SBC V8 Water Pump Failure, 3 Styles of Pumps Tested BYPASS THERMOSTAT UPDATE Options

[nick mironov]

My Renegade water pump failed yesterday. The pump impeller is stamped steel and the blades all just folded over or sheared off. I understand that the cast impellers are much stronger, but that not all manufacturer's cast models will fit into the Renegade housing. Anybody have experience with cast impeller pumps that will fit into the Renegade housing?

Since there is no bypass in the Renegade system, Renegade instructions are to limit the motor RPM to 3,000, or less, untill the thermostat opens. I have observed this, but the pump still failed after 5,500 miles. Renegade now makes a bypass kit, which I going to try, but I would still like to get a more durable pump.

Nick

[SLITS]

It is hard to imagine that a pump would see sufficient backpressure in a system to flatten the stamped steel impellers. It would seem that the pump would cavitate before that happened. Just speculation.

If it's the same that was used some time ago, it is more than likely a GMB pump. The person that was making the stamped aftermarket impellers was making them out of some very weak material. There was a notch (indentation) in the blades to form somewhat of a gusset for strength.

The impellers could have been stamped from heavier gauge material, but then they wouldn't have been as inexpensive.

The only question as to whether the stock Big Block Chrysler impeller would fit is the depth of the impeller in the housing (the impeller thickness). A cast iron one could be made to the specifications, but one would have to order at least 300 pieces. There is to limited a market for that.

Alternatively, the stock cast iron one could more than likely be machined to appropriate dimensions.

All this is speculation, as we do not have a back housing to examine the fitment of a stock pump / impeller. Oh, and the original pump it was patterned after is fully cast iron. I posted an image of it in the previous thread about the same problem.