Aluminum Heads + Freshwater

[mphatc]

What's the general consensus? This engine will spend 99% of it time trailered to freshwater . .and 1% in salt, but trailered . .

I don't want to run an enclosed cooling system. Is this sensible, or am I looking for trouble?

MPHATC

[MOP]

Aluminum does pretty well if flushed, corrosion can be slowed to minimum. The other problem is electrolysis even in fresh water, a few of the guys that I spoke with that were at the 1000 islands complained about the white pitting on the drives. I would consider going over to closed cooling for the protection and a little more performance or stick with iron.

[smoothie]

My motor has had them on since 1978,granted it only had 150 hrs on it and sat in a garage not started for 13 yrs,but when I detuned the motor the heads looked like new and thats with antifreeze in them for that long,boat was ran in freshwater only.Just be careful changing spark plugs and use anti-seize on em.

[mphatc]

M.O.P.

White pitting on outdrives when run in freshwater is the result of the wrong anode. Most marinas sell zinc, and don't even know that freshwater requires magnesium.

My Alpha suffered from this until I refinished it and installed the correct anode.

But when the engine is not running, let's say at the dock or on the trailer, there's very little if any water in the heads . . ? right or wrong?


mphatc
wanting to build the lightest weight FSB . . . :)

[MOP]

The anode thing I do know about learned it in school many years ago, kind of forgot about it till it was brought up on the board. I believe the heads are still full or mostly full at rest. Honest you engine will more than likely wear out or break before you need to worry about the aluminum heads. But as many of the guys have pointed out performance and economy is better with closed cooling.