The Stovebolt Site Forums The Shop Area Engine Shop short water pump

Hi. I am trying to fininsh the install of a 235 in my 55 first series. The guy I bought it from gave me a new shorter water pump. I installed the pump and bought a fan with a larger hole in the center to fit over the pulley but the fan hits the harmonic balancer. A longer pump the fan willl hit the radiator.Any ideas? does this motor even need a harmonic balancer. the pulley lines up fine. Thanks In advance for the help.

Tony

A lot of the fans hit the lower pulley and must be tweaked to keep from hitting. Usually, depending on the fan you have, all it takes is a slight forward bending to clear. Patrick's sells a fan for his short pump that is supposed to clear. I used one from a 56' Chev car and tweaked it.

Hi Dave, This fan would require a lot of tweaking. It hits it full on. I could take tin snips to it and remove about 1.5'' form the lenght of the blade but that seems extreme and would reduce my cooling cap. Does your 235 have a harmonic balancer on it?

I would use an adapter and a 216/early 235 water pump. This raises the water pump and fan for clearance and better cooling because the fan covers more unmasked area.

I think thats the water pump I have though I can't be certain. But what I need to know is do most 235's have a harmonic balancer or do they just have the lower pulley?

They need a harmonic balancer. A short water pump is not he same as a 216 water pump. The short water pump fits in the block just like a long pump, but the adapter raises the center of the 216 pump up to mid head level.

I've been down that same road with the "short water pump" that had the fan hitting the Harmonic balancer and put the stock fan blade too close to mount the radiator in it's stock position.

The solution to this problem is to buy an adaptor plate that mounts to the block...you have to drill and tap a couple holes and bolt a 216 waterpump onto the plate. This gives you the proper distance from the stock mounted radiator, raises the pump/fan up so it is centered on the radiator and gives you the proper belt alignment. I bought my adaptor from pre68Dave on this site for $40. and the install took about 30 minutes. You can get the 216 pump from NAPA with either a 3/8 or 5/8" pulley.
Several vendors offer a "short pump kit" at a dear price and I still haven't figured out how they get the proper clearances and alignment!!!
The beauty of the adaptor plate is that when your pump needs replacing you can get one off the shelf at a reasonable price and better yet, locally.

I've got some pictures of the 216 pump and the adaptor plate in my webshots:

http://community.webshots.com/user/Fla54Chevy3100

Hope this helps.

thanks guys I'll find the adapter. I new there must be an answer

Tony........
Whats already been said,
Pre68dave cause he,s a Bolter and Jim Carter
In Stock.
Been There Done That
Regards

how do I find Pre68 Dave

I reread your post and am afraid we've gotten confused.

If you are putting a post 54 235 in a post 54 truck you don't need an adapter or shortened pump, all you need is the stock pump.

If you put a later 235 in an earlier truck you need a shorter pump because the later engine is longer than the original.

The later engine also mounts the pump lower so some people use adapters to raise the pump higher inorder to get it centered infront of the radiator. Other people lower the radiator.

You don't have to move your pump up or down or in or out if it is the right engine in the right truck. You said you were putting a post 54 235 in a 55 first series, so unless I'm confused, I think what you need is a stock pump.

A 1955 first series would need pump work if using any 55 second series or later engine. A 55 first is basically a 54.

I honestly don't know what the vintage of the motor is ,only that it is a 235. The truck is a 55 first series 3100. I purchased the truck with the engine in the truck. the radiator had been pulled. When I went to reinstall the radiator I found that the water pump that was on there hit the radiator. In a box of parts that came with the truck was a brand new water pump which I installed. Now I have the clearance from the radiator that I need but the bottom of the fan touches the harmonic balancer. I don't know which waty to go now. Taking all suggestions.

Thanks
Tony

If the core support hasn't been hacked on and you want to keep it looking stock go for the pump adapter. The adapter lets you buy a stock over the counter pump and use a stock un tweeked fan blade that are easy to find. I've used both and swear by the adapter. I'm curently running one on a wench truck with a 235 that gets ran hard and gets idled a lot and never had a hint of over heating or any other cooling problems that I've had with the short pumps. In short it keeps everything where it belongs including the temp gauge

When you say the fan touches the harmonic balancer I'm not sure how much. If it hits the pulleys you've got something to deal with, if it is 1/8th of an inch or less you could tweak it. up to a 1/4 or 3/8 you could probably get another spacer.

'54 is when the new longer 235 was introduced w/full pressure oiling and insert bearings, by 55 all the 235's were the newer ones. So if the truck is 551st or later there shouldn't be a length problem with a 235. If you've got a pre-'54 235 the problem would be that it is furhter from the radiator 'cause its shorter.

To figure out the year of the engine you'll need the numbers on the passangerside of the block near the starter.

NM51, 1955 second series truck was the first year to use the longer lower water pump. The length of the engine did not change.

Is centering the fan on the radiator a must?

I have a '59 261 in a '52 3100. I currently have a new short shaft with the original fan. The fan hits the harmonic balancer by more than 1/4". I am going to try the adapter and hopefully center the fan and clear the harmonic balancer. The adapter is on order I'll post my results once I get the adapter mounted probably in the next couple of weeks!

I know there are many short shaft conversions out there that work fine with just the right combo of parts. Having the fan centered is only one of the many benifits of using the adaptor.

I pulled the starter and found the number underneath it reads "CON 4 A239" there are numbers in front of the distributor that read "3764476" Do these numbers mean anything? Pre 68 Dave someone earlier mentioned you as a possible source for the parts I need. Do you know the part and if so do you have it and how can I reach you to arrange the purchase.

Tony

Hi Guys, Just trying to keep this going and find the answer. The numbers on the right side of the block behind the starter read "CON4 A239". And there are numbers on the same side just in front of the distributor they read "3764476". Does anyone know the vintage and if this is the motor that will require this adapter and if so is there a part number for this piece and where can I get it. Pre68Dave if you have these parts I would like to talk to you.

Thanks
Tony