I might not be that good with my choice of words. The phenomenon seems simple to me, not sure about the explanation.

If I happen to pull apart some of my shocks soon I'll take some pictures to show you what I am talking about.

I run King Coil overs on my "Full Scale" Jeep and the "Shock Fluid" is silicone based and smells and feels a lot like the stuff we run in our cars. The Shock Engineer told me, that the Fluid will turn black just from the "Friction" of the piston moving through the fluid. Now on full size short course trucks the shocks get HOT but my Jeep crawls trails at like 5-10 mph and they get warm but not hot.
So I assume the fluid itself doesn't have to get "Hot" to see some change of color.
For my the shock oil in my Jeep comes out looking like the stuff in my Rc's.
Just my 2 cents

I would also expect shock oil to discolor with use only, not necessarily because of contamination.

Thanx for all the feedback. Interesting stuff. I sort of operate in a world of "wonder whys" and "what ifs". This was just one of those wonder whys. Did get a couple of what ifs from your feedback.

Shock oil shouldn't discolor simply because of use. That's similar to suggesting water would discolor because it moves through pipes. It's just contamination, mostly dragged on in the shafts. It's not particulate by necessity. EG: If you use traction compound, some of it is bound to make it onto the dampers and the rest of the car at some point. If anyone else uses traction compound, its going to make its way from the carpet onto your car. Oils leach from asphalt, too.

Does the M03 take a standard size servo or does it need a "mini" (haha pun intended) ??

Standard.

standard servo.

the's nothing mini about the m03, just the name.

Wow! This thread is super-active... I started a monster on shocks and it's taken me ages to catch up.

I can't quote/thank each of you but thank all for your advice/suggestions!

Obviously there's anecdotal evidence of regular leakage.

This is true actually. In clean conditions. Most NIP shocks and NIP parts will have chemical/cleaning residue on them (especially the inner surface of the shock cylinder when new), and will foul oil which then appears black (normally via particulate). Foreign matter ingress will also cause this and I can assure you, based on my experience with buggies, crap does get in via every shock orifice eventually, irrespective of the surface.

Clean oil, with nothing added, won't (read: shouldn't) discolour with use.

Our club regularly has two heats, sometimes three of minis. The MN State Champs Race should have four heats. Mini racing is alive and well!

HPI MX5 Shell on M05

Water doesnt degrage like oil does

Damper oil is usually silicone. It's essentially inert and stable.

Funny, it reminds me of a job I had at a place that made load cells that were embedded into roadways or truck scales. They were made from a block of stainless steel with a cavity hollowed out. Inside the cavity was the load cell, which looked as much as anything like a microchip, and a whole bunch of silicone gel to keep the water away from it. One of my jobs was to clean the silicone gel out if a part came in for service. That stuff was freaking impossible to deal with.

I used every solvent in the place - dozens of them - trying to find a way to "de-grease" these things. Nothing ever worked. That was the job where I also learned about methyl-ethyl ketone fumes being bad for you.....duuuuuuuuuuuuuhhhhh.

True. The oil in my carpet car comes clean out of the shocks after many uses. It may become a bit foggy, but no colour/discolour visible even after a year of racing. The shocks (alloy) though show no sign of wear on the inside or on the shaft, so I suspect there's no possibility of particulate contamination. These shocks though are a top quality Kawada shock.

Tamiya shocks are very good but I found wear inside some of them. The more recent ones are perhaps on par with the Kawadas or I may not have used them long enough to generate noticeable wear.

It's odd that a simple question like what makes shock oil turn black prompted so much comment. A couple of our local Mini gurus were commenting to me about it at the track. The discussion trackside led to a more important question.

What would be the effect on shock action or behavior?????

The simple answer is, black shock oil will make your mini faster

And thanks for the compliment Granpa, hopefully I will make it over to the USA again and I can cut some laps with you and some of the other locals