Did I kill my motor?

[pigeon]

Took my 951 to a track day at Watkins Glen a few weeks ago. Last session it starts missing so I pull it and shut it down. Clutch is on the floor but that's not the issue. It's making a horrible racket and #2 is not firing. A fresh plug didn't help and I confirmed that the plug is firing (timing light fires from all wires). The racket sounds like it's top end, but I pulled the cam tower today finally and apart from a couple soft lifters everything looks good, valve springs are in good shape and no obvious sign of bent valves. What's my next diagnosis step? Put it back together and run a compression test? Pull the head, since I'm more than halfway there?

[SolReaver]

You could put an air hose to the spark plug opening and listen for hissing out the intake, exhaust, or breather.

The crank might try to spin, so keep a lock on it.

[Capt Squid]

While the cam tower is off, take a look at the valve spring retainers and valve stems. If one of the valves is slightly lower than the others, you have a bent valve. Depending on how bad it is bent, you could have a slight miss to total crap out.

An extra cam tower nut was left in when one of my engines was installed. When it caught between the cam and lifter, it bent the valve and blew a hole in the cam tower. The engine barely ran.

[Techno Duck]

I would bet a burnt exhaust valve. Can test with either a compression or leak down test. If doing a compression it will show little to now compression on that cylinder, leak down will have all the air coming out the exhaust. No need to put the cam tower back on for either test.