8 replies to this topic

[minilee94]

Is there any difference in what size water pump pulley I run

It's a 1380

[Gremlin]

The bigger the pulley the slower the pump will run, so if you plan on doing lots of high rpm driving/racing/rallying go for a bigger one

[jime17]

I'm sure I read that some 1275 heads can foul a larger pulley.

[minilee94]

I thought the big one fails too I have a small one ATM but iv not run the engine yet

[HarrysMini]

As above, a smaller pulley spins the water pump faster and a larger pulley spins it slower. You want a larger one if you are going to be doing lots of high-RPM driving as if the water pump spins too fast, it becomes very inefficient. 

 

Looking at your build, I imagine it is going to be seeing high RPM fairly regularly (and possibly be tracked?), so if I were you I'd fit a larger one. 

 

I'm not sure about fouling, I guess all you can do is buy a cheap second hand one and fit it and spin it and see.

Edited by HarrysMini, 10 July 2014 - 10:13 AM.

[KernowCooper]

The large pulley in 4.75" in dai and can foul on the head if the head has been skimmed at some stage, only way is to try one and see

[minilee94]

I spoke to mini spares and I'm going to run the one I have which is medium sized pulley

[Dan]

The largest ones foul A series heads but clear A+ heads. There are more than 2 sizes too.

[minilee94]

Mine a a+ block but a 12g938 head (12g940) head

Iv got my old style pulley from my 1000 auto and that fits and I'm getting a large pulley tomorrow