Bukh 36 Anode replacement

[Jcorstorphine]

I have a 12 year old Bukh DV36 and wish to replace the engine anode. The anode is fitted to a brass plug with a 24mm hex head. The plug is located on the side of the water jacket. I have tried to remove the brass plug but it won't budge. I have a 6 sided hex socket so have a secure connection to the hex plug. My next step is to hire a 1/2" impact driver but I am worried that the force exerted by the impact driver may damage the cylinder block. I have run the engine up to temperature and sprayed penetration oil over the plug. So my question is, could I crackthe cylinder block.

 

[Moonbeam]

I used an impact driver (145Nm) several years in a row to remove the anode on our DV24 for annual replacement. No problems. Do you know when the anode was last removed? If not done regularly, it might have become very stubborn and even the impact driver might struggle.

 

[RivalRedwing]

A 2 or 3 ft pry bar on your socket should do it. Chance of cracking the block is vv unlikely

 

[Jcorstorphine]

I used an impact driver (145Nm) several years in a row to remove the anode on our DV24 for annual replacement. No problems. Do you know when the anode was last removed? If not done regularly, it might have become very stubborn and even the impact driver might struggle.

Thank you for your reply. I think it was last replaced about 2 to 3 years ago. Boat has not been used very much but I know it should have been replaced sooner.

 

[Jcorstorphine]

A 2 or 3 ft pry bar on your socket should do it. Chance of cracking the block is vv unlikely

Thank you, I have had a long torque wrench on it but no movement, I have a 3 foot long very heavy wall tube somewhere so will look for that.

 

[penfold]

Very unlikely to damage the block, possibly it will wreck the brass plug but they don't cost much. Have you tried tightening the plug? This can sometimes break the bond and allow removal. A couple of turns of PTFE tape on the plug reduces the likelihood of this problem.

 

[Saltram31]

I struggled with mine once on my DV20 but was reluctant to use force as the head will round off. I ran the engine to temperature and then tried again. Worked a treat. On my knuckles too.

 

[Daydream believer]

I have a Beta 35 & just placed a length of tube on the handle. The anode had not been changed for years. When I cleaned the heat exchanger (concerned about restricted water flow) I found a third of the holes blocked by the residue from the part of the anode that had dropped off & turned to paste. This had filled the end of the holes. I also found it impossible to remove the tubes so had to rod them through in situ

 

[Daydream believer]

Very unlikely to damage the block, possibly it will wreck the brass plug but they don't cost much. Have you tried tightening the plug? This can sometimes break the bond and allow removal. A couple of turns of PTFE tape on the plug reduces the likelihood of this problem.

On my engine the plug comes as part of the anode, so gets replaced each time one replaces the anode anyway. £14-00 for the worlds smallest anode when purchased from Beta

 

[RivalRedwing]

Very unlikely to damage the block, possibly it will wreck the brass plug but they don't cost much. Have you tried tightening the plug? This can sometimes break the bond and allow removal. A couple of turns of PTFE tape on the plug reduces the likelihood of this problem.

I've thought about PTFE tape before but couldn't buy into its use for fear that it might isolate the anode from the block, somewhat defeating the object of having a sacrificial anode it in the first place. Bet there are no data out there clarifying the matter one way or the other

 

[VicS]

I've thought about PTFE tape before but couldn't buy into its use for fear that it might isolate the anode from the block, somewhat defeating the object of having a sacrificial anode it in the first place. Bet there are no data out there clarifying the matter one way or the other

It would make sense to check that there is a good low resistance connection between the block and the brass anode carrier whenever the anode is changed.

.

 

[penfold]

It's a possibility, but a quick check with the multimeter can assure you of continuity and it does mean if it is forgotten one year you won't need to destroy the thing to get it out the next.

 

[Daydream believer]

It's a possibility, but a quick check with the multimeter can assure you of continuity and it does mean if it is forgotten one year you won't need to destroy the thing to get it out the next.

I can see the theory, but the pencil anode is screwed into the plug. There is no way of knowing if it is there or not. Any contact is through the anode, into the end of the plug & then into the body of the engine.
Unless I am mistaken, the anode does not actually touch the engine, only the plug. Hence any reading from plug to engine block will not establish if the anode is even there.
Perhaps others can advise if this statement is correct

 

[penfold]

Not sure where you're going with that; the multimeter is to confirm or deny continuity between the plug and the engine block. The OP wants to remove the plug as it's not been removed for several years, it's likely the anode is long gone but they won't know until it's removed for inspection.