6T5RUSH

You may have remembered my issues with blowing water pumps...well I just took the car out early this evening in preparation for the Pure
Stocks coming up on 9/16 & 9/17. Was experiencing a miss right at 5,500-5,600 r's. Has an MSD box with a 6,200 chip in it. Figured I had nothing to lose (KISS) so removed the chip and wallah, she pulled hard smoothly right up to 6,300-6,400 r's. That's my good news. My bad news is as I looked down my driveway I could see a steady drip line leading into the garage. Yup, blew the gaskets...again!

I can't see any cracks in the nose of the waterpump. In grabbing the fan (it's a factory replacement 7-blade fan for an air car (thinking of adding air as a winter project) there is a little rocking to the nose of the waterpump indicating to me the bearing are starting to go. I'm just wondering if there is a way to determine if this fan is out of balance and the source of my grief. I still have my original stock 5 blade fan (was a 300 horse when it was born). Maybe it's coincidental but when I converted to the LT1 cam I swapped in the 7 blade fan at the same time. With the '5 now seeing higher r's, I have been chasing waterpump and gasket failures. Pulley alignment is right on. Belt tensioning could have been the reason for the demise the first time but since then I have left enough slack to take that issue off the table.

So, is there a way to check the balance of this 7-blade fan. I'm thinking to just put the factory 5-blade fan back on when I replace this pump and see what happens.

Little further background. I'm running a GM replacement fan clutch (new last year) as well as a 180 thermostat and a brand new restoration radiator from Dewitts along with the factory metal shroud. No cooling issues whatsover.

Appreciate any help on checking the fan for balance.

Thanks in advance!

Jim

JohnZ

Jim, I don't know any way to check the balance of the fan without a shop having to fabricate a special setup to mount it in a machine, and that would be expensive. I'd go back to the original 5-blade fan, which should work fine when you convert to A/C anyway (by '67, all Corvettes used a 5-blade fan, with or without A/C).

6T5RUSH

Thanks JohnZ for responding! I've made up my mind to do just that. Didn't realize the 7-blade fan was phased out by '67. Tomorrow I plan on buying a GM water pump. Any suggestions on local sources?

Jim

magicv8

FWIW: I split the GM casting on several waterpumps in the front bearing area, before switching to the web reinforced type with larger shaft and bearings that started about 1971.

Your problem isn't unique. Here's a pic from my web pages, split the pump on the way to BG in Springfield on I55:

BarryK

Magic

loved how that C3 cruising down the road didn't bother to pull over and ask if you needed help

JohnZ

Your local Chevy dealer can get you one, or Paragon has the same new AC-Delco replacement (with an adapter bushing for the top bypass fitting) for about fifty bucks, or speed shops (like Ramchargers) have all manner of aftermarket pumps. If you want a rebuilt original 326 pump, Bill Mock in Oklahoma (918-333-0748) has them in stock ready to ship.

Donny Brass

Jim, I can get you a rebuilt orginal if you need it.......

magicv8

Barry - there were dozens of Corvettes on I55 headed to BG. In about 20 minutes, a couple in an LT1 stopped to help and went to Lincoln IL to get water for the rad - then got me to a NAPA store too.

More story at http://www.corvetteforum.net/classic...e/index3.shtml

6T5RUSH

Thanks guys for the suggestions. Hey Donny, give me a shout on that rebuilt GM waterpump. I want to hear more. Just may go that route...in my mind I'm thinking brand new to eliminate any quality issues from a rebuilder.

Thanks!

Jim

BarryK

well, I'm very glad to hear that another Vette stopped to help at least