Quote:
Originally Posted by ATaylorRacing
I took the parts to a knowledgeable speed shop and was told that a lot of that is happening now since nearly all the oil companies no longer add zinc. He stated that a lot of guys are now having scuffed bearings and camshafts if they run slightly loose clearances. He recommends only Shell Rotella or name brand synthetics...
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Glad you mentioned that...
The reason 'they' took zinc out of motor oil - which is an extreme pressure (EP) additive - is because it kills catalytic converters! That's what lead Mobil to reformulate Mobil 1 a couple times in the last few years. Mobil 1 is Gen 5 or Gen 6 now... I lost track and don't feel like Google'ing it... but they do reformulate it from time-to-time.
Anyway, Mobil took the zinc out of Mobil 1 oil in, like, 2001. This was fine for 'street cars', but Top Fuel racers started spitting cranks like popcorn. They pleaded with Mobil to come up with a solution.
Mobil started adding an existing EP additive that they used in gear oil - SuperSyn (worked like a charm) - and it solved the problem, but it was only available to drag racers! After about a year of 'secret testing' SuperSyn on Top Fuelers - everybody else started clamoring for it too, and Mobil added it to regular ol' Mobil 1 oil.
I figure if Mobil 1 (with SuperSyn) is good enough for 8000+ horsepower Top Fuel dragsters, and 18000 rpm F1 race cars, it's good enough for my 160+ horsepower 8200 rpm Honda CiViC...
And, since you mentioned it... I don't run Mobil 1 in all my vehicles - it's too expensive! In everything else, I use Shell Rotella T or Chevron Delo 400. These are actually diesel motor oils and
can be deadly to cat converters too, sooo...
Yes, when it comes to mineral oil, Shell Rotella T and Chevron Delo 400 stand head n' heels above the rest - highly recommended! If you don't wanna run synthetic motor oil for whatever reason, and don't particularly care about your catalytic converter, go with them! Otherwise, Castrol GTX (an offshoot of the ill-fated GTR racing oil - which gummed up street engines) is hard to beat, but it isn't in the same league as the oils mentioned above, IMHO.