Replacing Engine zincs

The status of the zincs:

Reference the picture above. The numbers below represent the % WEAR noted on the zincs that I removed..5% wear would indicate 95% zinc left (quote of the week candidate :grin:).

These zincs were installed new in December 2006 by a CAT technician during my engine survey. They had one full season on them (~ 85 hours), ~60 % brackish water (Back bay), ~5 % fresh (Upper Delaware/Chessapeake ,C&Dcanal , local rivers, etc) and ~35% salt (ocean).


Starboard engine:

3 in heat exchanger....all 5%
2 tranny cooler ....right side 50 % left side 80%
5 aftercooler.....all 60%
1 exhaust elbow.... 5%

Port engine

3 in heat exchanger.....all 5%
2 tranny cooler.....right side 50% left side 60%
5 afercooler.....all 60%....the back right one is the "devil"..:smt013
1 exhaust elbow.....5%
 
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I guess I wasn't clear...I meant the picture of the zincs in my first post in this thread...I really should have had pics of the worn zincs....I was too busy coming up with new cus' words....
 
GO back and read my post on zinc changing. The reason you had so much trouble is that corrosion bound the zinc body of the annode and they unscrewd from the plugs. I find it more cost effective to change the zincs more frequently rather than investing lots of hours hunting down the pieces left in the engine/heat exchangers.

I change all of mine in about 15 minuntes, but I can walk up to all of them....gotta love the 450DA engine room.
 
Frank:

I tried the tighten-first technique, but they were all in there pretty tight to start with. Besides, it wasn't the few that I had to fish out of their holes that took up all the time. My trusty set of thin tweasers took care of that. It was the one that I dropped and lost to the "nook-and-cranny-gods" and the one that the treads broke off in the plug itself. The tighten-first technique wouldn't have helped those two problem children anyway.

Do you have after coolers on your 3116's? If not, that's an extra 10 zincs right there I have to contend with...two of which were the problem children. I'm sure that the next change will take me less than an hour including setup and cleanup time.

BTW, I was able to buy a new plug at the local CAT parts store. A plug was $12 and the o-ring another $2. I also bought a spare. Almost $30 w/tax for two stinkin' little plugs....
 
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Having a full set of extra plugs and pencil zincs makes the job go much faster.
 
I have extras of all the brass plugs, but at $15 a plug for the aftercoolers plugs, the ONE extra spare will do. Besides, I will only be replacing zincs when I am at my dock, and if I run into this again the local CAT dealer is only a few miles away.

Thanks again for all the help and support...
 
My Humble Opinion on Zinc Brass: I read many are using pipe dope or similar anti sieze compounds or tapes on the brass. I think this is a bad idea.

The idea behind a zinc in an engine is defeated if the zinc is not in solid contact with the more nobel metals. Using a coating on the brass threads can insulate the brass and reduce contact. These brass lugs are pipe threads and will be self sealing when properly torqued and the need for a "locker" really isn't there.

The engine specs will have a torque for these lugs and that is all you should need. A great idea is to wire brush the threads, Male and Female, before re-installing a brass.

Then as Frank W recommends, check these every three or four months.

On the replacement of pencils into old brass, tighten the nre pensil threads in to the brass well, but be careful. Grip the new pencil as close to the brass as possible when tightening. The zinc is soft and too much torque can snap the zinc in two.

If you loose a zinc when removing , use long skinny needle nose pliers to grasp the zinc threads. Grasp the threads and rock the pencil gently left, right and back and begin twisting as you pull out. The idea is to break free any globs of debris and allow the zinc to be pulled out without breaking it off. If the zinc breaks ... you have to go spelunking so use care and caution removing a detached zinc.

Zincs are cheap and save engines. Check'em
 
OK...I just finished changing the engine zincs....second time since I own the boat. I'm convinced that the aftercooler zincs are possesed by the devil. They have different 'plugs' then the rest of the zincs. The 3 in the heat exchanger....no problem. The 1 in the exhaust elbow....no problem. The 2 in the oil cooler....no problem. The 5 'bastards' (little 'b') in the after cooler.....all related to the devil. I think I know my problem though , so hopefully someone else can learn from my mistakes. The plugs on the aftercooler zincs are not the copper tappered thread type, they are stainless steel plugs and they have a rubber 'O' ring for a gasket to make the seal. The problem is that it is too easy to overtighten them so that when it's time to change them, you can't turn to tighten a little before you losen them. This time, I only put them in with a little pressure on them....enought so that they don't leak. Hopefully, next year when I change them out, I will have enough 'room' to tighten them an 1/8 of a turn before I losen them and then they will all come out on the first try.

I spent most of my time fishing out the old zincs, and one of the zincs threads broke inside the plug again this year.....but I had a spare from last year so I had that covered. I'll have to replenish my spare aftercooler plug.

Oh....and after I changed all the zincs,including the genie, I started everything up to check for leaks, and noticed that my genie was leaking. I thought it was from the plug under the heat exchanger, but after another 45 minutes of up and down the ER I found that the plug end cap to the heat exchanger was cracked. Somebody......... and it wasn't me......must have overtightend the cap bolt and actually cracked the cap. I tried JB Weld, but it didn't work. I'll have to wait for Hansen Westerbeke to open in the morning to order a new cap. Nothing like spending 5 or so hours in the ER sweating your a$$ off....it was fun.
 
I made a set of extraction tools for pulling out zincs that unscrew themselves from the plug. I turned a piece of stainless to fit in the pipe threads where the plug goes then drilled and tapped the end of the stainless to fit the threads on the zinc. When I lose one, I stick my handy little thingy in the hole and screw it on the zinc and pull it out.

And you are right..........anytime you see an o-ring on a fitting or plug, it should be tightened enough to just begin to compress the o-ring but not enough to squeeze it out so you tighten the plug against what it mounts in.
 
Frank:

I'd love to buy one of your 'zinc extracting thingies'. I see a market for that tool. If you ever find the time between now and next season, when I have to do this all over again, put me on the list for the first one off the line

As an aside, I 'learned' a little trick to get those out myself. What I did was scew the cap on the lose zinc in the hole just to the point before the cap threads screwed into the hole. I then 'tapped' the top of the cap with a small tap and hammer. That caused the zinc to loosen up a bit in the hole and I could then pull up on the cap with a pliers and then do it again until I could wiggle the zinc out of the hole. But I'd still like one your extracting 'thinges'.
 
I thought I was the only one that had problems like this. I have 3196's with only 6 zincs per engine 2 on each of the coolers and 2 on the exchanger on the front of the engine.
Of course I had only slight problems until I snapped off number 12 witch resulted in some torch work.
Oh well I guess we all have our own cross to bear with each of our boats.
I still think the guys who design boats (especially the engine area) have some sort of grudge against the poor souls who have to work on them.
Jack
 
earthmover17 said:
I still think the guys who design boats (especially the engine area) have some sort of grudge against the poor souls who have to work on them.
Jack
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In my business, we're always saying that Architects ought to be required to spend at least a few years "in the field" actually building stuff before they sit down at their CAD's.

Same should hold true here- make 'em spend a couple of years in the engine room turning wrenches...
 
Any ideas how to get the nut on the exhaust elbow to move, got a great big wrench on it last time, but still couldnt get it off, well in fact the socket remained on it for about a month or so till it freed itself up
 
Chris1960 said:
Any ideas how to get the nut on the exhaust elbow to move, got a great big wrench on it last time, but still couldnt get it off, well in fact the socket remained on it for about a month or so till it freed itself up
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I don't know specifically what nut you are talking about but sometimes heat is the only answer. I don't mean a small pencil torch but real heat.
Jack
 
Jack, its the nut that holds the pencil zinc on the cast iron exhaust elbow on my (1996 ) Mechanical 3126's doesnt look like its been replaced for a while
 
Jack, don't forget to change zinc number seven (lower port side heat exchanger bonnet). I'm guessing you're counting the two starboard heat exchanger zincs, two in the oil cooler, and two in the fuel cooler. By the way, you should disregard the front zinc in the fuel cooler as it can get sucked into the raw water pump impeller creating yet, another CATastrophe. Storm
 
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On my 3126TAs, ALL zincs are down stream of the water pump/impeller. The impeller is protected by the sea strainer.
 
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