Diesel Oil Quality

[Chris_Robb]

I have a Perkins 4236 engine, and have been using a modern turbo deisel oil (15-40) in it. I have just been told that I should use a lesser quality oil as modern oils have too much detergent and may harm the engine.

I had assumed that as oil technology advanced, it was better to use something better than the original recommended oil.

Any ideas????

 

[Guest]

Don't listen to them .
The oil used in diesel engines is supposed to act as a detergent as well as lubricant
The best oil you can afford should always be used and changed ,in my view every six month's .I change the oil filter yearly and oil every six month's or before a long run.
Turbo's suffer from oil starvation and over heating
One tip is to let the engine idle before switching off to let the oil cool down the turbo's bearings ,the same when first starting up allow the oil pressure to build up before high rev's
Has your turbo got an intercooler ,because this helps
One other thing diesel engines tend to be long stroke engines and when the weather is very cold the oil thickens thus slowing the turn engine when starting from cold .
My old Landover suffered badly from this ,but renew the oil and cranking speed was back to normal
Typical though the new Landover which has a Mazda 3.5 td has the same problem
and because I've been working on the tug the oil has not been changed and the damm thing let me down this week ,even putting one of the tugs fully charged batteries on hardly made any difference .
Mick

 

[david_bagshaw]

there is a school of thought that goes along the lines of

when the engine was designed the best quality was 20 -50 therefore the build clearances were higher, leading to smoke etc when used with modern oils.

I would be intrested to hear how many agree with that, personally we use the best now available.



David
www.yachtman.co.uk

 

[Guest]

Modern oils are designed for modern close tolerance high output diesels and are mainly synthetic. The oils can be too" slippery" and inhibit the ability of piston rings to bed in. This can result in bore glazing, which will increase oil consumption, reduce compression, cause smoke and in extreme cases oil can also be blown unburnt out of wet exhausts causing visible polution. I suspect that you should be using an oil that does not exceed API CC specification. Most modern turbo diesel oils are API CE or CF, indicating a higher synthetic content. Certainly all the naturally aspirated boat engines I have owned or worked with (Daf, Lister, BMC, Perkins etc.) have all been run on API CC with good long term results, and in some instances the inadvertent or ill advised use of the likes of API CE or CF has caused bore glazing problems. Check with Perkins but I suspect you should stick to API CC, but not for your turbo diesel car!

 

[VMALLOWS]

This is becoming intriguing (several other threads running). Where do you get CC grade oil? Even CD is disappearing from the 'ordinary' outlets... most is claiming to be CE. At least it seems to suport my theory that 'cheap oil changed often' is better than 'expensive that lasts.........."

 

[Guest]

Yes it is getting harder. You certainly won't get it from Halfords! I get mine from a motor trade cash & carry, but suspect that an agricultural engineer might also stock the stuff.

 

[SNAPS]

There seems to be some misunderstanding about what a turbo does, a turbo is exactly the same as the item they used to call a supercharger and it increases the air pressure going into the combustion chamber thus increasing the oxygen available to burn the fuel. we had a fleet of 60 new 8 tonne lorries with turbochargers. At first we had a few cases of overheating turbos, then I instigated instructions that all drivers must carry out "run-up" and "run-down" procedures. "Run-up" consisted of allowing the engine to idle for at least two minutes when starting up before revving the engine. This allowed the lubricating oil to reach the turbo before it was worked hard. Similarly, "run-down" consisted of allowing the engine to idle for at least two minutes before switching off, this had the effect of maintaining the flow of oil to the turbo until it had a chance to slow down. If the engine was switched off immediately without a period of idling, the flow of oil to the turbo is cut off as soon as the engine stops, but the turbo is still birling round at a great rate of knots without lubrication and this is what causes it to overheat. Whether the turbo is in a boat engine or a lorry engine, or whether it is diesel or petrol, the principle is the same, lubrication must be maintained in the turbo or it will overheat.
constant attention must be given to this matter if overheating is to be avoided.

JACKTAR

 

[brianhumber]

Oils have to :
keep metallic surfaces apart by boundary and fluid film lubrication
keep in suspension any products of combustion
prevent corrosion
To achieve this even good quality base oils have additives:
anti-oxidants, corrosion inhibitors, wear reducers, detergent dispersant, alkalininty, pour point depressants, VI improvers, anti-foam agents, anti-bacterial additives.
Not all oils will have all of the above.

It is only required to change your oil when its gets too dirty or becomes to contaminated. People play safe by changing every winter, but if your engine is in good condition run on low sulphur fuel this is too often. When you start to get into real engine sizes with oil conditioners/separators then the oil lasts as long as the vessel. When your sump is 5,000 galls its too expensive to change every 6 months!

 

[Guest]

Forgive me for just a small correction here ..... A Supercharger is driven by belt / chain or other direct drive from the engine. It runs moderately cool as a consequence and normally NOT part of the lub system.
A Turbo-charger is driven by the exhaust gases trying to get past a fan which in turn drives another fan to increase the inlet air pressure. A turbo is often linked to the lub system and also generally runs a lot hotter than a supercharger, due to the exhaust gases used to drive it.
If you have a Turbo Diesel engine, then I would suggest that this is generally a higher revving and more modern style engine than a lot of us other 'Jack-tars' use.
Personally in my old Perkins 4-99 ... I use the cheapest Diesel rated oil I can get, but then again its an old 1950's Bus style engine and tolerances are a lot greater than the new jobs ! I also own and run Oil Product testing facilities .... and cannot really find any reason to use anything better in it ! Now when I talk about my cars .... that's a different matter altogether............

 

[ccscott49]

You are quite correct in your run up and run down procedures, but a supercharger and a turbo charger are two very different beasts, a turbo charger is driven by exhaust gases, so does not slow down instantaneously when the engine is stopped. The supercharger is mechanically engine driven, it stops when the engine stops, it also runs at engine temperature, not at exhaust temperatures. Superchagred engines do not need the high temp lubricity of tubocharged engines. For the other matter, you shopuld use standard diesel engine oil for naturally aspirated engines, synthetic is an uneccessary expense, buy your oil from a fishing boat supply oulet or a oil dealer, not from halfords in little tins! Big drums, which we need for larger engines, are much, much cheaper per liter. If you have a little engine, still buy a 25 liter drum, you will use it in a couple of years, dont think it goes off, we stored the stuff for years in the army! I was using 20 year old oil, in tanks with V12 supercharged petrol engines, they ran fine! Without problems. If you are concerned about the oil, change it more often!

 

[coliholic]

I've got VP AQAD 30 turbo engines from '86 in my boat and I use Castrol Agripower oil. For those who understand all the numbers, its SAE15W-40, ACEAE2 &E3, API CG-4/SG. I've got no idea at all as to what these numbers refer. I use it cos its about £35 for 25litres, I can get it easliy at my local agricultural dealer and it's what the big tractors, combine harvesters etc use and I'm told they run for hours at a time at fairly fixed revs and power just like our boats. So to my mind an oil that will "look after" a very expensive engine in a tractor or combine, will do the job for me.

I change oil and filters twice a year. In the autumn so there's nice clean oil for the winter, and then early summer, so I guess the oil's not really being overused. Perhaps I'm over cautious but an oil change is costing about £20 in oil and a tenner in filters. Not overly expensive and takes about an hour to do both engines.

From other comments earlier, is the general opinion then that an oil can be too good? How can that be? It either provides the lubrication and cooling required or it doesn't.

 

[ccscott49]

You have got the right idea! Changing twicw a year, with normal use say 400 hours a year, perfect, the opil will never get out of spec. Synthetics will do the job, but are too expensive for our types of engines, I'm not talking about intermittent supercharged, turbocharged intercooled high performance jobbies here! But normal low boost pressure and normal aspirated engines. The tolerances for the old engines were such that the oil didn't need to be as good, it wasn't available! The old lotus car engines were built wiht very slack piston clearences, to reduce friction and boost power as they were run with low pressure, high volume oil pumps also to release more power, they burnt oil at a rate of a pint evrey 100 miles and were meant to! Use good diesel engine oil, leave the synthetics for those that need them, in most cases we dont!

 

[roger]

Betamarine specifically - if verbally - warn against using turbo diesel oils for the BD722 as they say it is likely to contribute to glazing bores of engines used a lot of the time on idle. They also point out that the Kubota base unit they use is designed for use on small excavators on building sites where they will be idling most of the day.

 

[adarcy]

Re: Warm-up NO

Dear SNAPS and my "old friend" ccscott49

Out comes one of my favourite hobby horses. I am afraid the I think you are completely wrong to talk about warming up a diesel (especially modern turbo) by idling for 2 minutes. Glazing here we come!

I agree 100% with the parts of the thread about coooling down a turbo before switching off. Usually in a boat, by the time you have chugged up the river or manoevered in in idle and secured the ropes, the turbo will have cooled down. Car engines had a lot of trouble, especially the early Audi turbos in Germany, hammer along the autobahn, pull into a service area and switch off. The heat soak from the turbo carbonised the oil in the turbo bearings. Audi gradually changed to having a separate air fan AND a separate water pump that ran electrically after switch off to keep some circulation to cool the turbo. It's funny but , even now, Mercedes don't find it necessary.

Anyway back to the point, when you start a turbo the oil gets to the turbo almost immediately ( as it doesn't syphon back) just as to the main bearings. Your turbo is being lubricated just as well as the main bearings and does not need to be warmed up with minimal load by idling. I accept one shouldn't "hammer" a cold engine but idling when cold causes glazing and I think your advice is completely for engines new or old.

BTW interesting bits in the thread about ships with oil conditioners, I always thought that oil aged by oxidation which breaks down the long chain molcules reducing detergency and lubricity and film retention at high temperatures (the 40 or 50 part of 15W/40). I understood this to be a time open to the air and 12 months was the accepted limit.

Anthony