36 replies to this topic

[dklawson]

Others in the U.K. will have to speculate on ZDDP and Rover's oil specification. I simply don't know.

Over here the ZDDP debate/argument rages on. I simply refuse to take part in the discussions anymore as each side gets nasty about it and each side points to "independent studies" backing their side of the argument. Personally, I use quality oils and if they have the ZDDP... great. If they don't, I use an additive as I consider it cheap insurance.

[Gulfclubby]

Best not to have a cat (I love cats, but the furry ones), then you don't have to worry about burning it with a carb or clogging it with ZDDP. The classic Mini is never going to be a very ecological car, no matter how much you try, so why bother?

[Cooperman]

I just use Valvoline Racing 20w50. No additives, nothing added, and it's first class oil.

[mini-luke]

Best not to have a cat (I love cats, but the furry ones), then you don't have to worry about burning it with a carb or clogging it with ZDDP. The classic Mini is never going to be a very ecological car, no matter how much you try, so why bother?

We don't have much choice in the matter, a late Mini will never pass emissions without a cat.

[R1minimagic]

The main reason for reducing ZDDP in the latest spec of oils (API CJ-4, ACEA E9 etc) is that they are low SAPS oils (Sulphated ash, Phosphorous & Sulphur). This is only on the very latest spec of oils (see API or ACEA oil sequences for specs) to protect diesel exhaust aftertreatment devices such as DPF's (they clog with ash) and SCR systems (NOx reduction). The reduction is only about 20-30% compared with previous spec although people talk about it as though all the ZDDP has been taken out - it hasn't!! The older spec oils are still available so just use those!!

ZDDP is considered a 'wonder molecule' by oil formulators, the mechanism of action is not fully understood, however, what is known is that it degrades in high temperature, high pressure zones in the engine (it is an extreme pressure or EP additive). These are regions such as piston rings, camshafts/followers and gears. There are not really any other molecules presently known that can replace ZDDP so it is still used, although ZDDP covers a large range of molecules (it is a family) so they are constantly tweaked to meet whatever the latest spec is.

As a Mini engine is unique in sharing oil in engine and box, the oil has a tough time in terms of 'shearing' (large molecules get broken down into smaller ones). The least shear stable additives are 'viscosity modifiers' (VM's), these are high molecular weight polymers that break down quite easily under shear conditions (e.g. a Mini gearbox!). However. i think that in a 20W grade oil there shouldn't be that much VM. It will be used more in lower weight grades such as 0W, 5W, 10W to give thickening at engine operating temperature (approx 90-100C bulk oil temp).

[R1minimagic]

And by the way - ALL engine oils have additives in them (approx. 20-30%). The rest is base oil (70-80%).

If you ran an engine on base oil alone (no additives) it would be wrecked in next to no time (this is why additives where developed in the first place back in the early 1900's!!!)

What you need to be careful with is adding your own 'extra additives' e.g. STP etc etc

Every oil that is commercially available has to pass umpteen tests (even for very small tweaks in formulation) so making your own formulation by mixing and matching isn't really recommended unless you know a bit about oils and how they work, most people don't have a clue!

Just saying 'i used it in mine and never had a problem' isn't really telling you anything - did you strip the engine down and rate all the components to see if they were ok?!! Probably not!

[mini93]

anywho... i use velvoline in my mini, can get it for about £20 a tub when u buy 4 at a time... boss even runs it in some 205 engines as thats what the engine builder recomended