Engine zinks

[rsmith]

So we all we all get worn down by a barrage of opinions that may be true or not. When I first joined the HOF any electrical or bonding question was answered with "well Caulder says..." Caulder a god like figure bellowing answered to electrical questions from on high. Members would quote scriptures from his bible with cult like belief.
So after nearly 40 years of using engine zinks I ran out of my stockpile 2 years ago and joined the no zink cult.
Here's what I found when I opened up the pumps after 2 years. Yes that's electrolisi pitting on the cover plates.

[doc g]

How do you tell the difference between cavitation pitting and electrolysis?? What dissimilar metals are there in the RW pump?? I had the same thing on my previous boat's pump after I stopped putting zincs in the pump side because all they did were break off early and end up in the intercooler. I thought it was just cavitation.....Pat

[rsmith]

It ain't cavitation around the bolt holes or where the gasket sits

[rsmith]

I always changed them before they got too bad or broke off. I mean do you wait till your tires are completely bald whith cord showing before you replace them?

[MikeP]

Interesting...our boat has never had zincs in the water pump since new (per log entries). I pull the impellers every winter and have been doing it every year since we purchased the boat in 2004 and the cover plates are smooth with no pitting.

Since neither of us is using zincs in the pump it makes me think that the pitting is not directly related to whether there is or is not a pump zinc. Maybe something to do with the bonding system? Maybe the type of screws used on the plate (bronze vs SS, etc)? Maybe the gasket sealing material - some kind of metal as used in some of the anti-seize products?

This subject is certainly not one I have any expertise at all in and it seems fraught with conflicting info/opinions. Heck, the fact that US practice is bond all metal and european practice is to NOT bond anything makes it pretty darned confusing!

[Avenger]

That pink color in the pits definitely says galvanic corrosion.

[saltshaker]

That pink color in the pits definitely says galvanic corrosion.

I thought that was from the rainbow coalition.

[Boatsb]

Thats a more accepting outlook.

Accept me for who I am not for the fact that I will not ever in any way work within the boundaries of common society, never will respect the opinions or beliefs of others who fit the norm and will never become part of the majority because you cant force me to.

I do need an acronym though.

[rsmith]

Interesting...our boat has never had zincs in the water pump since new (per log entries). I pull the impellers every winter and have been doing it every year since we purchased the boat in 2004 and the cover plates are smooth with no pitting.

Since neither of us is using zincs in the pump it makes me think that the pitting is not directly related to whether there is or is not a pump zinc. Maybe something to do with the bonding system? Maybe the type of screws used on the plate (bronze vs SS, etc)? Maybe the gasket sealing material - some kind of metal as used in some of the anti-seize products?

This subject is certainly not one I have any expertise at all in and it seems fraught with conflicting info/opinions. Heck, the fact that US practice is bond all metal and european practice is to NOT bond anything makes it pretty darned confusing!

Nothing's changed in the last at least 20 years same grease same SS screws in the pump cover just left out the zinks for the last 2 years. It's possible the cover wasn't making good enough contact to bond it to the system

[Finalee]

So now do you just flip it? Should be good for another 20.