Aluminum heads
 

I have a 302 V8 single engine in a boat primarily used in salt water.

I'm pulling the motor and plan to do a few upgrades to try to get some more HP out of her.

I currently have GT40 Iron heads. almost all of the aftermarket heads are aluminum.

How do aluminum heads get along with saltwater?
Is it a complete pain, or not a big deal?

they dont.. either add closed cooling, or stick with iron. You have 2 things working against you, dissimilar metals, and salt water.. the perfect storm.

i just went through this, and have spoke with others who went through the same

Thanks for confirming that.

I guess Iron it is.

ken2,
Certain vendors will provide a hard anodized coating of cylinder heads and intake manifolds that mitigates the effects of corrosion. We currently have 75 + sets in the field, some of which have been in service in excess of 5 years. None of these heads have been removed from service, or shown any adverse reaction to salt/brackish water conditions.
Bob

can I get any aluminum heads anodized? or is there more to it then that?

Do you guys have something for a Ford 302?

Is the anodization inside all of the water jackets??? What about the heads deck surface? Most of the corrosion I have seen with aluminum heads has occurred where the water jackets on the heads line up with the water jackets on the head gaskets and block.

The one's I've used were hard anodized and then machined. Because they are submerged in fluid for the anodizing process every orifice is anodized. Even without anodizing just taking five minutes to flush your engine every time you come out of the salt will keep everything in good shape.

I also drain them right after.

Those blue o-ringed plastic drains from Mercruiser are wonderful. Just keep a few backups in case you decided to break one off. LOL.

Ken,
Yes, all of our heads are available hard anodized. The BBC heads are stocked, the SBC/SBF heads will require ~1week additional lead time.

I have seen, on rare occurrences, slight pitting at the coolant transfer interface when the engines are run and stored for long durations (without flushing) in salt water. I am not aware of any instance where the structural integrity of the head has been compromised. We recommend Cometic MLS gaskets also, as they have less tendency to wick water.

Bob

Here's a couple pics of an anodized head. It's a little tough with the lighting but you can see the anodizing in the water jackets.

I had alum heads on mine motors for less than a year. They were coated and supposed to be OK in salt. Boat was religiously flushed with in 10 minutes of coming out of water using salt away. NEVER sat in water - ever!

Had to tear down and was surprised at all the corrosion in less than a year (about 25 hours). Don't use them!!!!

+1, ive heard the same story from other guys.

Only way to make them last is to drain them, get the water away from the 2 surfaces. That or Closed cooling, Anti Freeze seems to protect them.

there is a reason Mercury doesnt run Alum heads on fresh water cooled motors, and only on Closed Cooling systems.

Wow Bill, I have EPD Aluminum heads on mine that Larry worked up before he got out of the biz and they are going on 8 seasons now and I have had 0 problems with any corrosion. I had to pull the port motor this year due to a leaky header that in turn killed the crank and rod and piston on one hole and the heads are super clean. These have been run in the salt 99% of their life.

Sorry you had such a bad time with aluminum, I am not saying you are wrong but what you saw has not been the case with my heads and what I have seen.

Bill,

Who is the manufacturer of your cylinder heads?

Regards,

Bob

I've heard of a few guys that have had issues using salt away and aluminum. Don't know if it's just coincidence or there's something there..?

4 seasons on my aluminum heads all in salt and flushed with fresh water nothing else and no corosion. I would build another engine with aluminum heads again with no problem.

One thing we may be forgetting here is stray current combining with salt and dissimilar metals on some of your boats. That may explain why one boat with aluminum heads holds up great and another doesn't.
Outboard motors have aluminum blocks/heads and seem to hold up very well. They do use some sort of coating in the water passages but its certainly not as tough as military spec anodizing.
I have a 1994 Yamaha 130 on my little tunnel and recently flushed the engine with a mixture of vinegar and water and it really cleaned out the water passages. Dont give much credit to the increase in water pressure as it was more likely due to having a different water source but look at the crap that came out of the engine suspended in the water.

http://www.youtube.com/watch?v=mKu8KkPFRnw

Flushing with water and vinegar will definitely prolong your aluminums life.

Before

http://www.flickr.com/photos/65811281@N07/6133149278/

After

http://www.flickr.com/photos/65811281@N07/6132602179/

Not sure, but I "think" Edelbrock..
My buddy (Rogman on OSO) had EXACT same issue. I think he got 40 hours before pulling. Both his motors had same amount of corrosion.
He now has iron eagle heads (I think) and after 3 years they look brand new.
I am not convinced on using alum heads in salt.

The 180cc World cast iron heads work really well. if you are building a strong 347, the 200cc models are capable of 500hp with a good bit of cam.

Aluminum castings can be anodized after all machining operations have been performed. Used heads can be anodized, but must be stripped and cleaned first.

Properly done, anodizing completely prevents subsequent corrosion, but it the anodizing is scratched thru - it opens a "wound" that can infect the surrounding areas.

Many anodized castings are improperly "gasket matched" or deburred by engine builders as a result of "habit" and this gives entry to a path of corrosion. Once anodized, the coated surface must be preserved.

As a side note, anodizing is a form of corrosion. The electrical current ATTACKS the aluminum and changes the upper surface into a form of mineral (aluminum oxide). Once changed, this surface will NOT conduct current or react to the normal range of antagonists that would normally continue to attack aluminum.

MC

Would you buy BBC iron heads if the pricing, HP/TQ results and acceleration were the same as as CNC aluminum? Say 800+ HP N/A? Jim Valako has made us 3 sets. The relativety small increase in boat weight won't likely show on the GPS and they should last indefinitely.
Ben

Ok ..you got my attention .....how to you inject the Vinegar? Hose end sprayer? ....If you look at the salt away type injector the hole the water has to flow thru is ridiculous ....I would sat 1/4" or smaller ...m

Who does this for heads?

From experience - find a 351 and do some work to that engine. That 302 will need a lot of exotic parts to make it produce a noticeable HP increase.
I went from a merc. 188 ( 302) at 188 HP stock to over 500 HP with more money spent than you can imagine.
I had a SMALL engine bay and the engine cover was hitting the exhaust. Glastron Carlson CVX 18.
I wish I could have gone to a 351.
everything should bolt up the same. the engine will be a little bit taller and wider.
Your exhaust will move but if you are running rubber hose connectors they should give that much.

closed coolant system .

just changed my motors to closed coolant system.

This thread was started ages ago by the guy with the 302.

Besides that, I vote for closed cooling too, however, there was a guy on here recently that had his heads rotted from outside. Salt air/water attacked areas near exhaust ports/header flanges.

If you gets heads hard anodized, make sure they are done after machining, not before. As mentioned, any areas with anodizing that have been machined off, well, defeats all purposes of anodizing. Canfield used to anodize after. I'm not sure about Dart and Brodix - must ask ! I know AFR machines after anodizing. :(

If getting heads and/or intake hard anodized after machining, make sure they keep atleast threaded head accessory holes (for ground cables) and spark plug holes non anodized. You need plugs grounded ! I grounded coolant temp sensors on their exterior, since the t-stat housing will be electrically dead, or unless you ground the housings with a separate ground wire. T-stat housing normally grounds thru intake which grounds thru...... :)

absolute plating in Norwood,Ma.located on Bridge st.
they did our 1075 merc heads to a mil spec coating and then some.these were brand new heads,they have to be,also had to remove guides and all the helicoils.
hope this helps a little.

no,,and the spark plugs went in nicely.
2-2.5 mil spec and we asked them to leave it in longer and it came in at around 3.8-4.

we didn't,,these heads were on a merc 1075.