Changing Beta Pencil Anode every six months?

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FairweatherDave

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With the first time of winterizing my Beta 25 engine I thought I should explore the engine a bit and change the pencil anode. As part of winterizing you suck up antifreeze mix through the sea water part of the cooling system and I did this. Then I have changed the pencil anode which was well wasted. But obviously the anode is not going into a seawater situation until I launch the boat next season. So does the six month rule apply from now or when back in the water? When does the clock start? (I do know they are not expensive, particularly when compared to the engine, and I do know I need to do more serious reading about anode protection). And I did do the heat exchanger rodding job while I was there. Thanks for any replies.
 
With my 13.5HP Beta I needed to change my anode a couple of times per year. I would check mid-summer. After the first couple of years the rate of degradation gradually slowed 'til I only needed one per year. Now 10+ years down the line I could probably get by with one every two years (but I do still swap it out every winter).

PS check the other thread on anodes to find a cheaper-than-Beta source of anodes.
 
I assume the anode is somewhere on the seawater side? No need for any anodes on the fresh side. An anode needs to be immersed in water to do anything for you, so if the system is drained there is little point in putting it in. OTOH if you put it in now it won't waste at all and will be ready for next season.
 
I just check them from about 9 months after putting them in. Also found that the rate of decay has slowed over the years - not sure why.

Have never felt the need to change the raw water for antifreeze in the winter - what is the reasoning behind this?
 
Pye_End said:
I just check them from about 9 months after putting them in. Also found that the rate of decay has slowed over the years - not sure why.

Have never felt the need to change the raw water for antifreeze in the winter - what is the reasoning behind this?
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Because salt water freezes at about minus 2 degrees centigrade
 
Pye_End said:
Have never felt the need to change the raw water for antifreeze in the winter - what is the reasoning behind this?
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It's one of those things that some boat owners feel they should do but there is little point in it. In many cases most of the seawater side of an indirectly cooled engine is rubber, along with metals that resist corrosion. In some cases there is an anode in the heat exchanger to protect a galvanic couple that may be there, e.g. tubes of a copper alloy such as aluminium brass (more expensive) or brass (cheap) and a stainless steel jacket. Either way, filling with antifreeze will have no beneficial effect. Flushing with fresh water and draining is the best treatment.

There is a slightly stronger argument with a seawater-cooled engine that is mostly made from cast iron. Filling it with antifreeze solution, or circulating the solution through it when it is hot, adds corrosion inhibitor. However, cast iron is pretty good at resisting corrosion and there are plenty of such engines several decades old that have never seen antifreeze. To my mind the best way of resisting frost damage is total draining, after flushing through with fresh water. A few automotive engine marine conversions may have aluminium parts in them and in this case the corrosion inhibitor would be highly beneficial.
 
Pye_End said:
Have never felt the need to change the raw water for antifreeze in the winter - what is the reasoning behind this?
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I normally circulate a mix of antifreeze, water and a dollop of oil through the engine whilst the boat is ashore and I'm warming the oil to drain it. I used to do that with the old Volvo raw water cooled engine and I've just carried on. Probably far less benefit to the indirectly cooled engine but I don't like the idea of salt water sitting in any part of the engine over winter.
 
vyv_cox said:
It's one of those things that some boat owners feel they should do but there is little point in it. In many cases most of the seawater side of an indirectly cooled engine is rubber, along with metals that resist corrosion. In some cases there is an anode in the heat exchanger to protect a galvanic couple that may be there, e.g. tubes of a copper alloy such as aluminium brass (more expensive) or brass (cheap) and a stainless steel jacket. Either way, filling with antifreeze will have no beneficial effect. Flushing with fresh water and draining is the best treatment.

There is a slightly stronger argument with a seawater-cooled engine that is mostly made from cast iron. Filling it with antifreeze solution, or circulating the solution through it when it is hot, adds corrosion inhibitor. However, cast iron is pretty good at resisting corrosion and there are plenty of such engines several decades old that have never seen antifreeze. To my mind the best way of resisting frost damage is total draining, after flushing through with fresh water. A few automotive engine marine conversions may have aluminium parts in them and in this case the corrosion inhibitor would be highly beneficial.
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Hi Vyv

Just curious. Why is flushing the seawater side of an indirectly cooled diesel with fresh water and then draining better than flushing the seawater side through with last years fresh water / antifreeze mix. It might be unnecessary if you flush and drain it properly (although I would always worry there was some water left in there) but is there an issue? After all it's quicker and doesn't cost any more?
 
I believe the heat exchanger body on the beta is Aluminium. When i had one, I always flushed it through with antifreeze.

Re the anode: just check it every so often, only takes a couple of minutes unless the access is really poor? There is nothing hard and fast about the six months figure, that's just a reasonable starting point, you can check it as often as you like.
 
vyv_cox said:
I assume the anode is somewhere on the seawater side? No need for any anodes on the fresh side. An anode needs to be immersed in water to do anything for you, so if the system is drained there is little point in putting it in. OTOH if you put it in now it won't waste at all and will be ready for next season.
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On my Beta 20 the anode is on the freswater side.Saltwater doesn't enter into contact with the aluminium housing.
 
I change the anode yearly, usually about 2/3rds worn. Beta 25. Also get the screw in type anode as on ebay, not the glued in Beta ones(which fall out).
 
Pye_End said:
... Also found that the rate of decay has slowed over the years - not sure why. ...
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I have always assumed that the rate of anode consumption declines as the protected components build up a passivation layer (e.g. of copper oxide) from new. This was I think raised in a thread a while back on strong acid cleaning of the heat exchanger tube stack. One of my reasons for not doing so (unless obviously necessary to remove thick deposits) was that the acid cleaning could attack the passivation layer and expose fresh metal, which would in turn increase the anode consumption rate. Once a passivation layer is established on new components, reduction in anode consumption will presumably essentially cease, and the anode consumption rate settle at some minimum level. I believe that makes sense chemically, and I don't recall reading anything which contradicts the reasoning.
 
Well thanks all, much appreciated and I'm guessing this thread might carry on a bit. I'm gonna start a thread on why I'm not getting e mails when someone replies, so please don't answer that one here. But slightly back on topic. When replacing the heat exchanger I found replacing the O rings and being confident they are in the right position a little anxiety provoking. I will be looking for leaks when I start her up.
 
FairweatherDave said:
Well thanks all, much appreciated and I'm guessing this thread might carry on a bit. I'm gonna start a thread on why I'm not getting e mails when someone replies, so please don't answer that one here. But slightly back on topic. When replacing the heat exchanger I found replacing the O rings and being confident they are in the right position a little anxiety provoking. I will be looking for leaks when I start her up.
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dont over tighted the end caps, the "O" ring is designed to keep the metals apart
 
donm said:
And the end caps have locating nibs to ensure that they are re-fitted in a particular way to ensure a watertight fit
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As far as I could see the locating nibs were only on the end cap with all the pipe work. Hope I've got it right. Will be testing berore launch though
 
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