Date: Fri, 26 Mar 2004 23:48:31 -0400 From: Dexter J <lamealameadingdongnospamlamelame.org> Subject: Re: Should I buy this 1992 9000 Turbo with 168,000 miles on it ...
Salutations: >>> They don't change their oil often enough. No way non-synthetic oil is >>> not >>> completely useless before 10k miles, Kilometers, maybe... > On 26 Mar 2004 21:50:52 GMT, LauraK <lkrznospamcomnospam> wrote: > Depends on what kind of driving you're doing. > lauraknospamousergraphics.com > http://www.madmousergraphics.com > web design, print design, photography Actually the difference is this. Except for last summer - most of England and Europe is on average 5-10 degrees cooler than most populated parts of North America and there in is one of the problems with mileage or time based oil change schedules. I maintain that the correct answer is to acquire an accurate set of oil and transmission gauges and pay occasional attention to them as you go. Granted - for the most part oil thins and/or carries particulate more in step with engine condition and tune than driving style. However in terms defining a wise 3/6 month or thousand mile interval - attributable oil degradation is importantly related to environmental conditions in which your respective car operates seasonally. For example - you run a high mileage engine in Europe where it is often damp and not so warm. Your oil thins at a greater rate than certain north American SAAB brothers or sisters because of hydroscopic action in the block and fuel blow by through the seals and rings on cold starts. Thin your juice enough and eventually the baby burps a bearing one cold morning. For our American cousins in Texas, where the average ground temperature is much higher and air much dryer, oils tend to revert to a more granular state over time - which more readily presents the possibly of catastrophic failure under load and heat. There is more ongoing evaporation of unspent fuels and water vapor in the block - but they face the problem of concentrating carbon levels as the oil itself evaporates with the vapor and unspent fuel. Fine carbon in an increasingly fuel and humidity rich environment acts as a bit of a lubricant - but viscosity is thinning at lower temperatures and pressures. Almost the opposite is the case in a dry, high temp environment where viscosity is increasing at lower temperatures as more concentrated carbon crystal is in movement across your bearing faces. Both oils behave much the same way at temperature, but both wearing the engine differently as the clock ticks over. Brother Grunff's '86 T16 looks the way it does under the cam cover because it is changed as indicated by the actual condition of the oil, no doubt careful attention to warm up at start and a generally good 'Carma'(tm) for helping out so many folks on this NG. For him, the semi-syth makes sense because he is more likely to pass it through the main seal as he will be thinning his oil more quickly than brother Fred. However - brother Fred isn't thinning out as quickly as brother Grunff and his seals are more likely swelling than cracking - his greater concern is the potential for surface failure in the block. Synthetic is *very* good at holding it's set viscosity into extremely high temperatures - but no better at keeping larger carbon crystals from forming in the fluid or handling evaporation demands as dictated by the condition of his engine. Anyway, as I mentioned earlier - I'm getting my '89 block prepared and I am searching carefully for a really accurate set of gauges for oil pressure as well as transmission and oil temperatures. I'm also fitting an engine hour clock under the hood when it finds a home. Much is often made of the social 'effects' of marketing and my take is that much of the wisdom related to automobiles is misplaced. Horsepower isn't really as important to most folks as Torque - mileage can be important when you are discussing chassis issues, but engines and electrics are related to how many hours, in what conditions and how closely the maintenance is adhered too. Lubricants and cooling fluids, natural or otherwise, are entirely subject to application. Thusly - I still think the best hope anyone has of getting it right is to have realtime monitoring in place. If there is any improvement that I would like to see focused on myself - it would not be in new oils - but in more effective filter, breather and monitoring technology. Sorry for the great length - pet subject of mine.. -- J Dexter - webmaster - http://www.dexterdyne.org/ all tunes - no cookies no subscription no weather no ads no news no phone in - RealAudio 8+ Required - all the Time Radio Free Dexterdyne Top Tune o'be-do-da-day Mississippi John Hurt - Frankie http://www.dexterdyne.org/888/197.RAM
 |
 |
 |
 |
 |
