Packard Forum Index » Post-War (1946-54)

I know some newer engine have torque to yeild head bolts, but will I need to source new studs when I open my '51 327 to fix the engines smoking issue? Planning on next year to get money for the parts needed. Also if new studs are needed where are they sourced from.

Hi Stan:

If you are not boring the block and just doing a service overhaul you don't have to remove the studs.

Torque to yield was preceded by "bolt stretch" that was used by Rolls-Royce (at least). The principal behind the method is that once the bolt begins to yield there is no increase in clamping force. Once the bolt yields it does not return to the shelf length and must be replaced.

The objective is equal clamping force.

Packard did not use the method.

Hope this helps.

Makes sence, I figured as much as the head will be no problem just need to get under the car to figure out how to get the pan off. It seems to be possible as I think I remember there service manual even having instructions on how to hone the motor while it was still in the car.