1967 L79 with C60 water pump

[Keith B.]

I recall reading that certain years with L79 and C60 that the water pump hub was pressed onto a different height then without C60. But I don't remember if the N40 played a role into that or not. So can anyone fill me in?

[Leif A.]

Re: 1967 L79 with C60 water pump

Keith,
From the '67 TIM&JG:

[Keith B.]

Re: 1967 L79 with C60 water pump

thanks Leif I was just brainstorming as I just found dad a correct 326 pump for his latest project. then I remembered about the water pump hub on C60 cars. but couldn't remember the combo of options for the hub. luckily his car does not have N40. so this was just overthinking on my part.

[John D.]

Re: 1967 L79 with C60 water pump

At some point wasn't there was a reinforcement spacer added between the pulley and hub to prevent pulley failure that would take up at least part of the offset ?

[Chris T.]

Re: 1967 L79 with C60 water pump

The reinforcement goes between the water pump pulley and the fan clutch hub.
WaterpumpPulleyReinforcementTSBDR-66-40.jpg

[James W.]

Re: 1967 L79 with C60 water pump

Would the water pump hub press-on location be the same on a '65 with A/C and N40 as it is for a '67? My '65 is equipped that way and after having it rebuilt I had to re-ajust the hub to make the belts line up correctly. It also had the reinforcement spacer installed when I took it apart.

James

[Joe R.]

Re: 1967 L79 with C60 water pump

Yes, the N40 was an essential ingredient for the revised hub position on the water pump, but only when A/C was also included. A short summary is as follows:

1) There were two different pulley families used on small block Corvettes. Base engines had "standard groove" pulleys and high performance engines had "deep groove" pulleys.

2) In addition to being deeper, the grooves on a deep-groove pulley were, by necessity, wider (a fixed angle for the "V" forces a deeper groove to also be wider). So, the center lines of the grooves on a 2-groove, deep groove water pump pulley were 1/8" farther apart than the centerlines of a standard-groove pulley.

3) The result was that the water pump flange for a deep-groove pulley set was positioned 1/8" farther out (toward the radiator) than the flange position for a standard-groove pulley set.

4) For 1967, for example, this all worked fine because the 300 hp water pump was a different part from the 350 hp water pump, so there was (almost) no confusion about the position of the flange on the water pump. The 300 hp water pump flange had the standard-groove position, while the 350 hp water pump had (with one exception) the deep-groove position.

5) For the 350 hp application equipped with BOTH power steering and A/C, the addition of the third groove on the crank pulley to drive the power steering pump presented a problem. The power steering pump pulley was so far forward that it interfered with the frame kick-in in front of the power steering pump. So, for ONLY the 350 hp engine configured with BOTH power steering and A/C, the standard-groove pulley set was used, which moved the power steering pump pulley back by 1/8".

6) This meant that for the 350 hp engine equipped with BOTH power steering and A/C, the flange on the water pump had to be located 1/8" farther back than for any other 350 hp configuration.

7) A consequence of this change was that the engine code for a 350 hp engine that had BOTH power steering and A/C was a unique engine code of HP, rather than the HT code used for most other configurations of the 350 hp engine. The only difference between the HP code and the HT code was the position of the flange on the water pump.

[Keith B.]

Re: 1967 L79 with C60 water pump

Thanks Joe that was a very detailed explanation