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The 5/8" shaft on my water pump broke and wiped out the fan and radiator. The PO installed a prior year pump on my 73 BB and used the 3/4" pulley and fan clutch from the 73. I bushed these to fit correctly, but it was probably too late. I believe these vibrated badly and caused the shaft failure. Luckily it occurred in my driveway. Looking t my options now.
Pictures below.
Last edited by 2mnyvets; Sep 21, 2020 at 08:35 AM.
I'm sorry to see that, but thank you for posting the aftermath! A plurality on this Forum enjoys the stock-style spinning wheel of death at the front of their engines, but when an electric fan fails, it doesn't take out your radiator. Did your fan shroud survive intact?
Now thats what I call a flex fan, bet it catches some air!! Kidding aside glad it didnt happen on the road
Lost a balancer once on the fwy (327 with no bolt) took out the radiator, dented the hood similar to yours.
Thanks for all the suggestions and advice. Not sure where I am headed with the repair. I am considering rebuilding the water pump if I can get a shaft that is 3/4" that will fit into the C2 water pump housing. If not, I am probably going to go with a Stewart Pump. The shroud was not even touched so that is good news, As far as the fan goes, It was an aftermarket 6 blade fan and it does have aluminum blades. I glass beaded and powdercoated it. I believe the fan is supposed to be a 7 blade fan. Problem is that the car would overheat if it idled for extended periods with the AC on. It idles at about 700 RPMs I added the AC and don't know if the idle should have been increased to increase fan speed and air flow. My seals are all new so that shouldn't be the cause of the overheating. I was half-heartedly looking for a 7 blade fan to see if that increased idle air flow,, but they are expensive.
I was trying to keep the engine compartment looking original so I didn't consider electric fans, but now that I will be going back with an aluminum radiator and possibly an aluminum pump the original look is going away quickly. It looks like the Champion radiator and electrical fans will actually be cheaper than the replacement radiator and mechanical fan and clutch. It looks like it is a wash if I include the alternator upgrade. I am considering the Dewitt package. It appears to be a much better designed/thought out, but is almost double the price or $500 more.
Any thoughts?
Last edited by 2mnyvets; Sep 21, 2020 at 07:26 PM.
Thanks for all the suggestions and advice. Not sure where I am headed with the repair. I am considering rebuilding the water pump if I can get a shaft that is 3/4" that will fit into the C2 water pump housing. If not, I am probably going to go with a Stewart Pump. The shroud was not even touched so that is good news, As far as the fan goes, It was an aftermarket 6 blade fan and it does have aluminum blades. I glass beaded and powdercoated it. I believe the fan is supposed to be a 7 blade fan. Problem is that the car would overheat if it idled for extended periods with the AC on. It idles at about 700 RPMs I added the AC and don't know if the idle should have been increased to increase fan speed and air flow. My seals are all new so that shouldn't be the cause of the overheating. I was half-heartedly looking for a 7 blade fan to see if that increased idle air flow,, but they are expensive.
I was trying to keep the engine compartment looking original so I didn't consider electric fans, but now that I will be going back with an aluminum radiator and possibly an aluminum pump the original look is going away quickly. It looks like the Champion radiator and electrical fans will actually be cheaper than the replacement radiator and mechanical fan and clutch. It looks like it is a wash if I include the alternator upgrade. I am considering the Dewitt package. It appears to be a much better designed/thought out, but is almost double the price or $500 more.
I was trying to keep the engine compartment looking original so I didn't consider electric fans, but now that I will be going back with an aluminum radiator and possibly an aluminum pump the original look is going away quickly. It looks like the Champion radiator and electrical fans will actually be cheaper than the replacement radiator and mechanical fan and clutch. It looks like it is a wash if I include the alternator upgrade. I am considering the Dewitt package. It appears to be a much better designed/thought out, but is almost double the price or $500 more.
Any thoughts?
I have the dual Spal fan assembly that DeWitts sells. DeWitts also sells a line of radiators through Zip for $400- each. This link should show all of them.
I have used the Dewitt's Aluminum with SPAL fans now on two of my cars. The 1972 Big Block Road Race Replica I build with a Gen VI 496/565 engine stayed cool during operation. I am going with the same Dewitt's setup for my 1974 Convertible with L-82 enhanced engine. I always swallow hard when I order them but once installed you will never regret buying them. I did not purchase or paint them black, I stayed with the aluminum look.
Good luck on your decision and best regards,
David Howard
Here is a summary of how I am going to fix the car. For the water pump I called zip Corvette and they told me that you could not put a shaft with a ¾” inch pilot into a casing that had a 5/8” pilot, so I went with the Stewart stage one water pump. The reason I went with the stage one is the Stewart tech rep told me that the three different stage pumps had the same flow. The flow was 45 GPM at 1500 RPM and 120 GPM at 4800 RPM. He said the original pump was 30 GPM@1500 and 90 GPM@4800.
The difference between stage 1,2 and 3 are as follows: stage 1 has a cast iron body and cast iron impeller, stage 2 and 3 have aluminum casings and a stainless steel impeller. Stage 3 has a thicker pulley mounting flange. I saw no advantage to the aluminum or stainless steel impeller so I went with the cheaper Stage 1.
I went with the Dewitt combo radiator with the 1” tubes. I purchased it from Wilcox Corvette. He had two in stock. I would have liked to go with the 1-1/4” tubes but that radiator would not ship till November 9th. For those looking for a radiator, it is included in the Willcox Weekend sale.
I did not go with the Zip Dewitt radiator because that was not a direct fit radiator. It appears the Zip radiator is a more generic radiator that is made by Dewitt.
I upgraded the alternator to a 150 amp Powermaster alternator. I will upgrade the wiring by putting an 8 gauge wire in parallel with the 10 gauge wire that's existing now. This will keep the current in the 10 gage wire and in the gage about the same as with my 63 amp alternator. The gage will read about 40% low though. I am going to wire the SPAL fans directly to the back of the alternator. Under normal circumstances the power for the fans will come from the alternator and it won’t tax the existing wires. I am not sure about adding a new ground. The alternator bolts to the block so that may be sufficient. I will measure resistance and decide whether an additional ground is needed.
I appreciate all your help. Let me know if You see something I did wrong or if you want more information.
Edit: I did look at the Champion radiator Combo. There is no good reason I didn't go with it. Depending on which Champion radiator you compare it to, I paid 200 to 300 more for the Dewitt and may not have as much cooling as with the Champion. Usually I base every decision on "value", this one was just a personal preference.
Last edited by 2mnyvets; Sep 24, 2020 at 05:25 PM.
You did the right thing, in the long run youll be happy with it. Choked when I paid for mine and cooling is still borderline (not enough fan) but thats my bad judgement. (A body) it made a night/day difference on my C4 they are known to be gauge watching cars hah! No more..can run around town for 15 min or so in 90 deg heat and barely hit 175..once moving it cools down super quick fan almost never runs unless Im in traffic. The stock sytem was horrible.
My '69 BB does. I'm not sure if it's original or not.
I am pretty sure my fan was not original. I thought my BBC was supposed to have a 7 blade fan but I searched the AIM and can only find a 5 blade fan PN 3991420, listed. Due to manageable idle overheat issues, I was halfheartedly looking for a 7 blade when this happened. 7 blade fans were in the $300 range. With the alternator upgrade and going with Dewitt, It cost me about $200 more to replace the mechanical fan with the electrical. Had I gone with Champion or assembled the electric fans myself It would have been a wash to about $50. This is because I felt I needed a new 7 blade fan to resolve the overheat. I wanted the electric fans for better belt access and access to the timing marks and the crank pulley. .
Catastrophic Water Pump Failure
