Loud Intermittent Tick from Top of Engine

[ghrarhg]

Engine:

1988 2.8 Block w/100k on it. New cam, pushrods, lifters, springs w/retainers & locks, 3500 valves and 3400 heads 2 years ago. New turbo last year.

Background:

Last fall, I had a ticking sound that got much worse as I drove home from work. I stored the car for the winter and haven't driven it since. I started working on it this spring without much luck.

Things I've checked:

Compression = ~140 psi across all cylinders.

Pulled Valve Covers, all rockers tight, all pushrods tight. Turned the motor over by hand a few times to make sure there wasn't a loose pushrod somewhere in the cycle.

New injectors (Needed to step up anyway)

Fuel Pressure at idle ~34 psi, ~41 psi with vacuum line removed.

Oil is clean, no metal particles.

I'll post a video up as soon as I can get back over to the car (still stored for the winter).

Does anyone have any ideas?

[jmgtp]

Collapsing lifter perhaps?

Can you run it with the valve covers off? If so you can try to isolate a loud rocker with a screwdriver (big end to your ear) or a stethoscope. Worked for me when I had a tick in my LT1 and had to adjust readjust valve lash. Of course the 60v6 you can't really adjust lash but at least it might lead you to the noise.