[y5e06]

While out on my run last night I was pondering the issues I'm having w/ my new clutch (arrghhh!). I then began to wonder, "How do race cars break in their clutches when they can't drive them easy on the street first?" So that then expanded to other items such as engines, rear end (gears), etc.
If the car isn't street legal, and you need to put in 500 miles or so on a specified part to break it in, what do you track only guys do? Are the items you use 'race only'? i.e. they don't require the same breakin proceedures and come near 'ready to use'? What methods are used on a clutch, or even an engine, when you can't put in those easy miles before beating on it?

[GlennCMC70]

for a clutch, its not the number of miles, it's the number of gear change's or starts from a stop. manufactures will tell you 500 miles assuming you will make a number of gear changes durring that distance. i've broke in clutch's by doing a 4000 rpm clutch drop w/ a nasty burnout and not driven a single mile prior. clutch worked perfect for a very long time. RR is not as demanding as drag racing on a clutch. just do some (4-5) 2-3K "lurches" then let it cool. should be fine.
as for a motor, well as mitch said, a dyno is best. but you could always use the "jackstand" dyno to do what you can. same goes for the rear end. w/ the diff, you just want to drive "normal" and let the teeth wear in to each other, but the most important thing is the heat cycling. thats what make the metal hard and strong. i believe the corrct term is "work hardining". you don't want to get them too hot too quick or for too long.