QUOTE(Mark Henry @ Apr 16 2019, 02:37 AM)
Not saying this is the case, 40K is pretty good, but #1 reason for TOB failure is drivers who rest their foot on the clutch pedal. They press on the pedal enough that the bearing is always spinning, causing premature failure.
The cutch should be used sparingly, I produces a lot of pressure on the crank (bearing) thrust surface. I've seen two 996 engine failures from thrust bearings failure directly related to clutch overuse. Starting in neutral and even shifting to neutral and letting your foot off the clutch at stop lights is a good habit to get into.
TOB is easier to replace than thrust bearing failure., so I agree with Mark... Easy on the clutch, especially if you have a high pressure one.
Also, this is why it's a good idea to install a double thrust bearing on the cam because of the side loads on the camshaft (buy two cam bearing sets, it's cheaper than buying a double thrust bearing cam set - they just combine two sets anyway).