64 Water Pump 3859326, what to do

[Larry M.]

There is a guy who posts here with a 70 model who says it has never been out of his control but once for over 4 hours; what a blessing that must be.

There is another guy who bought a similar car with what he thought was 70k miles max (broken speedo) and was extremely bummed out that, on removal, it was obvious the water pump had been rebuilt. How could this be at such low miles.

Well, on to the point. Attached is the back side picture of the unit removed yesterday from my 38,000 mile 64 fuelie. I'm pretty sure of the miles but I'll really never know for sure. I could feel side play in the shaft and, from a post yesterday, Duke Williams advised I get it rebuilt. It is clear it has already been rebuilt (or replaced). First: from old posts you would conclude that a back plate with the ribs between bolt holes was not introduced until 67 or later; second: six different headstamps on the screws; third: full paint on the back (and on the timing chain cover). But it is the right casting with no date code and I think the S1 on the back means Saginaw. So the question is what should I do. It is already in the mail to Bill Mock who I think will put any back plate and any screw head stamp on it for the same money. The car was built 11/25/63.

I think (I'm guessing) that the correct plate looks just like my pic but without the ribs between holes. But it is conceivable it was flat with pan head screws. The plate I have is best for reliability but you can see it when installed on the car. Does anyone know (or have a strong opinion based on something)?

Second, any data of the head stamp for early 64. I think Bill has every thing ever made.

Thanks in advance for your help. As I write this I'm thinking I should have read the judging manual first but from reading posts I doubt it will answer the question. I'm going to read it anyway.

[Dino L.]

Re: 64 Water Pump 3859326, what to do

Not an expert on this topic, but my first thought is that waterpump has been off your engine before....based on the paint coverage.....does your timing cover show complete coverage as well? I was thinking both should show light coverage on rear as it was assembled on engine when painted? Of course I could be mistaken....

[David L.]

Re: 64 Water Pump 3859326, what to do

This link about W/pump back plates may help.

Dave

https://www.forums.ncrs.org/showthre...ght=water+pump

[Joe L.]

Re: 64 Water Pump 3859326, what to do

There is a guy who posts here with a 70 model who says it has never been out of his control but once for over 4 hours; what a blessing that must be.

There is another guy who bought a similar car with what he thought was 70k miles max (broken speedo) and was extremely bummed out that, on removal, it was obvious the water pump had been rebuilt. How could this be at such low miles.

Well, on to the point. Attached is the back side picture of the unit removed yesterday from my 38,000 mile 64 fuelie. I'm pretty sure of the miles but I'll really never know for sure. I could feel side play in the shaft and, from a post yesterday, Duke Williams advised I get it rebuilt. It is clear it has already been rebuilt (or replaced). First: from old posts you would conclude that a back plate with the ribs between bolt holes was not introduced until 67 or later; second: six different headstamps on the screws; third: full paint on the back (and on the timing chain cover). But it is the right casting with no date code and I think the S1 on the back means Saginaw. So the question is what should I do. It is already in the mail to Bill Mock who I think will put any back plate and any screw head stamp on it for the same money. The car was built 11/25/63.

I think (I'm guessing) that the correct plate looks just like my pic but without the ribs between holes. But it is conceivable it was flat with pan head screws. The plate I have is best for reliability but you can see it when installed on the car. Does anyone know (or have a strong opinion based on something)?

Second, any data of the head stamp for early 64. I think Bill has every thing ever made.

Thanks in advance for your help. As I write this I'm thinking I should have read the judging manual first but from reading posts I doubt it will answer the question. I'm going to read it anyway.

Larry-------


I don't think that a 3859326 casting was ever originally used for the 1964 model year.

[David L.]

Re: 64 Water Pump 3859326, what to do

Larry-------


I don't think that a 3859326 casting was ever originally used for the 1964 model year.

Joe,

My notes indicate that the 3859326 water pump was used on 1963-1965 Corvettes w/340 & 375 HP. The same pump was used in later years (1966-1968) but the threaded hole was larger.

Dave

[Joe L.]

Re: 64 Water Pump 3859326, what to do

Joe,

My notes indicate that the 3859326 water pump was used on 1963-1965 Corvettes w/340 & 375 HP. The same pump was used in later years (1966-1968) but the threaded hole was larger.

Dave

Dave-------


I don't think so. I believe the 3859326 was first used for the 1965 model year and then through the 1967 model year. All 1965-67 examples used on Corvettes had 1/2" NPT bypass fitting. The 3/4" bypass fitting examples came along later in SERVICE.

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Dave, thanks for the input. As for the casting number, Bill Mock told me over a year ago that the 326 was one of the correct numbers for my car and the Dobbins "VetteVues" book also lists it. As for the link, I'd seen this before. It is the best that I have. In it Joe says the #2 plate was used starting in 1961; I'm going with that. As for head mark I'll likely go with "EL double circle"; "E double circle"; or "L" if I can get it. As an interesting note, after reading all the posts I could find I downloaded the attached picture which is a fifth variation. The poster, and I'd have to go back and find it to know who that was, said is was from an NOS 69 pump. Since it does not have the rib between the holes you'd think it was an earlier version but who knows. It could be aftermarket also. Also, I did read the judging manual; not much to go on there.

[Tracy C.]

Re: 64 Water Pump 3859326, what to do

Larry & David.

This has come up several times. You should consider what Joe has offered here and read this thread. The 326 didn't come along until later.

https://www.forums.ncrs.org/showthre...ter+pump+sinor

tc

[David L.]

Re: 64 Water Pump 3859326, what to do

Dave-------


I don't think so. I believe the 3859326 was first used for the 1965 model year and then through the 1967 model year. All 1965-67 examples used on Corvettes had 1/2" NPT bypass fitting. The 3/4" bypass fitting examples came along later in SERVICE.

Joe,

You are correct. I just got an email from Andy of NJ (aka " Mr. 63") confirming that the 3859326 pump was not used on 1963's. I will correct my notes.

Dave

[Larry M.]

Re: 64 Water Pump 3859326, what to do

I've read the attached stuff and have this question/proposition. It discusses the 326 as having been used in the MY65 cars but if it was drawn in 5/65, assuming any time at all to get into production it is unlikely any made it into 65 cars.....cast, machine, assembly, engine assembly and then car/engine assembly in St. Louis. So I'd guess that they could have only been used in MY66 cars or later (maybe a very few MY65). Now, if dating started in 11/65 then by Jan 66 cars would have had dated pumps. So an undated 326 would have been an early 66 item only and I guess only on high horse cars(350HP?) so it could be a rare item (unless tons were made for service replacements). Does this line of reasoning make sense?

[Page C.]

Re: 64 Water Pump 3859326, what to do

Larry,
Your reasoning make sense but I think they started dating these pumps before 11/65. I have some 608 pumps that's are date K34, A275, D255, F145, and have seen one dated E124. I thought they started dating water pumps around March of 1964.

[David L.]

Re: 64 Water Pump 3859326, what to do

I have or once had the following dated water pumps:
3782608 - F254, C205, D216
3859326 - L47

[Larry M.]

Re: 64 Water Pump 3859326, what to do

I hope folks don't wear out on this without taking it a couple of steps further. I DID research on the forum for the screws and therefor missed the iceberg of posts on the water pump itself. You can read for hours on this. Someone should write a book. Here are the things I've learned which lead me to pose what I think is an important question:

1. Bill Mock once wrote Alan Drake and said he thought 90% of MY64 SHP/FI cars had an undated 326 pump and 10% had the undated 175.
2. But based on an original drawing date of 5/65 many on this forum have concluded the 326 was not used. Possibly the 609 was used but the 175 is most likely although I have not read where anyone, other than Bill, says they have evidence of a 175 on a MY64 car.
3. Many people say they have seen date codes prior to 11/65 but many believe the 326 was not dated at Saginaw until then and Joe Lucia says no 175's used in production were dated.
4. So, as Alan Drake concluded, I need to find an undated 175 with the small bypass hole for my car. The undated Saginaw GM1 pattern 326 with the small bypass which I've already sent to Bill Mock is a valuable and maybe rare piece but only good for very late MY65 or early MY66.
5. But something else bothers me: in the posts it says that data from the Grey Iron Works says the 175 was derived from the 326. Even if the 326 was never produced it would of at least had to have been drawn to be the parent on the 175. So how can the 5/65 first drawn date be right?

[Dan H.]

Re: 64 Water Pump 3859326, what to do

I hope folks don't wear out on this without taking it a couple of steps further. I DID research on the forum for the screws and therefor missed the iceberg of posts on the water pump itself. You can read for hours on this. Someone should write a book. Here are the things I've learned which lead me to pose what I think is an important question:

1. Bill Mock once wrote Alan Drake and said he thought 90% of MY64 SHP/FI cars had an undated 326 pump and 10% had the undated 175.
2. But based on an original drawing date of 5/65 many on this forum have concluded the 326 was not used. Possibly the 609 was used but the 175 is most likely although I have not read where anyone, other than Bill, says they have evidence of a 175 on a MY64 car.
3. Many people say they have seen date codes prior to 11/65 but many believe the 326 was not dated at Saginaw until then and Joe Lucia says no 175's used in production were dated.
4. So, as Alan Drake concluded, I need to find an undated 175 with the small bypass hole for my car. The undated Saginaw GM1 pattern 326 with the small bypass which I've already sent to Bill Mock is a valuable and maybe rare piece but only good for very late MY65 or early MY66.
5. But something else bothers me: in the posts it says that data from the Grey Iron Works says the 175 was derived from the 326. Even if the 326 was never produced it would of at least had to have been drawn to be the parent on the 175. So how can the 5/65 first drawn date be right?

Larry, good point on the 175 derived from 326. Think it was a typo or something. Anyone else have information?
Dan

[Joe L.]

Re: 64 Water Pump 3859326, what to do

I hope folks don't wear out on this without taking it a couple of steps further. I DID research on the forum for the screws and therefor missed the iceberg of posts on the water pump itself. You can read for hours on this. Someone should write a book. Here are the things I've learned which lead me to pose what I think is an important question:

1. Bill Mock once wrote Alan Drake and said he thought 90% of MY64 SHP/FI cars had an undated 326 pump and 10% had the undated 175.
2. But based on an original drawing date of 5/65 many on this forum have concluded the 326 was not used. Possibly the 609 was used but the 175 is most likely although I have not read where anyone, other than Bill, says they have evidence of a 175 on a MY64 car.
3. Many people say they have seen date codes prior to 11/65 but many believe the 326 was not dated at Saginaw until then and Joe Lucia says no 175's used in production were dated.
4. So, as Alan Drake concluded, I need to find an undated 175 with the small bypass hole for my car. The undated Saginaw GM1 pattern 326 with the small bypass which I've already sent to Bill Mock is a valuable and maybe rare piece but only good for very late MY65 or early MY66.
5. But something else bothers me: in the posts it says that data from the Grey Iron Works says the 175 was derived from the 326. Even if the 326 was never produced it would of at least had to have been drawn to be the parent on the 175. So how can the 5/65 first drawn date be right?

Larry------


One other thing to keep in mind: the 3859326 is a part number that strongly implies a late 1965 release. So, the part number is consistent with the date on the drawing. I don't think that you'll find any other original part number used on a 1964 Corvette which is numerically as high as 3859326 (or, even close to that).