Bukh DV20 oil change. SAE30 ? plus how to drain the sludge

Back on topic, if an engine sludges out there are 2 main reasons why. Firstly the oil has been used for far too long and secondly, the oil selected did not contain enough detergent additives to keep the sludge in suspension until the oil is changed. bukh engines are very tough heavy blocks, BUT they do need a resonable oil flow and sludge will eventually block the intake screen which can result in a total fork up as the oil fails to flow around the engine. One symptom is the engine oil pressure out of lower limits or the warning light on just after a good run at a high power setting. The hot thin oil starts to get stuck trying to get through the oil pump intake screen.

Best solution is to remove the sump and clean the intake screen, but if that's not possible just change the oil twice and shift to using a major brand, (Definitely not Russian), high detergent oil, run the engine for a few hours and change both the oil and filter again. Never play around with oil flush additives, although if you must then Castrol and Liqui Moly make a pre oil change flush that is used at idle just before the oil and filter change. DO NOT GET ANY OF THAT ADDITIVE IN THE GEARBOX!
 
UMM just looked up complaints about LUKOIL and too many to list.

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the first thing they cut out in oil to save money is the additives, detergents and Zinc based anti wear/corrosion compounds that account for about 40% of a good oils contents.
 
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TNLI said:
UMM just looked up complaints about LUKOIL and too many to list.

[Unwelcome Content deleted]

the first thing they cut out in oil to save money is the additives, detergents and Zinc based anti wear/corrosion compounds that account for about 40% of a good oils contents.
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Did you read post #4?

A 1986 Bukh DV20, 1600 hours, stripped as clean as a whistle. I pulled the pistons and rods, freed the corroded in rings - a VERY tricky job - cleaned the ring grooves, refitted the rings and re-used the big end shells. They were as new and were within spec using plastigauge. No sludge whatsoever, the pump intake screen was not blocked. I dont believe the motor had been in bits before.

It is important to understand oil and an engines requirements. I was a regular visitor behind the Iron Curtain 1970 to 1989. Their vehicles suffered the same problems as non Communist vehicles. The lubricants I purchased with my prize money from motorbike racing - cash was not convertable so oils, tyres and tools were purchased to be sold later - gave the same level of service as those I purchased in the UK. Some screenwash fluid I bought in bulk was FAR superior. It had so much alcohol I think you could have got pissed on the fumes.

Detergent oils prevent the sludge build up of earlier oil types by holding the particles in suspension to be collected in the oil filter. Many older engines had no oil filters. Some motorcycle engines used built up crankshafts and used the central cavity as a centrifugal filter.

My mate Bob has a modern car that has its first oil change at 20,000 miles or two years, whatever comes first.

It has technology and lubrication requirements poles apart from the OP's enquiry about the almost antique Bukh marine engine.

Horses for courses.................................................. :cool:
 
TNLI said:
IF IN DOUBT, READ THE INSTRUCTIONS FOR THE EXACT TYPE OF ENGINE AND GEARBOX, Some manual gearboxes like the old BMC use the same oil for their gearboxes, but some like the more modern Yanmars do not.
Also do yourself a big favour if you want a block to last and use the best oil and filters available. In my opinion that means if the dealers Bukh oil is too expensive then look up the required API ratings for engine and box, then select an oil made by a real good major brand oil company like Castrol, Mobil, Shell or Liqui Moly. API do not checks oils sold in the UK or EU, so if you use a cheap junk oil like LUKOIL it can be out of specification. It's also a good idea to look at the required viscosity vs start temperature graphs for a Bukh, as the vary from an 0W30 in the artic to a 20W50 in the summer etc. Apart from the quality of oil and filters, try to avoid cold starts by heating the engine bay or using heat pads on the sump.
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Nothing about price. For last 25 years my dv20 didn't have any single problem. I use only original parts as well..

What i found in bukh manual, it says,
Engine oil 15w-40 API CC/CD or CF-4, sae30 / 20 ili SAE 15W-40, 2,75l oil capacity.

Sail drive API CC/CD, MILL-L- 4615 or BW7 gear. SAE30 ili SAE 15W-40, 3,3l oil capacity.

We used Shell helix hx3 for decades but its difficult to find recently.

And i haven't even get the answer on my question but Lukoil has API exactly what BUKH requires....
 
dolac said:
Nothing about price. For last 25 years my dv20 didn't have any single problem. I use only original parts as well..

What i found in bukh manual, it says,
Engine oil 15w-40 API CC/CD or CF-4, sae30 / 20 ili SAE 15W-40, 2,75l oil capacity.

Sail drive API CC/CD, MILL-L- 4615 or BW7 gear. SAE30 ili SAE 15W-40, 3,3l oil capacity.

We used Shell helix hx3 for decades but its difficult to find recently.

And i haven't even get the answer on my question but Lukoil has API exactly what BUKH requires....
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The Lukoil website suggests that their product is just as good as those of European competitors. It is ridiculous to suggest that they deliberately downgrade their lubricants - they would not last in business for long if they did
LUKOIL LUBRICANTS EUROPE
 
vyv_cox said:
The Lukoil website suggests that their product is just as good as those of European competitors. It is ridiculous to suggest that they deliberately downgrade their lubricants - they would not last in business for long if they did
LUKOIL LUBRICANTS EUROPE
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Exactly ...

What would I know ? I only looked after Base Oil and full blend Lubricating Oil shipments to UK / Europe / USA / Caribbean... in addition to the Gasoline and Diesel blending.

In fact one of the Clients had the London Transport Contract - my company looked after the supply for that ...

You would be surprised at the receivers for Lukoil and others products .... Carrefor ..... London Transport .... as well as distribution into well known brand names forecourts ... and supermarkets .....

Until recently russian origin products made up a large % of the fuels and lubs you guys in UK used.

I can also mention USA ..... but we'll leave that one for now.
 
Rhylsailer99 said:
Don't forget before you drain the oil to get the engine nice and warm otherwise it takes ages to suck it out.
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Yup - and make sure if the engine doesn't have a sump drain you have a sucker outer!
When I drained the oil in the first boat I had with a (Betamarine) diesel, shortly after liftout, I discovered it didn't have a sump drain. The manual said it did but in the words of Manuel "look you great halfwit - he no here!":ROFLMAO:
I returned with a Pila extracter but of course the engine/oil was cold...🥶
 
vyv_cox said:
The Lukoil website suggests that their product is just as good as those of European competitors. It is ridiculous to suggest that they deliberately downgrade their lubricants - they would not last in business for long if they did
LUKOIL LUBRICANTS EUROPE
Click to expand...
The only thing is, can I use same oil for saildrive as well? Cuz what i have found on BUKH book manual, this oil has all the standards BUKH's saildrive requires.. i don't know what oil would someone recommend?
 
dolac said:
The only thing is, can I use same oil for saildrive as well? Cuz what i have found on BUKH book manual, this oil has all the standards BUKH's saildrive requires.. i don't know what oil would someone recommend?
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The workshop manual says the sail drive oil is the same specification as the BW7 gearbox. The spec for the gearbox is API CC or CD, either SAE 20 or 30. No higher viscosities than this. I would assume that a 15w-40 multi grade would be acceptable
 
Refueler said:
If the API / Specs are as required - then whats problem ?
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This particular oil I posted, it says it is for engine.. so, beside same specification, didn't know can i use it for saildrive or should be special oil with the "gear oil" label on the package....
 
vyv_cox said:
The workshop manual says the sail drive oil is the same specification as the BW7 gearbox. The spec for the gearbox is API CC or CD, either SAE 20 or 30. No higher viscosities than this. I would assume that a 15w-40 multi grade would be acceptable
Click to expand...
yes exactly.. this is monograde as BUKH recommends monograde.. I believe multigrade oil would not make any damage either....
 
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