63 L76 water pump questions

[Bruce D.]

Guys. I need some help with a few questions about a 63 L76 340 hp waterpump please.
1. judging manual says that casting number should be 3859326 for a late 340 hp motor, yet some are telling me that the 326 pump was not used untill 64 and the 609 pump is correct for all of 1963.
2. early water pump has a casting number of 3872609 in the manual ,but i think the 8 and 7 are transposed and it should be 3782609.
3. who supplies a repro bypass 87 degree hose fitting for the top of the pump with the logo and the series of diamonds on the side?
4. Anyone ever see a small 3 to 4 inch metal disk with 4 holes that fits between the water pump pully and the pump. Looks line about a 1/32 in spacer?

thanks

[Joe L.]

Re: 63 L76 water pump questions

Guys. I need some help with a few questions about a 63 L76 340 hp waterpump please.
1. judging manual says that casting number should be 3859326 for a late 340 hp motor, yet some are telling me that the 326 pump was not used untill 64 and the 609 pump is correct for all of 1963.
2. early water pump has a casting number of 3872609 in the manual ,but i think the 8 and 7 are transposed and it should be 3782609.
3. who supplies a repro bypass 87 degree hose fitting for the top of the pump with the logo and the series of diamonds on the side?

thanks

Bruce-----


I don't think that any 1963's originally used the GM #3859326 waterpump casting. Some late 1963 may have used the 3839175, though. Most 63's used the 3782609 (which is the correct number). This is a difficult-to-find and expensive casting.

I don't know who supplies the fitting you described.

[Alan D.]

Re: 63 L76 water pump questions

#3 Long Island (21-12)
#4 Sounds like the pump was rebuilt and the shaft was pressed on a little more then the spec so spacer used to aline things back up.

[Larry M.]

Re: 63 L76 water pump questions

[QUOTE #4 Sounds like the pump was rebuilt and the shaft was pressed on a little more then the spec so spacer used to aline things back up.[/QUOTE]


A few mid-years used these factory spacers......but not sure about 1963. I believe that Paragon still has them (Paragon Item #846).

Larry

[Michael H.]

Re: 63 L76 water pump questions

The print for the 3859326 water pump is dated either late 64 or early 65 (can't remember, and I don't feel like digging it out) so that would make it "somewhat unlikely" that a 326 pump would ever have been installed on any 63.

[Michael G.]

Re: 63 L76 water pump questions

While it is possible that some 63's had a bypass fitting with just a series of diamonds (as shown in the manual), all of the original 63 bypass fittings that I have seen on low mileage cars have a series of diamonds with a "P" in each diamond. The "P" stood for a now-extinct Detroit-area manufacturer (can't remember the name just now). I have been told by judges that the "P" is incorrect, that it stands for "Paragon", but, per Paragon, that is not true. You may want to buy a repro without the P, just to pass judging, but certainly do not throw away one with the "P"'s as it is an original. Here is he mark to look for, it may be on a different facet of the hex:

DSC00705.jpg

[Bruce D.]

Re: 63 L76 water pump questions

thanks to all of you for your information. I appreciate your time and interest.....

[Alan D.]

Re: 63 L76 water pump questions

Mike, have the same problem on that part!

[Paul J.]

Re: 63 L76 water pump questions

It is widely accepted that the JM is incorrect. The 3859326 pump supposedly was first seen around Nov. 64.

[Joe L.]

Re: 63 L76 water pump questions

While it is possible that some 63's had a bypass fitting with just a series of diamonds (as shown in the manual), all of the original 63 bypass fittings that I have seen on low mileage cars have a series of diamonds with a "P" in each diamond. The "P" stood for a now-extinct Detroit-area manufacturer (can't remember the name just now). I have been told by judges that the "P" is incorrect, that it stands for "Paragon", but, per Paragon, that is not true. You may want to buy a repro without the P, just to pass judging, but certainly do not throw away one with the "P"'s as it is an original. Here is he mark to look for, it may be on a different facet of the hex:

[ATTACH=CONFIG]42391[/ATTACH]

Mike-----


I think the "P" denotes Parker-Hannifin Corporation. They're still very much in business although I don't know that they still make this particular fitting.

[Wayne M.]

Re: 63 L76 water pump questions

. .....A few mid-years used these factory spacers......but not sure about 1963. I believe that Paragon still has them (Paragon Item #846) ...

A few years ago, GM still had the spacers Gr 1.062 #3720616.

[Joe L.]

Re: 63 L76 water pump questions

A few years ago, GM still had the spacers Gr 1.062 #3720616.

Wayne-----

They're now discontinued but aftermarket spacers are available. GM called these things "reinforcements", I suppose because of the curved perimeter. The aftermarket spacers are flat. However, they come in different thicknesses to solve just about any pulley alignment problem (except cases in which the hub is too far forward). Moroso is one manufacturer.

[Wayne M.]

Re: 63 L76 water pump questions

..... You may want to buy a repro without the P, just to pass judging, but certainly do not throw away one with the "P"'s as it is an original. Here is he mark to look for, it may be on a different facet of the hex:

[ATTACH=CONFIG]42391[/ATTACH]

Here's another shot of one with the "P" in the diamond; nothing on the other faces.

The '65 TIM&JG says: " logos on two faces of the hex; one side a series of diamonds .. the other may have a logo with "CP" inscribed within a diamond and a circle, which repeats vertically"

Wonder which is correct ?

[Larry M.]

Re: 63 L76 water pump questions

Mike-----


I think the "P" denotes Parker-Hannifin Corporation. They're still very much in business although I don't know that they still make this particular fitting.

I agree. Larry

[Michael G.]

Re: 63 L76 water pump questions

I've seen the "CP" on some old swap meet parts, but never on an untouched car. I'm told, though, that the CP version was supplied on some 63s. I have a repro version of the CP on my black car. I'll post a photo tomorrow.