N62 Engines

[Turbo_Bimmer]

Last weekend, I met a friend that I didn't see for a couple of years. He's a BMW tech. I told him I was selling
my E46 to get a N62 X5 (4.8is or 4.4i).
His reaction was like I anticipated. Requires lots of maintenance, etc, etc.
I told him I was ready to deal with all those problems, even transmission problems.

But, when he started talking about N62 engines getting replaced at a very high rate because of cylinders
getting oval toward the top, I became speechless.
BMW doesn't sell short blocks, only long blocks, at 20K retail... ouch!
He says that the M62 was not doing that and is more reliable, true??

I then asked him if those 'N' engines could be rebuilted, and he said no, well, BMW doesn't do it.
I read on this forum that someone had success inseting sleeves in one of those engines. Could that person tell
me if it was a custom job, of those sleeves/pistons are available through engine rebuilding shops?

If some BMW techs on this board or N62 owners read this, could you tell me if you have seen this wear pattern
on the N62, or they are isolated cases.


Lastly;
There is something he told me that could help N62 owners with idle problems. He told me that replacing the
intermediate levers, and shaft doesn't always solve the problem. They found that the valves were getting a lot
of deposit on them and were either sticking, or not closing properly. He says he now removes both heads,
disassemble completly, and clean / gring all the valves by hand + change the levers + shafts. It seems to solve
the problem.
I really wanted a N62 X5, but now I'm not sure if a M62 will be more bulletproof.