Originally Posted by oldbogie
It's done when the ring grooves are re-machined on a used piston or to correct machining errors on new pistons or when running a newer narrow rings in a piston machined for wide rings.
It's a practice I never subscribed to so I can't give you any insight as to how long its good for. My assumption has been that it's a band aid solution from a century ago when vehicles didn't go far nor fast and keeping things running cheaply thru the depression was the paramount concern. I see it as a "Grapes of Wrath" era thing like knurling pistons to run in ridge reamed bores, grinding valves and seats with gritty oily compounds, and shimming bearings are remnant processes from that era designed to keep an engine limping long enough to get from Oklahoma to California.
Bogie you are right on the money!
My father told me when in my pre-teen years I started to work on motors that him and my mother drove a Model T from Oklahoma/Kansas to central Texas.He bought a stripped model T off of a farm for 15 dollars.He tore in to the motor, cut thin strips of leather and fit them behind the rings and fit thin ring spacers on the ring lands.He cut up leather belts(the kind that holds you pants up!)soaked them in motor oil and fit them to the rods because the Babbitt was gone.They could make 20-30 miles a day down roads that were basically cow trails.They would stop a camp on the side of the road each night and my father would drop the pan and replace the leather in the rods that were loose .The last few days of the trip he ran out of leather so he used some canvas that was on the seat of the T.It toke them about a month to drive about 700 miles and the motor did fine as long as he didn't push the RPM'S much past idle.
So I guess if you put your mind to it you can do about anything.
Lost your job yet?
Keep buying foreign.