H2O pump rebuild saga....C2 SB

[Jim V.]

OK...chapter two...in the 1965/327 h2o pump rebuild. After my initial 'Bubba" job I sourced another correctly dated 608 pump. I am an a roll...right?...wrong! After pressing the impeller on, low and behold, the darn shaft binds...%*&)(*+!. It appears the supplied cartridge seal in LIC's rebuild kit is too tall for the original cast impeller. The pic shows the new seal on the left and the original shorter seal on the right. In all fairness the LIC instructions warn of non-original impellers being too long. This perplexes me since this is an original impeller (pictured). So....are short seals available and where? Or must I swap the cast impeller for a stamped replacement? Or am I forced to outsource the rebuild?

Thanks all!

[Joe L.]

Re: H2O pump rebuild saga....C2 SB

Jim------

I'm not so sure that there is a difference in the height of the seals. The new seal on the left is a SEAL AND SEAT assembly. The old seal on the left looks like it just shows the separate seal assembly. The seat is a separate part. That's how all of the old seals and seats used in waterpumps were configured. If you compare the SEAL section of the old and new seals, I don't think you'll see any significant difference in heights. Whatever difference there may be will be accommodated by the the compression of the seal when installed.

Is there a GM casting number on the impeller?

[John D.]

Re: H2O pump rebuild saga....C2 SB

Jim, I see you have been struggling with the pump issue. Sometimes it just pays to give a certain job to a person who specilizes in it.
Try Ron Burke-Classic Chevy Water Pumps in Scottsdale, AZ. He's a first class guy and does a wonderful job. saddlerockranch@msn.com He is also a big vendor at Corvette Carlisle and I met him in person last month. Really nice fellow to deal with. Very honest and does a good job. If nothing else he may be able to answer some of your questions.
I had two pumps rebuilt for my 63. First I had the wrong pump naturally. It was a 326. After a ton of posts on here I was soon convinced that I needed a 609 pump. So I bought one that was already rebuilt but had it rebuilt a second time to make sure. So as you can see it's not easy or cheap doing things twice. John

[Jim V.]

Impeller number

Hmmmm....can't see what you mean. Here is pic of another assembled shaft, bearing, and seal. The old seal is way shorter than new, even with the seal spring compressed it is taller than the original. Casting# on cast impeller is 3704164. Suppose I will try LIC tech tomorrow to see if they can comment.

[Jim V.]

Re: H2O pump rebuild saga....C2 SB

Thanks John. I know you what you mean...but...I can't help myself from diving in. And yep it often becomes an expensive education. I may go with your rec if the seal becomes much more of an issue.

[Joe L.]

Re: Impeller number

Jim------

The impeller is a correct one. So, that eliminates that as a possible problem.

Is the old seal a 1 piece seal and seat assembly (like the new one) or is it a separate seal and separate seat? I can't tell from the picture. I can't see a seat on the old seal, but there may be one there. I've never seen an original 608 waterpump with a 2 piece seal/seat assembly. Of course, this one may have been rebuilt before.

This type of rotary seal usually has a carbon seal face which mates with a ceramic seat. Sometimes, they have a carbon seal face with a carbon seat (the first type is called carbon-ceramic and the second type carbon-carbon). The seat (whether it's a captured style or a separate style) is sealed to the impeller with a thin rubber gasket. The seat always rotates with the impeller and shaft.

The seal is, of course, stationary as the shell is pressed into the waterpump casting. The interface between the seal face (stationary) and the seat face (rotating) is where the "action is" and where sealing takes place. The very close tolerance fit between the seal face and the seat face makes for a virtually leak proof seal. It's not completely leak-free, though; that's why there are weep holes in all waterpump castings that use this sort of seal.

[Joe L.]

Correction

I should have said that I've never seen an original, first-run '608' waterpump with a 1 piece seal and seat assembly. Of all those I've taken apart (and, there have been many), every original pump had the 2 piece seal and seat.

[Jim V.]

Seat....what seat?

Joe...Thanks for your guidance. Both your knowledge and willingness to help seems to be boundless. Thanks again.
So...I know one of my disassembled pumps to be an original un-rebuild pump. Thanks to your vivid description. I now "get-it" on the seal (stationary pressed into housing) and seat (rotating with the shaft and impeller). From the two pumps (one original and one probably rebuilt) which I have disassembled, it appears both are in fact two part seal and seat. However...it also appears as thou the seats are simply the backside of the impeller itself as compared to a separate part. Can this be? If you look closely at the previously posted photo there is no separate shaft mounted seat to be found. Hmmmm...

I will call LIC and see if they can help. At any rate I will need another seal/seat assembly since I "hosed" the new one pressing it off the shaft.

Thanks

[Joe L.]

Re: Seat....what seat?

Jim-----

I've never seen a Chevrolet (or, for that matter, ANY) waterpump that used the surface, machined or otherwise, of the impeller as a "seat" for the seal. Check the impeller carefully to see if there might be a seat which is somehow pressed into a "recessed" area surrounding the bore of the impeller. I've not seen this configuration, but I suppose it could have been used.

Also, check to be sure that the seat didn't get "lost" when you disassembled the pump.

[Gerard F.]

I think I got the same kit.

Jim,

I just received my S/B waterpump rebuild kit from Corvette Central in the mail today, and the one piece seal in it looks just like the new one in your picture. So naturally, I'm interested in how you make out, before I tear into my original (which is still on my 67).

I'll bet we have the same kit. The number on the new seal is 116514 and it came in a kit with one double sided sheet of instructions (along with the shaft, gaskets, insertion tool and cover bolts.

Under the instructions for pressing the impeller on the shaft in says;
(*NOTE: original impellers have a dimension of 5/8" *if you have a "longer" impeller it must be cut dowm to work with the seal provided.)

I think the * and dimension that they are talking about is the overall thickness of the impeller, but it reads as clear to me as mud.

I would assume from this mud that if you had an impeller 5/8" in thickness, it would work with the seal.

But maybe not. Let me know how you make out.

Jerry Fuccillo
#42179

[Jim V.]

Re: I think I got the same kit.

Jerry....the kit contents are the same. I did buy mine through LIC...but I suspect they are from the same unknown source. My new one piece seal/seat (thank you Joe) has a different part number from yours however....JCI (I believe Johnson Controls) and G37 both on the face of the seal. I totally agree with the ambiguous 5/8 thing. My original cast impeller is over 3/4 in total thickness but a tad over the 5/8 at the thinest point at the circumference of the center hole. I bet these kits are generic and the seal/seat is matched to something other than the C2 era impeller. At any rate, I will contact the gurus at LIC tomorrow and pass-on their words of wisdom on the issue.

[Joe L.]

Re: I think I got the same kit.

Jim-----

In this case, I believe that "JCI" refers to JCI Industries. They are a supplier of many industrial parts and service. They supply a lot of parts for pumps and I'm familiar with them from my many years in the water and wastewater field. The mechanical seals used in many automotive waterpumps are, basically, the same as those used in many other types of pumps. In fact, the seals used for automotive waterpumps are the "low end" types of seals when you look at the "industrial spectrum".

For example, the bellows used in automotive waterpump seals is usually made of neoprene or buna-n compound rubber. These types of rubber are only good to a temperature just above where most automotive cooling systems operate at. That's one of the reasons why waterpumps often fail soon after a serious overheating event.

If one "steps up" to industrial grade seals, one can get seals with, for instance, Viton bellows. This material has a much higher temperature capability than those mentioned above.

Of course, the price also goes WAY up. I purchased a very high grade seal for a particularly important 608 waterpump that I rebuilt many years ago. I got it from John Crane Company, another supplier of industrial components. With my city employee discount, as I recall the price was about $60. And, that was a good 15-20 years ago.

What did you determine regarding the seat in the old pump? There absolutely has to be one for the seal to work.

[Jim V.]

Missing Seat...

Joe...I went through the grainger catalog under centrifugal pumps and found Flowserve seals made in exactly what you are referring to....buna...viton...and teflon with seal rings of carbon, plastic and silicon carbide. Yikes...I am out of my element. The rebuild kit appears to be a type 68 designed for use in pool and spa pumps. Grainger states they replace US Seal Type B and Crane Type 6a. Didn't find a cross to the JCI seal however.

We have a real mystery on the seat side. Anecdotally, both of the 608 pumps I disassembled appear to use the hub of the impeller as the seat! Honestly...One impeller/shaft/bearing/seal is still together as an assembly and there is no sign of a seat. LIC tech support is due in tomorrow am...so I will try them then. My expectations are low...but I hope I am surprised. I suspect they are going to tell me to get a different impeller.

Has anybody out there used this seal in a 608? Suppose I should start a new thread with that in the subject.

Thanks Joe!

[Joe L.]

Re: Missing Seat...

Jim------

I did a little more research. It may well be that earlier '608' pumps did use an impeller for which the machined hub surface served as the impeller.

The impeller you have is the casting first used for the 1955 V-8 waterpump and used thereafter to, from what I can tell, 1967.

I have several of these GM #3704164 impellers. However, all of these came out of pumps that had been previously rebuilt. ALL have a reduced thickness hub. I don't think that GM ever made them this way since, as far as I can tell, there was only 1 finished part number made from the 3704164 casting and that was also known as GM PART #3704164. So, I expect that these impellers were likely machined down by commercial rebuilders. The dimension that I have for the hub thickness, as measured with the impeller laying on the flat surface and measured from the plane of the flat surface to the inner surface (i.e. the surface that would serve as the seat on your pump) is right at 5/8". If yours is greater than 5/8" measured as I described, that's your problem.

In 1968 GM changed to a different impeller for all small block waterpumps. This was used through ABOUT 1975. It was GM casting #3923250 and the only version I know of has the same finished part number. These have a slightly different configuration than the 3704164, but the main thing is the thickness of the hub is 5/8" and it was made that way---not converted. I have several NOS examples of this rotor and that's they way they are, too.

In about 1975, GM changed to the stamped steel impeller. I have several of these, too. They have a reinforced hub, but it's still 5/8" thick.

I expect that when commercial rebuilders encounter the older pumps with the 3704164 impellers that have not been previously converted, they machine down the thickness of the impeller hub so that they can use the newer style seal/seat assemblies. I am VERY confident that the newer style arrangement, whether it the one piece seal and seat or the 2 piece separate seal and seat, are much better functionally than the old style. After all, GM went to this style in 1968 and they did it for a reason.

So, the long-and-the-short of it is I would not even attempt to use the existing configuration even if you could get a seal to work with it. Keep in mind that if you were to do that, you would have to use the existing "integral seat" as the seat that would mate with your new seal's carbon face. I'd say that's a prescription for almost certain problems. That's very likely one BIG reason why rebuilders convert these things to the later style.

If I were you, I would have the existing "integral seat" on this this impeller, which otherwise looks to be in very good condition, machined down so that the hub thickness is 5/8". Then, I think you'll be "good to go". Otherwise, you could obtain a new stamped steel impeller and use it. However, I think your best bet is to use the existing impeller modified as I described.

[Joe L.]

Photo Addendum

Jim------

Attached is a photo of, on the left, the 3704164. This is a used version that looks like it's "been around the block" a few times and, undoubtedly, been through at least 1 commercial rebild. You will note how the hub surface is wide and FLAT. I believe that this represents the machining that was done by the rebuilder to convert it for the later style seals.

The impeller on the right is the 1968-~1975 GM #3923250. This is a used example but the NOS versions I have are 100% identical. Note the hub section is narrower, but the surface is still FLAT. This is the configuration necessary to work with the separate seat. The thin gasket on the rear of the seat seals to this flat surface.

There is one downside to using the existing impeller suitably machined. That is the fact that you will have reduced interference fit surface area for the shaft in the impeller. How can that be? Well, I'll post another picture of the REAR surface of the 2 impellers and you'll understand why.

The only way around this is to either obtain the later style impeller, perhaps scavenged fro another pump that has one or use the stamped steel impeller. However, keep in mind that rebuilders successfully use the apparently machined down impellers. So, if they can, you can.