2000 TC, Rocker arm support

[xlfan]

Any ideas why this happens
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[rigidthumper]

I've seen that happen in the shop. Top end disassembled for a cam swap, reusing stock pushrods, with pumped up lifters. Tech tightened one rocker standoff bolt completely before moving on to the next one. After he got it all back together, fired it up, made a racket. Asked me to listen to it. Heard it, shut it off, and started the enquiry. "Notice anything weird as you were going back together?" He reported a "clink" as he started  tightening the second bolt on the same side. I said "as you went around the horn, little at a time on all 4 bolts? He said "No, take one all the way down, then the next"
I asked him "what does the book say about that"? He replied "this is faster"
I said "Congrats! You get to do it over, while reading to me from the manual"

(I had heard that "clink" sound, before  )

The strongest metal cannot withstand the weakest mind

[Bunjie40]

Judging by the time lapse and replies I would think you gave up.. But I'll bite..

Could be several things..
1) as Rigidthumper described in assembly...
2) Rocker mount bolts loosened up while riding and you kept going even though the motor was noisy...
3) valve to piston contact... Revved the "Potty mouth" out of the motor and with valve float the lifters pump up and BANG...

You never stated how you led up to this point.. Did it happen after a fresh assembly? did it do it while going down the road?? Need more info..