Pencil Zinc Question

[WindyT]

Firstly, yes. I've learned my lesson.  Bought this boat in July 2017 with a brand new zinc and was told it was a once a year thing to check by the guy that surveyed the engine / rebuilt the heat exchanger in June 2017 prior to purchase. I stand corrected as the HX pencil zinc is 99.9% gone. 

Looking for ideas here.  I appear to have an 1/8" zinc with a 3/4" female threads on the actual HX unit.  I had already read about cutting down zincs and was prepared, but the way in which this fits into the HX seems to be potentially unique after the rebuild with a 3/4 adapter liquid welded on top of the smaller (1/2") sized - hard to explain but perhaps take a look at the picture.

My 3 questions:
1) is there any way to just dissolve the zinc so I can re-use the previously jury rigged system?
2) Has anyone had a similar issue / know of an easy way to reproduce this adapter?
3) Should I bite the bullet and just remove the entire HX to make sure no zinc fragments inside / clean it / potentially retap the threads? 

Thanks for everyone's advice!  ... planning to do my seasonal oil change tomorrow.  Here is to hoping it goes a bit better than this pencil zinc!

WindyT

[KWKloeber]

WT

What do you have there, a reducing bushing with a pipe plug in it?
You don't have a 3/4" pipe thread.  It looks like maybe a 3/8 NPT thread and the plug (if that's what it is) may be 1/4" NPT.  That's just a guess. Take them to a hardware store and they can tell you the thread size.

Looks like you want a pencil zinc (if you're in salt water) with (guessing) a 3/8 NPT thread. What you have looks like some PO jury rigging. Once you have a correct one, you'll see that the actual anode typically screws into the "nut" so you can replace just the anode, or replace the whole shebang.

K

[Noah]

FIRST some Questions:
1. Do you have a 2 in. or 3 in. HX?
2. Can you please attach a photo of your HX?

Caveat: I am not a mechanic but, the following is based upon my experience:
Although not the cheapest, you can buy the complete screw-in zinc "assembly" (pencil zinc and brass threaded carrier/cap) from Catalina Direct.
https://www.catalinadirect.com/index.cfm/product/1637_943/engine-heat-exchanger-zincbr38-thread-1116-wrench.cfm


Occasionally, removing the end cap of the HX and seeing if any debris (broken off zincs) is inside and removing/shaking them out, is recommended. But, if you change the zincs regularly (quarterly or semi-annually, depending on local conditions) you won't need to do this.

[WindyT]

Re: hardware store.  I think that may be the most logical course of action.  I actually went to toadmarine.com and bought the 'official' pencil zinc for the M35... and my zinc is quite a bit skinnier.

Re: zn length: 2"

Re: thread. the 3/8 plug threads into the HX nicely.  Just the Zinc doesn't fit as it is 1/8 (?), I believe.  This based on the 1/4 zinc I purchased being too large for the hole where the zinc belongs.   So what I believe was done is this jury rigged combo plug was created to accept the larger thread size but smaller zinc?

[KWKloeber]

Are you saying that there is a smaller diameter hole beyond the hole for the nut (3/8 NPT)?
Theoretically the way it **should** work as far as I've seen is that if the anode fits inside the OD of the nut it will fit the Hx. Can you confirm or get a pic looking into the hole and also in the end with the cap removed. I don't see what the issue is because the anode is smaller than the OD of the reducing bushing which is how the replacement Zn should be.  A pic of the Xn you got?
Perhaps that isn't a plug as I first said, but is a 1/4" NPT Zn threaded into reducing bushing?
Unscrew that and you could tap the remaining Zn out and replace with a 1/4" Zn. I'm guessing st the thread size.
PERHAPS....... forensically thinking.... PO got tired of cutting off 3/8 Zns and used the bushing to take up some of the length of the 1/4" or 1/8" Zn he used??? That seems the most logical looking st the jury rig.
Quite a neat outside-the-box solution if that's the case.

[Stu Jackson]

>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
PERHAPS....... forensically thinking.... PO got tired of cutting off 3/8 Zns and used the bushing to take up some of the length of the 1/4" or 1/8" Zn he used??? That seems the most logical looking st the jury rig. Quite a neat outside-the-box solution if that's the case.

Ken, quite possible.

WindyT, some of our skippers have reported having to cut zinc ends off to fit into a HX, regardless of size of HX.  I posted a picture, many years ago, showing how I never had any issues with zincs in my HX.  I'll see if I can find it.

[Stu Jackson]

Try these:

http://c34.org/bbs/index.php/topic,4279.msg24636.html#msg24636

http://c34.org/bbs/index.php/topic,8171.msg57168.html#msg57168

Please read them both.

Good luck.

[scgunner]

    The fitting in your hand looks like the standard HX nut that's been drilled and tapped to accept  a pencil zinc nut, it also looks like you have what's left of a standard size HX zinc(3/8") not a pencil zinc. My original HX wouldn't accept a full length zinc so it had to be shortened, later model HXs altered the fitting location which now accepts the full zinc.

      I'd say you've got three options, that thing in your hand is a throw away.

         1) you can make up another Rube Goldberg and use a pencil zinc

          2)you can replace your HX with the newer model(expensive)

           3)or you can cut to fit your zincs

     One more thing, anytime there is a change; relocating your boat, or even a new neighbor you should check your zincs monthly, at least for the first few months to make sure your zincs aren't being impacted by the change.

[Roc]

Based on the color of your engine, looks like an M35B.  If you buy the Westerbeke zinc ($$$), the length will be correct, don't need to cut it down.  If you buy an aftermarket zinc (much cheaper cost, couple dollars at best), you will need to saw off a little so the tip of the zinc will not hit the top of the HX when it's screwed in all the way.  Older engines have a wider diameter thread.  The M35B zinc has a smaller diameter (3/8 I think).

[Ron Hill]

Windy : You can go to almost  ANY marine store (West/Defender/ etc) and purchase a new Zn with in a threaded holder.  As Roc said I believe that you have an M35b engine with a 3/8"NPT.  I always check the length Zn needed by inserting a #2 pencil in the hole and measuring.

I'd take off the end closest to the threaded Zn hole and get the old Zn out of the inside.  Then go to Glen-Mar marine (800) 282-0123 and buy an end cap assembly #5373 which will have a new end gasket.

Always post your Hull# when asking a question so we know what model C34 and engine you have. That way you'll get a correct answer to your question!!

A few thoughts

[Stu Jackson]

>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Always post your Hull# when asking a question so we know what model C34 and engine you have.

WindyT,

Go to the Profile tab and then update your profile to include your signature or avatar with your hull # and the rest of the kind of information you see from most respondents.

Good luck with the parts. 

[Jon W]

As an FYI you can buy the zinc anode only in different lengths. My boat uses 1/2" with 3/8" NPT. I recently bought 1 1/2" and 1 1/4" lengths at West Marine. PN 6670897 and 6670905 respectively. List price $2.29 each and no more cutting. They have lengths from 1 to 2".

[KWKloeber]

This is info that I had gathered over the years on what anode fits what..... sizes may have changed so take the below with the value of the paper that it's printed on.

k

If your anode plug takes the following wrench, get the corresponding anode ***:

### 7/16" wrench - (anode #1)
### 11/16" wrench - (anode #2)
### 9/16" wrench - (anode #3)

** HUGE caveat - this is for the correct OEM Hx,
if PO installed a different Hx, then your mileage may vary.
If your cleanout cap bolt is in the way - don't cut off your anode, just.... 'er, get a shorter bolt,

*****
(#1)
M-25, M-18,
2" Hx; anode Length: 2", Dia 1/4" / 1/8" NPT - plug 1/4" UNC; 7/16" hex head

Zinc anode w/ plug
Universal p/n 301069
Canada Metal p/n CME00 / UPC: 10628309103191 / Substitute for Universal p/n 301069
West Marine sku 519017 / mfgr p/n CME00 / $6.99
Anode only -- WM sku 524611 / mfgr p/n CMEZ00 / $2.99

****
(#2)
M3-20
M-25/XP
3" Hx; anode Length: 1-1/4", Dia 1/2"; NPT: 3/8" - Plug 3/8" UNC / 11/16" hex head

Zinc anode w/ plug
Universal p/n 301068
Canada Metal p/n CME1F / Substitute for Universal p/n 301068
West Marine sku 6670863 / mfgr p/n CME1F / $5.79
Anode Only -- WM sku 6670905 / mfr p/n CMEZ1F / $1.79

****
(#3)
M-25XPB 3" Hx
Length: 1 3/4" Dia 3/8" 1/4" NPT - Plug 5/16" UNC / 9/16" hex head

Zinc anode w/ plug
Westerbeke p/n 11885
Canada Metal p/n CME0 / Substitute for Westerbeke # 11885
West Marine sku 332155 / mfgr p/n CME0 / $6.99
Anode only -- WM sku 307314 / CMEZ0 / $2.99

[WindyT]

So much thanks for the help all. 

Mystery solved.  the PO used a reducing bushing to allow for multiple sizes of zincs to be used (I ended up using the 1/4" size).  Strange system though as I still had to cut down the length of the zinc. 

Lesson learned and I don't think this is said often enough on this sight - I really love / appreciate the C34 support community!  What an awesome group!
Hopefully one day I'll be a contributing member, but until then, thanks everyone for all the work you put into this site / community!

WindyT

[KWKloeber]

WT, the bushing is 3/8 npt x 1/4 npt?  Or is it 3/8 x 1/8 npt and the actual zinc OD is 1/4"?
What zinc number or length zinc did you buy and cut the length to?
Did it hit the bolt for the end cap or what?

Yours aside, I honestly cannot understand the continuing annual dilemma about zincs and Hxs. 
There are 3/8" npt zincs sold as short as 1" (as long as 2-1/2".) 
And 1/4" npt zincs as short as 3/4" (as long as 1-1/2".)

As Stu says in his posts, measure what you need and buy it, even if yours is different than the OE Hx.

The one that fits the OEM 3" M-25XP and M-35 Hx is 3/8 npt x 1-1/4", size E1-F.  Why doesn't everyone just buy the zinc that fits rather than cutting down / jury rigging something else?    Ain't rocket science?  I can't wrap my head around this self-created "problem-o." 

This is like "I have to keep cutting down the vanes on my sea water impeller because they are too long."  Just get the right effin part in the first place!

down off the cube (soapbox.)

k