ionian
Member
Should I be worried about not replacing the anode on my 20yr old Bukh, given that no water seems to be present when engine is stopped, and the threads on the anode 'plug' are worn and it wont screw in with the anode in place.
Bukh DV20
- Thread starter ionian
- Start date
cliff
Active member
Yes, I think you should be worried after a year or so or at least I would be if i was you and planing to keep the boat/engine.
The DV24 in mine suffered a similar problem - Solution was to drill out the old threads in the block and re-tap 3/8BSP then make a new anode carrier out of a solid 3/8BSP plug by drilling a 4.2mm hole in the end of the plug and and tapping it 5X0.8 metric thread to take the anode stub.
Bukh anode carrier is 14mm diameter 3/8 BSP is approx 16.66 mm (0.656") with a tapping hole of ~19/32 or 39/64" depending on how tight you want the threads.
This work can be done with the engine in situ.
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The DV24 in mine suffered a similar problem - Solution was to drill out the old threads in the block and re-tap 3/8BSP then make a new anode carrier out of a solid 3/8BSP plug by drilling a 4.2mm hole in the end of the plug and and tapping it 5X0.8 metric thread to take the anode stub.
Bukh anode carrier is 14mm diameter 3/8 BSP is approx 16.66 mm (0.656") with a tapping hole of ~19/32 or 39/64" depending on how tight you want the threads.
This work can be done with the engine in situ.
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aidancoughlan
Member
I agree, replacing the Zinc Anode does seem to be an important issue. On the Bukh20 in my boat , the previous owner emphatically warned me several times to change the Zinc Anode immediately - he had neglected to check if for 6 months or so. When I replaced it the previous one was 3/4 eroded - so if it wasnt there, I presume the corrosion would have happened on the engine itself.
mercman
New member
definately we are bukh dealer after many years of corrosion what we find is the wet liners corrode around where the sealing o-rings to the crankcase are and water slowly finds its way into engine
gordonmillington
New member
I have picked up the point that no water emerges when you remove the anode carrier and that you are unable to put in a new anode as there is insufficient space. I think there may be a buidd up of deposits in the waterways. I found a similar situation some years ago. A bit of prodding soon open up the waterway, water emerged and it was possible to install a full length anode. I suggest you check that out.
That was about 10 years age on my DV20. It is still going strong.
That was about 10 years age on my DV20. It is still going strong.
jerryat
Active member
I agree with your thoughts. I have recently completely stripped own my twenty year old 20hp (after 7 seven years continuous cruising) to fit new liners, pistons etc etc as part of a complete and very expensive re-build, and did indeed find a build up of calcium(?) deposits within the water cooling system.
However, I think there may be another problem not of 'our' making. I normally make my own anodes by turning down bar obtained from the suppliers which cost around 40p each, but had run out during the extended cruise. However, I bought a brand new 'official' replacement anode, but just couldn't get it to fit, no matter what I tried. I took it back to the chandler who readily exchanged it for another, but that wouldn't screw in either! Now as I had just completely cleaned the interior of the head down to clean metal (and re-primed it) I knew it wasn't build-up, but I couldn't get the plug/anode into line and wasn't prepared to risk cross-threading it, even though the plug would screw in easily on it's own.
In the end, an engineering pal of mine took a few thou. off the diameter in his lathe, and bingo! a perfect fit.
I just wonder whether there's a batch of 'formal' Bukh anodes floating about that are very marginally too big! Just a thought, and hope it helps!
Cheers Jerry (PS. Aren't Bukhs superbly easy engines to work on?!!)
However, I think there may be another problem not of 'our' making. I normally make my own anodes by turning down bar obtained from the suppliers which cost around 40p each, but had run out during the extended cruise. However, I bought a brand new 'official' replacement anode, but just couldn't get it to fit, no matter what I tried. I took it back to the chandler who readily exchanged it for another, but that wouldn't screw in either! Now as I had just completely cleaned the interior of the head down to clean metal (and re-primed it) I knew it wasn't build-up, but I couldn't get the plug/anode into line and wasn't prepared to risk cross-threading it, even though the plug would screw in easily on it's own.
In the end, an engineering pal of mine took a few thou. off the diameter in his lathe, and bingo! a perfect fit.
I just wonder whether there's a batch of 'formal' Bukh anodes floating about that are very marginally too big! Just a thought, and hope it helps!
Cheers Jerry (PS. Aren't Bukhs superbly easy engines to work on?!!)
mercman
New member
Agreed. half a dozen spanners and an allen key flat blade screwdriver and a couple of service parts......we did have some mcduff anodes get thru genuine parts somehow which didnt fit
ionian
Member
Thanks for the replies on this topic - guess this week is a good opportunity to prod poke and file while the gales blow themselves out.
Still a bit dubious what good its doing if no water is present most of time - cheers
Still a bit dubious what good its doing if no water is present most of time - cheers
Bronze Age Man
New member
Anode plug is hard to find in DV20 despite the manual & 1 photo on the web. Previous owner never changed anode in the great lakes area so imperative I find the correct plug. Some reports say it's brass but I don't have a brass nut!
Anyone have a good photo? Don't want to undo something else by mistake!
Anyone have a good photo? Don't want to undo something else by mistake!
snooks
Active member
Reach over the top of the engine and reach down the block towards the gearbox. Before your hand reaches the gearbox you'll feel a big bolt head (around 24mm IIRC). Unscrew that and you should find what's left of the anode. Also it has a copper washer on it. Don't loose this.
Replacement bolts can be got from Bukh in Poole.
Some service monkey didn't put the copper washer on our old Bukh so kept tightening until it didn't leak. Three mechanics couldn't undo it, or didn't want to risk undoing it without damaging the bolt. We got a new bolt, but it was a hell of a job to get out.
Replacement bolts can be got from Bukh in Poole.
Some service monkey didn't put the copper washer on our old Bukh so kept tightening until it didn't leak. Three mechanics couldn't undo it, or didn't want to risk undoing it without damaging the bolt. We got a new bolt, but it was a hell of a job to get out.
Mistroma
Well-known member
Spot on, from memory, it's near the top and just inboard of the exhaust and slightly below it. You will feel the nut just a little bit down from the top of the cyl. block. I also remember it as 24mm and that I always used an open ended spanner because it is close to the throttle and I couldn't get a socket into the space. The threads on the plug were also worn down on mine. However, I was able to clean out the threads in the block with a tap & some patience before fitting a new "plug".
When the engine was about 15 years old I spoke to the owner of another boat and he'd never heard of that anode. I showed him where it was fitted and helped him remove the plug (no anode left of course). His Bukh was exactly the same age as mine and he'd had the boat for the same number of years. I had replaced the anode every year and took the view that I might have another 10 years use after his failed through corrosion. He must be very lucky as the engine is still chugging away, having benefited from regular anode changes ever since.
When the engine was about 15 years old I spoke to the owner of another boat and he'd never heard of that anode. I showed him where it was fitted and helped him remove the plug (no anode left of course). His Bukh was exactly the same age as mine and he'd had the boat for the same number of years. I had replaced the anode every year and took the view that I might have another 10 years use after his failed through corrosion. He must be very lucky as the engine is still chugging away, having benefited from regular anode changes ever since.
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alan_d
Well-known member
Kwik Decision
Active member
The anode plug is easily found as described by others. On ours it is even labeled Zn, (stamped on the face of the brass nut) so there can be no mistaking it!
Twister_Ken
Well-known member
You have a brass nut, but it's painted red!
cimo
Member
my anode holder takes a 22mm ring spanner.
The anode plug is located towards the top of the water level when stopped. but the cooling jacket always holds around 1.0 liter of water. The drain plug is located starboard side just above the oil filter, (23 in mistromas exploded diagram). Theres another on the underside of the exhaust manifold, but undoing 23 will empty the block.
common enough problem when fitting new anodes apparently - you can turn/file down the diameter of the anode as mentioned, or try cutting a bit of the end if its easier. Scraping the crud off the inside wall of the block with a screwdriver will help get the holder started square to the threads too.
Judging by the rate of wear on mine, I sleep all the better knowing some form of anode is installed!
The anode plug is located towards the top of the water level when stopped. but the cooling jacket always holds around 1.0 liter of water. The drain plug is located starboard side just above the oil filter, (23 in mistromas exploded diagram). Theres another on the underside of the exhaust manifold, but undoing 23 will empty the block.
common enough problem when fitting new anodes apparently - you can turn/file down the diameter of the anode as mentioned, or try cutting a bit of the end if its easier. Scraping the crud off the inside wall of the block with a screwdriver will help get the holder started square to the threads too.
Judging by the rate of wear on mine, I sleep all the better knowing some form of anode is installed!
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