Aluminum Heads In Salt Water???
05-13-2007, 10:55 PM
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Aluminum Heads In Salt Water???
This is going on a blown 489. I'm trying to decide if my new heads should be aluminum, will they live in salt water with a raw water cooling system? 3/4 of the time will be fresh water the rest will be in the ocean....Thanks.
05-13-2007, 11:19 PM
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I knew a marine mechanic that had aluminum heads on his blower engines. He said he used them for seven years, took them off, and resold them. 100% salt use. It's just how you maintain them. I think the whole aluminum/salt thing is blown way out of proportion. If you think about it, what is your outdrive made out of? I have aluminum intakes on my Formula, and I recently pulled the t stat housing to check for corrosion. Not a sign of it. They have been on for at least four years.
05-14-2007, 07:55 AM
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I bought anodized AFR aluminum heads for my 500HPs. Although I flush religiously, the heads corroded in a year to the point where water was spraying out between the deck and the heads. I boat in brackish water.
I have gen 6 blocks, the heads are based on gen 4 GM style heads. The gen 6 blocks have elliptical or triangular water passages. Gen 4 heads have round holes for water passages that are smaller than the holes on the heads. So, the head gasket sealed on the triangular part of the head gasket and held water between the head gasket and the head which did the damage.
In my case, all it took was a few trips into salty water and the damage was done. BTW, the main part of the water passages that was anodized looked great. I just had crevice corrosion on the face of the head where it meets the head gasket. Welded up the heads and installed closed loop cooling so the problem should be gone.
I have gen 6 blocks, the heads are based on gen 4 GM style heads. The gen 6 blocks have elliptical or triangular water passages. Gen 4 heads have round holes for water passages that are smaller than the holes on the heads. So, the head gasket sealed on the triangular part of the head gasket and held water between the head gasket and the head which did the damage.
In my case, all it took was a few trips into salty water and the damage was done. BTW, the main part of the water passages that was anodized looked great. I just had crevice corrosion on the face of the head where it meets the head gasket. Welded up the heads and installed closed loop cooling so the problem should be gone.
05-14-2007, 11:21 AM
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05-14-2007, 12:15 PM
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If you use Salt-Away you should be OK. However, if you have any area where the aluminum touches steel look out. Corrosion will be amplified and a nice size hole can form in the aluminum head in a short period of time. Your first indication may be water in your oil. The corrosion will actully push the head up from the block. Espescially in areas like Thunderstruck mentioned where deposits can form are the most vulnerable.
I recently had to replace the gimbals on my #6's. Over the years salt had corroded the aluminum surrounding the lower steel pin. The expansion of the corroded metal actually cracked the housing around the pins.
I recently had to replace the gimbals on my #6's. Over the years salt had corroded the aluminum surrounding the lower steel pin. The expansion of the corroded metal actually cracked the housing around the pins.
