Zinc Pencil?

[daveinrenton]

Don:

I got paranoid reading about an anti-corrosion heat exchanger zinc pencil mentioned in a Boat US article and realized I have never changed such a thing in the A4 ever. Is there such a thing that may need attention I missed?

[Don Moyer]

Dave,

Universal never installed zincs in the Atomic 4. Their simple position seems to have been that the castings were made from a corrosive resistant alloy and that zincs were unnecessary.

We have heard of several customers installing small pencil zincs through the water jacket side plate, but to this point we have no credible evidence that these zincs have any measurable positive effect on the corrosion process.

Don

[daveinrenton]

Don:

One of the great things about the service you provide us A-4 users is to calm unecessary fears such as the one I posed. This, in addition to the many real-life and executable solutions you share, is very much appreciated.

Dave

[pugetsails]

Dave,

If you have freshwater cooling there is probably a zinc pencil in the heat exchanger (not in the engine). I change mine on a very irregular basis. The old one has always eroded away by the time I get around to it. I have not noticed any corrosion problems in 25 years.

Dave

[daveinrenton]

Thanks, I have the raw water cooled engine. I'll remember your comment if I ever change to fresh.

[msauntry]

I replaced one of my cylinder block drain plugs with a 1/8 pencil zinc just for kicks this past spring. When I pull the boat and winterize, I'll pull the zinc and see what's happened to it and post back here. Probably a waste of effort since it hasn't had one for at least three decades. There is no shortage of corrosion inside the block, though. My raw water cooled engine has flakes of rust inside every time I open up the side access plate.

[uniexpany]

Hello -

Let me apologize in advance to all of you who change your zincs every year but I have not changed or inspected mine in four years and now that I want to change it the brass fitting that holds it is really stuck. Based on prior experience the easiest fix will probably be to get a new exchanger. But anyway...

Anyone have any long-term experience running without the anode? Just wondering if I need to replace the exchanger (engine is running fine and not overheating) or can go another year or two?

Thanks! Chris

[Kurt]

I you absolutely can't get that zinc out (I have heard of others who have forced it and broke the heat exchanger........) and the engine doesn't have any cooling problems now, it might be a good idea to just flush the heat exchanger with muratic acid or vinegar. I would probably just use vinegar if you are not experiencing problems. I don't see why you couldn't get several years of use out of it, especially if you flush it at least once a year.

[hanleyclifford]

I have been running copper exchangers without zincs for 20 years. I have had two failures. In both cases it was the solder that failed and I was able to re-solder the leak in one and the other is awaiting repair. It is the solder that is being protected by the zinc.