Hawk81A-2

[JtD]

Originally Posted by Plane-Eater

EDIT: Like I mentioned above, I'm not an engine expert, but wouldn't closer tolerances also allow (at least to some extent) higher loads than the design rating without the same level of wear or failure? IE, you could run the engine at - for example - 115% rated output without as much / as many of the corresponding wear and problems that would cause on a stock engine? So along those lines, by the time you did finally start getting high-load related failures, you'd be running at WAY more than just 5 or 10% above max rated output?

Not necessarily so, closer tolerances can contribute to less power loss and less variance in parts failure. For instance, if you achieve the same compression in all cylinders with zero tolerance, tolerance will see some cylinders with higher than normal and some with lower than normal compression. Operationally, you'll have to run the engine at a boost level which is save for the cylinder with the highest compression, so it is save to increase boost level when you have no tolerance at all. However, you can increase the boost level so that with zero tolerance all cylinders fail, while you'd still have some cylinders running on the engine with tolerances.
For prop reduction gear I don't know the effects of tolerances, but frankly there's little I can think of to turn a rejected part into a superior one. That might be a reason they were the weakest link.