Bukh DV 48 engine knock at 1500 hours, HELP PLEASE

[Bill B]

Hello, I am new to this blog and have a Ron Holland 43 sailboat equipped with a Bukh DV 48 turbo diesel w/15XX hrs on the clock. I am the second owner of four years finalizing a total refit effort. Engine ran great before refit, ran great when we started it up and for + 5 hrs of use after, however has always smoked a little and somewhat shake at 2100 RPM (thinking it is somewhat out of alignment). My cruising RPM is approx 2300 and the engine oil, cooling fluids, all filters, diesel etc were changed prior to departure.

 

I was motoring along while transporting and out of nowhere the engine started to labor, or so it seemed. I gave it more throttle and it quickly went down to a stop. I started it again and as I increased throttle, it slowed as if it were running low of fuel. Having 2/3 tank on the gauge, I opened the fuel line, plenty of fuel flow, changed the fuel filter, cleared the fuel separator, checked and secured connections, cracked the injector lines to verify pressure (good pressure), then ran out of my thinking options. Now when I start at idle, it is smooth but as soon as I give it throttle it shakes and then knocks; I immediately shut it down and called the Coast Guard who called a tow company and ultimately a tow. Having no sails on board, I incurred a $1500 tow bill, a very long day and a massive head ache (so to speak!). I would greatly appreciate any informative help please? I don't know these engines and have not experienced this before; seems like a crank or rod bearing to me, but I don't know? I am located in Portland, Oregon USA.

[Tony Brooks]

I doubt anyone on here has a DV48 as this is a UK inland boating forum and we rather tend not to have turbocharged narrowboat engiens but afew have the non-turbo version the DV36.

 

You give no indication of your your experience so it is possible that you may be looking at a fouled prop.

 

It is a direct injected engine so may well smoke a little at below turbo cut-in speed.

 

I note that you do not mention engine temperature, possibly the most important thing. I find this a bit difficult because the Bukh standard instrument panel has a temperature gauge but no oil pressure gauge. The DV48 might be different though.

 

Your engine will either be direct raw water cooled or more likely indirect raw water cooled so my first though would be a blocked sea inlet, strainer, or broken raw water pump causing overheating and partial then full seizure. However we need a temperature reading. If this is the case if you did not let it cool down enough it would still be seizing when you tried to restart.

 

This range of engines have internal balance weights and if they have not been timed correctly will lead to engine shake getting worse as speed increases but this would not be slight at 2100 rpm so I agree about possible misalignment except in the UK the DV36 is normally supplied with an Aquadrive. I have no idea about US practice. Small end bearings tend to tap a bit like a tappet and would rarely be described as a knock.

 

Knocking at one particular speed is more likely to be an engine mount, possibly cased by excess vibrations, than a big end bearing. That would tend to knock at all speeds and get louder as speed increases. Small end bearings tend to tap a bit like a tappet and would rarely be described as a knock.

Then there is the question of diesel bug blocking filters, especially if the boat has been stood for 4 years. If you are sure it was not an overheat please change the fuel filter(s) and cut the engine filter apart and tell us exactly what has been trapped in the filter.

[by'eck]

Had a similar issue with a Volvo TMD31B turbo diesel. The shaking was due to severe fuel starvation but only manifested at a little above idle, despite new primary fuel filter element. Almost as though a vacuum had developed in the fuel lines. Cured by thorough clean out of Separ conglomerator/filter and lift pump followed by fuel polishing.

 

With hindsight the main issue was the fuel lift pump that had nearly a cm3 of crud within. Seems it would just about provide enough fuel at high revs but once those had been lost would not rev again.

[Bill B]

Went to the boat today, engine runs smooth at idle, give it throttle and it gets rough and shuts down. My thoughts now are a blown Turbo. Anyone know of an alternate or substitute Turbo part number? Anyone know a reasonable and good stateside turbo repair center?

[Tony Brooks]

Ah well if you will not take advice from two people who are UK inland engineers then by all means go your own way. As I said we do not have turbo-charged engines on UK canal boats so are very unlikely to know any turbo part numbers, let alone one from a very rare (on UK canals) engine.

 

In the UK there are specialists who rebuild/refurbish turbos, I expect you have the same in the USA, as at a few car or better still truck repair shops for contact details.

 

I can not see how a blown turbo can cause an engine to shut down, make loads of blue smoke (burning oil), yes. Make loads of black smoke, yes, buy not spinning and overfueling. Lack or power, yes but not shutting down.

 

I also note that you have not clarified the type of cooling system you have or the coolant temperature when it shuts down so we can not rule overheating out. Having said that from such information as you have provided it still sounds like fuel starvation to me but until you take steps to diagnose that AND post the results here I can not give further advice.

 

I suppose the fuel tap(s) on the tank are fully turned on.

[larkshall]

A blown turbo can't cause an engine to shutdown. Ok at idle you say, runs rough when you apply power, leading to a motor stall? Presumably box in neutral?.

 

Odd on its fuel related, either you not getting enough air in, or fuel in. Is it the same hot or cold?

 

The last time I encountered this problem, in was fuel filter relaleted, and that was less than three hours running afterwards. We had a mixture of the bug, and condensate in the tank. This got churned up whilst motorsailing with an angle of lean on.

[Naughty Cal]

Ah well if you will not take advice from two people who are UK inland engineers then by all means go your own way. As I said we do not have turbo-charged engines on UK canal boats so are very unlikely to know any turbo part numbers, let alone one from a very rare (on UK canals) engine.

 

In the UK there are specialists who rebuild/refurbish turbos, I expect you have the same in the USA, as at a few car or better still truck repair shops for contact details.

 

I can not see how a blown turbo can cause an engine to shut down, make loads of blue smoke (burning oil), yes. Make loads of black smoke, yes, buy not spinning and overfueling. Lack or power, yes but not shutting down.

 

I also note that you have not clarified the type of cooling system you have or the coolant temperature when it shuts down so we can not rule overheating out. Having said that from such information as you have provided it still sounds like fuel starvation to me but until you take steps to diagnose that AND post the results here I can not give further advice.

 

I suppose the fuel tap(s) on the tank are fully turned on.

A seal has gone in our turbo on our VP KAD32 at the moment. It went as we were crossing the Wash on our way back from the Fens in July with no warning. The first we knew we had a problem was about a third of the way out of the Lynn channel when the boat suddenly went from cruising happily at 3600rpm with a speed of 30 knots to labouring and dropping revs at an alarming rate, eventually managing to sustain 5 knots max speed at 1200rpm. It made for a long run back to Boston and waiting out in the Wash for the next tide. There was no smoke at all.

 

On getting back into Boston we set about investigating the problem. Obviously fuel filters were our first port of call these were spotless as we expected. It was only when we opened the air box and found oil in the box that we realised we had a turbo issue.

 

Plans are to take it off and get it refurbished this winter whilst the boat is out of the water. For now NC has had her wings clipped and is limited to "slow speed" cruising which isn't such a big problem as we don't have any big trips planned now. Our last two breaks for this year are both inland cruises.

[Kieron G]

Hi N/C . I wouldn't run the engine any more until you get the turbo sorted if i were you. Also make sure all oil is removed from intercooler and pipes before restarting.

[Naughty Cal]

Hi N/C . I wouldn't run the engine any more until you get the turbo sorted if i were you. Also make sure all oil is removed from intercooler and pipes before restarting.

It is being used until November when it is to be lifted for the winter.

 

The oil in the box is minimal and easy enough to remove at regular periods. The oil loss is so minute it has not even registered on the dip stick yet but we are keeping an eye on it. The engine is keeping the correct oil pressure and temperature and running as sweet as ever at river speeds, so we are not unduly concerned for now.

 

When the turbo is removed for refurbing the rest of the system is to be cleaned out and flushed through to remove any oil residue.

[Kieron G]

The reason i wouldn't run the engine myself is that oil leaked into the intake side of the engine from a leaking turbo can cause a run-away especially if it is allowed accumulate in the pipes etc. This happened at power station when a Volvo loading shovel had turbo replaced with out intercooler and pipes being drained / cleaned out & when engine was started it ran away on the oil it was sucking in.

[Bill B]

Hello, I guess I was unclear on the blue smoke, it does "not" bellow blue smoke and runs smooth and quiet at idle. It does burn a little blue smoke and always has... I called a turbo re-builder/re-fitting company, speaking with the re-builder tech/engineer, and he stated a bad bearing if it leads to a warpage or spun cartridge will make quite the racket and can definitely be confusing being its' proximity on the engine. I agree, the shutting down is puzzling to me as well, intuitively, and may very well be an issue? My thoughts are if it were an engine bearing you would hear it at idle as well at a minimal of throttle (which to be clear is when it makes noise and shuts down). Immediately after it shuts down I can restart the engine and it runs at idle perfectly. It very well may be a fuel distribution issue, don' know. As for the heat, when the issue happened I worked all around the engine and it did not seem unusually hot. It was hot to the touch as one would expect, but the exhaust hose and head were touchable, not that you could rest your hand on the head, but touchable. I checked the oil thru the dip stick, oil was good and that area as well was not hotter than one would expect. The cold water intake filter was full and the engine burped water thru the exhaust as it always has, clear passageways.

 

I put it in neutral and the shaft rotated smoothly and effortlessly. It has new cutlass bearings in both housings and the Maxi Prop was cleaned, lubed, inspected and re-refit. Same engine diagnosis results in neutral as in gear. The engine also operated with the same issues cold as it did when it happened after 5 hrs use.

 

I am not trying to ignore anyone but to assess past data that is no longer available can only be answered as best I can, and I am trying, the best I can!!!

 

RE the turbo, totally agree, the oil passageways must be cleared as was also the recommendation from the re-builder.

[Naughty Cal]

The reason i wouldn't run the engine myself is that oil leaked into the intake side of the engine from a leaking turbo can cause a run-away especially if it is allowed accumulate in the pipes etc. This happened at power station when a Volvo loading shovel had turbo replaced with out intercooler and pipes being drained / cleaned out & when engine was started it ran away on the oil it was sucking in.

That's a risk we are willing to take.

[Tony Brooks]

Th engine uses a Bosch rotary injection pump and they can be self bleeding so depending upon how long you have to spin it on the starter for you may be sucking air into the system. If there is any form of restriction along the fuel pipes or in the filters you could get exactly your symptoms but with a rather long spin before it starts. You also have two "lift" pumps. The normal one and a transfer pump in the injector pump. That one could suck air in after the lift pump.

 

I stress the "with longer spinning before starting".

 

Your injector pump should have a large banjo bolt with "out" stamped on the top mounted right on top of the pump. When the engine stops try loosening this and spinning on the starter. Fuel should leak out immediately, if air bubbles are in the fuel or if there is a delay in fuel delivery then an air leak or fuel blockage is likely. An engine suffering from fuel starvation is likely to run roughly before it cuts out.

 

You also have an energise to STOP fuel stop solenoid so if something is energising it when running the engine would stop but you would not get knocking or rough running.

[J R ALSOP]

Just been speaking to my lad Nick at TWMarine who has sent Bukh spares out to Canada, their number is 01663 745757. www.twmarine.co.uk

[billS]

That's a risk we are willing to take.

 

Can you acess your air intake quickly?

[Naughty Cal]

 

Can you acess your air intake quickly?

Yes.

[billS]

Splendid.

 

Carry on

[Bill B]

Wow, excellent information. In concern of a melt down of the turbo I am removing and inspecting that first then going on. My main concern is of a broken apart turbo launching particulate into the intake. I will most definitely look into the fuel delivery system after clearing the turbo issues no matter what. According to the tech, the knocking could have been the turbo breaking apart, which may be damaged to the point that the area between the intake and exhaust is compromised. In any case, I am gone until 9/3 and it seems ruling the turbo out would be a great first order of business, then I will try my best to understand the fuel delivery system as you have pointed out. If this offers any info, it starts quickly upon hitting the ignition key and continues to do so.