4 Bolt Water Pump Questions
 

I posted this on the heating and cooling forum, and got no responses. Maybe someone here can answer the question.

I pulled the water pump off my 62 GP to change the pulley. I'll address the pulley problem in another thread. The pump that I removed is shown in the first pic. It appears that the impeller blades are curved in the wrong direction. Rotation of the pump moves the convex side of the blade into the water. I have two other pumps that are also shown. The blades on these two are curved in the opposite direction as the blades on the first pump, but appear to be curved correctly.
Also, the blades on Pump 1 and Pump 3 are approximately 3/4" deep, the blades on Pump 2 are 1/2" deep.
Does anyone know which is the correct pump. The engine is a stock 62 389.

Thanks for your help,
Les

The pump I pulled off of an all original 60 Bonny 389 was like pump #3. Pump #2 is for a 61-63 Pontiac Tempest 4 cyl. Look at the gap behind the impeller on pump #2. That gap is not on #1 . That is because the impeller for the Tempest 4 cyls is thinner & is set farther into the timing chain/pump housing so it only pumpes coolant to the right side of the housing for the right head. I have seen the style in pic #1 also, It may be for an early (55-58) reverse cooling system???

Keith

That "reverse cooling" water PUMP is an old wive's tale. Just a different impeller design. Still turns the same way and the basic shape of the cavity the pump sits in is the same. I've run both types of pumps (as well as a stamped steel pump) for a number of years in my '57 GMC (Pontiac) V8 with no cooling problems.

I don't know about the depth difference between a 4 cyl and 8 cyl pump. I do know that the impeller needs to be fairly close to the "water input hole" in the center of the timing cover in order for any pump to work correctly. This is not normally a problem with 4 bolt pumps, but causes all kinds of grief with 8 and 11 bolt pumps where the clearance between the pump impeller and the input port can be too big.

Below is some info I submitted to the Yahoo Pontiac 1950's e-mail list a few years ago:


I ran across a really good manual titled "Fans Reference Guide" by
Ontario Power Generation while doing some research at work. I realize
that this article is speaking to fans and air, but a fluid is a fluid
and I see no reason it doesn't apply to water pumps as well. It
discusses four types of Centrifugal Fans, which is how a water pump
operates. They are Airfoil, Backward-inclined, Radial and
Forward-curved. Some of them look "backwards" to dummies like me, but
they all have advantages and disadvantages.

Go here

http://www.energyefficiency.org/eece...a?OpenDocument

and then click on the pointer to the .PDF file.

By the way NAPA's part number for the cast iron impeller pump is 58594.

Les, et al:

here is some semi-recent info on this...

http://forums.maxperformanceinc.com/...light=impeller

and a link to a thread that has nearly 1000 replies as of St Patties Day:

http://forums.maxperformanceinc.com/...d.php?t=411256

water pump numbers
 

Try this page

http://www.teufert.net/pontiac/wat-pump.htm

Sorry, my link above was not valid. This one should be:
http://www.energyefficiency.org/eece...a?OpenDocument

Then click on the fansReferenceGuide.PDF icon

Somewhere back in the archives:
I posted a rather long thread about the 4 bolt pumps and the impeller issue. I had a rather lenghty discussion with the Remamufacturer over the fact that they were putting on the wrong impellers. I remember one of them saying that the "Revese one was better" I actually laughed at the engineer and asked him if he even knew the flow direction of the water in the car the pumps went in to.

BC, that was in my first link...