Oil Pump Question

Hi Guys,

Is there a preference between an aluminum oil pump and a cast base oil pump?

I read somewhere that steel ones expand differently and can leak. Any thoughts?

Cheers

Newt

I have two cast iron melling pumps in service at the moment, they do have a different expansion rate to aluminium, people refer to the pumps leaking internally and of having oil pressure problems, make sure they fit the oil pump bore correctly when you are building the engine, some aluminium pumps have the same issues with two much clearance in the bore and these leak as well. both my cast iron pumps have no oil pressure problems or leak externally.