The Stovebolt Site Forums The Shop Area Engine Shop 235 fan fit (not)

There are dozens of posts on this topic, but none seem to fit my unique situation, so here goes...

I have a '49 half-ton with a '58 235 engine. When I purchased the truck, I noticed there was razor-thin clearance between the fan blades and the radiator (about 1/8-inch). I did some research and realized I needed a short-shaft water pump. So, I dropped a wad of cash on a new pump (Classic Parts) thinking this was an easy solution to an easy problem. The pump was advertised as the perfect solution for fan/radiator clearance issues. I installed the new pump and life was good.

But nothing is as easy as it seems. I'm ready to install the fan and now I have several new issues. First, the new water pump has a different bolt pattern, and the original fan doesn't fit it. The old bolt pattern was 1-3/4 inches center-to-center with a 5/8-inch hub. The new pump has a 2-1/4-inch bolt pattern with a 1-inch hub :mad: . My second issue is, even if the bolt pattern were correct, the fan does not clear the harmonic balancer. I need some sort of spacer to push the fan closer to the radiator to clear the harmonic balancer. So, I spent $160 on a new water pump, and several hours of my time, and ended up making a small problem much larger. At least the old pump and fan worked! For what it's worth, the fan is 19-inches in diameter with four blades. I don't know if this fan was originally from a 216, 235, or some other engine.

Yes, I should have checked all these fit issues before installing the new pump. I live and learn. Given the fact that I already painted and installed the new water pump, I probably can't return it. The easiest solution would be a different fan, but I don't know where to find one that fits. I'm trying to keep my rig looking stock, so I don't want to install an electric fan or something that obviously does not look original. Any ideas?

I currently have a 1955 235 in my 52 pickup. With a short shaft water pump and a 216 fan the clearance between fan and balancer is 1/8" or less, and clearance between fan and radiator is only enough to get a belt on very carefully. It works, but I needed 4 washers to space the fan off the water pump pulley so it would clear the balancer.

Had it been an option, or had I known at the time I would have used the water pump relocation plate and a 216 water pump. And if I ever run the engine again that's exactly what I'll do.
I suggest you do the same right now, yes you've wasted some money, but you'll be much more satisfied when it works right and you don't have cooling problems.

Do a search, you'll learn a lot about the water pump relocation plates and what's involved.

Grigg

Is the bolt pattern I described above typical of fans on 235 engines? If not, can somebody identify the make, model, and year of a donor fan that would match this pattern? Thanks.

i believe the 235's have the same bolt pattern but not positive. i do know that i have a 62 engine in my 54 and the short shaft pump and the 54 fan bolted to it.

on my truck I said heck with the fan machined the pulley for bolt up and ran a electric fan (a pusher) on the front of the radiator used a GM electic temp. sensor to run a relay turning the fan on and off works great in FL

I think that the later 235 fan blades (late 55 and newer, probably) have different bolt patterns and bolt size that the earlier 235 (and all 216) fan blades. It also looks like the earlier blades had an 18" diameter and the later blades had a 20" diameter.

The $160.00 short shaft pump is listed for 1947-54

AS Tim posted, the 1955 & later blade doesn't fit the earlier pump.

So, it appears I have 3 options:

Option 1 - purchase an 18-inch, 216 or early 235 fan and install it on my short-shaft pump. The fan would cost $29 + shipping (Jim Carter). The down-side is potential cooling issues.

Option 2 - drill and tap 4 new holes in my short-shaft pump and a larger hole in my 19-inch, late-235 fan. Use washers to clear the harmonic balancer.

Option 3 - sell my new short-shaft pump (assume $100 loss). Buy a long-shaft pump and an adapter plate ($140+shipping), and hope my late-model 235 fan bolts up to this configuration. Total cost would be $240, but the up-side of this option is better cooling.

I think I like Option 2, but I'm wondering what else I'm forgetting. Has anybody tried this? I'm also a bit nervous about adequate cooling. In this part of California, it frequently exceeds 100F in the summer.

Option 3:
- water pump relocation plate - $45 delivered (be sure to ask for instructions to be included)
- old style (1955-1st or earlier, short shaft) water pump - about $75 from Rockauto.com or NAPA

I'll second Tim's choice/advice, option #3

Grigg

Somehow I knew you'd say that.

Note to self.... blame tclederman and Grigg when wife finds stash of hidden receipts and/or asks if this project will ever be finished.

I wrote a long post about this problem.
First, the crankshaft pully is a differant diameter from 54 and earlier (smaller diameter) than 55 and later.On some trucks you can not use a 55 pulley because of an interfernce problem with a the front crossmember. If you try to use a 54 and earlier crnakshaft pulley and a short shaft water pump with a 55 and later water pump pulley (significantly larger in diameter) the water pump will not turn fast enough. So I finally went with the adapter plate and have no problems.

Another option I believe is that PATRICKS sells a a 55 and later short shaft waterpump with a 54 and earlier water pump pully on it so you can use your 54 and ealier pulley.

John Gott

Can one of you guys confirm that a NAPA Auto Parts '49 water pump, part number WP 58125, will work with the relocation plate? Go to www.napaonline.com and type in the part number. I already bought the wrong pump once, and I don't want to do it again. My main questions relate to shaft length and bolt pattern at the relocation plate. I'll check the bolt pattern for the fan before I buy it.

Yes, that is the old-style pump for use with a 5/8" fan belt.

You'll need the gasket listed for your truck's year (1949) to match the pump side of the plate; and, a gasket listed for the engine's year (1958) to match the block side of your plate.