We apply the hone ourselves using a screwdriver.
I received a VQ25HR engine with a terrible diagnosis: it knocks when cold, but the knock goes away after warming up. They said it was the pistons. I took it apart and was surprised, as there was no sign of wear in the piston group, so there was no reason for the knocking to come from there. It later turned out that the left exhaust manifold had been loosened, or rather, not tightened. My eldest son, 14, unscrewed it by hand, without a ratchet or extension, using a 14mm open-end wrench. It turned out the exhaust was passing through the gasket, which is double-layered, and was creating a ringing noise. As the engine warmed up, the noise went away due to expansion. I decided to adjust the hone, as antifreeze was apparently getting into cylinder 6, and there was a scratch on the wall of cylinder 1. I couldn't remove it completely, but I did remove the burr. What it is or where it came from, I don't know. It's known the engine wasn't using oil. Using diesel fuel as an emulsion and a screwdriver, we spin the engine at low speeds, without fanaticism, and add diesel fuel while spinning. Until the hone becomes uniform.