Engine Oil

[zsuprausa]

I was talking to a friend of mine who drag races and we got off on a tangent about oil. He highly recommended that I should use Rotella 15W-40 in my 91 Supra Marauder with the PCM454 or go get a packet of GM assembly lube and add 2oz at each oil change. The previous owner had always used Penzoil 40w. My friend said the issue is the older motors don't have roller cams and need the metal additives in Rotella or most other "off road" or diesel engine oils. He said a few years ago most of these additives were removed or reduced in all the "on road" engine oils because it caused issues in the catalytic converters. The newer engines didn't need the additives because they were mostly roller cams. He said not running the Rotella, adding the assembly lube, or running a racing oil will greatly increase the risk of wiping the cam shaft in these older motors.

Seems sensible to me. Anyone else heard this concern?

[michael hunter]

ZDDP is the additive . I use Mobil 1 15W50 . According to Mobil the 15W50 has the additives needed to keep the cam and lifters protected.

[rludtke]

My opinion,

While the additives probably don't hurt, they do add cost. Mechanical pushrod valvetrains have been around a lot longer than oil additives have been, and operating in very abusive environments such as racing etc. We don't actually operate our engines that hard.

I believe that the modern multi-grade oils have a lot of benefit to offer, but I draw the line at pure synthetics and / or extra additives because of expense. Changing your oil and filter often will probably offer greater benefit for the dollar over the long run than anything else, especially when you consider how easy this sport is on our engines.

[tg0824SSVGG]

Rick,

I can agree with much of what you said, except the part about we're easy on these
engines. Not sure you how use your boat, but in general, these engines idle or are
running at 4000 RPM much of the time. Not like a car, with a transmission that
can shift and keep the RPM's much lower once you're cruising along -- the engine
on these are actually beat much harder than a car engine, especially a "regular" car
in stop/go. -- or at least this is what I have been told and thought for years.

Thoughts?

In any case - I know for Indmar, they recommend Penzoil 15-40 - but also suggest
the Rotella is fine (which is what I use, not crazy about Penzoil here) -- but this is
an older PCM with quite different "parts" than the modern engines.

Todd