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

[nick mironov]

This type of failure is a typical problem with the SBC conversion, since there is no bypass water flow circuit for cold (closed thermostat) operation.

I talked to Renegade, and they are now preparing to market a bypass system and they are going to sell me one. This should elieve the stress on the stamped impeller, but I would still like to have a cast impeller.

I found the previous thread on this subject, and it still appears that no one has identified a specific model number for a cast impeller pump that wil fit the renegade housing. Stamped impeller pumps don't seem to be a problem to find or fit.

Although one would expect that the stamped and cast impellers to be manufactured to the same specifications to be interchangeable in the same housings, apparantly they are not. Steve at Renegade says that some of them will fit with a double gasket and some need to be trimmed to fit in depth and even in diameter. Steve runs a 6,000 rpm 302 at the track and is successfully using the bypass with a stamped impeller pump.

Nick

[Mike Bellis]

This type of failure is a typical problem with the SBC conversion, since there is no bypass water flow circuit for cold (closed thermostat) operation.

I talked to Renegade, and they are now preparing to market a bypass system and they are going to sell me one. This should elieve the stress on the stamped impeller, but I would still like to have a cast impeller.

I found the previous thread on this subject, and it still appears that no one has identified a specific model number for a cast impeller pump that wil fit the renegade housing. Stamped impeller pumps don't seem to be a problem to find or fit.

Although one would expect that the stamped and cast impellers to be manufactured to the same specifications to be interchangeable in the same housings, apparantly they are not. Steve at Renegade says that some of them will fit with a double gasket and some need to be trimmed to fit in depth and even in diameter. Steve runs a 6,000 rpm 302 at the track and is successfully using the bypass with a stamped impeller pump.

Nick

I've never heard of this problem before. I have thousnds of miles on mine without any problems. I used to own a big block Mopar. I'll see if I can track down an exact model number for you. Mopar pumps are cheap. If you go to your FLAPS and tell them you have a 1970 Charger 440 with A/C they can pull one and you can look at it. I have seen with Mopar engines the stamped pumps can corrode the impeller and lead to premature failure.

[computers4kids]

This type of failure is a typical problem with the SBC conversion, since there is no bypass water flow circuit for cold (closed thermostat) operation.

I talked to Renegade, and they are now preparing to market a bypass system and they are going to sell me one. This should elieve the stress on the stamped impeller, but I would still like to have a cast impeller.

I found the previous thread on this subject, and it still appears that no one has identified a specific model number for a cast impeller pump that wil fit the renegade housing. Stamped impeller pumps don't seem to be a problem to find or fit.

Although one would expect that the stamped and cast impellers to be manufactured to the same specifications to be interchangeable in the same housings, apparantly they are not. Steve at Renegade says that some of them will fit with a double gasket and some need to be trimmed to fit in depth and even in diameter. Steve runs a 6,000 rpm 302 at the track and is successfully using the bypass with a stamped impeller pump.

Nick

I've never heard of this problem before. I have thousnds of miles on mine without any problems. I used to own a big block Mopar. I'll see if I can track down an exact model number for you. Mopar pumps are cheap. If you go to your FLAPS and tell them you have a 1970 Charger 440 with A/C they can pull one and you can look at it. I have seen with Mopar engines the stamped pumps can corrode the impeller and lead to premature failure.

Actually, this is the third SBC conversion that has had impeller failure in the last year: 1 Tony in WA, 2 drivability and 3 nick in SF.
Here's the best thread on the pumps that I've seen.(IMG:http://www.914world.com/bbs2/uploads_offsite/i239.photobucket.com-4253-1273205192.1.jpg)