my bandit

I'm looking at an E63 AMG that has a misfire. It just underwent a Renntech tune and while on the dyno, it supposedly had the timing chain skip a tooth. From what I know, the valves are undamaged but that's unknown until the engine gets completely checked. However, is this a common problem? I'm expecting the replacement would be around $3k from the dealer to replace the chain and gears.

chiromikey

Not that it couldn't happen but I've never heard of this on any of the AMG platforms...

my bandit

I haven't been able to find anything about this happening either. Granted I'm well versed on the GM LS platform where it can happen but I know these timing chains are much more robust than the LS engines.

chiromikey

Are they sure it's a timing chain? The common misfire associated with tunes is due to spark blowout. Have you confirmed the misfire is for an entire bank of cylinders rather than 1 or two?

gaspam

^ +1, unless they have direct evidence that it was timing chain skip, I would think it is plugs as its pretty common on tuned M157 cars

also a motor with a jumped timing chain will have slow/hard starting because the firing sequence is retarded due to chain that has jumped a tooth, two or more teeth probably wont start at all.... so if your car is starting fine then i doubt timing chain has jumped

2012 CCB E63

Whomever you are speaking to is telling you
No way it 'skipped a tooth' these are dual over head cams with multiple chains




It's possible the adjusters are worn out and there is a bunch of slack/noise but no way it 'skipped a tooth' and didn't do damage to the valves.

There are plenty of E63s out there, skip/run far away from this one.

shardul

iTrader: (1)

What everyone else said.
If you are worried about the misfire start off be removing the plugs and inspecting their condition.