6.5 water pumps

[sctrailrider]

Yea, I wondered that also, I may give them a call and see what they have to say..



I don't have a way to test the flow of any of the pumps, I'm investigating how a setup could be installed on a running motor without spending a lot of cash.. I wouldn't mind changing pumps a time or two, but with my humvee fan system I can't use a spin on type pump...

[Kennedy]

My guess is that like most products it was designed/engineered for a more mainstream application: the SBC Then I would assume adapted (quite poorly) to the 6.5 application. Maybe they used a standard size impeller or maybe they used the older 6.2 as a pattern, but rather than create a proper diameter piece it was left as is.

My guess is that when it comes to impelling water flow the end clearance is less critical than the side clearance but to what extent???

[ronniejoe]

Tip clearance is critical. This large clearance will allow flow recirculation which hurts efficiency and capacity.

I would like to the see the impeller from the front. It looks like it might be a shrouded design which can improve flow. However, the large tip clearance probably loses everything that they gained. Again, the shroud thought is just a guess, since I can't see the front.

Automotive water pumps are generally quite crude when compared to even centrifugal well pumps. It seems to me there is a lot be gained there. Cost is a major driver in automotive production.

Oh, and by the way, I am an engineer.

[More Power]

I found the link to a story I wrote in 2008 that addresses this topic.

https://www.thedieselpage.com/features/dualstats.htm

[ronniejoe]

Mr. Fuller is/was a training instructor. He can offer some good insight. However, his comment about the "coolant flows through the engine with no restriction whatsoever and travels too quickly to absorb enough heat" is not sound from an engineering perspective. Faster fluid flow is associated with increased convective heat transfer coefficient which means increased transfer of heat through convection from the cast iron surfaces to the coolant. I've heard this "old wive's tale" before. It simply doesn't make any sense.

The reason that you shouldn't leave the thermostats out is that to perform best with highest efficiency, the engine operating temperature should be regulated to the design specification. That's what the thermostat does.

[JohnC]

Mr. Fuller is/was a training instructor. He can offer some good insight. However, his comment about the "coolant flows through the engine with no restriction whatsoever and travels too quickly to absorb enough heat" is not sound from an engineering perspective.

Very diplomatic!

The same logic would argue that, to keep cool in the summer, you should run your fans as slow as possible so the air has more time to absorb heat from your body...

One other thing that some thermostats contribute is blocking off the bypass passage as the engine temperature increases, forcing more coolant through the radiator.

[john8662]

Glad to see very like minded conversation about the two HO pumps. I too have heard that the spin on pump is balanced flow and argued the point that there is no proof of that. I need to see some proof myself that it does flow any different than the 4-bolt pump.

My current logic is the spin on pump was just an industry change that favored that design is all. I think that change is impractical, as I like the 4-bolt setup as it's easier to service for me, at least with common tools.

I've been studying the water pump designs like pictured in these postings this year myself, mainly to gain a better understanding of design changes. The study came about in justifying and seeing the function behind the Peninsular v-belt water pump that I now own the tooling for.

I got the misfortune recently of having to produce a new pattern for the cast iron impeller wheel that goes into the Peninsular pump, so I had to justify the engineering behind it and of course the economics of production to continue the item.

The design engineering spec sheets call for closing the gap between the impeller and the housing. In looking at an 80's v-belt AC Delco pump, I can clearly see why they did it (lots of gap similar to the 80 gph serpentine pump pictured in these threads). I too am behind RJ's engineering on a smaller gap being ideal. Other than the wheel being larger to fill the void the wheel has some other design changes.

This coming summer I am considering doing a test with a variable speed DC motor with the water pumps. have to machine pulleys for the motor and pumps tho...

Anyone know what the RPM the pumps form their rating? For example at what RPM does the HO pump produce approximately 130GPM?


J