Mirror bore

What is the consensus on “mirror bore”? That is a process that instead of using steel cylinder liner inserts uses a spray on steel coating in the aluminum block. Haven’t heard of any drawbacks except a rebore isn’t possible.

Beats the heck out of the high-silicon aluminum bore. Solves the problem of liners coming loose and it is cheaper than the cast-in-place liners. Helps heat transfer, too. I am all for it.

Sounds like the Plasma-Arc wire transfer used on the GT-350 and Gen 3 Coyotes. Staggeringly high oil consumption was a problem with those.


There have been several sleeveless bore treatments for aluminum blocks, some work, some not so much (Vega, BMW’s Nikasil).