sacrificial anodes

[Brian]

For maximum protection of aluminum heads, in conjunction with using antifreeze, what would be the better material for sacrificial anodes to be made of?; zinc or magnesium? Thank you.

[4dFord/SC]

Here's what I use: http://www.no-rosion.com/norosioncoolant.htm

[jimTN]

I believe all the major vendors carry a drop in that has a wire to secure it. I have them in all my cars that have alumn heads. Got mine from Lang's Antique Auto Parts.

[19Fordy]

Originally Posted by Brian

For maximum protection of aluminum heads, in conjunction with using antifreeze, what would be the better material for sacrificial anodes to be made of?; zinc or magnesium? Thank you.

This will help you. Magnesium will corrode faster than zinc, I think, according to this chart.
http://www.corrosionist.com/galvanic...sion_chart.htm

[Brian]

Thank you 19Fordy, that verifies that magnesium would be the way to go. Brian

[Deuce Man]

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Most marine supply catalogs offer what we call pencil zincs. This is a ss pipe plug with a zinc threaded into it. I have used them for years in my aluminum heads without problems. Rich

[fordman]

Question: what happens to the sacrificial magnesium that dissolves in the radiator? do you periodically flush the powder out to prevent buildup?

I was a pipeline engineer 1957-1992; we used cathodic protection to prevent external corrosion. the magnesium anodes sacrificed themselves until there was nothing left but powder or mush.

I am sure 'they' have conquered that problem; I am curious how they did it.

fordman






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[FlatheadTed]

Brian Boat shops carry them for out board motors

[Deuce Man]

By the way watch your head gaskets, try to find gaskets without any copper rings, Copper and aluminum are not happy next to one and another in the presence of water [an electrolite] will try to post a picture of my pencil zincs later, Rich

[fourtydlx]

Try West Marine, they carry pencil zink that screws into a pipe plug.

[Deuce Man]

This is what a pencil zinc looks like. Looks like it was made for the job doesnt it? We use these to protect the cooling system on marine diesels that cost a half to a million bucks a pair. They come in different pipe sizes, I believe this one is 3/8 npt. It cost under $10.00 and a replacement anode is under $2.00. Cheap insurance! Yes West marine sells them as well as most other marine supplies Hope this helps. Rich

[JonC]

I have concerns about using Al, heads as well. I haven't taken any precautions because I really don't understand why or why not. I do wonder what modern cars use if anything since it seems like alot of Aluinum heads are used either in aftermarket or in normal production. Is it the grade of Al that makes a differance or is it that coolants used nowdays prevent some of the issues. Can someone help me understand this issue.

[19Fordy]

Jon, I think the biggest concern is when aluminum heads are used with copper gaskets. This combination creates an electrolytic reaction whereby the alum head begins to corrode. Modern antifreezes do have corrosion inhibitor mixed in with their coolant to prevent this. Just think of all the aluminum engine blocks and heads being manufactured today - but without copper head gaskets. Have a look at this chart http://www.corrosionist.com/Aluminum...Corrosion.html and pay special attention to the second paragraph where it says, "In a couple with chromium or stainless steel in atmospheric or other mild environments, the rate of aluminum galvanic corrosion is low. In a couple with copper, however, the corrosion rate of aluminum is high."

[B-O-B]

I purchased the roadster with the engine already installed & it has an aluminum intake & water pump (sorry but it's a 350)I suspect a lot corrosion going on.

[19Fordy]

In the post above I quoted a source that said: "In a couple with chromium or stainless steel in atmospheric or other mild environments, the rate of aluminum galvanic corrosion is low. In a couple with copper, however, the corrosion rate of aluminum is high." Does the word "couple" mean that the electroltical corrosion of the alum will occur ONLY if the aluminum head is in physical contact with the copper head gasket OR does it mean that the alum. and copper DO NOT have to be in physical contact with each other in order for corrosion of the alum. to happen? Also, in a case where you are using alum. heads and copper head gaskets, will the sacrificial anode still work if it is just suspended in you radiator top tank so that it is not touching any metal?

[Deuce Man]

19 Fordy I dont completely understand the above, but the sacrificial anode must maintain continuity with the sorrounding dissimilar metals you want to protect.I am pretty sure you will have galvanic corrosion even if the steel is between the copper and the aluminum. We protect the underwater metals in boats with a big zinc mounted on the transom underwater, It is connected to all metallic equipment, to be protected with 8 ga wire [bonding system]. I dont think the zinc in the radiator will work! Rich

[19Fordy]

This is also very interesting.
http://www.finishing.com/354/05.shtml

[JonC]

Fordy, thanks for the information, in my case i'm not going to worry about it. My 36 has Al heads but I did not use copper gaskets, just never sieze on the studs along with a composite gasket. I will let the modern anti freeze take care of the rest just like the modern cars, I suppose the next time the motor needs rebuilding I'll know if that was a smart decision thanks again Jon

[hardtimes]

Originally Posted by JonC

Fordy, thanks for the information, in my case i'm not going to worry about it. My 36 has Al heads but I did not use copper gaskets, just never sieze on the studs along with a composite gasket. I will let the modern anti freeze take care of the rest just like the modern cars, I suppose the next time the motor needs rebuilding I'll know if that was a smart decision thanks again Jon

Jon,
Just for a little more 'peace of mind' and for just few bucks you can get the rod pictured above from any plumbing place also...as they are also used in water heaters,etc. Everyone has a water heater,eh

[Deuce Man]

JonC Better read the ingredients on the can of anti sieze. unless you bought pure nickel neversieze, which is very expensive, the main ingredient in most anti sieze compounds is copper. I know it is silver, but that doesnt change anything. We used aluminum steering wheels on tapered and keyed stainless shafts on our boats for many years. Had a bear of a time come removal time, no matter how much never sieze we put on them. One day my mechanic read the ingredients on the can, the old dissimilar metals game again. we have been using a teflon lubricant since then and not a hint of trouble. Rich