45 replies to this topic

[ClitheroeMini]

Just out of interest I'd like to see peoples preference, Mineral, Semi-synthetic or synthetic, which do you think makes your mini run better?
Thanks for the input
Ben

[thebullet]

Mineral. Always used 20w 50 valvoline racing oil.

[mab01uk]

Whatever type of oil you use it needs to be suitable for protecting the Mini's gearbox as no other modern car has shared engine/gearbox oil.

Millers Transverse M 20w50
Mineral oil especially formulated for the combined engine and gearbox such as the mini, but for better gearchange etc use MILERS002 except on rebuilt engines where pistons must be allowed to bed in using non synthetic oil.
http://www.minispare....aspx?pid=38658

or Millers CTV Semi-Synthetic 20w-50 with Gearbox protection for Minis
http://www.minispares.com/Product.aspx?ty=pb&pid=38659&title=OIL%2020/50%20SEMI%20SYNTHETIC

Edited by mab01uk, 30 October 2012 - 11:58 PM.

[ClitheroeMini]

Even on the later SPI's? I know its same set up but better be safe than sorry!

[xrocketengineer]

Mobil 1 15W-50 SPI at less than 45000 miles. Coincidence?

[ClitheroeMini]

Ha well I guess thats sorted then! Cheers!

[iMurray]

I use 10 40 mineral oil... Bad?

[SA MINI]

I use 10 w 40 mineral oil. For my auto. With regular changes my mini runs a lot smother on that

[Tamworthbay]

Mobil 1 15W-50 SPI at less than 45000 miles. Coincidence?

To be fair I did that to my clubman 20 years ago and it always ran on mineral, my right foot was the main problem. But I always use mineral, I get a job lot of comma sonic 20w50 and change it every 2000miles or 12 months in the mini. In my daily MGB I change it every 4 months and have never had any problems. Be careful though as they also do a super cheap one called motorway that isn't to any spec and is best avoided for anything other than the lawn mower.

[mab01uk]

Back in the 1960/70's there was not such a wide choice of engine oils, 20-50 became the norm and fwd BMC/BL cars with Issigonis style shared engine/gearbox oil was a very common layout.......but as most fwd drive cars eventually adopted the seperate end on gearbox (even BL/Rover) and the old BMC/BL shared eng/gearbox oil layout died out leaving only the Mini left in ever reducing numbers, so most oil producers stopped adding any EP/gear protecting types additives to their engine oils and modern cars switched to ever thinner grades of synthetic based oil more suitable for modern engines built to very close tolerances.

I would still use a 20-50 multigrade with all the gearbox additives included, even where BL were recommending a thinner multigrade oil for later Mini's but it is a personal choice, some won't agree....later MPi Mini gearboxes have had some problems.......

Edited by mab01uk, 31 October 2012 - 12:56 PM.

[jaydee]

To be honest that diff damage is too serious to be caused by an oil, mobil1 is a trusted brand and many people are using it on their classic MGs..
Beware that synth oils can cause seal shrinkage and go past clutch oil seal and, in some cases, even through the timing chain seal.
But a synth oil will outperform a mineral anyday.
20w50 is the correct grade for the high tolerance A series engine and its shared gearbox, there are great oils on the market like Millers, Valvoline, Royal purple etc.. Castrol is good for road use but i experieced early oil degradation on harsh use, it lasted about half the time millers lasted before pressure drop occurred on high load (i dont know if you get what i mean)..
10W40 is reccomendable for winter use when temperatures are below 5°
Its very important that you pay attention to the API spec because cam and follower and the gearbox itself need an hgh content of ZDDP, which is very low on the current SJ/SL/SM ratings (due to the use of cat converters).

You'll find a lot of oil infos here:
http://www.kewengine...ity_ratings.htm

[jaydee]

I would still use a 20-50 multigrade with all the gearbox additives included, even where BL were recommending a thinner multigrade oil for later Mini's but it is a personal choice, some won't agree....later MPi Mini gearboxes have had some problems.......

Rover reccomended:
Oil specification:
10W/30 engine oil, meeting
RES.22.OL.G4 or ACEA A2:96.
on MPI ownres handbook.
Thats due to commercial reasons i hope, otherwise they must have gone mad at some point.
And heres probably the reason for all the gearbox failures and the excessive wear on camshaft and followers (even more noticeable on models fitted with high lift rockers).

[firstforward]

• 
  Does using synthetic oil damage engine seals?
  No. Synthetic motor oils are perfectly safe for all rubber seals.

[Mini_Magic]

I use 10 40 mineral oil... Bad?

20W/50 would be better, particularly for the gearbox.

[Orange-Phantom]

I'm with mab01uk on this one!

I use Millers CTV 20W50 Semi Synthetic which is specifically designed for Mini's, in my 7 Port.

If you do not have a hot motor go for the Millers Classic Mini 20W50 Mineral.

I have actually spoken to the chemist at Millers who help develop and test the oil. His oil analysis from various engines included a 300bhp turbo a series and it was fine! (Mind you he would say that)!

Speaking with him (and Peter Vickers who built my Engine) it's the viscosity improvers (the long chain molecules) in the oil that the gearbox and especially the diff smash to pieces and eventually turn the oil thin, which is why the older synthetic type oils were bad for Mini's as the viscosity improvers couldn't stand up to the punishment of the A Series and Gearbox/Diff combination.

Really you need an oil with shear stable viscosity improvers in it i.e. Millers! (Or a 20W50 Motorbike oil which is designed for shared engine and gearbox applications).

You still can't beat frequent oil and oil filter changes though. I'm aiming to do mine every 3000 miles or yearly. Saying that I'm on my third oil change at 1800 miles!