Engine Oil: what's best?

[ammerty]

Is Magnatec the only Castrol oil which is bad for the valve stem seals?
I bought 3 bottles of Castrol Edge Titanium 5W40 (Repco special) and plan in doing an oil change in a few hundred thousand km.

I have HPR10 in there now but have nothing to compare too though I feel my lifters after warm have gotten louder with the HPR10

I've used Castrol Edge Titanium 5w40 recently, during which I did a 2500km return trip from Ipswich to Mackay, and I found it fine.
I too bought a bottle while it was on special last week and will use it after I use up my Shell Helix Ultra 5w40, which I still have a couple bottles of.

Though you may want to consider changing your oil sooner than 'a few hundred thousand km'. I've heard that's no good for longevity...