HV oil pumps

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smallblockGT

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Ok so i was just wanting to get some more experienced input on this subject. I am building what would be considered a mild street 318. I bought a new m72hv oil pump for it. My uncle, who granted is no motor guru, but has built more than myself said it wasn't a good idea to use it in my motor unless I was going to use an extra capacity pan. He said what has happend to him before is if you set at a higher rev for too long your oil psi will drop dangerously low because it is sucking the pan dry faster than it can drain back. Is this a legitimate worry, or another one of those myths circling between backyard motor builders? FYI I am ussing the stock oiling system, but I did take the time to clean off the casting flash around the cam tunnel, etc. thanks guys I just wanna have this straight before it goes together!
 
He is correct. The HV pump will suck the pan dry during a high rpm run. It takes a short time for that pump to suck the pan dry. Use a regular pump. There is NO need for a HV pump in most builds.
 
Unless you keep RPM above around 6500 or more for long periods, it ain't gonna happen. Sounds like about the same thing your Uncle said. He's right. An HV oil pump is fine, as long as you run the hardened intermediate shaft with it. The bigger pan is probably not necessary, but it's also a good compliment.

All that said, you probably don't actually need the HV pump, but since you already have it, what the hell?
 
I always run a high volume, high pressure oil pump with a windage tray. Used one on a stock pan 273, kept it wound up, 3,000 to 6,000 rpm, all the time. Rebuilt it 40 years ago, still have it, probably has 200,000 miles on it. You can gain Horse Power with a standard pump and pressure, but I run a lot longer than a quarter mile at a time. I figure it is extra insurance on a motor I want to run for years.
 
Thanks guys. It's not a big deal to get a std. pump since my maint. Guy at work already said he'd buy th HV for his smallblock he's building if I decide not to use it. It is destined to be a street motor, actuall not far from a daily driver. I'm not gonna be unrealistic and say I'm not ever gonna drive it hard, but I wouldn't say it will be often. So although it may not be necessary, would it maybe add to the longevity of the motor. Oh and I am running a factory windage tray if that makes any difference whatsoever.
 
With an HV pump (and also a standard pump) you can always 'tune' your oilpressure by varying the oil viscosity.

That's how I ended up using synth. 5w20 oil in my stock 318 to end up with 20+ psi pressure @ 550rpm in Drive and 40-60 @ cruising speeds.
 
I'm running one in in my 360, but I have a hardened intermediate shaft and an 8 quart oil pan. In the future I will run a regular pan and probably a regular oil pump.

On the plus side I have really good oil pressure at idle in really hot weather.
 
Question..?

If the oil galleries are not opened ...aka made larger....how does more oil from the HV pump get to the top of the engine?.....60 psi with a standard pump in stock oil galleries is less oil volume then 60 psi with a HV pump with stock galleries?

got a standard pan with HV pump in 73 340 duster.....been driving it for about 8 or 9 yrs.....been down the drag strip a dozen or so times...never once lost oil pressure..

I believe I read the HV pump might take 8 hp to drive over the stock pump....

Use whatever makes you sleep the best at night.............
 
Well a lot depends on when the relief spring opens, a standard pump will be at 60psi and the same exact engine with a HV pump will show maybe 75 because they usually have a stiffer spring. Now if you leave the HV pump in but install the standard pump relief spring it will also show 60 psi, the difference is if you have large tolerances the HV pump with it's bigger/taller rotors displace more oil to fill the large tolerances thus holding better presure, even with the standard pump relief spring in.:???:
 
I really thing its the lack of baffles in the stock oil pan, that cause a low oil pressure more then the pump.

I don't thing a HV pump will suck the pan dry...how ever, it may pull more oil out of the pan, and with out baffles to keep the oil in the bottom under hard acceleration/deceleration you could get a momentary low oil pressure, were the standard pump may not.
 
Cudafever said:
I really thing its the lack of baffles in the stock oil pan, that cause a low oil pressure more then the pump.

I don't thing a HV pump will suck the pan dry...how ever, it may pull more oil out of the pan, and with out baffles to keep the oil in the bottom under hard acceleration/deceleration you could get a momentary low oil pressure, were the standard pump may not.
Click to expand...

I would have to agree with this statement. I spun #5 rod bearing in a fresh 340 w minimal (less than 1000) miles. HV oil pump, stock pan and stock windage tray. I did open up my oil passages as well, so am moving a higher volume of oil. Was about the 3rd time under hard acceleration and spinning her at 7500 w loss of oil pressure (never good). ALL DONE...... knocking like hell. Was able to save and regrind the crank had replace 2 rods that were ruined. Running the same motor now w no windage tray and a kevko pan. Spin her all the time up to 7500. Closer to 10000 mi on it now. Only 1 extra qt of oil, but I believe the baffle design provides better oil control. I learn from my mistakes. Cost me about $700 to redo the crank and rods. Would have been cheaper to buy a better pan from the get go. There again. most guys don't spin there street car up to 7500
 
I have a 360 with HV pump and stock pan and never had oil pressure problems.
I feel a 360 needs a HV pump because the main journals are bigger and I run full groove bearings.
A 273 with the smaller mains and 1/2 groove main bearings will probably be fine with a stock pump.
 
Cudafever said:
I really thing its the lack of baffles in the stock oil pan, that cause a low oil pressure more then the pump.

I don't thing a HV pump will suck the pan dry...how ever, it may pull more oil out of the pan, and with out baffles to keep the oil in the bottom under hard acceleration/deceleration you could get a momentary low oil pressure, were the standard pump may not.
Click to expand...

I agree. Had a HV pump with a stock pan on my old 360 and it would lose oil pressure on a hard take off for a couple seconds then came back up. Several times I opened it up down the highway for quite a distance and the oil pressure never dropped.
 
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