DV36 - Anode bolt head size

LittleSister

LittleSister

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Can anyone tell me the size of the head of the bolt/plug on the side of a Bukh DV36 that holds the anode?

I know it's somewhere in the region of 22 to 25mm (assuming I'm looking at the correct thing!), but I didn't have a socket to fit it, and poor access meant I couldn't accurately measure it to buy one.
 
And don't panic if the old anode drops off before you withdraw it.

You'll find it, doing no harm, at the bottom of the water jacket if you ever have to pull out the wet liners.
 
On the DV 20 it is 22mm as others have said. On DV 20 it is difficult to get a socket on the head and a open ender is useless, I use a ring spanner and it works for me. I find it needs to come off each year to replace the anode.

David MH
 
I am still unconvinced that a tiny pencil anode inside a huge block of iron is going to do anything useful at all. If it IS needed it is going to waste away in days or weeks. If it is not needed it is going to react over time with the brass plug and fall off ....which is what many people seem to report. My BUKH20 is 34yrs old, and the pencil anode hasn't been changed for the last 30. The engine hasn't disintegrated, and it has had NOTHING done to it other than oil-changes and replacement Alternator and Starter.

Edit: Correction: I HAVE changed the rear oil seal ..... but that was only because I had the gearbox off, and it would have been silly not to do it at the time:D
 
Last edited:
VicMallows said:
My BUKH20 is 34yrs old, and the pencil anode hasn't been changed for the last 30. The engine hasn't disintegrated, and it has had NOTHING done to it other than oil-changes and replacement Alternator and Starter.

Edit: Correction: I HAVE changed the rear oil seal ..... but that was only because I had the gearbox off, and it would have been silly not to do it at the time:D
Click to expand...

Wow! Impressive. How many hours has it done?

I'll stop sweating about not having checked my anode yet. I see the DV20 manual says to check it every 25 hours!

Overtaken by other events this weekend, so I haven't had a chance to deal with the anode plug. It is in a quite different location to the DV10 & DV20, on the starboard side of the engine, under the exhaust manifold, above the oil cooler, forward of the water pump, and aft of the starter motor. Couldn't get a spanner anywhere near it, but I think a socket will do the trick once I've confirmed the size of the hexagon. The pencil anode is the same as the DV10 and DV20, but I'm not yet certain whether the plug holding it is the same size.
 
LittleSister said:
...but I think a socket will do the trick once I've confirmed the size of the hexagon...
Click to expand...

Can't you get a pair of good old outside calipers on it? Or take a mould of the head with blutac, putty, plasticene? Pencil/paper rubbing, or silver paper, or just trial and error with a socket set until you find the right size.
 
A belated report back. The anode carrier bolt is 24mm on the DV36.

When I eventually took it out, there was not only no zinc left, but also the thread from the old anode had corroded away, so I couldn't get a new one in (particularly galling as I've somehow ended up with about half a dozen of the pencil anodes themselves!).

I will at some point investigate how much Bukh want for a new anode carrier (Bukh part 000E4819, 'Plug for zinc anode'), bearing in mind Vic Mallows scepticism as to the anode's value.
 
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