01-06-2018, 12:18 AM
The key issue with a lot of rebore work is just what the bore measures when you slide a Mercer guage down from top to bottom. Bores with pretty looking cross hatch honing might not actually look so great then.
A while ago, I bought a "newly rebored" block from a "well known auction site" it had 3 thou' taper top to bottom on the worst cylinder with a 4 thou' variance between the bore diameter from the smallest cylinder to the largest cylinder.
I wouldn't want any company to try to pull those bores back to an approximation of parallel using a rigid Delapena style hone, I'd want it bored properly in the first place. Then the hone is simply knocking the peaks off the bored surface.
BTW, I used my usual (not cheap) company to rebore this particular block to +80, when it came back there was absolutely no variance shown from the Mercer guage top to bottom - sometimes you do get what you pay for
A while ago, I bought a "newly rebored" block from a "well known auction site" it had 3 thou' taper top to bottom on the worst cylinder with a 4 thou' variance between the bore diameter from the smallest cylinder to the largest cylinder.
I wouldn't want any company to try to pull those bores back to an approximation of parallel using a rigid Delapena style hone, I'd want it bored properly in the first place. Then the hone is simply knocking the peaks off the bored surface.
BTW, I used my usual (not cheap) company to rebore this particular block to +80, when it came back there was absolutely no variance shown from the Mercer guage top to bottom - sometimes you do get what you pay for