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Question about pencil zinc fit up issue on FWC 318

chucka

Contributing Member
"I have a FWC LM318. It has a

"I have a FWC LM318. It has a 4" dia. Sen-Dure heat exchanger. Every year, when I replace the pencil zinc I have to grind it down because the zinc's I can buy hit one of the legs of the heat exchanger.

Here is what the stock pencil zincs look like from most marine supply places.
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Here is what it looks like after I grind it to fit. Is there someplace to find zincs that are already tapered down?
283426.jpg
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Here is what it looks like installed (with the end cap of the heat exchanger removed. It's not that easy to see in the last photo, but the zinc hits that bottom leg of the heat exchanger. If you try to force it in, I think it's possible the zinc could snap off the brass plug and you might not even know it if the end cap wasn't removed from the heat exchanger.

Does anyone else have this issue? What do you do about it? It's a pain in the neck, but I stick the zinc in the chuck of my drill press and grind away material with a 60 grit abrasive. if I had a lathe I would turn it down. I'm probably removing about 1/3 of the zinc to get it to clear the bottom leg of the heat exchanger.
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It always feels good when I fire her up for the first time of the season. Nothing like the throaty rumble of the V8!
Best,
Chuck"
 
"Chuck:

you can buy zincs i


"Chuck:

you can buy zincs in smaller diameters...they just won't last as long. you can also get them in different lengths. Buying just the pencils is the best way to go. If you break off the old one inside the nut, a propane torch will melt old the old stub, usually in under a minute."
 
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