Do NOT change your engine oil

[961]

Originally Posted by toxophilus

I know that it's probably slightly irrelevent, in that bike engines are built to much higher tolerances than car engines, and are much more critical of oil, but I remember a few years ago "Bike" magazine ran a Honda CBR600 from brand new for 20000 miles flat out, without servicing, on the circular test track at Bruntingthorpe.

When they stripped the engine, they found that it was all still within factory tolerance and when the oil was analysed it was found to still be serviceable (albeit in a borderline condition).

Not sure if it proves anything, but perhaps oil changes every 5000 miles aren't totally necessary. It won't stop me from doing it though!

But the vast majority of engine wear occurs in the seconds after the engine is started and in the minutes until it reaches full operating temperature

Once that period is over, wear is minimal

[Spike1918]

What utter arse gravy all this is! FFS, do folk believe everything they read on the WWW these days?
IF you want to hear anything about oils from folk that know what they are talking about email this company:

http://www.morrislubricants.co.uk/lu...pany.asp?wp=72

The S70 gets semi-synth 10W/40 every 5000 miles.
One of the bikes gets fully synth 10W/40 every 3000 miles and the other two 10W/40 semi synth at the same intervals.
All Halfords own brand oil as I have a trade card.

I`ve never had engine wear problems beyond normal EXPECTED wear.

[iantowil]

A friend blew the small end bearings on a Yamaha FZR1000R EXUP back in 1990. Left the oil just over 4,000 miles instead of changing at 3,000miles. In the following years it became common knowledge that "EXUP" engines HAD to have regular oil changes at the specified service interval - 1 conrod was £120 back in 1990 :-(

[Daim]

Originally Posted by 961

But the vast majority of engine wear occurs in the seconds after the engine is started and in the minutes until it reaches full operating temperature

Once that period is over, wear is minimal

Yep! That is why you can drive a car for a long time without oil, when the engine is warm, as the rests of oil is more than enough to cover the lubrication. But as soon as you push the engine to it's limits, the lack of lubrication hits the engine...

[v40bart]

Originally Posted by Daim

Yep! That is why you can drive a car for a long time without oil, when the engine is warm, as the rests of oil is more than enough to cover the lubrication. But as soon as you push the engine to it's limits, the lack of lubrication hits the engine...

Surely not? Oil takes a vital amount of heat out of the components, you'd be mad to drive any distance without oil pressure...

[Spike1918]

Indeed, without oil the tolerences between components are lost, the heat dissipating properties lost!

[iantowil]

You can run a steel cold mill on water rather than a 2% oil/water emulsion but the motor currents go through the roof - big motors too, around 5MW, so the currents are correspondingly large. It will do it, but doesn't like it, and the rolls/sheet suffer micro-welding in such circumstances.....I know as we did it by mistake :-(

[Daim]

Originally Posted by v40bart

Surely not? Oil takes a vital amount of heat out of the components, you'd be mad to drive any distance without oil pressure...

With the lubricant in the bearings already you can drive for a very long time, before any damage occurs. If you accelerate hard etc. there is of course an instant fault.

[IanLD]

Don't quite follow that. Had a Rover 214 that had the cranshaft oil seal pop out on the M6. Saw the oil trail starting and pulled over to the hard shoulder from the outside lane as quickly as I could. Had to get through the traffic so needed to steer and brake so couldn't kill the engine.

By the time I stopped it had started to clatter, and once at the garage, terminal damage to big ends and main shell bearings diagnosed. Oil warning light was only on for the last few seconds of the engine running, but damage was still done.

Car was running on fully synthetic which was regularly changed, so wear was down to the lack of oil and pressure.

[kebab10]

Do not change your oil! What utter, utter brown stuff. Oil is a vital component on ALL manner of engines and mechanical devices. No oil for lubrication and they stop. Sorry but its rubbish.