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

[joyfull]

I need an oil change on old DV20. I looked on Ebay and the SAE30 is listed as lawnmower oil. Would that be ok and how many litres for engine and gearbox.

I bought a pela 6000 to extract the oil and I read somewhere that if used down the filler cap it will not get to the bottom sludge. Is there some way of getting a good clean out as the engine is in a Centaur and so the drain plug is probably inaccessible.

The Bukh supplied brass oil extractor pump has sadly seized and broken off! Not sure where it was fixed to the engine and whether I can use that pipe as access point for the Pela.

This is the Ebay oil
OUR SAE 30 HORTICULTURAL OIL IS A PREMIUM QUALITY MONOGRADE LUBRICANT. IT IS DESIGNED TO MEET THE REQUIREMENTS OF A WIDE RANGE OF 4-STROKE ENGINES FITTED TO LAWNMOWERS, RIDE-ON MOWERS, TILLERS, CULTIVATORS, WACKER PLATES, PRESSURE WASHERS, GENERATORS, WATER PUMPS, BRUSH CUTTERS AND SOME STATIONARY ENGINES.

PERFORMANCE LEVELS: API CD/SD, CCMC D1,

MIL-L-2104B, MIL-L-46152B

 

[RichardS]

Just buy Comma / Morris / Westway SA30 car engine oil on eBay.

You won't get out the sludge, if there is any, so just get as low into the sump as you can. The dipstick tube or this other one you refer to will probably be the best.

Richard

 

[Poignard]

I use Castrol Classic XL30 monograde SAE30 in my BUKH DV10.

I can drain the sump by removing the drain plug but usually I use an extractor pump similar to a Pela but a different make. Its suction tube can reach to the bottom of the sump via the dipstick tube, as you can see on this drawing .

 

[rotrax]

I pulled our Bukh DV20 in bits four years ago after a seawater ingress problem.

The installation in our Steel Hartley 32 allows the sump to be drained and indeed removed with the engine in situ. When the sump was removed, and after close inspection before cleaning, sludge was NOT a problem on this 1600 hour engine. Very clean internaly.

Not sure why you would be using a Pela type pump down the oil filler cap.

I always use the dipstick hole - ensuring the engine is at normal temperature. I cut the tip of the tube at a shallow angle and can feel when it touches the bottom of the sump. Without the shallow cut I found it was possible to completely block the pipe with the sump base, so no oil out!

Looking at the above drawing it appears that the pipe down the dipstick hole is a goer.

Good Luck.

 

[LittleSister]

You don't have to use SAE 30 oil in the Bukh. 15w-40 (for diesels) is generally considered suitable, and has been used for years without problems by some - see this thread Bukh Engine & Gearbox Oil. (There are several other previous threads on this very issue.)

Definitely avoid synthetics, and go for the 'older diesel engines' grade of API 'CF-4'. See Vyv Cox's excellent website for more info on oils (and much more) Oil for yacht engines

The standard gearbox for DV20s uses the same oil as the engine, but do check your manual/installation, as some other gearboxes need ATF instead.

 

[neilf39]

I used halfords 15/40 straight mineral oil in my Bukh. Switched to Tesco 15/40 straight mineral oil when halfords stopped stocking it. Used pela pump down the dipstick hole. Oil quantities are in the maintenance guide. If you google it you will find it. Covers bukh 10 and 20.

 

[langstonelayabout]

The very stickiest sludge stuck to the bottom of the sump will stay there unless you remove the sump and have it cleaned.

Assuming you are afloat, the best way to do a 'normal' oil change is to prep the materials and tools then go for a 2 hour motor at reasonably high speed to get the motor and oil up to the correct operating temperature.

The moment you arrive back at your mooring do the oil removal immediately. It will be hot, thin and carry most of the suspended 'grot' that you are looking to get rid of. The sooner you get the old oil out (via a Pela or through the sump plug) the better. You can then change the filter and refill the motor with the correct grade of oil.

If you aren't yet afloat, I'd leave it until after launch. Warming the engine makes the world of difference to the oil.

Oil changes aren't rocket science, but are made easier by having the oil nicely warmed to operating temperature.

 

[lw395]

I used halfords 15/40 straight mineral oil in my Bukh. Switched to Tesco 15/40 straight mineral oil when halfords stopped stocking it. Used pela pump down the dipstick hole. Oil quantities are in the maintenance guide. If you google it you will find it. Covers bukh 10 and 20.

what do you mean 'straight'? Very poor term to use.
It can mean 'monograde' but you're suggesting a multigrade.
It can mean 'non detergent'.
It can mean not having other additives.

 

[lw395]

I need an oil change on old DV20. I looked on Ebay and the SAE30 is listed as lawnmower oil. Would that be ok and how many litres for engine and gearbox.

I bought a pela 6000 to extract the oil and I read somewhere that if used down the filler cap it will not get to the bottom sludge. Is there some way of getting a good clean out as the engine is in a Centaur and so the drain plug is probably inaccessible.

The Bukh supplied brass oil extractor pump has sadly seized and broken off! Not sure where it was fixed to the engine and whether I can use that pipe as access point for the Pela.

This is the Ebay oil
OUR SAE 30 HORTICULTURAL OIL IS A PREMIUM QUALITY MONOGRADE LUBRICANT. IT IS DESIGNED TO MEET THE REQUIREMENTS OF A WIDE RANGE OF 4-STROKE ENGINES FITTED TO LAWNMOWERS, RIDE-ON MOWERS, TILLERS, CULTIVATORS, WACKER PLATES, PRESSURE WASHERS, GENERATORS, WATER PUMPS, BRUSH CUTTERS AND SOME STATIONARY ENGINES.

PERFORMANCE LEVELS: API CD/SD, CCMC D1,

MIL-L-2104B, MIL-L-46152B

'Lawn mower oil' is usually a monograde oil, with no detergent in it. This is intended for small and ancient engines with no full-flow oil filter.
If an engine has been run on this for a long time, the dirt will be in the form of sludge. Adding a detergent oil (i.e. nearly any 'car oil' these days), will result in all this sludge suddenly getting mobile around the engine, which may be disastrous.
If you change to a detergent oil, you need to at least flush out with more than one oil change, maybe a specialist flushing oil, better to at least have the sump off and clean it. Some old engines, e.g. British bikes like BSA, have a sludge trap in the crank which must be cleaned out.

The oil blenders/merchants who deal with the classic motorcycle trade will have good products and advice on their websites.

If the sump will come off with the motor in the boat, I'd do that.
On some boats, it's worth adding a little secondary drain plug at the back low corner of the sump.
I drilled and tapped one of mine for an M6 bolt, to drain the last cupful into one of those trays that takeaways come in.

Does this engine have full flow filter?
Hope that's helpful?

 

[Poignard]

This is an email enquiry I sent to Castrol a few years ago:

“I have a BUKH 10hp single cylinder diesel engine fitted to my sailing yacht.

This engine was built in 1982. It is quite slow running and, being directly cooled by sea water, it runs fairly cool. Even though the engine is used as an auxiliary engine in a sailing yacht, I try to make a point of running it long enough for it to warm up. The boat is laid up ashore in the winter months.

The engine is in good condition but I am uncertain what lubricating oil I should be using nowadays. Should I stick to the monograde oil specified for it at the time it was built, or is it better to use a modern multigrade oil?”

​

This was the reply:

"I would suggest ideally a fairly basic 15W-30 would be ideal – Castrol Agri MP 15W-30, or you could use a straight SAE 30 - Classic XL30 ( Castrol Classic Oils – 01954 231668 should be able to supply )

Kind regards

Andy Griffin

Advanced Technical - Automotive and Industrial Lubricants"

 

[neilf39]

Very sorry to upset your sensibilties, not an expert. Doesn't 15/40W automatically mean multigrade then? By saying straight I meant no additives. I shall obviously have to take a course before replying to posts in case I might not say exactly the right thing.

what do you mean 'straight'? Very poor term to use.
It can mean 'monograde' but you're suggesting a multigrade.
It can mean 'non detergent'.
It can mean not having other additives.

 

[Poignard]

Very sorry to upset your sensibilties, not an expert. Doesn't 15/40W automatically mean multigrade then? By saying straight I meant no additives. I shall obviously have to take a course before replying to posts in case I might not say exactly the right thing.

Even when you do say the right thing, somebody will say it's wrong!

 

[Bilgediver]

The lawn mower oil may not be unsuitable unless it specifically refers to diesel engines on the can.

These elderly diesel engines work best on mineral oils and whereas a few years ago you could purchase such as this in supermarkets either marked as for petrol or diesel this is no longer the case. You will now find Mineral oil in most supermarkets and Halfords marked suitable for for Diesel and Petrol . This is the better choice for most older boat engines. Products are also availableble from companies such as Morris who have been blending oils with additives for elderly cars since the days these cars were youngsters.

Remember that the reason we buy oils from Castrol..Mobil....Morris etc is that they are genrrally not straight unblended oils. These companies make a living blending a straight oil that they buy in with various additives to make them suitable for particular services. Some years ago you wouldn't think of putting oil for a petrol engine in a diesel. It is progress that they now blend oils suitable for both. Synthetic oils are another matter and I would prefer not to use them in our low rated engines .

 

[lw395]

Very sorry to upset your sensibilties, not an expert. Doesn't 15/40W automatically mean multigrade then? By saying straight I meant no additives. I shall obviously have to take a course before replying to posts in case I might not say exactly the right thing.

I was thinking you meant mineral not synthetic.
Don't all multigrades have 'additives' of some sort?

 

[PaulRainbow]

I need an oil change on old DV20. I looked on Ebay and the SAE30 is listed as lawnmower oil. Would that be ok and how many litres for engine and gearbox.

I bought a pela 6000 to extract the oil and I read somewhere that if used down the filler cap it will not get to the bottom sludge. Is there some way of getting a good clean out as the engine is in a Centaur and so the drain plug is probably inaccessible.

The Bukh supplied brass oil extractor pump has sadly seized and broken off! Not sure where it was fixed to the engine and whether I can use that pipe as access point for the Pela.

This is the Ebay oil
OUR SAE 30 HORTICULTURAL OIL IS A PREMIUM QUALITY MONOGRADE LUBRICANT. IT IS DESIGNED TO MEET THE REQUIREMENTS OF A WIDE RANGE OF 4-STROKE ENGINES FITTED TO LAWNMOWERS, RIDE-ON MOWERS, TILLERS, CULTIVATORS, WACKER PLATES, PRESSURE WASHERS, GENERATORS, WATER PUMPS, BRUSH CUTTERS AND SOME STATIONARY ENGINES.

PERFORMANCE LEVELS: API CD/SD, CCMC D1,

MIL-L-2104B, MIL-L-46152B

Just suck out as much as you can via the dipstick tube, not the filler cap. Then refill with 15/40 mineral oil, available from the likes of Euro Car Part, Halfords etc.

 

[peter gibbs]

I need an oil change on old DV20. I looked on Ebay and the SAE30 is listed as lawnmower oil. Would that be ok and how many litres for engine and gearbox.

I bought a pela 6000 to extract the oil and I read somewhere that if used down the filler cap it will not get to the bottom sludge. Is there some way of getting a good clean out as the engine is in a Centaur and so the drain plug is probably inaccessible.

The Bukh supplied brass oil extractor pump has sadly seized and broken off! Not sure where it was fixed to the engine and whether I can use that pipe as access point for the Pela.

This is the Ebay oil
OUR SAE 30 HORTICULTURAL OIL IS A PREMIUM QUALITY MONOGRADE LUBRICANT. IT IS DESIGNED TO MEET THE REQUIREMENTS OF A WIDE RANGE OF 4-STROKE ENGINES FITTED TO LAWNMOWERS, RIDE-ON MOWERS, TILLERS, CULTIVATORS, WACKER PLATES, PRESSURE WASHERS, GENERATORS, WATER PUMPS, BRUSH CUTTERS AND SOME STATIONARY ENGINES.

PERFORMANCE LEVELS: API CD/SD, CCMC D1,

MIL-L-2104B, MIL-L-46152B

I use Castrol 15-40W. Very goo value.
As for cleaning out the sump - I tip some oil into the engine let it slip down and syphon it out - if it comes out clean, job's done.

PWG

 

[joyfull]

Finally started on the oil change today with SAE30 mineral oil.

The DV20 is new (to me) though the 44 year old boat looks like it has not been serviced for years and the Bukh is original figment. It runs (with white smoke after 10 minutes) ok. So I only want to approach gently as all the bolts are tight/rusty/seized.

Also all the wiring is a mystery, old, corroded, and some ends just hanging and going nowhere.

So far I have replaced the alternator, but have no voltmeter as it had rusted and I have no idea which wires to use.

Dv20 is a tight fit it my Centaur. Access almost impossible to oil and fuel filters on the sides. I have a pela pump for the dipstick. I can also feel under the engine to the back of the sump and think I can feel a sump plug on the vertical back plate (if you see what I mean- no plug on the underside.

I am going to use the pela vacuum pump but wondered how safe it might be to try and disturb the sump plug. (Because resecuring might be stressful if it is tight, washers, damaged head/thread etc.).

Also question about the engine anode. Should I change? I read somewhere that they can end up inside the water jacket if you make a mess getting them out.

The gearbox dipstick with the sort of Allen key head is very rusty and reluctant to move so far by hand with a couple of wd40 doses.

Is it screw fix or straight pull up and down. I don't want to force it. Any thoughts?

 

[peter gibbs]

Finally started on the oil change today with SAE30 mineral oil.

The DV20 is new (to me) though the 44 year old boat looks like it has not been serviced for years and the Bukh is original figment. It runs (with white smoke after 10 minutes) ok. So I only want to approach gently as all the bolts are tight/rusty/seized.

Also all the wiring is a mystery, old, corroded, and some ends just hanging and going nowhere.

So far I have replaced the alternator, but have no voltmeter as it had rusted and I have no idea which wires to use.

Dv20 is a tight fit it my Centaur. Access almost impossible to oil and fuel filters on the sides. I have a pela pump for the dipstick. I can also feel under the engine to the back of the sump and think I can feel a sump plug on the vertical back plate (if you see what I mean- no plug on the underside.

I am going to use the pela vacuum pump but wondered how safe it might be to try and disturb the sump plug. (Because resecuring might be stressful if it is tight, washers, damaged head/thread etc.).

Also question about the engine anode. Should I change? I read somewhere that they can end up inside the water jacket if you make a mess getting them out.

The gearbox dipstick with the sort of Allen key head is very rusty and reluctant to move so far by hand with a couple of wd40 doses.

Is it screw fix or straight pull up and down. I don't want to force it. Any thoughts?

Love Bukhs. totally reliable and so DIY accessible. Run for ever.
Keep off the sump oil plug if access is difficult. Use the Pela.
Engine anode melts away fast - bet there's nothing much on yours. Replace for sure.
Difficult to start? Squirt a little oil in the air intake
Do check value clearances - easy to remove top cover.
Gear oil - trying to recall if it's one system all through, if so no need to pry gear box open. Check it out.

PWG

 

[LittleSister]

Also question about the engine anode. Shthe ould I change? I read somewhere that they can end up inside the water jacket if you make a mess getting them out.

The gearbox dipstick with the sort of Allen key head is very rusty and reluctant to move so far by hand with a couple of wd40 doses.

Is it screw fix or straight pull up and down. I don't want to force it. Any thoughts?

Yes, do change the anode if you can. Don't worry about any bits falling inside. I've read of others having this happen without ill effect.

I can't quite remember the details of the gearbox dipstick, but I can check tomorrow and will let you know.

Do check value clearances - easy to remove top cover.

Gear oil - trying to recall if it's one system all through, if so no need to pry gear box open. Check it out.

If you do remove the rocker cover, before you do note the size of the gap between the bottom of the cover and the top of the engine block. If you tighten the cover down too hard when replacing it you can compress the gasket too much, with the result that the cover touches the decompressor and holds it slightly open. This caused someone I was in contact with no end of grief and confusion until he finally deduced the problem.

The gearbox oil is definitely separate from that of the engine.

 

[joyfull]

Found major oil leaking around the oil filter. Seal does not seem to be working. The metal all feels rusty around where the gasket fits. Is there a solution by sanding around to smooth?