oil pump question

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gunmetal72

gunmetal72

Life is a dark ride
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Hi all. Still working on getting all the parts together for my 340. I am in need of some info for he correct oil pump. I was thinking I would use a high volume low pressure pump and wanted to know if I need to use a bigger oil pan or could I still use the factory pan. Thanks
 
Hello fellow Canadian! We are practically neighbors.
Street, or Strip.
How high you thinkin of revving that race motor?And how are you planning to get the oil back into the pan?And just how loose are the bearing clearances?Have you done any oiling mods?
It doesn't take long to suck the pan dry, if the oil can't get back fast enough.My Eddies can store a lot of oil up top.
 
Use a standard pump and save yourself a headache. A standard pump oils my high 11 second 360 E body Cuda
 
I like to run the hv pumps with high pressure springs.

You need to bang the oil pan a bit to fit the taller hv pumps.

Not much, but about 10-15 minutes worth. Lay the pan on the block surface without a gasket, then keep banging it until the pan will sit flush on the block surface without any interference. Focus on banging on the front edge and the front radius along with the area just behind it on the bottom surface until you can get the holes to line up and the pan to sit flush. Then when you assemble it with the gasket, it will be fine...

The Mopar oil pumps come with a 55-65 psi spring, and you can order the high pressure spring to get it up to 75 psi if you wish.

Or all Mellings pumps have a 72 psi spring. They don't make a lower pressure spring for theirs, if you get a mellings HV pump, it will have the higher pressure spring (close enough by 3 psi).

If you need to know how to change the spring, go here:

http://www.forabodiesonly.com/mopar/showthread.php?t=301617
 
AJ/FormS said:
Hello fellow Canadian! We are practically neighbors.
Street, or Strip.
How high you thinkin of revving that race motor?And how are you planning to get the oil back into the pan?And just how loose are the bearing clearances?Have you done any oiling mods?
It doesn't take long to suck the pan dry, if the oil can't get back fast enough.
Click to expand...

Not going to race it, just for street use, no oiling mods done. max rpm will prob be 6000 but will not see high rpm for any sustained length of time. Not sure of the exact bearing clearance but crank is 10 over with new rod and main bearings, roller cam, lifters and rockers. edlebrock heads and intake.
 
gunmetal72 said:
Not going to race it, just for street use, no oiling mods done. max rpm will prob be 6000 but will not see high rpm for any sustained length of time. Not sure of the exact bearing clearance but crank is 10 over with new rod and main bearings, roller cam, lifters and rockers. edlebrock heads and intake.
Click to expand...

That would be - Crank is 10 under.

Big clearances = HV pump. Otherwise std pump.
Cheers
 
I would use the HV pump and the high pressure spring. I have seen more damage done by what I think is low oil pressure than I ever had with high oil pressure. Like rocker and pushrods damage, rocker shafts galled etc.
 
I was hoping I could use the stock pan, Don't really want a pan that will scrape the road when you hit a speed bump. Is there a pan available that does not hang down to far
 
There is a fair amount of misconception going on about these pumps.

1. The theoretical difference in flow volume of the HV pump is 20% over the standard pump, and have been advertised/measured at 18% or so over the standard. But that extra only flows into the engine in a limited, lower RPM range.
2. Once either pump's output pressure hits the relief spring limit, then neither pump flows more than the other into the engine.... either pump at that point will provide whatever oil the engine's oiling system will take AT THE RELIEF SPRING PRESSURE, and the rests just recirculates inside the pump via the relief valve. The HV just recirculates more.
3. The HV pump will put out more pressure at the lower RPM's and reach the pressure limit sooner than the standard as the revs increase. So for equal relief springs, the HV has that advantage and will thus flow more oil into the engine AT THE LOW RPM's; I can't see any thing but good from that for typical engine use. And if the clearances are bigger, then it will help for sure.
4. As said, once the relief valve opens, they flow equal amounts into the engine, so for exclusively high rev use, the standard pump won't flow any less than the HV pump, and the standard pump will take a little less power to turn, which may matter at over 3000 or 4000 RPM, but would be of no consequence for street cruising.

BTW, we recently bought a Mopar Performance HV pump, and it actually was a Melling with the higher pressure spring. There was no need to mod the oil pan. It is a stock 273 pan on a 340. We kept the stock pickup.
 
gunmetal72 said:
I was hoping I could use the stock pan, Don't really want a pan that will scrape the road when you hit a speed bump. Is there a pan available that does not hang down to far
Click to expand...

Use it. Several years ago I had an all original numbers match 72 340 Duster. The engine was wore out when I bought it, so I went throught it. I installed a HV pump with the orginal pan with no oil pressure issues.

The only problem I ever had was a 67 440 that I rebuilt and put in a 71 RR. I put a high pressure pump on it and had to run an extra quart of oil in the stock pan to keep the pressure from fluctuating. I ran that motor hard for five years with an extra quart of oil in it. When It needed freshened the bearings looked like new.

Don't be afraid of HV pumps, as mentioned there a lot of misconceptions about them.
 
In an assembled engine on the stand, is there a way to tell if the pump is a hi volume or regular pump without removing the pan? Curious if there is a test that can be performed.
 
Made 7 passes down the drag strip last weekend with a high volume pump with eddy heads. Stock 5 quart pan...never sucked the pan dry....LOL...
 
70aarcuda said:
Made 7 passes down the drag strip last weekend with a high volume pump with eddy heads. Stock 5 quart pan...never sucked the pan dry....LOL...
Click to expand...

..........That's the biggest misconception...............I have used the HV pump in many engines from stock motors to radical motors...........not 1 problem...........kim......
 
70aarcuda said:
Made 7 passes down the drag strip last weekend with a high volume pump with eddy heads. Stock 5 quart pan...never sucked the pan dry....LOL...
Click to expand...

oldkimmer said:
..........That's the biggest misconception...............I have used the HV pump in many engines from stock motors to radical motors...........not 1 problem...........kim......
Click to expand...

Agreed. I too have used HV pumps with stock pans and have never sucked the pan dry. I ran into a problem with my old 360 with a HV pump and stock pan where the car took off so hard it uncovered the pickup starving it for oil. Pan baffles solved that. I like the HV pumps cause they build pressure at low rpm's better (just my preference) but I rarely use the high pressure spring (only in a race car with lose bearing clearances) because simply said you do not need that much pressure. Pressure is the resistance to flow so it doesn't matter if you have 50 or 75 psi of pressure, the oil isn't flowing. The only thing you do by running high pressure is heat up the oil more causing it to thin out and waste more horsepower turning it
 
Rocket said:
In an assembled engine on the stand, is there a way to tell if the pump is a hi volume or regular pump without removing the pan? Curious if there is a test that can be performed.
Click to expand...
I never measured one, but I would expect the HV to be a bit taller in the body. The pump rotors are 20% taller in the HV vs the standard. And, if it is a Melling, it will have 'HV' at then end of the PN as in M72HV for the SBM. There is a PN for the MP part that can be looked up.
 
I have sucked a pan dry racing after 2-3 minutes at higher RPM's but it was not a Mopar. The design did not have any flow restriction in the head oiling feed passage.
 
nm9stheham said:
There is a fair amount of misconception going on about these pumps.

1. The theoretical difference in flow volume of the HV pump is 20% over the standard pump, and have been advertised/measured at 18% or so over the standard. But that extra only flows into the engine in a limited, lower RPM range.
2. Once either pump's output pressure hits the relief spring limit, then neither pump flows more than the other into the engine.... either pump at that point will provide whatever oil the engine's oiling system will take AT THE RELIEF SPRING PRESSURE, and the rests just recirculates inside the pump via the relief valve. The HV just recirculates more.
3. The HV pump will put out more pressure at the lower RPM's and reach the pressure limit sooner than the standard as the revs increase. So for equal relief springs, the HV has that advantage and will thus flow more oil into the engine AT THE LOW RPM's; I can't see any thing but good from that for typical engine use. And if the clearances are bigger, then it will help for sure.
4. As said, once the relief valve opens, they flow equal amounts into the engine, so for exclusively high rev use, the standard pump won't flow any less than the HV pump, and the standard pump will take a little less power to turn, which may matter at over 3000 or 4000 RPM, but would be of no consequence for street cruising.

BTW, we recently bought a Mopar Performance HV pump, and it actually was a Melling with the higher pressure spring. There was no need to mod the oil pan. It is a stock 273 pan on a 340. We kept the stock pickup.
Click to expand...

nm nailed it with this post. Number 3 is by far the number 1 reason I say to use the HV pump. I don't want to type a book out but these engines have different oiling requirements than other brands do. Extra oil and added pressure always helps these engines. Always. I would rather have the HV/HP pump and 50 pounds at idle than some of the low pressure I see some guys are using.
 
oldkimmer said:
..........That's the biggest misconception...............I have used the HV pump in many engines from stock motors to radical motors...........not 1 problem...........kim......
Click to expand...

Exactly! A HV oil pump will not suck a stock capacity pan dry on a street/strip motor, that's an old wives tail. Maybe a road race engine, but any motor that runs for extended high rpm use, needs more than a stock type oil system. I've run a HV pump with a stock pan more than a few times and never had a problem. Whether an HV pump is actually need, or not, is another matter. As stated above, it depends on the engine, bearing clearances, and intended use.
 
I have sucked a stock oil pan dry before!(HV pump) had to run a extra Q of oil to keep it from happening.

Was a BELIEVER........until i got tired of a oil pan leak and removed it to find that the smallest of a dent in the pan hand turned the pick up, up!

Fixed pan, fixed pickup, had a buddy make a cheap tin baffle. Never had to add a extra Q again. One of them three thing fixed the problem......or maybe it was all three,You Decide.!:D
 
http://www.summitracing.com/dom/sea...amily/mopar-small-block-la?retaillocation=dom

would this pump have more pressure than the stock pump and would it sit lower in the pan where I would not be able to use the splash pan? If it does have more pressure, would it be better to change out the spring from the standard pump. The engine should have good pressure because it is a fresh build but more volume at idle would be the bug gain? I have had oil pressure issues in other engines at low rpm but that also might be because of bigger clearances in the bearings.
 
There gets to a point in some engine builds where a HV pump and a higher pressure regulation is warranted,and your engine is NOT one of them.
Whenever you ask about oil pumps you will always get those who straight away say" Oh I always use a HV with high pressure". The reason for that is because they simply don't understand where the oil pump fits in relation to the whole oiling system, so they go with what they consider is the safest option and usually it's the wrong option.
Anyone here who is telling you to go to a HV pump , don't know what they are talking about..
 
gunmetal72 said:
http://www.summitracing.com/dom/sea...amily/mopar-small-block-la?retaillocation=dom

would this pump have more pressure than the stock pump and would it sit lower in the pan where I would not be able to use the splash pan? If it does have more pressure, would it be better to change out the spring from the standard pump. The engine should have good pressure because it is a fresh build but more volume at idle would be the bug gain? I have had oil pressure issues in other engines at low rpm but that also might be because of bigger clearances in the bearings.
Click to expand...
That is the standard Melling SBM HV pump. It will have the same pressure after reaching the pressure limit as a standard pump if the same spring is used in the pressure relief valve.

I would expect that PN to have the heavier spring with a 72 psi limit. Either pump can have/use the heavier or lighter spring; it all depends on the spring wire diameter.

Yes, more volume (due to more pressure) at idle and low RPM's would be the difference. I don't get too awfully excited at the difference as it is only 18-20% flow difference, tops. I can't tell you the pressure difference at, say 1000 RPM; I have no data on that.

What do you mean 'splash pan'? Is that the windage tray? It should fit either pump. It bolts into the engine in the same way.

BTW, are you replacing the intermediate shaft that drives the pump?
 
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