MB engines... are they weak?

[Josh]

Just remember that "industry standard" is often synonymous with "painfully average", and this applies to more than just the automotive industry.

[Colin]

suzuki engineers wrong and josh right hhhmmm something dosn't sound right to me

[Brayden]

Yes I should also mention that my 5k change is also done with a "shitty nappy" given that the filter should not be sufficiently clogged after that amount of time. However like Fritz my oil is looking more like black coffee than honey by 5k and that is using a semi-synthetic oil.

[Colin]

is your motor fumey????

[Brayden]

No the only fumes are fuel related. The oil isn't as black as I make out, but given the flogging I give the thing I like to change it as often as necessary. However it does leak an awful lot of oil onto the exhaust. Ahh well, that will be fixed when I pull the motor to plumb turbo lines into the sump...

Speaking of turbo, I need to have a chat with you Col. I'll call soon.

[Colin]

turbo= sad thing at the moment i need another one ...anyone got one

[Josh]

suzuki engineers wrong and josh right hhhmmm something dosn't sound right to me

Funny as that may seem, you have completely misread what I am saying.

Lets face facts: The industry standard 12-month/10,000km oil change interval is not decided by the engineers who craft these engines, but by the pencil-pushers who hand down the specification to them.

'We want this vehicle to have 20,000km service intervals. Make it happen.'

I don't believe for a minute that a 543cm³ 3-cylinder engine that spends the majority of it's running time between 3000RPM - 6000RPM should have the same service intervals as a lumbering cast iron 3.0L-4.0L Holden / Ford 6-cyl or V8 that spends the majority of it's running time between 1500RPM - 3000RPM.

People are also often mislead to think that synthetic oils simply provide the same quality of protection as mineral-based oils and that the only advantage in running these oils is less frequent service intervals. The fact of the matter is that synthetic oils (such as Mobil 1) not only have better viscosity characteristics for cold starting, they have better detergent chemistry, lower friction coefficients which not only reduce wear but lower running temperatures, do not break down at the chemical level resulting in oil sludge as mineral-based oils do, and they burn clean, drastically reducing carbon deposits and making them the ideal choice for rotary engines.

There will never be a perfect standard right across the board for service intervals. It's just important to bear in mind that these industry standard practices are not engine specific, they are a compromise between keeping manufacturers protected against warranty claims and keeping consumers happy with the lowest cost, most infrequent service intervals possible. And, at the end of the day, are the manufacturers really interested in building anything to last?

[evilgidget]

You've been reading way too many sales brochures & carton labels during your time at SCA, haven't you Josh?

[Josh]

That and talking to revheads, the ACT Rallying folks and phoning suppliers with questions.

Oh! And taking the time to ignore all the crap being force-fed to me in order to draw my own logical conclusions...

[fritz]

...and they burn clean, drastically reducing carbon deposits and making them the ideal choice for rotary engines.

When I had my S1 rx7, the mob at rotomotion (the biggest rotary mob over here) told me that I shouldn't use mobil 1 or any synthetic oils. They recommended mobil XHP (they sell mobil oils as well)

A lot of people do however reccomend it...

Ongoing rotary debate I guess...

[Colin]

old mechanic's saying black oil is good oil ,its doing it's job of picking up carbon deposits and taking them to the oil filter

[Josh]

old mechanic's saying black oil is good oil ,its doing it's job of picking up carbon deposits and taking them to the oil filter

Sure! As long as it hadn't already reached saturation point from being left in there too long...

[Shayne]

so what would happen if you just changed your oil filter instead of changing th oil would it just filter out the carbon deposits??

[Colin]

no you still have to change your oil theres only so much it can take

[Josh]

so what would happen if you just changed your oil filter instead of changing th oil would it just filter out the carbon deposits??

No Shayne, changing both oil and filter are equally important. The technical explanation behind what Colin has already said is that engine oil begins to break down at a chemical level due to a number of factors, mostly due to the constant heat exposure and chemical contamination. Carbon deposits aside, engine oil becomes contaminated quite easily from other sources which paper filters can not filter out, such as other hydrocarbons being throw into the engine, eg. petrol.

It's very important that cars doing a lot of short trips have their oil changed frequently because these engines spend much of their time cold and running with the choke on. The excess fuel washes oil off the walls of the cylinders and eventually makes it's way into the sump, contaminating the oil as a whole which ultimately results in a 'thinning' effect. This lowers the viscosity of the oil and weakens it's film strength, drastically affecting the amount of protection the engine oil can provide.

Now, in most instances, cars get to run for a good half hour after making it to peak engine temperature, which allows plenty of time for the excess petrol to evaporate out of the oil and thus our oil remains in good health. In the case of vehicles that do a lot of stop-start driving, the engine may never get to peak operating temperature, let alone maintain such a temperature for an extended period of time. The result is that the oil is contaminated much faster than an engine subjected to longer running times after cold starting, and this is why the car with only 20,000kms since new from the little old lady who only ever took it down to the shops every Sunday is not always the car with the freshest engine.