Cold oil temps = mega wear on bearings/cams/rings etc, Same with water temps, Engines are build to have the correct clearences at the temps they were designed for.
In the RB's case its low 80's for water temp.
Running at 60 degrees means the pistons are loose in the bores, and have a tendancy to break.
If the motor is built to run cold, eg NASCAR motors, than the clearences are a lot tighter, when they get hot they break.