[s-cars] update - was ping vs. rattle

[james McCarthy]

Thanks to all those who chimed in so far.

So here's what happening:

It's evolving... began with rattle/clatter/ping noticeable at 2800-3200 - didn't hear with WOT - I thought (perhaps) because I was just blasting through it.
It's growing in volume (and RPM range now at 18000) to a very audible and and become more rhythmic tick - almost valve like but more regular and stronger with the occasional valve clatter I've gotten when the oil got a tad low (down a quart). Can also faintly also hear it with falling RPM (off throttle) where as before you had to be on the gas.

While standing with the hood up and modulating the throttle it really sounds like it's coming from the head to me - released the serp belt (no change). Still don't hear it at idle - but perhaps I will soon...

It's definitely RPM related in frequency - no difference with clutch in or when stationary. 

Several listers speculated headgasket failure - for a little background I replaced the head gasket 1 year ago and put new lifters in at that time. Compression is 130 in all 5 with no coolant loss and no washing machine cleaning effect on any of the spark plugs - so HG seems less likely (no way to check leak down at home).

Doesn't seem like exhaust leak - stromung with no heat shields - as it sounds higher up. All exhaust studs are in place (wagner RS2 unit).

One last tidbit is it seems to get louder once the car is warmed up.

So where to go from here? Tempted to tear off the valve cover but if everything looks OK what next.

Any thoughts you have would be greatly appreciated.

Thanks
-jamie