[morsing]

I think maybe there's a distinction between "needed" and "beneficial" to be made here.

Modern car makers don't care if their cars last more then 100 000 miles, but as a classic car owner, I do. I don't mind adding some additive every oil change and I think it will make a difference to both rings/cylinders and cam followers.

That said, my cam follower gap hasn't changed in 250 000 miles but two of my cylinders are leaking air past the rings now.

Regards,
Henrik Morsing