Not sure if this is of any help but worth a look if your interested unless you have allready seen it.

www.gulfoil.ie/lubricants/datasheets/1540-Gulf-Sup...f

Thanks. Seems like good stuff. Very high TBN. Its not the same stuff though. Newer spec and different company. I'd guess Superfleet isn't a registered name, or Gulf's corporate lawyers aren't aware that CPC is using it.

What is the probability of damage to a petrol engine from a C-spec oil?

I'd have thought it was very low, but I don't know. Perhaps nobody does, but I thought I'd post on the off-chance that somebody out there might.

Here is a link to some relevant info, suggesting diesel lube oil may not be good for your petrol engine, even more so if it has a catalyst.

www.machinerylubrication.com/Read/28576/comparing-...s-

Thanks. That's of interest, though the cat stuff doesn't apply to this car and the cold start stuff (which is viscosity-related rather than C-oil specific) doesn't apply in this climate (Taiwan). That leaves

"When you put this extra additive load in a gasoline engine, the effects can be devastating to performance. The detergent will work as it is designed and try to clean the cylinder walls. This can have an adverse effect on the seal between the rings and liner, resulting in lost compression and efficiency."

Could happen with a coked-up engine I suppose, which mine might be. OTOH I'd think it could unstick piston rings and so perhaps improve performance. Sounds difficult to predict.

With an engine in good condition (which admittedly mine might NOT be) a dramatic effect on compression seems rather unlikely.

I have, however, read "somewhere" that the over-basing necessary in diesels tends to erode tribofilms in petrol engines, which might lead to higher wear in metal to metal contact areas such as the cam lobes.

I would probably use it (IF I did) blended with CPC SAE 40 which has a base number of around 6, so that would perhaps reduce the effective overbasing of the mixture..