|The sleeves may have the correct piston clearance in an unstressed state. |
However, when the sleeves were installed with the impact driver or shop pressed, the sleeve ID decreases as a result the interference fit with a resulting hoop compression stress in the sleeve wall.
Have seen some videos on You Tube where the there is no interference fit on the N series engine and the new sleeves just drop into the bore and have to be secured with a special Locktite sleeve adhesive.
If the interference fit is excessive the installer may run the chance of cracking the block using an impact driver.
It was not clear from Jason's You Tube video on his 9N engine rebuild ,if he installed the sleeves with the impact driver tool or the machine shop pressed the sleeves into the block.
The episodes that cover this sleeve issue are #10 & #12, ...could not find an episode #11.
According to the video the new pistons would not slide throught the newly installed sleeve(s) without honing to size.
It is more difficult to hone a steel sleeve than a cast iron sleeve or cast iron block.
Since there is a wide variation, .005" ,in the sleeve OD from my own experience, some sleeves compress more in ID than others. If the purchaser is "lucky" and has a .001" interference fit on all the sleeves the piston will probably have acceptable clearance without have to perform a honing procedure.
Also, the original block bore has a manufacturing tolerance.
What do expect for cheap foreign $150/ 4 piston-sleeve set, ...tight tolerances?
Again, if you get lucky no honing is required.
Have rebuit dozens of engines of all types with sleeves, including outboard engines which have a habit of melting pistons and throwing pieces of steel rings. Each rebuild required honing the sleeve to fit the piston , properly with the correct clearance.