Toyota D4d - common fault and how to fix.

[gensetsteve]

Here's a good read for you!

 

Motor Oils - Fuel Economy vs. Wear

 

Interesting read. I have been aware for many years that lightly loaded engines and really good quality clean oil can mean shiney glazed bores lots of breathing and not many hp when it's needed. I don't like changing generator oil every year unless we find fuel dilution.

 

I would think for a Perkins Diesel engine a good quality 15/40 turbo Diesel engine lube would be ok

[Wood wasp]

Yes interesting read and thanks for tips on correct oil. Engine works hard so slightly thicker sounds good.

[TimberCutterDartmoor]

Interesting read. I have been aware for many years that lightly loaded engines and really good quality clean oil can mean shiney glazed bores lots of breathing and not many hp when it's needed. I don't like changing generator oil every year unless we find fuel dilution.

 

I would think for a Perkins Diesel engine a good quality 15/40 turbo Diesel engine lube would be ok

 

Good point about bore glazing; ice cream vans idling all day every day were the classic victim.

 

How do you measure fuel dilution? UOA or a really sophisticated method like watching the spread of droplet on tissue (as I do for the forwarder!)?

[Wood wasp]

If engine gets good sustained workout can the glazing effect be burnt off?

[TimberCutterDartmoor]

Yes interesting read and thanks for tips on correct oil. Engine works hard so slightly thicker sounds good.

 

Another consideration is power density (aka bmep); the higher the hp per cc the higher the internal loads on finite bearing surfaces etc and the thicker oil will afford greater wear protection, especiallly in an engine running non stop all day vs a car doing the school run.

[TimberCutterDartmoor]

If engine gets good sustained workout can the glazing effect be burnt off?

 

Extremely good question; this (RL again lol) product lol

 

Red Line Synthetic Oil - Motor Oil for Racing - Engine Oil Break-In Additive

 

was used in a-series racing when I were a lad; proven better run-in in respect of rings etc.

 

AFAIK glazing cannot be worn-in and you will never re-hone the bore and the latter is best for oil control in conj with the o/c ring.

 

RL say on there product data not to use their oils for break-in - "allow X miles"

 

From wiki:

 

Diesel engines can suffer damage as a result of misapplication or misuse - namely internal glazing (occasionally referred to as bore glazing or piling) and carbon buildup. Ideally, diesel engines should be run at least 60-75% of their maximum rated load. Short periods of low load running are permissible providing the set is brought up to full load, or close to full load on a regular basis.

 

Internal glazing and carbon buildup is due to prolonged periods of running at low speeds or low loads. Such conditions may occur when an engine is left idling as a 'standby' generating unit, ready to run up when needed, (misuse); if the engine powering the set is over-powered (misapplication) for the load applied to it, causing the diesel unit to be under-loaded, or as is very often the case, when sets are started and run off load as a test (misuse).

 

Running an engine under low loads causes low cylinder pressures and consequent poor piston ring sealing since this relies on the gas pressure to force them against the oil film on the bores to form the seal. Low cylinder pressures causes poor combustion and resultant low combustion pressures and temperatures.

 

This poor combustion leads to soot formation and unburnt fuel residues which clogs and gums piston rings, which causes a further drop in sealing efficiency and exacerbates the initial low pressure. Glazing occurs when hot combustion gases blow past the now poorly-sealing piston rings, causing the lubricating oil on the cylinder walls to 'flash burn', creating an enamel-like glaze which smooths the bore and removes the effect of the intricate pattern of honing marks machined into the bore surface which are there to hold oil and return it to the crankcase via the scraper ring.

 

Hard carbon also forms from poor combustion and this is highly abrasive and scrapes the honing marks on the bores leading to bore polishing, which then leads to increased oil consumption (blue smoking) and yet further loss of pressure, since the oil film trapped in the honing marks is intended to maintain the piston seal and pressures.

 

Unburnt fuel then leaks past the piston rings and contaminates the lubricating oil. Poor combustion causes the injectors to become clogged with soot, causing further deterioration in combustion and black smoking.

 

The problem is increased further with the formation of acids in the engine oil caused by condensed water and combustion by-products which would normally boil off at higher temperatures. This acidic build-up in the lubricating oil causes slow but ultimately damaging wear to bearing surfaces.

 

This cycle of degradation means that the engine soon becomes irreversibly damaged and may not start at all and will no longer be able to reach full power when required.

 

Under-loaded running inevitably causes not only white smoke from unburnt fuel but over time will be joined by blue smoke of burnt lubricating oil leaking past the damaged piston rings, and black smoke caused by damaged injectors. This pollution is unacceptable to the authorities and neighbors.

 

Once glazing or carbon build up has occurred, it can only be cured by stripping down the engine and re-boring the cylinder bores, machining new honing marks and stripping, cleaning and de-coking combustion chambers, fuel injector nozzles and valves. If detected in the early stages, running an engine at maximum load to raise the internal pressures and temperatures allows the piston rings to scrape glaze off the bores and allows carbon buildup to be burnt off. However, if glazing has progressed to the stage where the piston rings have seized into their grooves, this will not have any effect.

[gensetsteve]

Good point about bore glazing; ice cream vans idling all day every day were the classic victim.

 

How do you measure fuel dilution? UOA or a really sophisticated method like watching the spread of droplet on tissue (as I do for the forwarder!)?

 

do tell more about the spread of droplet on tissue never tried that is a timed thing depending on brand of tissue. I would imagine you can tell from experience how fast it spreads out ?

I can normally tell if we could have a problem the way it falls of the stick, the smell, and if the engine has only done an hour since last year but the oil is half inch higher on the stick. The main offenders are sets with Hugh bulk tanks on stands because the pressure by passes the seals in the lift pump and fuel system. If I suspect a problem sample goes of to findings and I think they use uoa

[TimberCutterDartmoor]

do tell more about the spread of droplet on tissue never tried that is a timed thing depending on brand of tissue. I would imagine you can tell from experience how fast it spreads out ?

I can normally tell if we could have a problem the way it falls of the stick, the smell, and if the engine has only done an hour since last year but the oil is half inch higher on the stick. The main offenders are sets with Hugh bulk tanks on stands because the pressure by passes the seals in the lift pump and fuel system. If I suspect a problem sample goes of to findings and I think they use uoa

 

Yes the old trick is to rest the end of the dipstick on blue roll (the big blue rolls you get from industrial supplies) and watch the speed at which the drop extends out on the tissue. Slow movement shows little or no dilution and fast spread shows fuel dilution, in some cases the centre will be black oil and the fuel will go out further less coloured. Your techniques are much the same; the smell is as you say a good initial test too.

[tommer9]

YOu still buying jap crap and suffering with it jon?

[gensetsteve]

YOu still buying jap crap and suffering with it jon?

 

Yes get a d4 Jon mate can't beat it