I'm in the process of rebuilding the 5.4L engine out of my 1999 Ford F250. I'm going to replace the pistons (and rings) because the black (teflon?) coating on the piston skirts is worn off and there is some grooving on the pistons that I can feel with my fingernail. Since I am replacing the piston and rings I will at least hone the cylinders. The cylinders themselves look good, I can see the factory crosshatching. I think the measurements might be telling me a different story, but I'm having a hard time understanding the specs in the Ford factory manual. The only specs I see related to the cylinder bore are as follows, and I don't really understand what the different grades mean:
Cylinder bore diameter
- Grade 1 90.200mm - 90.210mm (3.55118in - 3.5515748in)
- Grade 2 90.210mm - 90.220mm (3.55118in - 3.5519685in)
- Grade 3 90.220mm - 90.230mm (3.5519685in - 3.5523622in)
Additionally I would expect to see a taper and out of round spec, but I don't. So the question is, with the measurements I have provided do I need to bore my cylinders and get over sized pistons?
The spec is 3.5520 (I think), but that doesn't match what the manual says. The differences in measurements is what really matters at this point though. I highlighted all measurements that were not exactly the spec.
