[Larry Brumfield]

Except for the first time (explained below), if you want accurate torque, you better torque and re-torque COLD. By cold I don't mean pack the engine in dry ice, just cooled off. The time for it to cool off would vary depending on the outside temperature and how hot the engine was when you turned off the ignition. Naturally the outside temperature will dictate how cool it will ultimately get. Now having said this I wouldn't want to re-torque the engine with 100 degree Texas sun beaming down on it. Just use common sense.

Now as referenced above, I tell people to re-torque the first time when the engine is warmed up and all others only when the engine is cooled off. The reason is because I have seen the copper-clad gaskets compress so much and the nuts get so loose after the first run that if one waited for the engine to cool off, water might leak or seep into the engine. Since one re-torque is not enough there's no need to worry about the loss of accuracy the first time.

Now back in the Model A days, some had a different theory. Since pistons, when heated, often run with only a single thousandths of an inch clearance, the theory was that the block might get distorted from being RE-torqued while the engine is cold and this might put the squeeze on the pistons (binding with the cylinder walls) when the engine warmed up to operating temperature and everything expanded. Consequently, the re-torque of the cylinder head was often done when the engine was warm or at full operating temperature.

I've seen no evidence of this. In my opinion if they get in a bind, the pistons were too tight to start with.

Always Re-torque when cooled off.


Larry B.