06-04-2002, 05:37 PM
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Charles, what Brian said is the gospel. [img]smile.gif[/img]
__________________
 SECOND AMENDMENT: AMERICA'S ORIGINAL HOMELAND SECURITY! |
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#12
06-04-2002, 08:36 PM
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The M54DS is the RAIV 60 psi oil pump. Perfect for what you need. I use it myself in my 455 and it does offer about 55-60 psi at a sustained cruising rpm.
Brian is ok but not the best. If he was, he'd be able to get 672 hp from a 350, get his name plastered all over a few non-make specific magazines and THEN get to be the "guru" of a website only 3 people look at. Until he accomplishes those feats, he's just one of us! Is'nt(sp) that rihgt(sp) Brain(sp)? |
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#13
06-04-2002, 09:33 PM
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And I would also have to have the ability to have people invite me over for dinner, only to be served franks and beans.
__________________
Just a blind squirrel looking for a nut. |
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#15
06-04-2002, 10:05 PM
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Make sure you take your "Melling' oil pump apart. I have had a lot of problems with their oil pumps.
 Pitted balls, Rusty machining inside. Contaminated machine oil coating inside. Loose pressure relief spring nut. BTW: They won't do anything for ya if it fails or causes a problem.  I was told. Quote. If it says Hi-Volume or Hi Performance ...... No warrantee UnQuote.  Melling wore me out. I'm no longer using or recommending Melling Products. Quality control?????? and people complain about Foreign made products.
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#16
06-04-2002, 10:16 PM
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Rocky, being a simple person, can you help me understand the comment below?
"All Pontiac oil pumps are the same volume pump. Difference in volume comes from having different ratio drive gears". Can you tell me where I can get some of those "different ratio drive gears"? Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#17
06-04-2002, 10:22 PM
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OK, So what is the Melling 54F? Must be the 80psi? I ran it on two 400s with solid cams and they loved it. Got one for the 428 and I'm thinking about getting one for the 455.
[ June 04, 2002, 10:52 PM: Message edited by: Garry Sr ] |
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#18
06-04-2002, 11:02 PM
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The standard volume pumps have the 5/8" pickup. The high volume pumps have 3/4" pickups. The pump gear voume is the same for all the pumps unless you have one of those magic "different ratio drive gears" You can't buy any pump on the aftermarket that has not been mfg. by Melling originally.The M54F is the 80psi pump.(does not come with P/U).it is always a good idea to tear down the pump for inspection.Melling has always been responsive to me even though I buy their pumps in an Elgin box.Depends on the attitude I guess. BTW different ratio drive gears don't exist.
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
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#19
06-04-2002, 11:24 PM
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Ken, thank's for clearing that up. I need a new set of your book's as mine are pushing 30 years and have had it. Please post your phone number or e-mail me so i can order them. For some reason your new web-site will not work for me. Thank's
__________________
"Three may keep a secret, if two are dead" ~ Benjamin Franklin ~ |
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#20
06-05-2002, 12:06 AM
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Tom V, I'm pretty sure Butler carries higher volume oil pumps. He's got some billet pumps that's high volume for the race motors. I don't think any of the parts adapt to a traditional pump.
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