2gm20f inline zinc
- Thread starter Mark7604
- Start date
Mark -
Can you tell the rest of us us where this thing is mounted in your cooling water flow layout? Do you know what it is supposed to do?
Charles
Can you tell the rest of us us where this thing is mounted in your cooling water flow layout? Do you know what it is supposed to do?
Charles
I would recommend that you check with Yanmar technical support. This looks like a add on that someone other than Yanmar installed.
I have checked with Yanmar and this was an add-on maybe by Hunter. I checked with Hunter and the people I talked to were not even born when this boat was built. The device is inline (sorry about the "online" typo) zinc situated downstream of the sea water intake for yanmar cooling. I am aware that 2gM20 do not have zincs in the engine. The zinc/bronze device is bonded to the engine. I would take it out, but I regularly eat up a pencil zinc every year or so and this would be damage to the engine.
Looks like it may be a home made device. I have never seen one .. Might be helping the tubes in the exchanger? A good plumbing shop probably could make one .. A side note... if it is leaking, seems like the zinc may not be doing what it needs to be ?? Or .. think how bad it would be without that device?
Here is a possible explanation.
At one time the threaded fitting on the canister was used to install a temperature sensor whereas today you thread in a zinc. The threaded stud/nut (opposite side) was for a ground wire which was fastened to the motor block. The assembly was installed in the outflow of the seawater path and the sensor wired to a temperature gauge. This assembly allowed installation of a separate temperature gauge driven by its own sensor independent from the stock overheat buzzer/lamp.
If the theory is true - then today the unit does nothing and the zinc just protects the do-nothing canister.
Since there is no longer any need for this apparatus you can chuck it and replace the entire section with new hose.
Charles
At one time the threaded fitting on the canister was used to install a temperature sensor whereas today you thread in a zinc. The threaded stud/nut (opposite side) was for a ground wire which was fastened to the motor block. The assembly was installed in the outflow of the seawater path and the sensor wired to a temperature gauge. This assembly allowed installation of a separate temperature gauge driven by its own sensor independent from the stock overheat buzzer/lamp.
If the theory is true - then today the unit does nothing and the zinc just protects the do-nothing canister.
Since there is no longer any need for this apparatus you can chuck it and replace the entire section with new hose.
Charles
Thanks for all the replies. Interesting theory Charles. I like your logic. I, however, think that this is probably not the case. I bought this Hunter 31 about 25 yrs ago when she was 2 years old. I don't think the previous owner changed anything from standard stock.
Again, I probably won't worry about it but I do regularly replace the zinc and it does dissolve over 1 yr.. I know Yanmar doesn't have a zinc, but I do worry about electrolysis.
Again, I probably won't worry about it but I do regularly replace the zinc and it does dissolve over 1 yr.. I know Yanmar doesn't have a zinc, but I do worry about electrolysis.
OK - if so then this will work exactly the same as what you have now, it won't cost much, and it won't leak.
Obtain a tee, female threaded fittings, etc., and two hose barbs. Solder on a tab or drill and tap the tee for a machine screw as a ground point. You can use copper, bronze, iron or even stainless. An aluminum one is available from Summit Racing.
Charles
Obtain a tee, female threaded fittings, etc., and two hose barbs. Solder on a tab or drill and tap the tee for a machine screw as a ground point. You can use copper, bronze, iron or even stainless. An aluminum one is available from Summit Racing.
Charles
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Now I'm thinking and that's dangerous
Ken
I agree you should be able to build your own out of plumbing parts. Now you got me thinking: What is it actually doing for you? And why is the zinc being eaten up? Your system is clearly different than most of us. Is the zinc somehow electroplating onto something else? enclosed like that it can't be from a hot marina. I wonder if your raw water is acidic?
Ken
Charles/Ken, Brilliant idea! I was mentally stuck thinking about replacement rather than creating a new part. Your attached picture got me searching the Internet. I found the part you attached. Even better, I found this website brasscraft.com and they have every imaginable fitting.
I don't especially understand the nuances of electrolysis and have always wondered why Yanmar doesn't need zincs. I suspect the part in question was put in for some reason. I definitely will replace this part, even if it isn't doing anything esp since the zincs periodically dissolve. For me, the risk of my engine dissolving to not worth experimentation.
FYI, I very rarely, if ever, replace the zinc for many years while on Lake Ontario. At various marinas in Charleston I do replace zincs ever year or so.
I don't especially understand the nuances of electrolysis and have always wondered why Yanmar doesn't need zincs. I suspect the part in question was put in for some reason. I definitely will replace this part, even if it isn't doing anything esp since the zincs periodically dissolve. For me, the risk of my engine dissolving to not worth experimentation.
FYI, I very rarely, if ever, replace the zinc for many years while on Lake Ontario. At various marinas in Charleston I do replace zincs ever year or so.
" . . . I don't especially understand the nuances of electrolysis and have always wondered why Yanmar doesn't need zincs . . . "
A Yanmar heat exchanger is made from a nickel/copper alloy. These alloys are highly passive and very resistant to galvanic potential differences so anodes were not necessary according to the design engineers at Yanmar - and they are pretty good.
Evidently your predecessor owner figured the Yanmar engineers got it wrong. Nevertheless, if you feel better about having an anode in the mix it certainly will not hurt.
Charles
A Yanmar heat exchanger is made from a nickel/copper alloy. These alloys are highly passive and very resistant to galvanic potential differences so anodes were not necessary according to the design engineers at Yanmar - and they are pretty good.
Evidently your predecessor owner figured the Yanmar engineers got it wrong. Nevertheless, if you feel better about having an anode in the mix it certainly will not hurt.
Charles
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But wait, your engine is an "F". Meaning that you have antifreeze right? And a heat exchanger. No raw water goes into your engine right? It this possibly protecting the heat exchanger?
Jeff
Jeff
Yanmar engines for fresh water cooled antifreeze according to yanmar utilizes a zinc gasket for thermostats. I purchased one last fall. Capt.Rob
That's because salt water...
Our recommendation is to check the zinc at least every three months in salt water.
Usually if left too long the zinc does its job and simply almost disappears, requiring the removal of the HX to get the crap out of the small hole.
I check mine very three months, most but not all of the time it needs to be replaced.
The only things that the zinc can protect are things in the water that the zinc is in.. in this case, the water pump case (no corrosion problem there), the end caps of the heat exchanger, the internal side only of the heat exchanger tubes (may offer slight protection there.).. In a Yanmar 2 GMF, those are made of alloys that are very resistant to electrolysis.. The siphon break before the exhaust ell disconnects the ell from any protection of that zinc while the engine is off.
On the coolant side of the engine, the anti-freeze protects the engine internals from corrosion. That is the engine block and head, the coolant pump, and the water heater heat exchanger tube inside only.
On the coolant side of the engine, the anti-freeze protects the engine internals from corrosion. That is the engine block and head, the coolant pump, and the water heater heat exchanger tube inside only.