Can I use 0W40 fully synth oil in my R400 Duratec?

[aerobod - near CYYC]

The 5w50 would therefore not be adequate for the R500, if it was absolutely needed for the R400, though? Also the later derivatives of the Duratec in the current Eco range seem to have a similar if not the same bottom end (not sure if the journal bearings are different), most of the detail changes are intake and tuning related.

[David_Long]

 . . . and that's why I (and many other engine builders) suggest a 10w60 for more extreme track driving. :) . But you are being pedantic, so lets agree to disagree.

[aerobod - near CYYC]

Trying to avoid being pedantic David, just looking at all the data points available. Would you know why SBD specify 5w40 for their 2.0 Duratec race engine builds?

[David_Long]

Again you're being selective with the information - they also sell and provide as an option 10W60 for the Duratec.

https://www.sbdmotorsport.co.uk/ford/duratec.html?cat=39&is_ajax=1

[aerobod - near CYYC]

They specify the 5w40 for their engine builds: https://www.sbdmotorsport.co.uk/wp/wp/pdf/SBD_Duratec_Oil_Recommendation_sheet.pdf but say that the 10w60 is applicable for use when the oil temperature is not controllable in a particular implementation.

[David_Long]

I think that document says that more or less exactly what I've been saying.

They suggest 5W40 (which I think is high risk), but they are winning sprints and generally perform well in events. Perhaps it gains them a few BHP and makes the customer dyno runs look good, and wins them events for that matter. And that may be what they are all about.  Certainly my dealings with them showed they are focused on performance first. I do find it odd that they feel to the need to mention about bearing failure symptoms though.   

But the perspective on here is a little less extreme. In the tests I did a few years ago, I ran a season on 5W40 and the winter overhaul of the engine showed issues with cam bearings, and 'big ends' for that matter. The engine ran well and would have probably gone on for some time.   But someone giving it 'all' on track days for hour after hour deserve a bit more longevity and so my advice has moved to 5W50 as the minimum.  10W60 is better, but if budget allows a new engine every now and then, use something thinner for an extra few BHP. 

[aerobod - near CYYC]

I will keep an eye on my oil pressure a bit more closely on track, but I'm currently well within the SBD pressure recommendations within the hardest I can push the 0w40 oil I use.

I've generally followed their Duratec recommendations, as my 9A4 map is provided by them for my engine, to their AlphaN fuel mapping (I removed the Caterham MAP usage), but I have tweaked the fuel maps slightly to account for my engine variations, as opposed to having them do a remote tune, with my car being in Canada.