pencil zincs

fourreins · Post by **fourreins** » Mon Feb 28, 2011 7:32 pm

Hoping you all can shed some light on this for me. I boat in freshwater and am told I should be using a magnesium divers plate on the boat. They seem easy enough to find. My question is this... What about the pencil zincs? Nobody seems to sell magnesium pencil zincs. Seems like you would want to use the same type in the engine. Do you just use the zinc? Also how do you determine the size of the replacements? It looks like you need to know the threading size???? I am replacing them on my 1989 454 cursdaders... looking for the heat exchanger as well as the oil cooler. Can anyone help?

Allen Sr · Post by **Allen Sr** » Mon Feb 28, 2011 8:13 pm

The oil cooler ones can get tricky as I found out last fall. One oil cooler had been updated and took a different size length wise. As far as the plugs going in you can see them easy enough to know if they are 1/8" or 1/4" pipe. Also double check your heat exchanger to see if you have them in the freshwater side also. When I replaced mine in the fall I pulled the end plate off on the raw water side to make sure I cleared everything out. This winter was the first time for me so I know there are a lot more knowledgeable people out here. Good luck.

prowlersfish · Post by **prowlersfish** » Mon Feb 28, 2011 8:56 pm

You can pull the old ones out and match them up . The plugs are NPT and only in the raw water side

fourreins · Post by **fourreins** » Mon Feb 28, 2011 9:41 pm

Is the npt the same for all the Crusader engines? If not how do you determine what it is? I was also told not to use any thread sealant when replacing because it would ruin the the bond between the nut and the heat exchanger. Does this sound correct? If so, wouldn't it leak water?

prowlersfish · Post by **prowlersfish** » Mon Feb 28, 2011 10:49 pm

fourreins wrote:Is the npt the same for all the Crusader engines? If not how do you determine what it is? I was also told not to use any thread sealant when replacing because it would ruin the the bond between the nut and the heat exchanger. Does this sound correct? If so, wouldn't it leak water?

There are different NPT sizes thats why I said to match them up if you can't tell the size by looking . some say not to use sealant BUT I always do and know many pros that do . You will find good contact if you check it with a ohm meter. and the come out easier too with the use of sealant.