Torque plate

moper said

Understood. How long ago was that? Did they own a good profilometer?
I've built engines that were plate honed, but when measured the bores were straight and round all the way up to the deck without the heads in place. There should be a measureable distortion without the heads if it's done properly.

Click to expand...

We had plenty of gauges. Our line ran 500,000 engines per year for daily drivers. We also had a CMM (Coordinate Measuring Machine) room in our inspection department that we also could get things measured on.

Each pass on the bore took off less and less metal. Our rule was that you use the boring operations to get you to the proper size, then "scratch the surface" with the hone. You just take a little bit off with the hone, but it's mostly to get the surface finish to spec.

When they changed over to the "smooth bore", I was the one who had to have everything measured and submit all results to the design group for their approval before launch. (mid-year launch at that - not a clean break between model years :banghead:). Diameter and surface finish at 10 levels of the bore every 45° in each cylinder. :violent1: