64 Water Pump 3859326, what to do

[Larry M.]

Re: 64 Water Pump 3859326, what to do

I think it would be great if Michael Hanson or Mark Gorney who have the Grey Iron Works information would go back again and look at those source documents. In two different posts I see where Mark says that data says the 175 was derived from the 326 but he also says that GIW did not cast the 326 until MY65. I'm not a gear head and I don't think I've been injected with the "know everything about old Corvettes" needle and I don't have any parts manuals...but I really appreciate the people who have and know this stuff. They help me. All I want to do is get my car right....and I don't even get it judged...I just find it to be fun. And I think everyone needs to keep an open mind about that May 1965 drawing date. I just spoke with Bill Mock who now has my 326 unit. He tells me that if I look he has posted a pic of a Feb 64 low miles Z06 car with an original 175 and I'm going to look for that. And he also says he is coming around to the conclusion that the 326 was not on 64s based on the NCRS discussion. And as a result and as said in the post Tracy references above the 175 should have been the SHP/FI pump for 64 and most of 65 MYs whereas the 326 with no date would only have been on early 66s (maybe a few 65s). The problem I have is this: the 326 with no date and small hole is much more plentiful than the comparable 175. Bill will tell you the 175s are more rare than the 326s. Something isn't making sense here....that's my two cents.

[Larry M.]

Re: 64 Water Pump 3859326, what to do

I wanted to make my point above numerically. for 64/65 there were 16000 L76/79/84. For half of 66 there were 3800 L79. So 1 in 5 of these pumps should be a 326. The reality is that less than 1 in 5 is a 175. How could that be? Could it be that a bunch of NCRS types are hoarding these things and skewing the known data?

[Bob J.]

Re: 64 Water Pump 3859326, what to do

I wanted to make my point above numerically. for 64/65 there were 16000 L76/79/84. For half of 66 there were 3800 L79. So 1 in 5 of these pumps should be a 326. The reality is that less than 1 in 5 is a 175. How could that be? Could it be that a bunch of NCRS types are hoarding these things and skewing the known data?

Ever think maybe more than one foundry cast pumps but only Saginaw supplied Flint?

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Bob - you haven't said enough above so I can be sure of your point. I'm certainly open to that point but in the numbers above I'm thinking about castings with no date and the small external bypass hole. And in this time frame I don't think there was much other Chevy production with this requirement. If the 66MY required this in some other vehicle in quantity, regardless of casting source, that might explain the issue I'm putting forth. It would need to be the 66MY, first half (assuming they also started dating in Nov 65 as Saginaw allegedly did), if the part was first drawn in May 65. If not, then my question is still valid.

[William M.]

Re: 64 Water Pump 3859326, what to do

Re: Pictures of the 3839175 water pump
The first two pictures show the front and the third picture shows the rear with the correct back plate. This back plate was used on all small block water pumps from 1961 through 1969. After 1969 the back plate had the "rib"MVC-005S.JPGMVC-006S.JPGMVC-029S.JPG between the bolt holes for better sealing.
Bill Mock #93

[Dan H.]

Re: 64 Water Pump 3859326, what to do

Thanks Bill, I'm of the opinion that since the 175 pump has been found on low mileage original 64 SHP and FI cars that the 175 was the assembly line unit for most of 64. These cars were the 'hot rods' of the Corvette line, and probably had some early water pump failures. Doesn't appear that the small hole 175 was serviced, but the 326 was on the shelves at GM for replacements/warranty work in 65. The 175 appears to be an update of the 609. Later, as the part numbers show, the 326 was adapted to provide for pulley clearance and larger bypass hole on top of the pump for truck aplications etc.

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Dan - Bill Mock has said in his posts and to me that he has personally never seen but two real deal 175 pumps(no date, no pulley relief, small bypass hole) since 1978, both is his posession, one of which I'm sure he posted above. He no longer has either. He has located a third for me but hasn't seen it yet. He also told me he was going to reach out to some folks with low miles cars he knows of to try to get data on an original in an unmolested car. He did point out to me the pic on page 227 of the Adams book which I think clearly shows one on a 64 SHP. I've read a lot of posts and have not seen where anyone said they had a real deal example. Having said that, I believe they exist and other threads say the Grey Iron paperwork documents this. I'm wondering what data you have of them being found on low mileage cars.

[Dan H.]

Re: 64 Water Pump 3859326, what to do

Dan - Bill Mock has said in his posts and to me that he has personally never seen but two real deal 175 pumps(no date, no pulley relief, small bypass hole) since 1978, both is his posession, one of which I'm sure he posted above. He no longer has either. He has located a third for me but hasn't seen it yet. He also told me he was going to reach out to some folks with low miles cars he knows of to try to get data on an original in an unmolested car. He did point out to me the pic on page 227 of the Adams book which I think clearly shows one on a 64 SHP. I've read a lot of posts and have not seen where anyone said they had a real deal example. Having said that, I believe they exist and other threads say the Grey Iron paperwork documents this. I'm wondering what data you have of them being found on low mileage cars.

Hi Larry, after rereading all the posts for several years now, I would say no 326 pumps were used on 63/64 SHP/FI Corvette engines. Bill Mock has a picture of low mileage 64 FI engine in Vin15153, super documented car in OK with 175 pump. Also Gene Dresden owned 64 FI Vin03429 with a 175 pump. Look at Noland Adams book page 229, top picture, you can tell it's a 175, not a 326 pump. Most of these pumps were long gone 45 years ago and replaced with 326s. With approx 8496 175 pumps installed in 64 some are laying around somewhere. I'll check also.
Dan

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Ok-I'm throwing in the towel. I've been communicating with Michael Hanson who is no longer a member, but he has provided a more detailed description of what the Grey Iron papers say. And what he says makes a more compelling case. I guess, as Dan suggests above, that when the 175s went bad and were services by 326s and subsequently went into the rebuild mill that they got spread to the four winds in grocery getters and so on....and then to the crusher. I'm copying in Michael's comments which I think tell the story:

Larry....

The part number 3859326 that appears on the Grey Iron Works paperwork is for the casting only. Not a complete machined and assembled water pump. The paperwork from Grey Iron is dated 5 December 1964. That would probably be a normal lead time for a casting that would eventually be sent to GM for machining and assembly. There may be a drawing/print for the casting that is dated around that time.
The paperwork that I have from Grey Iron for the soon to be completed and released 3859326 casting shows that it will also be used for service for the 3839175 pump that is already in existance. The 175 would then be used to service 1964 through 1966 models but made from the 3859326 casting. The paperwork shows the years 1964, 65 and 66.
I have the original Grey Iron sheets that show this information and mid 1965 date. I also have the original GM drawing/print for the complete assembled 3859326 pump that clearly shows a date of early/mid 1965. (I forget the exact month)
I'm no longer an NCRS member so I won't be able to post this on the discussion board but feel free to copy/paste it.
Hopefully, Mark will reply and agree with the above.

Regards,

Michael
The paperwork does say that. It says "3839175, make from 3859326". But this was for future castings. When the 326 became available at Grey Iron in late 1964, they would then use the same 326 casting to make the 175 for future assembly and service. But this doesn't mean that GM had received the casting at that time. The sheet from Grey Iron for 1964 has no mention of a 3859326, at all. It only shows the 3839174.
I was there when the incredible absolutely untouched 1500 mile green/saddle 65 FI convertible was first cleaned up in about 1974. I think the VIN is 12,030. It did not have a 3859326 water pump. (and several other ultra low mileage cars around that time)
I know a lot of folks would like to think the 326 was used all the way back into the late part of the 63 model year (because the 63-64 NCRS judging guide incorrectly shows this) because these pumps are easy to find but it just didn't happen that way.
Also, as previously mentioned, the part number range is in the very same range as most of the other mid production 65 parts that are new for that same time period. Most of the newly released parts for the new mid model year 396 engine are in the very same 3859xxx-3860xxx range. Other early, or start of 1965 production parts for the model year begin with part numbers that are not in that same numerical range.
Part numbers in a lower numerical range are used for the 64 model year. I don't think any numbers in that same 3859xxx range are seen in a 1964 assembly manual.

[Dan H.]

Re: 64 Water Pump 3859326, what to do

Bingo! Word of caution, the 175s on Ebay are the later cast ones with the 326 top configuration, dates, 3/4 inch bypass, etc.

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Thanks for the advice but I've got this one. Bill Mock has my new one coming.....I'm boxing up my first born now to pay him.

[William M.]

Re: 64 Water Pump 3859326, what to do

Picture is of the engine with FI unit removed of the 1964 "Z06" Corvette coupe #15,153 that I owned years ago and was purchased in Bartlesville,OK new. In the past I posted copies of the window sticker, title, warranty book, air scoop installation instructions,etc at the Technical Discussion Board(probably in the archives now). Since 1978 I have only owned two "real" undated 3839175 water pumps with the 1/2" NPT bypass hole on the top. These were both cores that I purchased and rebuilt. Also, since 1978 I have rebuilt 4-6 "175" water pumps for customer's 1964 Corvettes with the 365hp327 or 375hp327 engines.
Bill Mock #93
Bartlesville,OK
Phone918)333-0748, cell (918)214-52061964#15153.jpg

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Bill sent me pics and shipped me a very nice rebuilt 175 so I'm set. But in our last conversation he said something which destroys my final conclusion above. He said he believes that all 326 service units were 3/4 bypass hole. If that is true then having a 326 small bypass with no date is nearly a miracle. My point is not to debate that as he and others are much more knowledgeable on this than I. I just thought it worthwhile to pass on this view. He has seen a lot of pumps over the years.

[Joe L.]

Re: 64 Water Pump 3859326, what to do

Bill sent me pics and shipped me a very nice rebuilt 175 so I'm set. But in our last conversation he said something which destroys my final conclusion above. He said he believes that all 326 service units were 3/4 bypass hole. If that is true then having a 326 small bypass with no date is nearly a miracle. My point is not to debate that as he and others are much more knowledgeable on this than I. I just thought it worthwhile to pass on this view. He has seen a lot of pumps over the years.

Larry-------


As far as I can tell, Bill is correct. The SERVICE waterpump assemblies which did or could have used the 3859326 casting were machined for 3/4" bypass. These were GM #3848072, GM #3890017, 3998206 and 3998207. The SERVICE pump assemblies used both the 3839175 or the 3859326 castings.

The pump assemblies with 1/2" bypass must have been PRODUCTION-only.

[Larry M.]

Re: 64 Water Pump 3859326, what to do

Joe - as I said above, I'm not going to argue this. But if you believe the May 65 first drawing and the Nov 65 start of date coding then the non dated small bypass 326 would have been very late 65 (maybe) and first half of 66 for the L79 engine. In Corvette this would likely be less than 4000. I don't know the numbers for the Nova; don't know if it was even used on the Nova. Having one of these is truly a miracle. But lots of folks have experienced this miracle. I guess Corvette types are blessed.