The Stovebolt Site Forums The Shop Area Engine Shop Water Pumps: Short shafts, long shafts. What's up?

What's the deal with the short water pump shaft? We are putting a '56 261 into our '49 2 ton. The stock water pump came with no pulley. While the alternator and the crankshaft pulleys line up fine, the long water pump shaft is way ahead of the other pulleys. I imagine I can find a cone shaped pulley to offset the belt rearward. I hear a lot of talk about the short shaft pulleys. So, somebody please educate me. Which is a better setup? Long shaft with cone pulley or short shaft with flat pulley? While we're talking about it, how do I go about shortening my long to a short, if I should so decide?

If you put a mid 50's or later 6 cylinder in an older truck, you need to either use a short shaft water pump or use an adapter plate with an older style water pump, otherwise you won't have enough clearance between the fan and the radiator.
Samantha

OK, I can handle that. Is there a popular way to cut the shaft on my existing pump or is it just a lot easier to buy a short shaft pump? What's the secret to getting the flange off of the existing shaft?

YEP, listen to Samantha...I have been going through the same issue this weekend. Our PO and others years ago (as we have learned here) butchered the radiator support and moved the radiator forward but the fan will not be centered. I have just finished three days of welding & fabricating to correct the PO's crappy work. I fabricated and reinvented what was left of the old radiator support to include rest pads for the bottom of the radiator and a horizontal support rod. On a 3100 the radiator housing holds the front of the truck together and on ours it was left un-bolted and the shims and pads were gone. The PO cut the upper latch panel to move the radiator forward and the radiator was basically pulled apart at its mounting flanges which were helping to hold the front of the truck together. Now the radiator is at the shop. Why do all this work you say? Just buy a new support housing, latch panel, and a short pump? Easy, because I can and my labor is free but the rest of the items cost an arm and a leg. DO NOT cut on your truck! Save yourself lots of time and money......buy the right pump...!

PS.. I crawled under the truck at least 45 times bolting and unbolting items. Mocking up the support and lifting out the radiator at least 10 times. Calling my wife to hold the other end of the wrench 25 times. Two dinners missed and one cut finger with a sore back and 3 trips to hardware store and FLAPS....altogether a great time had by all...T/C Steve

When I put a late 50s 235 in my 48 5 window 1/2 ton with 3 on the column I got a new water pump from NAPA for the year of the engine. This was a long shaft water pump. I removed the back cover on the water pump and put a block on the impeller then on my press I pressed the fan hub down till the pulleys lined up. Then cut off the shaft sticking in front of the fan hub. I used this set up in my 48 for 6 years with no problem. My water pump was not in the center of the radiator, but still seemed to cool okay. Temps here in central Cali are well over 100 in the summer

You can use a cutoff disc to cut the shaft after pushing the hub down like Larry said. First find a shorter pulley so you'll know how far to push the hub and how much shaft to cut off.

There are various pullies that will work. One is the 292 Ford from the 50s. Of course you don't find them in wrecking yards now like we did in the 70s when I did my first one.

Be sure to get a pulley close to the diameter of the late model 235 pulley. A smaller pulley will run your pump too fast preventing heat exchange.

The flange is just pressed on? A little press work and it just slides? Seems like it's gonna need a little welding to keep it in place once I'm done, yes?

Yep....even with the water pump being lower we never had an heat issue and in Grass Valley it can get HOT! While doing all the other work to the radiator support we decided on a new SS flex fan and will report back on the results.

My uncle says rule of thumb water pulley dia. should be close to harmonic balancer dia. for stock applications?

My uncle said if you are going to re-press the pulley flange down make sure you support the impeller VERY well as they are cast iron and will crack and you won't know until it comes apart.

A Walter's narrow kerf Zip wheel will cut through the hardest of steels at your local welding supply 4.5" x 5/8" for your angle grinder....T/C Steve

You don't need to weld it, its a press fit so it will stay where you put it.

The problem with the late 235 in an earlier truck is that the fan sits too low on the radiator for efficient air flow. I run a shortened water pump on my 261 but I run an electric fan and don't bother with a mechanical fan. It works fine and stays cool even in 100 degree heat, but it is a big fan.

I haven't even decided on a fan yet. We may go electric or we may go OEM. I'm just trying to spin the water pump for now. Thanks for the info.

I just bought a pump from Jim Carter-Kept my fingers crossed that the right one came. It did...kinda...it's the right length but this pump must have other applications..The pumps generally have one large outlet and one small one. The pump I got had two small outlets and one large one. I assume I can find a threaded plug at some plumbing supply house for the extra outlet.

Keith

Keith,
Check out Pace Performance, they have all the plugs,fittings,and hard to find little items for water connections available in S.S. or steel..for a very good price.actually any of them hard to find fittins they have from vacume to water pumps and a big selection of general stuff.
Tim

Thanks Tim-I'm on my way.

Keith

The waterpump with 2 small outlets is for a 261. A standard pipe plug from the hardware store will plug the extra hole for use on a 235. It could also be used for a thermostatic fan switch if you are into that sort of thing.

thanks Cletis-I'll have to hit Home Depot on the way home from work-Maybe could be used also to heat a manifold if I go that way-

Have a good one-

Keith