Need R3v's opinion - broken timing belt, just pulled the head off

[ChaseN]

Hey everyone

I'm working on a M-Tech 2 appearance package 'vert for a buddy of mine. He broke the timing belt last week, and now I've just pulled the head off to see the carnage below. It looks like all 6 (!) exhaust valves hit the pistons, and no intake valves. Now, I've read many people just file down where it hit some to avoid any hot-spots, and slap a new head back on and go. Just to be on the safe side, I've attached pics to see what you all think. Damage doesn't look that bad really, but I thought I'd get y'all's opinion as well.

Should I just file it down a bit and go? That's where I'm leaning right now.

Also, whats the deal with all the carbon buildup in cyl #1 compared to the rest? Is that normal? Should I attempt to get any of it out?

Thanks!

Chase

(The pics are in cylinder number order, i.e. 1-6)

[KenC]

If you think you can smooth them out to avoid hotspots, I'd do it. It's an M20... they're a dime a dozen. I'd check compression in #1 when you're done though. That looks like a ton of sludge. I'm guessing your friend changed his oil last when he did the timing belt change? Haha

[nando]

I don't see anything too terrible in there. like ken says, smooth off the dents so you don't get hot spots. what you need to be worried about are gouges in the cylinder walls, if they are fine then slap a new head on and go another 100k miles.

oh, and change the fucking belt! It's unbelievable that after 30 years people still forget to change the belt on M20s. $50 in parts ends up costing them $500-2k in repairs. :p

as far as cyl #1, it could be leaking valve stem seals. But you're going to have to rebuild the head anyway, make sure they're replaced. Otherwise it could be bad rings. Depending on how far you want to go, it might be worth pulling the bottom end, and doing new bearings, rings, and a rehone, and having the block decked flat.

[ZM Blue Devil]

How did it go? Head arrive on time?

[twitch]

mine were worse than that.I spent a good 4 or 5 hours smoothing mine out and you could barely tell when i was done.Ive been running about 3k so far and no problems yet and im boosted as well.will save a lot of money of your willing to put the time in to make it perfect.I can post up some before and after pix if you want

[ChaseN]

Thanks guys, I knocked em down some with a little bit of sandpaper and all is well.

How did it go? Head arrive on time?

Perfect! head was at the house yesterday around 3. Finished it up early this afternoon and it runs like a champ! Spent the rest of today cruising around the blue ridge mountains with the top down, enjoying a late season 60* day. Perfect.

Thanks again Levent :)