63 Water Pump

[Jerry DiTullio]

What was the part number for a 1963 340 hp water pump?

Thanks

[Collin MacDonald]

Re: 63 Water Pump

The L76 and L84 water pumps number was 3859326. Casting dates for this pump was not applied to the pump until late 1965....However, early 63's used a water pump with 3782609, undated. The 609 pump has that bypass hole on it...Hope this helps. I don't know the dates when the 326 pumps were first used phasing out the 609...I know my 63 used the 609 and it was build late January 63.

[Michael H.]

Re: 63 Water Pump

Collin,

I have a feeling we may hear some disagreement on the use of the 3859326 pump for 63.

[Collin MacDonald]

Re: 63 Water Pump

Took if from the JM on page 113...own words of NCRS...maybe then how it is worded is bad/??

[Michael H.]

Re: 63 Water Pump

Collin,

About a year ago, there was a lengthy discussion on this board about the use of the 3859326 water pump on any 63 or 64 car. I think almost everyone agreed that the 326 never made an appearance until mid/late 65, if it did at all.

If you check the archives, using both hanson and 3782609, or Lucia and 3782609, it shoild bring you to the original discussion.

Is the 3859326 still listed as correct in the latest 63-64 JG?

[Michael H.]

(Message Deleted by Poster)

Message Deleted by Poster

[Philip C.]

:There are over 100 mistakes in 63-64 JM *NM*

[Ray C.]

Re: :There are over 100 mistakes in 63-64 JM

Hi! Phil

If the 1963 JG has over 100 mistakes, what would it take to get a copy of these mistakes? I am currently restoring a 1963 and would like to know the areas of discrepancy's in the current JG. This would provide me and others with information so we may research these areas prior to buying, changing, or restoring parts.

Thanks Ray

#36314

[Michael H.]

Here Link To The Original Discussion.......

....that was posted in January of last year. I think it should show, beyond doubt, that the 3859326 is not at all correct for any 63 or 64.

https://www.ncrs.org/forum/archive20.cgi?review=160069

[Joe L.]

Re: (Message Deleted by Poster)

Michael, Jerry, and Collin-----

This GM #3859326 waterpump thing is perplexing. As I've mentioned previously, I don't see how this casting could have been used for the 1963 (or, 1964) model year. There are several reasons for this. First, the casting number seems too late in sequence to have been used for 63-64. However, as I've said before also, using this sequence as an indicator of when a particular part was released is just a "rule-of-thumb"----it's NOT a "hard-and-fast" sort of thing. There ARE exceptions to the "rule-of-thumb".

Second, the date that I find on the GM drawing for the pump casting is May, 1965. That's just about what I would expect considering the part number. So, that's consistent. I can't find any dates, anywhere, on the drawing that are earlier than this date. That does not mean that there isn't, though. What I have may not be complete and there could have been earlier drawings. Unlikely, but nevertheless possible.

Third, many sources indicate that casting dates for the '326' pump began in late 1965. It could very well be that's about when the '326' pump began. In any event, since no castings have earlier dates, there's no way to verify from this if there were '326' pumps cast before 1965.

Fourth, we know that the 3782609 and 3839175 castings were being manufactured and used during the 1963-64 period. Why would Chevrolet have needed a THIRD, virtually identical casting? It's possible, of course, but seems unlikely.

Now, all of the above would seem to support the conclusion that the 3859326 waterpump casting was not used during the 63-64 period. However, some time ago I came into the possession of strong evidence to the contrary. This involves some old Saginaw foundry records (obviously old, hand written type records) which indicate that the 3859326 pump casting WAS manufactured for the 1963 model year. I don't have these handy, at the moment, and I don't have time to look for them, but I do have them here somehwere.

So, this throws earlier "theories" I have had into a "cocked hat".

[Michael H.]

3859326 W/Pump

I'm going to stick with my original postings and position on this. There were no 3859326 water pumps for the 63 model year and likely none for any 64's. At least none that ever made out the door and wound up on any car. I agree that some paperwork/prints may have been in existance in vary late 1963 but there's no way a finished 3859326 water pump ever made it the line in 1963.

[Wayne M.]

So what do I have ? "326" A _24_2

Per Joe L.'s comment on the thread/link you provided, he claims the casting was used into the '90's. So a date code as mentioned in the subject line could be Jan 24th 1972, 1982 or even 1992. The pump in reference has obviously been to a re-builder, as it has the dual bolt pattern pulley and the larger NPT 3/4" bypass fitting. I got it with a bunch of parts from an owner of a '64 and a '65. Can post a pic if would add to the discussion.

[Jack H.]

Add on...

If you lay the three pumps next to each other ('609, '175, and '326) you can SEE the natural design progression...

The upper boss on the '609 that's drilled/tapped for the bypass elbow has a small diameter and when drilled/tapped for the 'truck' configuration of the water pump (3/4-inch NPT) almost ALL of the upper surface of the boss is removed.

The '175 casting has more 'meat' with its upper boss being larger in diameter. So, much larger that they had to intentionally cast a 'flat' on the front vertical surface for the rear lip of the water pump pulley to safely clear the boss.

Then, the '326 pump's upper boss is larger yet with a much more pronounced flat (wider/deeper) on its front face for water pump pulley clearance. Other than those differences which ARE visible on the judging field, the three pumps are pretty much alike presuming you don't attempt 'heroics' with an inspection mirror/flash light to try and read casting numbers.

Joe's 'find' of hand written foundry records for the '326 pump dating back to the '63-64 era clouds the picture further regarding what's 'right' for '63L-65' Corvette, but it won't be the first time we've faced a Corvette mystery...

[Collin MacDonald]

Re: Add on...

Thanks for all this information. I use this JM as gospel, along with all the other documentation I got from NCRS and other sources... I am just disturbed to learn that over 100 mistakes are in the NCRS JM, and yet this is what is used to restore? Has this been corrected in the new JM, along with the 99 over mistakes? Its funny, when I first read it the way it was worded was confusing to begin with.

The value of having this forum and the NCRS members who are eager to help is really something that has become necessary along my four years of restoring this 63 coupe...Many thanks to all...you seem to learn something new each day here..now if we can only get this knowledge down in the written word...

Many thanks..Collin

[Joe L.]

Re: So what do I have ? "326" A _24_2

Wayne----

Yes, the pump was definitely manufactured into the late 80's or early 90's. So, I expect that the date is 1972, 1982 or, possibly, 1992. Besides, supposedly dates were not used on these pumps before late 1965, so even if it was a 1962 pump casting, then it should not have any date on it.