UBY289

Which do think is better a Aluminum water pump or a Cast one and why ? .Thanks

TexasAxMan

The aluminum ones are cast as well.

I asked this question a month or two ago but didn't get an answer I felt was complete. Hopefully someone will chime in.

Mustero

I personaly believe cast iron is better.Electricalisis for one thing.Dissimilar matals,iron & aluminum,in an acid base creates electricity.Anode & cathode ya know.There is also the problem of steel bearing in an aluminum case,whitch will wearout first??? Aluminum!!! Now I understand most aluminum pumps run the bearing in a steel sleeve but your still dealing with a softer metal.Now aluminum pumps do have there benifits,less waight,faster heat disapation,cool looks ect.but for longivetys sake I prefer cast Iron.

TexasAxMan

You have dissimilar metals anyway, the timing cover is aluminum, block is iron. It makes sense that the aluminum one will not be as strong, but I wonder what that means in the real world (i.e., do they really wear out faster).

JMD

It depends if you are talking "stock" or aftermarket.

It is my understanding that Ford used an aluminum pump in the small blocks through 64 or 65, I can't remember which year though. and went to cast iron thereafter for a number of years.

It is my understanding that if you have an earlySBF that was originally equipped with an aluminum pump, you have to stay with the stock style aluminum pump. If you have a car originally equipped with a cast iron pump you have to stay with a stock stylecast ironpump.

This is due to a difference in the timing covers. It is my understanding that the pumps willphysically interchange,but they will not flow correctly.

When going to an aftermarket style pump it must be purchasedto match the particular timing cover that is on the engine.

So, IMO, timing cover issues aside, cast iron or aluminum is strictly a matter of personal preference. We went with an aftermarket aluminum pump strictly for looks.

It might be that some of the unreconciled cooling issues that many Mustang owners face might be due to incompatible water pump / timing cover issues. ????????

Starfury

I have a Weiand high-flow aluminum pump on my 331 and I like it.The weight difference between the aluminum and cast iron pumpsis significant. Yes, electrolysis is a problem. Even with the aluminum timing cover you should be running some coolant with aluminum anti-corrosion additives. Prestone puts some in their standard green coolant, but some Water Wetter wouldn't hurt.

There aren't a whole lot of those OE aluminum pump cars around. They're out there, but not as common. The difference between the two is thatthe later cast iron pumps use a steel backing plate, the early aluminum ones don't. I don't believe you can put the OE style pump on a late model timing cover without serious issues, ie. coolant leaks.

JMD

I am assuming that a late style pump will bolt onto an early style cover, because if it did not, the book I got the info from probably would not have placed such emphasis on not mixing the pumps and covers?

There are a lot of people out there who seem to have unsurmountable cooling issues, could this issue explain some of the problems?



(I have to wonder how many early style timing covers might have cast iron pumps on them??)

TexasAxMan

How do you know if your cover was made for iron or aluminum? I got my engine complete except for waterpump, dist., carb and accessories. Is there a part number or something I can reference? The one on mine has the cast in timing pointer, if that helps.

67mustang302

Electrolisys is a problem but if you use the correct mixture of antifreeze/waterwetterand distilled water you'll be ok. Distilled water is the biggy, with less metal/salt ions it doesn't generate near the electrical charge, that combined with the right amount of af/ww generally leads to limited or no corrosion. Otherwise, aluminum is better cuz it's lighter and won't break your back when you install it. And aluminum is a softer metal than iron, but most of the aluminum alloys are very strong. The bearing in the water pump will fail long before the snout deflects.

Mustero

As far as I know.The timing covers are aluminum on all the small block fords.