Source for Z28 water pump?

[j-rho]

Working on building my '67 as a tribute and "technically correct" Z28 clone, for national-level SCCA autocross (http://www.rhoadescamaro.com/build)

I have what I believe is a correct pump bypass elbow: http://www.rickscamaros.com/camaro-water-pump-bypass-fitting-90-elbow-z28-1967-1968.html

But I've bought two different water pumps, and it is too small to thread into the opening at their tops.  My eyeball says the water pump openings are about 1", and the elbow threads are more like 3/4".

I'm sure you guys have seen this site, it's awesome, I reference the pictures all the time.  Looks like the elbow should thread right into the water pump:
http://67z28.com/gallery/albums/67%20Z28%20Restoration%20Photo%20Chronicle/Engine%20and%20Drivetrain/DCP_1732.jpg

So is my elbow not sized right, or is it the water pumps?  Do I have to buy this pump for it to work?: http://www.rickscamaros.com/camaro-water-pump-302-small-block-date-coded-1967-1968.html

For my rules, the water pump doesn't have to have the factory date code stampings, it just needs to be equivalent in performance (weight, water flow, etc.).  But it for sure needs to accept the correct bypass elbow! 

Any help the folks here can offer is much appreciated!!!

--Jason Rhoades

[1968 Z28]

Go down to your local hardware store or plumbing supply and look for a 3/4" male to a 1/2" female reducing bushing like this....

     

or a 3/4" male to a 1/2" female hex reducing bushing like this.....

     

Screw the bushing into the water pump using sealer and then screw the bypass fitting into the bushing using sealer.

[Paul68RS/Z28]

http://www.camaros.org/forum/index.php?topic=1997.0

[william]

There were two styles of bypass water pumps at that time. You have the larger one.

[JohnZ]

That same 326 pump was also used on '65-'67 small-block Corvettes with aluminum intake manifolds. There were two versions of that pump originally - one was machined for the Corvette and Camaro applications with a smaller NPT hole for their smaller bypass elbow, and the other one was machined for truck applications, with a larger NPT hole for their larger bypass elbow.

The castings with the smaller hole are getting hard to find, as commercial rebuilders routinely re-drill and tap the small-hole castings they get for the larger bypass elbow, as there's far more demand for the truck application than for Corvette/Camaro restorations.

If you have the large hole, you can use a reducer bushing as noted in the posts above, and grind it down flush with the boss on the pump, although most sharp judges will spot it. Bill Mock in Oklahoma City is the best-known water pump rebuilder/restorer for the Corvette guys, and will usually have dated small-hole 326 pumps available, but they aren't cheap. Bill has been doing Chevy pumps for 35 years, and is at (918) 333-0748, mockauto@aol.com.

[j-rho]

Thanks for the responses fellas.  Paul, that link was interesting hadn't come across it.  That the factory might have issued the car with a reducer bushing, means I can too.  I have Jerry's book but didn't see that mentioned, will have to look again.

[JohnZ]

Thanks for the responses fellas.  Paul, that link was interesting hadn't come across it.  That the factory might have issued the car with a reducer bushing, means I can too.  I have Jerry's book but didn't see that mentioned, will have to look again.

The factory didn't issue bypass water pumps with reducer bushings; they used the 326 pump machined for the specific application. There was only one 326 raw casting supplied to the engine plants from the foundry, and they machined them based on whether they needed the small or large NPT hole for the bypass elbow; water pumps were machined from the raw casting and assembled at the engine plants.

[69Z28-RS]

Even if the factory didn't use the bushiing, I can see no reason why YOU cannot use it within the rules for your class....  right PN..  right outlet... ..  there's no reason they should care if there is a reducer busihing there..     if they ask, tell them the threads were stripped and you bushed it yourself so it would be usable..

[68camaroz28]

Even if the factory didn't use the bushiing, I can see no reason why YOU cannot use it within the rules for your class....  right PN..  right outlet... ..  there's no reason they should care if there is a reducer busihing there..     if they ask, tell them the threads were stripped and you bushed it yourself so it would be usable..

Understand what you are referring to but not sure judges would agree. In NCRS you would have a deduction as JohnZ pointed out the pump came from the factory with the correct size and not with a "reducer bushing".

[Paul68RS/Z28]

Jason,

For the record, my pump does not have the bushing. I have to agree with Chick, I  would think a judge would take points for the bushing.

Paul

Thanks for the responses fellas.  Paul, that link was interesting hadn't come across it.  That the factory might have issued the car with a reducer bushing, means I can too.  I have Jerry's book but didn't see that mentioned, will have to look again.

[1968 Z28]

For my rules, the water pump doesn't have to have the factory date code stampings, it just needs to be equivalent in performance (weight, water flow, etc.).  But it for sure needs to accept the correct bypass elbow! 

According to the quote from Jason in the very first post, the existing water pumps with the bushing should meet the rules. It's equivalent in performance (weight, water flow, etc.) and it will accept the correct bypass elbow with the bushing installed.  But, maybe he should get a clarification from the rules committee, to be 100% sure.

I would think that he needs some advise from someone more familiar with the SCCA rules and not the restoration oriented rules.

Just my penny worth....

[j-rho]

Thanks again for your help guys (and gals?) - have the water pump going now, am on to the fan.

I found (here, and in Jerry's book) that the car would have been equipped with an 18", 5-blade, 4-rivet fan, with 3.25" diameter bolt spacing where it mounts to the fan clutch.

I found a replacement 3.25" fan clutch.  I haven't been able to find any kind of replacement fan to fit it.  Bought the nicest looking new 5-blade fan I could find, and it's clearly for the 3" diameter fan clutch mount.

Does anybody make a replacement fan that will fit my 3.25" diameter fan clutch?   Or would I be better off finding a 3" clutch for my 5 blade fan?
 
Trying to be as technically correct as possible, without spending $xxxx on original eBay stuff.  As long as the parts I use are no higher performing than stock, I should be OK.

Thanks again!!!

[68camaroz28]

For my rules, the water pump doesn't have to have the factory date code stampings, it just needs to be equivalent in performance (weight, water flow, etc.).  But it for sure needs to accept the correct bypass elbow! 

According to the quote from Jason in the very first post, the existing water pumps with the bushing should meet the rules. It's equivalent in performance (weight, water flow, etc.) and it will accept the correct bypass elbow with the bushing installed.  But, maybe he should get a clarification from the rules committee, to be 100% sure.

I would think that he needs some advise from someone more familiar with the SCCA rules and not the restoration oriented rules.

Just my penny worth....

Yep, I agree! My mind was thinking restoration judging, as I know zero concerning SCCA rules. Where's that rule book:)

[1968RSZ28]

According to Jerry MacNeish both, 1/2" & 3/4" NPT bypass hole, water pumps came from the factory on '67 & '68 Z/28s.  Jerry writes (see the link posted in reply #2 above)...

"There are variations on the NPT hole in the water pump and both are acceptable.  Some factory cars had a 3/4" NPT reducer to adapt the 1/2" NPT bypass fitting.  More on this in the new 4th edition Z28 book out soon,

Jerry"

I don't have Jerry's 4th edition, but his 3rd edition of "The Definitive 1967-1968 Camaro Z/28 Fact Book" states the water pump installed on all 1967 and 1968 Z/28 engines had two slightly different designs; one with a 1/2" NPT bybass hole and one with a 3/4" NPT bypass hole.  Jerry further explains that the water pump with the 3/4" NPT hole required a pipe plug adaptor. (page 85)

According to Jerry both water pumps are factory !

Paul

[JohnZ]

According to Jerry MacNeish both, 1/2" & 3/4" NPT bypass hole, water pumps came from the factory on '67 & '68 Z/28s.  Jerry writes (see the link posted in reply #2 above)...

"There are variations on the NPT hole in the water pump and both are acceptable.  Some factory cars had a 3/4" NPT reducer to adapt the 1/2" NPT bypass fitting.  More on this in the new 4th edition Z28 book out soon,

Jerry"

I don't have Jerry's 4th edition, but his 3rd edition of "The Definitive 1967-1968 Camaro Z/28 Fact Book" states the water pump installed on all 1967 and 1968 Z/28 engines had two slightly different designs; one with a 1/2" NPT bybass hole and one with a 3/4" NPT bypass hole.  Jerry further explains that the water pump with the 3/4" NPT hole required a pipe plug adaptor. (page 85)

According to Jerry both water pumps are factory !

Paul

I rarely disagree with Jerry, but I will on this issue. NCRS has been judging the 326 pump on both known-original and restored '65-'67 Corvettes for 38 years, and in all cases, any 326 pump exhibiting a reducer bushing gets a deduction and is scored as a replacement (the GM Service replacement 326 pump had the large bypass fitting hole so it would work on both car and truck applications and a reducer bushing came in the box).

The water pump was machined and assembled from the raw foundry casting at the engine plants, and they knew in advance exactly how many of each fitting hole size they'd need every day; there was no need for a reducer bushing at the Flint V-8 Engine Plant.