Heat exchanger zincs

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rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Anyone encountered and solved this trap? No way to get a new zinc into the heat exchanger without major work. Looks like I could loosen and rotate the heat exchanger, but I really don't want to disturb it.
 

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Dec 25, 2008
1,580
catalina 310 Elk River
Loosen the top nut of the engine mount and lift the engine with a breaker bar. It doesn't have to move much. Be careful about where you contact the engine with the bar so as not to damage anything. Also make sure you don't move the bottom nut on the mounting, or you may need to re-do you engine alignment. A real PIA!!!
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Thanks, I was hoping for a less involved solution. It is a near miss, so as you say I shouldn't need to move it much. Inexcusable design. How long do your zincs last?
 
Dec 25, 2008
1,580
catalina 310 Elk River
I change them every year, but we are in most lightly brackish on a mooring, so we could probably get away with 2 years, usally there are about 1/2 gone, so they come out no problem, it's just getting a new one in. I spose you could cut it off 1/3 and get it to go in.
 

gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
Rukidn,

Is the bolt the problem? My HX zinc is slightly to the right of the bolt. I use a box wrench to loosen it and remove it the rest of the way by hand twice a year. The old one comes out and the new one goes in without a problem. Takes longer to clean up any water than change the zinc. It's hard to tell in your picture if the zinc is directly over the bolt.
 

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Nov 18, 2010
2,441
Catalina 310 Hingham, MA
It's not a design flaw, your exchanger got moved at some point. Loosen the bolts above the transmission and reposition the exchanger. You might find that one of the mounting brackets broke.

Exchanger zincs should be at a minimum checked monthly. It may need to be changed that often depending on how much you use the boat. They are under $2 from boatzincs.com.
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Mine (and Witz) interferes with the bolt just enough to keep a new zinc from going in. This would vary from boat to boat depending on engine alignment. As suggested we could trim the end of the zinc just enough to get clearance. Viable solutions that each make a 5 minute job much more. Jacking up the engine risks screwing alignment or pulling something loose, cutting zinc reduces effectiveness and life. I'm leaning toward rotating the heat exchanger just enough ccw. More work in tight access, but a forever solution. I'll be alone on the boat next weekend so another project on the list.
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Missed gpd post. Yes we could slide exchanger to port to find clearance if no interferences. Will look and report next week.
 
Dec 25, 2008
1,580
catalina 310 Elk River
Come to think of it, when I first got the boat I changed it and don't remember having the problem. Now I do. Inbetween I had the exchanger off, replacing the damper plate. I bet I could move mine latterly or twist it and solve the interference problem as well.
 
Feb 26, 2004
21,951
Catalina 34 224 Maple Bay, BC, Canada
I'm leaning toward rotating the heat exchanger just enough ccw.
From http://c34.org/bbs/index.php/topic,6920.0.html

...there are TWO different 3 inch HXs.

Universal Part #302631 is the HX with two separated brackets welded to the shell. It is used on M25XP engines. The brackets are bolted to the back of the engine. This is part #11B on the Torreson parts page.

Universal Part #299835 is the HX without the bracket. It is used on M25 engines and those M25XPs that may, just may, have the HX that is held on by TWO HUGE HOSE CLAMPS. There is a separate bracket that bolts on to the engine, is shaped like a saddle, and has a slot for the hose clamps to grip and then grasp the HX [this is Torresson Part #12]. The HX is part #11A on the Torreson parts page. [Torreson Part #11, #299049 is the OEM 2 inch HX that came with the M25 engines. Many of us have upgraded to the 3 inch HX for our M25 engines.]


So, with one there should be wiggle room to move the HX. If you have the hose clamps it's a no-brainer. If not, seems you need to get more creative. I don't have one like that, so sorry can't help, but should have enough room on the bolt holes to slide sideways a tad, maybe?
 
Jun 30, 2010
37
Catalina 310 Bristol RI
I have the same problem with the zinc. See photos below. I tried to rotate the HX but found that it was welded to the bracket so I could not move it.

My solution was to disassemble the zinc. Unscrew the zinc from the brass bolt. I had just enough room to get the zinc by itself into the HX. Then reassemble the zinc by screwing the bolt back on. It may be easier to remove the end plate of the HX so you reach into the HX and hold on to the zinc when reassembling it to the bolt. Once it is reassembled it should be easy to screw the whole assembly into the HX.

Hope that works for you.
 

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Feb 26, 2004
21,951
Catalina 34 224 Maple Bay, BC, Canada
An "Aha" moment:

Loosen or remove the two bolts that hold the HX onto the engine. The hoses should give you enough flexibility to raise the HX enough to do the job.

Or do what New Horizons suggests.

Either way it's a pain, I know.

But I've spent so much time back there on my boat (see the link) that I can do it blindfolded.

Don't raise your engine...:):):)
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
I did try to separate the zinc, and rod alone almost goes past my engine stud. I'll try this plus loosen HX bolts.
 

rukidn

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Apr 23, 2012
158
Catalina 310 258 Sandusky, OH
Thanks for all of the suggestions. After reviewing all options, I chose to loosen the clamps and rotate the heat exchanger slightly back, CCW viewed from starboard zinc side. Only a few degrees allowed the zinc to clear the motor mount stud. Very easy fix. Access the clamp bolts from the back. See the subtle rotation in the photo.

There was no room on my boat to slide the exchanger slightly to port as it already hung up on the engine cover/stairs.

Zinc was completely gone when I bought the boat, and while I had a temporary solution in place, it is good to have this solid. From the look of my temporary, I may get 6-8 months life. /Ed
 

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