FYI
I am in the midst of a TR6 Rebuild with an engine that is .020" overbored.
While fitting up the pistons and checking clearances everything checked
out and the bore was concentric and to specs.
With the piston installed in the bore I noticed increased drag with #1
piston installed.
With rings gaps, skirt clearance correct I pulled the piston and didn't
see any issues.
Further inspection showed that the piston was cocked in the bore and had
score marks on the bottom of one skirt with the same wear just below the
oil ring on the other side.
After inspecting it with the machine shop we noticed that the ring
grooves were not fully machined on one side of the piston.
The rings would not move far enough in the groove and was proud of the
surface causing the piston to cock in the bore.
We collectively have not seen this before and have a new set of AE
pistons not County on the way.
Having spent many years in Automotive Engineering at one of the former
Big Three, these events are usually not one of's.
There likely are many more out there that ran down the line in the same
batch at the same time before it was caught.
These are new County Piston sets (I think made in Israel now).
I would inspect their parts very closely before you install them.
I also noticed machine chips in the machined groove of their Tri-Metal
Main Bearings (Israel).
The chips were in the machined groove and were plated over with the
babbit and copper.
I have had very good experiences with their parts in the past.
Just thought I would provide a heads up.
Glenn
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