But I have to ask the most reviled question on automotive internet forums.

What motor oil is best? I can start by asking what Enterprises uses when they build/test/ship their engines out. My CSR uses Mobil 1 10W30.

Greg,
Many have done a lot of research on the dyno and have their favorites. In general, when you ask those folks "which motor oil is best?" you will get an answer like "the slick stuff". Nothing wrong with that - they did the work and deserve the rewards... just letting you know the situation. I haven't done any dyno work but I have asked around and I use Mobil 1 as well. I believe that if you are losing anything to another oil, it's minimal, and I've had excellent reliability from Mobil 1 synth. I've been running it for as long as I can remember, except when breaking a motor in (which requires non-synth I believe).
Hope that helps.
Denny

GregCirillo wrote:I can start by asking what Enterprises uses when they build/test/ship their engines out. My CSR uses Mobil 1 10W30.

If you get oil from Enterprises, it is probably break-in oil. Use only as directed.

Going with what your CSR recommends is a good bet. Seems like someone from Enterprises told me once to go lighter for cold weather, heavier for hot. I am pretty sure it makes some difference, but not sure how much.

If you're really worried about it, you should instrument oil temp.

Dave

Hal B. wrote:http://www.mummbrothers.com/SRF_Stuff/Secrets/Driveline/oil_and_the_ford_escort_motor.htm

Fantastic. Thanks.

There has been a lot of chatter elsewhere during the past few years because the more recent API specs for motor oil dictate lower zinc and phosphorus levels than earlier API specs. Zinc and phosphorus are anti-wear additives; however, they are harmful to catalytic coverters. You may note that the Mumm Brothers document lists a phosphorus level of 0.1% (1000 ppm). Here's a link to a Mobil One document listing the zinc and phosphorus content of their oils:

http://www.mobiloil.com/USA-English/Mot ... _Guide.pdf

I don't know how important zinc and phosphorus are to an SRF engine, but the engne was certainly designed at a time when motor oils had high levels of zinc and phosphorus. To err on the safe side, I've used the "high mileage" versions of Mobil One.

Digging up an older thread. Presumably most are using 10W-30 oil. After reading Barry of Mumm Bros note on oil, noting he mentioned Vavloline synthetic, is the regular street synthetic or the VR1 racing synthetic?

Motul's 300V 5W-30 has nearly identical specs (actually slightly higher Kinematic viscostiy at high temps) as the Valvoline quoted in Barry's article but in a lighter weight. Anyone using the Motul 300V 5W-30?

Feff

Whatever's on sale at Walmart (usually 10w30 Mobile One Synthetic is the favored choice because you can get it pretty much anywhere). Really no need for a lighter weight oil (unless you're running in sub-zero weather). We rarely wear engines out; they tend to need refreshing primarily from abuse (over-rev/missed shifts) or from lean engine situations (harness, MAF, fuel pressure issues, etc.).