Hi Paul, > David, > Thanks for the info, and for being so frank. You don't seem to have much > faith in my old Toyota. ** I dont think I would say that. In my opinion Toyota are probably the best of the large Japanese manufacturers. Their diesels particularly are some of the best of the small diesels. A lot of their 2.4 and 2.8 litre diesel swb and lwb vans being used by couriers and others here clocking up high mileages have easily exceeded 1,000,000 km giving few problems when regularly maintained. Most of the time when these sort of vehicles give problems is when they have not been maintained properly or serviced by staff that are incompetant. If you look back over a vehicles history that all of a sudden gives problems you will invariably find a period when the vehicle was not maintained properly or at all.
> The smoke it blows is black not blue and very little oil is used between > changes,not enough to justify adding oil. ** Regardless of what manufacturers or owners claim virtually all vehicles use some oil. It may vary from very little where there is virtually no wear to a reasonable amount where there is a reasonable amount of wear particularly where the vehicle is an older vehicle. Oil useage is invariably related to speed, the higher the speed the higher the consumption. You may be in luck and the vehicle may last some considerable time yet. Black smoke is almost always unburnt or incomplete combustion due to injector timing or over supply of diesel. If you are using very little oil then this tends to suggest that the rings are in better condition than you imagine. Excessive smoke is more likely to be an injector problem than anything else if you are not using oil. > It has always been a smokey engine despite attention to injectors etc. The > ammount of smoke varies with engine load. Keeping the revs between 2,500 > and 4,000 and using a small "throttle opening" minumises it. Adjusting the > smoke screw only reduces the already inadequate performance. ** Tends to suggest an injector problem and adjustment rather than something else. After 350,000 > km the rings are most probably worn as indicated by the vehicles tendency to > creep forwards when parked on a slope and restrained only by engine braking, > low-range first. ** Yes does tend to suggest ring wear. > The following may sound like an add but should be familiar. > The Hilux is the most reliable,economical ,practicle vehicle I have ever > owned. (Lets not mention lack of comfort or character). Running costs so far > (fuel, oil,grease,servicing,parts, repairs,tyres,registration,insurance etc) > 11.9c/km. Fuel consumption 10L/100km. Last set of front tyres lasted > 81,000km,rears still going. Brakes relined 259,000 and 440,000. > Exhaust system replaced 259,000 and currently in good condition. > Clutch,gearbox,transfere case, front & rear diffs all origional. Used > daily, often carries load, current odometer reading 540,000km. End of ad. > and no I wouldn't sell it for quids. > Lets consider the operation of 4 stroke diesel engines. > unlike their petrol equivalent, diesels have no variable restriction in the > inlet tract (butterfly in carb or air inlet for fuel injection). Oil burning > in the petrol 4 stroke is usually associated with worn rings/bore or > faulty/worn valve guides or valve stem seals. It is most obvious when the > air pressure inside the cylinder is substantially less than that in the > sump. Such conditions occur when the throttle is suddenly closed at high rpm > or after prolonged idling. The diesel takes a full gulp of air at each > intake stroke regardless of "throttle setting" so the difference in pressure > between cylinder and sump at induction is not so great especially with > positive crankcase ventilation. > The increased pressure and temperature of the diesel engine combustion would > probably burn the lubricating oil more effectively producing black smoke > from an enriched mixture. > Ring blowby also feeds oil fumes to the intake. The original engine in the > Hilux was treated to some spray start (ether) by an unsympathetic unknowing > moron ( me) when it refused to start one winter. (Glow plugs coated with > soot don't warm the preignition chambers too well). End result broken > rings. ** If you have replaced the rings it dosnt suprise me that the vehicle smokes. What were the rings you used in replacement? Where they genuine Toyota rings? Even these are extremely hard to get exactly right because of a certain amount of wear already in the engine. Replacement with anything other than genuine Toyota rings always seems to give trouble. You would probably find if you pulled the emgine down and measured everthing up that invariably there is more wear in one or two cylinders compared to the others. Also very true of end gap clearance. This is where fitting a by-pass filter can help as rather than letting wear continue because of certain factors being out of balance they can help in letting things slowly balance themselves with the engine eventually settling down properly. Somewhere here I have a report of an engine that was stripped down in Jan 1996, rebuilt, and then run a lot of the time almost continuously until Jun 1998, clocking up over 19,000 hours, whereupon it was stripped down and everything was measured against the known measurements and specs, with the suprising result that there was virtually no wear in anything, and the most wear being in the top ring (2 and 3 thou depending on cylinder), 1 or 2 thou on the second ring, and 1 or 2 thou on the bearings. 50,000 km later things started to get interesting. The engine began > to run on the crankcase fumes. Usually this would occur as the "throttle" > was backed off just as a hill was crested. The engine would suddenly roar > and rattle whilst belching black smoke from the exhaust. Very disconcerting > for those following. Not only would the engine run on the fumes but it would > accelerate. ( can't understand why when the ignition was occuring well > before injection point).The only way to calm it down was to apply the brakes > firmly until normal running resumed, don't know the theory behind this. > Braking was also disconcerting for those following. The only time I have > ever witnessed this in another vehicle was when a Diamond Rio was delivering > a load of coal to the factory where I worked. This was a spectacular sight > and sound punctuated by the driver and his helper abandoning ship ** This does tend to suggest rings. As you will invariably be aware there are virtually only 2 ways oil leaves a crankcase and oil gets used. The first is through entering the cylinder and being consumed in the combustion process or being forced out the exhaust, and the second is through leaks. Have seen what you say above happen but it appears you had a bad case. B.r., David > > Regards, > Paul. > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > Please do NOT send "unsubscribe" messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
