The Stovebolt Site Forums The Shop Area Engine Shop Water pump problems?

I have a 1949 1/2 ton chevy truck with a 235 I just installed. I am trying to make it look as original as $ and ability is possible. The water pump was for the 235 and I shortened the shaft and bought what I thought was big enough pulley... about 5 and 1/2 inches across... but when I cranked the engine for the first time it water boiled out the overflow tube-- the thermostat opened fine in a pan on the stove--
I am now quite willing to buy one of those converted water pump kits if that's the issue.
What does that sound like?
any experience on the subject?
I have read the other topics related... but still cant figure out if the pulley size makes that much difference or if the pump is just defective ...thanks for any suggestions...

I think it needs a 6-3/4" pully. Sounds like yours pump is cavitating from spinnig too fast. The 216 fan is not designed to spin that fast either. I used a short pump from chevy duty, but I still had to move the radiator forward. If the larger pulley doesn't work, I would try the adapter kit for the stock 216 pump. Seen em on ebay for $40.

Well before you do anything rash. This is what I would do. First pull the Thermastat and drill a 3/16 hole in the flange. This will allow any traped air to get out of the engine. Secound did you use a 50 50 mix antifreeze and water or straight water. Next what is the TOTAL capacity of your cooling system? Find out and then measure the coolant that you put in. Is the 235 freshly rebuilt? You didn't say... What or where did you get the pulley? Just wondering ..

You said when you cranked it over for the first time it water boiled out the overflow tube. Could it be you over filled the cooling system? Or did this happen a few minutes after you started it up.? I am not trying to be a PIA about this I am just trying to figure out what is going on with your truck.

I got the engine when I got the truck and was told it was rebuilt- but my guess is that it has been several years from the rebuild to being installed- the previous owner kept the engine from freezing up by turning it almost daily...the mixture was around 50/50 and the temp gauge went up high- this took about 5 minutes of running...it has a new original size radiator...

the pulley was from a local speed shop so it's not original. I read from one of these articles that someone else used a pulley about that size... so I assumed it might work...looks like I was wrong.

How did you shorten the shaft? I need to do this to my 1956 235 cid installation into a v 53 chevy pu.

i took it to a machine shop with the pulley and had figured it would line up with the harmonic balancer pulley - we just cut off the excess and pressed the center hub down to the right place

Well I would still drill the hole in the flange of your thermastat. But I would think that you are correct in saying the pulley is too small. You may want to do a search "short shaft" and see if you can find the post that lists a F o r d part number of a pulley that will work.

Good luck and keep us posted.

If you can't find the number with the search feature send me an email and I will look for it in my files but it may take a day or 5!

Powerband I haven't yet found that number for the pulley. I think I may have it at work but won't be back there until next week. I will let you know if I come across it sooner.

The pulley that Patrick's sent me for my short shaft 235 water pump measures 7 1/8".

Kels

I used one from Patrick's also.

I later decided I needed a double pulley and went to the wrecking yard and found another the same size as the one from Patrick's, mated them together and ended up with a double water pump pulley. The F*#d pulley has the same bolt pattern, but it is a little smaller in diameter than the Chevrolet. Should work fine!!

Joe

I don't remember who it was but someone did find a F o r d number for a pulley that would work. I cant remeber if it was Four on the Floor or Tony or Kip or who but it was posted on the Bolt a long time ago. If anyone remembers please post it. I know that I have it somewhere but I cant put my hands on it!

That was me, but I don't remember what the number was. It still works great! I can pull the number off the pulley again if anyone needs it, but I don't think the pulley is available from dealers any more.

Have had a 1957 235 in my 49 for about 15 years. I kept the original pump so it is very tight to the rad, less than a fan belt width. I did not move the rad and so far I have been lucky with the clearance (or lack of it). It has about 8000 miles on it since the swap.