Coating for Aluminum Heads
 

I'm getting a set of Brodix Aluminum heads for my HP 500. Is there some kind of coating I need for them for corrosion, I've read some companies "marinize" their heads? I only boat in fresh water if that matters.

Hard coat anodizing
Tapped and locating holes will need to be coated with a stop off compound that keeps the coating off those areas.
Coating addes a few thousandths which will keep bolts and dowels from fitting.
It is also very hard.
AWESOME stuff though.

i ordered hard mill spec coatings when i ordered my brodix heads cost was about an extra grand a set

What is Hard Mill Spec? Is it just an option they offer ?

fresh water ?? save your money

I retired from the DoD and Mil-Spec means the same as commercial, the difference is Mil-Spec requires it to be tested to ensure it meets the specification. I know of no commercial outfit which would go thru that process unless they are also doing it concurrently for the DoD, its just to costly.

Agree with Speedy, your in fresh water don't bother with any coatings

I agree. Aluminum set of AFR heads bought in 1992. Used freshwater. Sold in 2014 with lots of life left.

yes. they also have a soft coat which wouldn't hold up to salt at the cheaper prices i have seen offered by edelbrock marine heads. which surprised me. maybe brodix is cheaper now. Also found out the hard coat process can damage the head by softening the aluminum. order took extra time because one set had that happen. the black coating turns brown when it happens it was caught before it reached me.
figured the boat might sell and end up in salt water and fresh water even has ph imbalances

One very important thing to keep in mind is you need to order the heads with the hard coat so they are coated before guides and seats are installed . If you purchase a pair of heads and try to have an outfit hard coat them afterwards the acid will eat away the valve seats and guides enough to were the guides will not be of any use and the seats will incur damage from this process as well. We are a Brodix dealer and have the heads coated before they install seats and guides thats their standard procedure and its about $375 per head . I would not consider building a marine engine salt or fresh water without hard coat anodizing. Best of luck Laz

PS here are a couple of shots of the cylinder heads and intake before anodizing with no guides seats or threaded inserts (yes the acid destroys the stainless from the inserts as well)

https://scontent.fmia1-2.fna.fbcdn.n...74&oe=5B3914C6

https://scontent.fmia1-2.fna.fbcdn.n...20&oe=5B73C16C

https://scontent.fmia1-2.fna.fbcdn.n...1b&oe=5B303C55