[SaabJohan]

Typical piston accleration figures for a normal gasoline engine at max rpm is 23,000 m/s^2, mean piston velocity around 18 m/s, max velocity of 29 m/s at 75 and 285 deg ATDC.

A typical NASCAR Nextel Cup engine peaks at accelerations closer to 50,000 m/s^2, mean velocity of over 25 m/s and peak velocities above 40 m/s.

A typical F1 engine peaks at accelerations around 94,000 m/s^2, mean velocites 25 m/s, peak velocities of above 40 m/s at 80 and 280 deg ATDC.

These peak accelerations (which occur at TDC) are equal to:
Normal car engine: 2,300 G
NASCAR: 5,100 G
F1: 10,000 G

This means that during the acceleration a 230 gram F1 piston puts a force equal to 2,3 metric tons on the piston pin, which in turn put a force equal to 2,8 metric tons on the top of the con rod and so on.
The forces in the normal car engine isn't that much lower, perhaps half due to the higher weight of the reciprocating parts in those engines.