High power normally aspired. How it lasts?

[NOSferatu]

If we take for example 2.0 TC tuned to about 185hp, how long it will last, if it is done according all instructions?
I mean street use. Competition use is definetly something else...
Do pistons eventually give up by fatique? TC's have huge piston speeds, everyone knows...
I have now one driven about 100000km, and I'm thinking that should I start making a new engine before that blows and breaks head and block and everything?
It doesn't consume any oil and works perfectly in every aspect, but fatique doesn't give any symptoms before it blows.

[Guy Croft]

Stress computation is by no means that easy. Sure, I have tables that I use, but I'm not going to predict the working life of an old set of cast pistons, rods in tuned engine. Throw them away and go to proven well-known make race material rods and pistons. This isn't a sales pitch by GC! Crack testing the old parts will only tell you if they are cracked now, not whether they will crack tomorrow. Everything I've done in the last 4 years (and if you have my TC book remember all those engines are some 12 years older now) tells me NOT to work with those very old parts any more.

Much depends on the actual metallurgical quality of the piston, rod, bolts, threads because when you do stress and lifing calcs you have to put in stress concentration factors to allow for impaired material, poorly formed regions etc etc. Much also depends on the mass of the parts and their actual tensile strength. For what it's worth the piston acceleration of the 2 liter TC Fiat goes from 29900 m/sec^ at 6800 (design red-line) to 41384 m/sec^ at 8000 rpm. Nearly double and so double the stress. The life of a NEW OE spec cast piston at continuous 8000 rev/min in the 2 liter unit is - as close as Sn data on cast piston material can tell me - about 19.75 minutes. The 2 liter rod bolts are close to their endurance strength at that speed too so failure could easily be there first.


GC

[NOSferatu]

I am now going to drive my cheaply tuned engine to it's very end, if it eventually gives up, because I have started collecting parts for a new engine. I already have H-profile rods and forged pistons by Supertech. I have plenty of old 132 based blocks and heads to start with...
Everyone today have turbocharged car, I prefer normally aspired.
Although my nick suggests else, I have no intentions ever to use nitrous oxide.