Model b waterpump help
 

I need some help. I just ordered a model b waterpump for my model b engine.
When I went to install the pump it did not sit flush with the head. When I compared it to the one that I took off it looked like the impeller stuck out a little farther. I was wondering if anyone ran across this or I just have a defective pump. Thanks Brandon

Re: Model b waterpump help
 

Make sure it is not just the end of the impeller shaft hitting inside the head.

Re: Model b waterpump help
 

Probably not defective, but they may have assembled the pump with the pump shaft a little "proud" of the impeller, this in expectation of wear on the boss inside the cylinder hear (look in the round hole where you mount the pump and you'll see the boss. As the boss wears your free play on the shaft increases.)

This extra may be their "norm" to provide as they may be expecting users to chuck the shaft in a lathe and turn back this shaft to create for themselves the target 0.005 to 0.010 end play.

Talk with your supplier about this. You may be able to give him some dimensions over the phone and he can determine if your pump is indeed defective or maybe he has another one which will fit better and save you the lathework.

Joe K

Re: Model b waterpump help
 

Thanks Joe. Sounds like I will call them and hopefully get some answers.

Re: Model b waterpump help
 

Are you running a stock head? The one with a big "C" on it? That head has a CR of about 4.6 to one. I run a B engine, but with a 5.9 CR Model A head. That also means I use a Model A water pump. Works for me.

Re: Model b waterpump help
 

I ran across the same problem when I installed a new shaft with impeller already pressed on in my B wp.The pump was about 3/8" short of meeting the head.I had to remove the repro impeller & install the old one,then it fit OK.The front of the new one was not machined deep enough.One more instance of crappy repro parts.I also drilled a 3/32" hole thru the imp & shaft & installed a roll pin.Sometimes when an imp is reused,they will not fit quite as tight as they should.If the imp was to come loose,the fan could propel itself into the rad.

Re: Model b waterpump help
 

That is my problem. My impeller is to worn to put it in. I'll call today to see if I can return it.