High volume oil pump
#1
High volume oil pump
I remember reading in a thread not long ago to not use a high volume oil pump on a street engine 350 build but the poster did not offer any explanation. Any thoughts out there on this?
#4
Thanks
Appreciate the feedback guys. I already had purchased the pump when I read that thread. Had me worried but if you ran one without issues I will go ahead and use the one I bought.
#5
In those situations where it has happened, oil starvation seems to have been the result of long periods of high-RPM use, like minutes over 5,000, which can happen in race applications, but pretty much never otherwise.
I have no personal experience with this, but that's my distillation of all the things I've read here and there.
I've got a HV pump that's been lying around that I will be putting into an old motor I'm going to be using - I figure if the bearing clearances are a bit large, this will keep the pressures up when it's hot and idling.
- Eric
I have no personal experience with this, but that's my distillation of all the things I've read here and there.
I've got a HV pump that's been lying around that I will be putting into an old motor I'm going to be using - I figure if the bearing clearances are a bit large, this will keep the pressures up when it's hot and idling.
- Eric
#6
The "HV pumps suck the pan dry" myth is right up there with "headers won't fit Supremes". I've run one on a street-strip car with no problems whatsoever. The only time you'll POSSIBLY have a problem is if this is a high mileage motor with all the oil return holes coked up - and if THAT'S the case, you have a bigger problem.
#9
That should not be a problem here as this is a going in a fresh rebuild. Clean with fresh seals etc. While we on on the oiling subject do you recommend expanding the oil holes in the bearings for better lube?
#10
I matched the blocks oil passages to match the bearings... Take a good look at those main bearing galleries... They are likely mis drilled.
#11
#15
I say yes. I have used the main to cam restrictors and saw no benefits but no problems either. I used restricted pushrods for years with my hyd cams. I currently use restrictors in the bores to limit the oil going up top. Big enough holes to let some oil thru to lube the lifters, but not flood the heads.
#16
#17
I've been refraining from commenting "but" a "street" 350 doesn't have oiling problems. A stock oil pump & pan is fine. When u get the pickup height where you want it, tack weld it. IMO, the hi-vol pump takes more power than a stock one so if it's not needed why use it. Those Oldsmobile engineers are looking smarter as I get older. Now on a BB Olds, if I had a hi-pump I would have a larger than stock (4 gt) oil punp, just for piece of mind. Ken
#18
The oil pump does NOT pump more oil THRU THE ENGINE because it [the pump] has more volume. Unless the pump cannot keep pace with flow- which is generally only at idle.
The pump [almost] ALWAYS provides more flow than can be forced thru the engine. The remaining flow dumps over the bypass back to the pump inlet.
So, a pump 10,000x as large will waste a lot of pressurized oil AT THE PUMP, but will not cause more oil to flow thru the engine, thereby "sucking the pan dry."
The pump output varies linearly [more or less] with RPM.
The oil passing thru the engine is [more or less] a steady rate, varying a little with the pressure developed by the pump, which at all speeds above idle should be the same 40 to 60 or whatever you set it to.
keywords for search: HVOP excess flow
Last edited by Octania; August 18th, 2013 at 10:41 AM.
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