Engine Zincs

[JLR]

It is that time of the year that I replace the zincs on my Detroit Diesels. However, I am thinking about the wisdom of doing so. Over the past 25 years or so, the only time I have ever had a problem with a motor running warm, it has been as a result of old zincs stuck in the raw water circuit of fuel coolers, boost coolers etc. Thus, assuming that the anode does not come out with the plug, I was thinking about not replacing the zincs on the engine. I have long ago decided not to replace the zincs near the water pump for fear of impeller damage. Although this is not a new topic, does changing zincs do more harm than good?

 

[bobk]

It is that time of the year that I replace the zincs on my Detroit Diesels. However, I am thinking about the wisdom of doing so. Over the past 25 years or so, the only time I have ever had a problem with a motor running warm, it has been as a result of old zincs stuck in the raw water circuit of fuel coolers, boost coolers etc. Thus, assuming that the anode does not come out with the plug, I was thinking about not replacing the zincs on the engine. I have long ago decided not to replace the zincs near the water pump for fear of impeller damage. Although this is not a new topic, does changing zincs do more harm than good?

You need to change the zincs long before they break off. I do mine twice a year on the Detroits and three times a year on the Westerbeke. BTW, are you using the correct zinc (square nut with a 5/8" thread on the zinc vs. hex nut with a much smaller thread)? The anode always comes out with the plug if you change it before that threaded part gets too thin. The other advantage is you can unscrew the old anode and screw in the new one saving the cost of the plug.

Bobk

 

[captddis]

I am in the no zincs in engines believer. They do more harm than good.

 

[Dan Mapes]

I pull the zincs, then boil it out with the phoso deal. The only place some crumbs might get is the shower head since that is not boiled out.

 

[JLR]

Well, I should have checked back in before I decided to change the engine zincs yesterday. Sure enough, one of the plugs on the heat exchanger came out without the anode. It was stuck and in trying to remove it, it went back in the hole. So, I am now thinking I need to remove the hose from that end of the boost cooler to find that anode. Not a fun job nor one I want to do after just winterizing the engines. Wish I had not changed the zincs.

 

[MikeP]

I haven't used zincs in some years now in the engines. Northern Lights Gennys - using the same engine materials that DD uses - does not install them or recommend their use. That's what really got me thinking about engine zincs...PLUS the fact that in our 71TIs, if you installed zincs in all possible locations - water pump and two in the HE, there is no water present at the zincs when the engines are not running - they are just sticking out into the "air," therefore doing nothing at all anyway. All they do that I can tell, is erode during engine operation due to the turbulence and plug stuff. I never pulled one that looked anything like normal zinc "wear" due to providing protection.

I also did a lot of reading and came to the conclusion that, IMO, any necessary protection is provided by the normal zincs present on the rudders/shafts/wherever in a properly bonded system.

 

[JLR]

No good deed goes unpunished. Mechanic says easiest way to remove the boost cooler is to unbolt the pipe that attaches to the heat exchanger in order to slide the hose off the cooler. Checked my maintenance records. Both the boost cooler and the eat exchanger were cleaned two years ago. Still debating whether to remove the cooler. If it will be done, I will wait until the Spring to do it. Sure wish there was an easier way. I do not want to use any acid in there as I have had bad luck on other boats with using acid in the coolers.

 

[rwappleton]

Not wanting to Hijack here but is there not a treatment that you can do that cleans the systems of crud without dis assembly and that will get rid of the remaining Zincs also. Barnacle buster or something like that?

 

[JLR]

There are several. However, it has been my experience or misfortune that on every occasion I used the acid treatment, I ended up with a leaking cooler (fuel at the time) afterward. Somehow, I think it may have eaten the solder in the coolers I had on that boat. Not willing to risk it again, if it can be avoided with some elbow grease.

 

[JLR]

Does anyone know the DD part number for the gasket that attaches the raw water elbow to the heat exchanger on my 1292 DDEC? It should be a simple square or rectangular four bolt gasket about 3" square or so. I will have one made when I go fishing for my zinc if I can't get one from DD. I do see it as part of a kit of many gaskets. The kit costs well in excess of $100 and I only need this one gasket. Thanks.