Bukh DV20 strange(?) noise

parsifal said:
What you could do, webber, is to eliminate as many sources of noise as possible. This will make it easier to listen to the noise that's worrying you, it may even disappear, indicating the noise wasn't coming from where you thought!

Take off the alternator belt and remove the water pump. Run the engine and try to locate the source of the noise using a long screwdriver as a stethoscope. Put the end of the handle against your ear and apply the business end to the engine in various places.
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Hi Parsifal,
Already made all this tests, the noise comes from there.
The teeth of sprockets have not that hook shape, but they seem worn to my (unexperienced) eye.
Unfortunately I have never seen a new one so can't say what's the degree of wearing down.
The distributor has given me prices: the 2 sprockets (upper and lower) come at more than € 500,00 :-(
 
webber63 said:
Hi Parsifal,
Already made all this tests, the noise comes from there.
The teeth of sprockets have not that hook shape, but they seem worn to my (unexperienced) eye.
Unfortunately I have never seen a new one so can't say what's the degree of wearing down.
The distributor has given me prices: the 2 sprockets (upper and lower) come at more than € 500,00 :-(
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Any chance of the distributor loaning you a sprocket for comparison?
 
Just managed to find this pic from last year. Clearly shows the chain is loose as it is in your vid. I really wouldn't spent €500 for new sprockets.tmp_28206-20150814_172453902016756.jpg

PS sorry it's on it's side!
 
Champagne Murphy said:
Just managed to find this pic from last year. Clearly shows the chain is loose as it is in your vid. I really wouldn't spent €500 for new sprockets.View attachment 59144

PS sorry it's on it's side!
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Thanks Champagne Murphy,
I agree on chain looseness, but it seems to me that the teeth of the lower sprocket (the only visible, actually) are longer on yours.
 
parsifal said:
Y
That's horrible. A classic case of water pump seal failure, eh? :(
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Certainly was. The oil level appeared to be rising! Had to return to Ramsgate and order parts, then repair on site. Did it and washed the sump through with diesel and oil once, then once again with oil. Made the tide with 10 minutes to spare!
 
hello. I have just installed a used DV 20 in my sailboat. The engine starts well and runs perfectly at all revs. I have this strange rattle and it'shard to hear exactly where it's coming from. I re adjusted the tappets which were way off spec and this made a big difference to vibration at low revs. Take note those who say Bukh engines are lumpy at low revs. I also ran it with the cover lifted to isolate the decompresion levers but the rattle was still there I removed the air cleaner alternator but the noise continued. I suspect it may have to do with the raised hand start ,water pump chain drive and roller bearing behind water pump. Any ideas please
 
fullset20 said:
hello. I have just installed a used DV 20 in my sailboat. The engine starts well and runs perfectly at all revs. I have this strange rattle and it'shard to hear exactly where it's coming from. I re adjusted the tappets which were way off spec and this made a big difference to vibration at low revs. Take note those who say Bukh engines are lumpy at low revs. I also ran it with the cover lifted to isolate the decompresion levers but the rattle was still there I removed the air cleaner alternator but the noise continued. I suspect it may have to do with the raised hand start ,water pump chain drive and roller bearing behind water pump. Any ideas please
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Hi fullset20,
After making a full refit of the handstart (every and each single item) the noise was still there.
A couple of weeks later and after a number of attempts I discovered that the noise was originated by the front counterweights (inside the front cover behind the flywheel, page E3 of DV20 Workshop manual): A clogged oil passage didn't allow lubrification and caused consumption of counterweights bushes and of the little shafts where they are inserted.
I found the problem alarmed by the high temperatures reached by the cover.
Sorry for my poor English :-|
bye
Francesco
 
Thank you for this post. I would never have thought of looking for noise from the counter weights and I will check the oil passages. I have both the covers off and I will be replacing the front crankshaft oil seal and the bearings on the upper shaft of the hand start/ water pump. I will run the engine for short time without the chain and listen!! Your English is a lot better than my Italian, but I am fluent in Spanish which is close, verdad! Un abrazo fuerte.
 
Well eventually got round to changing starter chain and bearing and seem to be a difference with the tension as the chain didn't touch the sides of the box like the old one, happy days i thought. Put it all back together repainted front in for a penny and all that. Started her up after sitting for a few months and after 30 seconds engine came to an abrupt stop after hearing slight grinding. Tried again and after initial sound of something catching ran ok for 30 mins, albeit the bloody rattle still there. Wish I hadn't bothered for all the time its took me. Time for someone to look at as its driving me nuts thinking something about to break when i least expect it. BTW does anyone know how the chain get its lubrication? Couldn't see when i had the case apart.
 
webber63 said:
Hi Parsifal,
Already made all this tests, the noise comes from there.
The teeth of sprockets have not that hook shape, but they seem worn to my (unexperienced) eye.
Unfortunately I have never seen a new one so can't say what's the degree of wearing down.
The distributor has given me prices: the 2 sprockets (upper and lower) come at more than € 500,00 :-(
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Have you tried Shaun Brackstone from marine enterprises? He sells bukhs so might have a set to sell.
Can you remove a link to see how that feel?
 
Well one problem after the next. Went to change oil and found it to be emulsified after 20 mins running grey in colour. Going for an engine flush and if that doesn't show improvement then will have to consider head gasket or cracked head. Now identified the source if rattle at bottom end of engine so thinking counterweights. Bugger with 3 days til lift in.
 
Pords said:
Well one problem after the next. Went to change oil and found it to be emulsified after 20 mins running grey in colour. Going for an engine flush and if that doesn't show improvement then will have to consider head gasket or cracked head. Now identified the source if rattle at bottom end of engine so thinking counterweights. Bugger with 3 days til lift in.
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I don't know whether your Bukh uses a directly driven seawater pump rather than a belt driven pump, but if it has a direct drive then that is the most likely cause and the easiest to fix.

Richard
 
I used to have a Bukh and got seawater in the oil. You should have a careful look at the seals on your water pump driveshaft, which is the most likely source of water ingress. If this turns out to be the case, the pump drive shaft bearings will be shot, which could account for the grinding noise. I seem to remember the hand start mechanism shared this bearing. Not difficult to replace. If the seawater has been in the engine for some time, expect further trouble - I certainly had some.
 
I had a weird problem with my Bukh. Seawater in the oil, but it wasn't the water pump seals. Mine is a later 20hp model so had the water pump with leak holes between the water seal and the oil seal so a water seal failure was immediately obvious: seawater spraying everywhere.

Curiously the problem only happened in the colder weather. And became evident the next time the engine was started.

Tried a new cylinder head gasket. And overhauled the water pump even though I knew it couldn't theoretically be the problem.

Eventually twigged that the seawater was only getting into the engine when it was really cold and not running. Still didn't know what it was and ran on another season or two by draining off the water in the bottom of the sump, if there was any, before starting the engine. In the main summer season there wasn't any water from one weekend to the next, but in the spring or autumn there could be.

Finally I took the engine apart one winter to see what it was. Feared a casting fault and a written off engine but it turned out to be very simple and cheap to deal with.

One of the cylinder liners, which each have two o rings to keep the cooling water out of the sump, had seal failure. One seal was distorted and probably never seated properly when the engine was originally assembled. The other one had been working ok in warm weather and while the engine was running but was letting water trickle into the sump in cold weather at rest.

I had great advice from the guys at Bukh UK at the time, who whilst saying they'd never heard of the problem before, helped me, by phone, with the diagnosis and repair. And when I put the engine back together, it ran perfectly and has never suffered from water in the oil since.

Something really satisfying in getting something sorted out through one's own efforts rather than paying someone else to repair or replace it. And of course I now know how all the ancillaries fit back onto the engine. And how the gearbox and flywheel are attached. And how to track down diesel leaks. The job was done largely in the saloon. Only one permanent scar in the woodwork!
 
Thanks guys. Will be starting surgery on her tomorrow. Checked water pump and couldn't see any obvious sign of seal failure and checked holes at the back whilst running. Had difficulty starting and would like to know if it was possible that I buggered something up by changing starter chain. Followed the workshop manual and pretty basic thing to do taking apart and putting back together and that's all I did. Oh well lift in cancelled as I am not getting this sorted in the next 2 days.
 
As you say, the most likely cause is that something has been disturbed when the chain cover and presumably the pump itself were opened and replaced. The chances of something else happening by coincidence are remote. Whatever else you do, you need to remove as much oil as possible as quickly as possible otherwise the bearing will be damaged. You'll only get about 3/4 of it using a suction tube through the dipstick tube so you need to flush it more than once AFTER the pump has been replaced as the engine needs to be run between flushes to mix round the oil in the bottom of the sump. The boys at Bukh recommended thinning the flushing oil first with diesel IIRC, and then either replace the pump or get a refurb kit with new seals and spindle. I went for a new pump, the old one was very tired so it was worth the cost. I'm not sure if the pump is available as a Johnson replacement, almost certainly is and if you can find it it will be enormously cheaper than Bukh who, although lovely people, are very pricey! That said, the advice from Bukh on the phone and the paper fitting guide that came with the pump were very useful when marooned in Ramsgate harbour!
 
Champagne Murphy said:
As you say, the most likely cause is that something has been disturbed when the chain cover and presumably the pump itself were opened and replaced. The chances of something else happening by coincidence are remote. Whatever else you do, you need to remove as much oil as possible as quickly as possible otherwise the bearing will be damaged. You'll only get about 3/4 of it using a suction tube through the dipstick tube so you need to flush it more than once AFTER the pump has been replaced as the engine needs to be run between flushes to mix round the oil in the bottom of the sump. The boys at Bukh recommended thinning the flushing oil first with diesel IIRC, and then either replace the pump or get a refurb kit with new seals and spindle. I went for a new pump, the old one was very tired so it was worth the cost. I'm not sure if the pump is available as a Johnson replacement, almost certainly is and if you can find it it will be enormously cheaper than Bukh who, although lovely people, are very pricey! That said, the advice from Bukh on the phone and the paper fitting guide that came with the pump were very useful when marooned in Ramsgate harbour!
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Are you/Bukh suggesting that the engine oil is diluted with diesel and then circulated around a running engine?

I must say that is the first time I have ever heard that and I certainly wouldn't recommend it without second and third opinions from qualified engineers as to whether it is a good idea.

Richard
 
RichardS said:
Are you/Bukh suggesting that the engine oil is diluted with diesel and then circulated around a running engine?

I must say that is the first time I have ever heard that and I certainly wouldn't recommend it without second and third opinions from qualified engineers as to whether it is a good idea.

Richard
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As I say, IIRC. The option was a flushing oil and it was only in there for a few minutes. I certainly trusted Al and Norm, they've retired now, it may be that the new guys disagree but whatever is used seawater HAS to be removed!
 
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