Would it be worth to hone these walls or not really?
Vq35de rev up 175,xxx ish kilometres spun a bearing on cylinder 6. So i’m in the process of tearing it down and rebuilding it.

Would it be worth to hone these walls or just leave them? All of them look like this with good crosshatching with little to none up and down wear. There are very small vertical marks on 2 walls that u can’t feel with your fingernail.

 

I've never rebuilt an engine (it's on my bucket list). However, I have done a lot of homework on engine building and it sounds like you have as well. Those look healthy to me. If there were/are signs of glazing or scoring that you can feel with your fingernail, then a re-bore or re-hone would be in order. If you have a bore gauge, I would check for any taper issues or if anything is "out of round." That kind of thing. The two cylinders with light scoring, I would try to clean up with a hone, but it's your call. It's one of those things I would do while I'm in there and for peace of mind.

Revup VQs are known for oil consumption, so I would take the time to inspect the condition of the pistons & rings. This was the theorized root cause for the excessive oil consumption (That or a bore taper machining defect).

Cheers!
-Icer

 

I agree those look pretty good still. Im currently going through the same with my rev up. I honed all of mine since Im replacing pistons and rings. if reusing the rings and theres no scoring that catches a finger nail I would send it. unless what icer said if the cylinder is out of round that should be addressed.

 

With experience building Nissan race motors, I'd say the most important factor is if piston rings are being replaced. If so, a fresh rehone is in order to make sure the rings seat properly. No use doing all that work on an engine and not getting all the benefits out of it.

 

If I was in your position heres my thought process:

Spun bearing: Engine needs to come entirely apart, and everything needs to be cleaned > bring to machine shop to have it hot tanked.

Its already at the machine shop, have them check the cylinders to make sure they're within spec, hone, and deck the block.

 

What DK said about piston rings …

When I tear-down an engine more often than not it’s getting fresh bearings, rings, gaskets, etc… so I usually ball-hone cylinders for fresh rings. I would also have a machine shop inspect the flatness of the heads and if there are any questions than have the heads machined.