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.