flanders

I'm pretty sure Honda here in Sweden recommended the Castrol TWS 10W-60 oil for both the S2000 and the EP3 CTR models a while back when they were new.
It was only recommended for serious track use though but still there were a lot of people using it without any problems that I can remember.
I never bought in to that thicker is better crap but it seems unlikely a -50 weight oil would have much of an impact.

Car Analogy

An oil that is too thick for sustained near redline operation at high load for extended time may not, probably would not cause immediate damage in normal usage. Normal including regular jaunts to redline.

Redline up through all gears is not the same stress as sustained redline at high load (high speed).

Mr.Matchbox

Just watched a Video from Motul Germany, some Subaru experts where visiting Motul Germany and talked about oil.

Very interesting and notworthy was, that the Subaru guy mentioned that most Subaru owners that have a stock engines with stock bearing clearances and use -50 or -60 oil (for better preotection?) end up with rod bearing damage!

So, for the S2000, my conclusion is: Stay with -30 or -40 oil as recomended by Honda. If -40, use a oil more on the thinner side. Read the data sheets of the Oil manufacturers.

For the few german speakers here, around Minute 11.05:

cosmomiller

Did your engines make their way into Airbus planes? Were you using powdered metallurgy and "growing" blades as a single crystal type and then fine tuning the shape?

I worked in Munchen in college one summer. I loved going to the Isar river at Wolfrathausen!

zeroptzero

It's all about operating temps and bearing clearances. 50 weights are too thick when used at normal operating temps or lower - like 100C oil temp, 70 degree exterior ambient temps or lower - as that is when they are extremely thick. If used in track conditions where you have elevated oil temps the oil will mimic a thinner grade oil like 30-40 so less likely to cause damage in those conditions. I personally would never use a 50 or 60 weight as I would never push the car that hard to get the oil temps overly high, so they would be too thick for my driving conditions.

My guess on cylinder 4 and rod bearing damage is always related to heat and lubrication - elevated oil temps, elevated temps of the engine parts, and/or lack of oil supply

I don't have a problem running a 40 weight like 5w-40 or 0w-40 in proper operating conditions. Those oils will always be synthetic as well.

jyeung528

exactly.

problem with running racing spec 50 and 60 weight oils is when you drive around and/or push it at normal operating temps.

Mr.Matchbox

Yes, of course. MTU works together with GE and Rolls Royce and deliver parts for civil engines. (Turbines, shafts, engine housings) All the millitary jet engines for the Tornado, Alpha Jet, Eurofighter and back in the days the Phantom and Starfighter where produced in munich, sometimes in European co-production. Also the engines for Helikopters and Transporters. https://www.mtu.de/engines/
I dont know exactly wich kind of metallurgy was used in making the blades, i can´t remember. It´s almost 40 Years ago.

The Isar at Wolfratshausen? Nice place!