The Stovebolt Site Forums The Shop Area Engine Shop '58 Water pump & pulley question . . .

OK . . . so I now know I've got a '58 - '62 Chevy 235 on my hands. It needs a new water pump. BUT, as this engine is a swap into a 1939 truck, the rumor is that the previous water pump had been shortened.

I purchased a shortened shaft water pump from Carters, but it apparently didn't bolt up right, and had a NARROW pulley.

The truck had a Wide pulley on the old pump, which, btw, deformed when we tried to press it off the pump.

What year did pulley sizes change? Or is this sort of arbitrary? My '44 has a narrow pulley, while my '50 has wide. I'm thinking they're 3/8ths inches vs. 3/4ths.

So can I find a Chevy water pump for a '58 with a WIDE pulley? Do the GM water pumps in the catalogs, with the wide pulleys, bolt up to the Chevy 235?

So many questions, so few hairs left to pull out . . .

-Michael :confused:

What do you mean "deformed when pressed from the pump" ?

The pulley is hold by the 4 bolts that also hold the fan. If you remove the bolts everything shoud fall appart.

Do you mean the disc that is pressed on the hub where the pulley is atached?

There are two ways to do the swap:

1. A short pump with a bigger pulley (runs slower to stop caviation) ask Tom Langdon or Patrick.

2. There is an adapter where you can use a original 216 pump (that is shorter anyways) and pully for the guys that want a 216 looking 235 becaus of the vintage look. It apears often on ebay.

And you should read this - it probably answers all your questions:

http://www.chevrolet.com.au/articles/engine_swap.htm

have fun, Frank

Frank,

The pulley clearly did not "just fall apart" when the fan bolts were removed. It was rusted or corroded on there pretty good. As soon as it was pressed, the holes all started to cave in, so we stopped.

Compared to the "new" water pump (with the narrow pulley) I bought, the old pulley seems like lighter grade metal, mounted onto a flat disk beneath. The newer pulley seemed like it was made of stouter metal, all one piece.

Not sure what that means. . .

I'm still confused about the pulley/belt size.

-Michael

I think I've finally got it figured out!

Between the truck owner, and Patrick of Patrick's, it sounds like the '58 235 that was swapped in, did NOT have a generator, so they had to use the old one. Because the old one (from the '39 216)had a broad belt, they probably also pulled the 216's harmonic balancer and swapped it onto the 235. THEN, they machined (somehow!)the water pump to shorten it, and/or swapped a broad pulley onto it. More likely, it's a 216 water pump, and NOT the appropriate one, fan-speed-wise.

Interesting how these trucks get mickey-moused together sometimes.

We're gonna get the right pump from Patricks, which WILL have a narrow pulley, and try it with a not-quite-narrow-but-not-quite-broad fan belt, and see if all the stuff will play nicely together.

Eventually, we'll want to swap out the balancer and generator, and get them all on the same, proper, page.

Stay tuned . . .

-Michael