Lets Talk About Oil Pumps!

[TrailBeast]

Correct if I'm wrong, but I would think that the main purpose here is to get the right amount of oil to were it's needed. Any excess pressure would cause excess heat and unnecessary wear?

Yep, but now we're getting into overthinking it.
Just use a standard pump and move on with it.

 

[Valkman]

Yep, but now we're getting into overthinking it.
Just use a standard pump and move on with it.

Your right, you can over think a lot, but the whole purpose of this thread is to find out what actually works.

 

[70aarcuda]

Car craft ran an engine on a dyno...difference between HV pump and standard pump was 4-5 HP...they found more horsepower in changing oil viscosity...

 

[TrailBeast]

Your right, you can over think a lot, but the whole purpose of this thread is to find out what actually works.

They all work, and they all have their place as well as drawbacks.

High pressure requires a stronger intermediate shaft (and sometimes a drive gear change)
High volume can starve the engine for oil at higher RPM's due to pulling the sump dry before the oil can get back down into the pan again.
A standard pump can have not enough flow and pressure for a loose engine.

For a regular performance street motor a standard pump is totally fine.

 

[BlueDream]

I used a stock replacement pump in both my 318 and 340. HV pumps are great too though.

 

[MrJLR]

Is the hardened shaft absolutely necessary with the HV pump for average street driving?

 

[318willrun]

when I was a kid, and didn't even know a hardened shaft existed, I ran HV pumps with stock shafts. I used Castrol GTX 20w-50 back then too. Never had an issue, but maybe I was dumb lucky. Now I don't buy HV pumps, so I still use stock shafts...

 

[TrailBeast]

Is the hardened shaft absolutely necessary with the HV pump for average street driving?

Out of peace of mind I would say yes, and if I was going to run a higher capacity pump of ANY kind I would use a hardened shaft. (but that's just me because one of my pet peeves is reliability)
I like to be able to confidently take off across the desert on an 80+mph 11 hour trip to the coast for example.

To be honest I really don't know the answer to that specific question.

 

[nm9stheham]

High volume can starve the engine for oil at higher RPM's due to pulling the sump dry before the oil can get back down into the pan again.

Mmmmmm.... a HV pump running the same pressure relief spring will put no more oil through the engine than a standard volume pump with the same pressure relief spring. The flow into the engine depends on the pressure is as well as other factors downstream from the pump. But in this pump design, the relief spring sets the max pressure and no more oil flows into the engine with either pump at a given pressure. The HV WILL flow more at low RPM's but that is because it keeps the pressure up better at low RPM due to the taller impellers.

The potential flow difference is not more than 18-20% in any case with the SBM HV vs standard volume pumps. This is quite a bit less than the max flow differences in the Car Craft test, so if that was a 3 HP difference between the std SBC pump and the BBC pump tested, then maybe it is 1-2 HP here, and then only at high RPM. Cruising, it is much less.....

 

[RustyRatRod]

Is this needed on a standard pump?

As cheap as they are, it's not a bad idea. It's not like they don't have an important job.

 

[RustyRatRod]

when I was a kid, and didn't even know a hardened shaft existed, I ran HV pumps with stock shafts. I used Castrol GTX 20w-50 back then too. Never had an issue, but maybe I was dumb lucky. Now I don't buy HV pumps, so I still use stock shafts...

I think we all did. I know I ran a LOT of HV pumps with stock shafts and never had an issue, but was it smart? Probably not. lol

 

[grimreaper]

I used to always use a HV pump "just for good measure" until I read a test done by a Mopar Performance Engineer back in the early/mid seventies. (I sure wish I could find my copy...Anybody got a copy they could post?) His testing demonstrated that a standard and high volume pump on a small block would flow the same amount of oil with unlimited resistance on the output if you don't provide increased supply volume. The limiting factor was the ID of the 3/8" pipe oil pump pickup tube. His conclusion was that any oiling improvements required an increased volume to the input of the pump to provide valuable effect. Once adequate supply was available the standard pump could supply whatever oil was required for all but the highest RPM engines with reasonable build clearances. He was a proponent of the widely recognized oiling mods but wanted to make people aware of the true bottleneck in the stock oiling. A larger diameter pickup tube is required to gain effective flow volume. The solution he recommended was a rear sump pan with the large volume pickup tube that enters through the bottom plate of the pump or the dual inlet that was popular at the time. That is not always an option for street cars so other means must be provided to provide greater volume to the pump intake.
Since 1975 I have always used a "blueprinted" standard volume pump with a larger volume pickup tube and had good success, even on my high windin' 273s and 340s.

 

[TrailBeast]

Mmmmmm.... a HV pump running the same pressure relief spring will put no more oil through the engine than a standard volume pump with the same pressure relief spring. The flow into the engine depends on the pressure is as well as other factors downstream from the pump. But in this pump design, the relief spring sets the max pressure and no more oil flows into the engine with either pump at a given pressure. The HV WILL flow more at low RPM's but that is because it keeps the pressure up better at low RPM due to the taller impellers.

The potential flow difference is not more than 18-20% in any case with the SBM HV vs standard volume pumps. This is quite a bit less than the max flow differences in the Car Craft test, so if that was a 3 HP difference between the std SBC pump and the BBC pump tested, then maybe it is 1-2 HP here, and then only at high RPM. Cruising, it is much less.....

Details,details.
Does he need a hardened shaft with a high volume pump?
No, but it sure adds peace of mind.

 

[Valkman]

Not much has been talked about pressure., who here has used a high pressure spring in a SV pump?

 

[67 gt]

I run the MP spring in the std pump but still use the harden shaft just for piece of mind and use Joe Gibbs Syn 15-50, oil pressure 70 cold & 40 hot @ idle