39 replies to this topic

[gaffer1986]

Ok, I think I won't be changing the oil every couple of months. But can it hurt?

[fezzasus]

Ok, I think I won't be changing the oil every couple of months. But can it hurt?

 

Yes! I've already described the issues with constantly exposing your engine to fresh oil. Mainly seal compatibility will be worse - some can swell, some can contract, some and crack. Used oil does not do this. 

[quimbles]

And I was about to change my oil........

[gaffer1986]

Sounds like you can't really win, change the oil it is bad for your seals, don't change it and it no longer protects your engine. And it is not yellow

[Nev]

Sounds like you can't really win, change the oil it is bad for your seals, don't change it and it no longer protects your engine. And it is not yellow

 

Try not to let your neurosis take over!
 

[aquilaproejct]

Maybe try changing half at a time? 😅

[Ivor]

 

A Ducati mechanic told me that there's no reason to change synthetic oil at all, it doesn't break down like mineral oil does, the discolouration is due to carbon deposit. That said, I still change mine but not every 60 days. Mad.

That's complete bollocks.

 

 

for what it's worth:

Probably not complete Bollocks as he ran a race Team, ran a ducati dealership, and knew what he was talking about, That said I suspect the truth lies somewhere in between, I used to change (mineral oil) in my cars every 12,000 miles, now with synthetic and semi synthetic it's every 20,000, wife's 03 fabia, owned from new (1 careful lady owner and me) is currently on 297,000, a semi synthetic oil change every 20,000.  My bikes don't do much mileage and so the oil (fully synthetic) does not get changed, my track bike is the same, it gets thrashed properly, or as properly as I can do it and the oil stays in, my recently retired track bike is an 06 Ducati 999 around 12,000 so not a lot, but proportional a lot of track miles, cant remember the last time I changed the oil in it, it still runs fine.

 

The only car I've probably changed the oil in more often than required is my VX, still synthetic oil, and I've had an engine go, the only one in 40 years driving cars and now bikes.  Opinion is the map probably caused the VX engine to go, but one never knows.......

[Arno]

Different approaches for different applications and all that..

 

Lorries/HGV's (esp. long distance ones) are usually using an engine oil that's heavily filtrated (several main stages usually supplemented with super-fine bypass filters) to try to get as much particulates out of it as possible. It's chemical condition is monitored regularly using oil samples and they will replenish additive packages as long as the base oil composition still meets the demands. Same goes for air filters on these which are changed based on the pressure drop before and after the filter and not at regular/fixed intervals.

 

For trucks this is a good system to maximise the use of the components time-wise and push cost down as much as possible by only changing parts that are proven 'worn out' or 'end of life'.

 

For (passenger) cars this is usually not useful as normal owners do not keep detailed (data) logs on their car and are not set up to change wear/use items like these in such a manner.

 

So for these the system of standardised milage/age replacement has come into play to keep everything ticking along for 99.x% of all owners.

 

It's quite possible that you could run a single oil change for much, much longer, but you'd need to really have the oil tested at regular intervals so you get an impression on when it's time to renew. However, longer term test results could also indicate that you need to shorten the change interval if contamination buildup or additive breakdown in the engine turns out to go faster than expected.

 

Bye, Arno.

[gaffer1986]

It seems that these engines to "go" quite often when they're tinkered with. Seems plenty of people have had problems after a supercharger has been fitted.

[fezzasus]

A Ducati mechanic told me that there's no reason to change synthetic oil at all, it doesn't break down like mineral oil does, the discolouration is due to carbon deposit. That said, I still change mine but not every 60 days. Mad.

That's complete bollocks.

for what it's worth:
Probably not complete Bollocks as he ran a race Team, ran a ducati dealership, and knew what he was talking about, That said I suspect the truth lies somewhere in between, I used to change (mineral oil) in my cars every 12,000 miles, now with synthetic and semi synthetic it's every 20,000, wife's 03 fabia, owned from new (1 careful lady owner and me) is currently on 297,000, a semi synthetic oil change every 20,000. My bikes don't do much mileage and so the oil (fully synthetic) does not get changed, my track bike is the same, it gets thrashed properly, or as properly as I can do it and the oil stays in, my recently retired track bike is an 06 Ducati 999 around 12,000 so not a lot, but proportional a lot of track miles, cant remember the last time I changed the oil in it, it still runs fine.

The only car I've probably changed the oil in more often than required is my VX, still synthetic oil, and I've had an engine go, the only one in 40 years driving cars and now bikes. Opinion is the map probably caused the VX engine to go, but one never knows.......

It is bollocks. I design engine oil and work very closely with base stock suppliers. The differences between the mineral oil branded products and synthetic oils are predominantly in the marketing. In fact, since the introduction of true synthetic oils, BP (and now everyone else) has been marketing refined mineral oil as synthetic on the argument that the refinement process makes it synthetic.

[fezzasus]

It seems that these engines to "go" quite often when they're tinkered with. Seems plenty of people have had problems after a supercharger has been fitted.

That's what happens when you take an engine designed for 150 bhp and ask it to do 250-300 bhp with no changes to the internals of the engine. Nothing to do with the lubricant

[fezzasus]

Different approaches for different applications and all that..

Lorries/HGV's (esp. long distance ones) are usually using an engine oil that's heavily filtrated (several main stages usually supplemented with super-fine bypass filters) to try to get as much particulates out of it as possible. It's chemical condition is monitored regularly using oil samples and they will replenish additive packages as long as the base oil composition still meets the demands. Same goes for air filters on these which are changed based on the pressure drop before and after the filter and not at regular/fixed intervals.

For trucks this is a good system to maximise the use of the components time-wise and push cost down as much as possible by only changing parts that are proven 'worn out' or 'end of life'.

For (passenger) cars this is usually not useful as normal owners do not keep detailed (data) logs on their car and are not set up to change wear/use items like these in such a manner.

So for these the system of standardised milage/age replacement has come into play to keep everything ticking along for 99.x% of all owners.

It's quite possible that you could run a single oil change for much, much longer, but you'd need to really have the oil tested at regular intervals so you get an impression on when it's time to renew. However, longer term test results could also indicate that you need to shorten the change interval if contamination buildup or additive breakdown in the engine turns out to go faster than expected.

Bye, Arno.

It's also extremely hard to define exactly what criteria to condemn a lubricant for passenger cars due to the greater diversity of applications. Usually in use monitoring of trucks is conducted by the fleet operator so they can easily define what normal and abnormal is due to having very narrow applications.

Oils can fail by base reserve depletion, viscosity increase through soot loading, oxidation, sludging with fuel. Viscosity decrease through fuel dilution. Water contamination from short distance driving, 3rd body abrasive particles, catalytic metals and so on.

There isn't a portable or cheap sensor for all of these so manufacturers define a drain interval designed on extreme use. For example Volkswagen conduct 300 hour full load testing on a single oil drain to evaluate suitability and this test regularly requires stoppage to replace ancillary components that cannot meet end of test.

Our attempts at replicating test conditions on chassis Dyno often kill gearboxes before the engine sees any lubricant related issues. The manufacturer drain interval is very conservative

[Nev]

It seems that these engines to "go" quite often when they're tinkered with. Seems plenty of people have had problems after a supercharger has been fitted.

 

The rings on an NA are not designed for the extra pressure, and the dynamic CR will be loads higher too (due to the boost). Both of those will likely contribute to increased blow by.
 

Edited by Nev, 08 December 2018 - 10:05 AM.

[gaffer1986]

I have been told before the Z22SE is designed to be supercharged?

[gaffer1986]

I have to say what Fezza is saying makes a lot of sense, marketing rarely miss a marketing trick. It also makes a lot of sense that manufacturers oil change schedule be well on the safe side. Mainly to get customers to use the dealers I guess, dealers need an incentive to sell their cars. Also, given it is his job. I just need to accept black oil is not a sign of bad oil. It is pleasing when you see yellow oil on the dipstick though. My turbo petrol Leon which I've done 131,000 miles in with oil changes every 19,000 miles has yellow oil even just before a change. ACEA C3.

[gaffer1986]

Surely it would be easy to design an oil that doesn't degrade the rubbers? Which part does the damage?

[fezzasus]

Surely it would be easy to design an oil that doesn't degrade the rubbers? Which part does the damage?

All the additives are surface active. This means they will go find other surfaces when exposed to them, including seals. As the oil degrades that additives become less surface active

[Bargi]

Ok. So where do you get these statistics from?

Sent from my SM-G950F using Tapatalk

It seems that these engines to "go" quite often when they're tinkered with. Seems plenty of people have had problems after a supercharger has been fitted.

Edited by Bargi, 09 December 2018 - 05:32 PM.

[gaffer1986]

 

All the additives are surface active. This means they will go find other surfaces when exposed to them, including seals. As the oil degrades that additives become less surface active

 

 

By surface active do you mean surfactant? Like an emulsifier that allows two liquids to mix more easily like washing up liquid.

 

So I guess this means new oil sticks to the rubber better than old oil which has a stronger surface tension.

 

Is oil bad for rubber then?

[DanGT]

Change oil as frequently as you want as long as you don't go over the oem recommended time/mileage

Oil breaks down and manufacturers test it as far as they can but it isn't an exhaustive test. Running an engine at peak load on a dyno with 1 litre of oil in it will break it down quickly to see what the wear is like after certain mileage but won't account for cold/hill/bump starts (poor example) and all the stuff which can't be accounted for. Audi are currently replacing tfsi engines due to high oil consumption caused by premature ring wear. Also the s4 engine with camshaft wear cos of people doing 20k service intervals as audi said long life was ok for it. Even with all information oems have with oil testing it's still not easy.