Question on the waterpump for my 69 SB

[Michael L.]

guys,

I just ordered a replacement waterpump for my 69 SB resto and noticed that the water pump flange has 8 holes in it. the one on the motor, that may be original but that I elected not to have rebuilt, has four. Which one is correct four holes or eight?

Mike

[Alan S.]

Re: Question on the waterpump for my 69 SB

Hi Mike,
I believe 68-69 original sb water pumps had 4 holes in the flange that mounts the fan clutch.
The service replacement pump's flanges had 8 holes.
Regards,
Alan

[Richard M.]

Re: Question on the waterpump for my 69 SB

You could remove the 4 hole hub from the original and the 8 hole hub from the replacement and install the 4 holr, but you'll have to disassemble the new pump to do that using a press, some deep sockets and a feeler gauge.

More info in this post.

https://www.forums.ncrs.org/showthread.php?108979-1967-Body-Lift-for-Chassis-amp-Frame-Restoration&p=759905#post759905

[Terry M.]

Re: Question on the waterpump for my 69 SB

guys,

I just ordered a replacement waterpump for my 69 SB resto and noticed that the water pump flange has 8 holes in it. the one on the motor, that may be original but that I elected not to have rebuilt, has four. Which one is correct four holes or eight?

Mike

Mike
The answer might depend on when your 1969 engine was assembled. My 1970 small block has the original water pump with an 8-hole flange. My engine was assembled January 14, 1970. You do realize that only you, and anyone reading this post, will know which flange is installed on your water pump.

[Joe L.]

Re: Question on the waterpump for my 69 SB

You do realize that only you....... will know which flange is installed on your water pump.

Terry and Mike------


That's the salient point. And I HIGHLY recommend against trying to change the hub whether it's original, or not.

[Michael L.]

Re: Question on the waterpump for my 69 SB

Thanks guys. That was going to be my next question. If it can't be seen I'm not going to sweat it.

Mike

[Richard M.]

Re: Question on the waterpump for my 69 SB

On early smallblock engines the hub can be seen from behind the water pump pulley with a mirror. I'm unsure about the 1969 model year engines and their pulley configuration.

If not judging, agreed, it's a moot point.

Pics for reference....

[Joe L.]

Re: Question on the waterpump for my 69 SB

Richard------

I don't see why it would be different for 1969 (or 1970) versus earlier.

Both of the hubs you pictured appear to me to be typical of GM-installed hubs. The front configuration with depressed area around the shaft orifice is typical of, if not exclusive to, GM hubs.

One thing to keep in mind: when hubs are re-used it often ends up after installation that there is excessive runout on the hub (and resultant excessive runout on the installed pulley, fan clutch, and fan). I don't know why this is but that's what I've found. Very little runout on the hub is acceptable (probably 0.002" or less) because it is magnified on the pulley, fan clutch and fan). Excessive runout leads to early waterpump bearing failure.

[Richard M.]

Re: Question on the waterpump for my 69 SB

Joe,

Good point regarding hub runout. I will have to check that on future rebuilds. I have seen much runout and wobble on some reproduction pulleys and fans though. I'm certain that doesn't help water pump bearing life either.

[David L.]

Re: Question on the waterpump for my 69 SB

In my collection I have an original 1970 Waterpump for a 1970 Camaro SS350 (Tonowanda engine) with casting # "3927170" and letter "T" (for Tonowanda) dated "A 27 70" (January 27, 1970) that has the 8-hole hub (diameter measures 2.64") with the depressed area around the shaft. The backside of the hub has the stamped letter "R" on one side and the number "0" on the other side. Could the "0" represent the year 1970?

Dave

[Richard M.]

Re: Question on the waterpump for my 69 SB

In my collection I have an original 1970 Waterpump for a 1970 Camaro SS350 (Tonowanda engine) with casting # "3927170" and letter "T" (for Tonowanda) dated "A 27 70" (January 27, 1970) that has the 8-hole hub (diameter measures 2.64") with the depressed area around the shaft. The backside of the hub has the stamped letter "R" on one side and the number "0" on the other side. Could the "0" represent the year 1970?

Dave

David, I think the letter R is the code for the manufacturer of the hub. I don't know what the 0 represents. It may be a code number for the press(if that's what they used) which was used to make it. Likely several were used, much like the codes used for cast parts and the various molds. Or it could be a inspection stamp. These are all obvious guesses.

Rich