Oh yeah, Rod Bearing

[Tim Rogers]

"George Roffe" <geo3@earthlink.net> wrote:
 > >The only thing that changes the noise is timing, the more you retard it,
the quiter it gets...

> Steve, that is knock, ping, detonation, etc.

> Seems kind of odd that is would happen at 17 deg BTDC and that you would
> have to retard it to 10 deg BTDC.  Are you *certain* about the timing
settings?

> It's definitely not rod bearings.  I'm 99.5% certain it's
> knock/ping/detonation.

I'll agree with George on this one (I usually do...)
Assuming that your distributor is in good condition (the timing is not jumping
around starting at 3200 rpm), the next thing to check is that you have spark
plugs of the correct heat range in the motor.
Past that, the next biggest cause of detonation would be significant build-up
of carbon deposits in the cylinder head or on the valves.
Maybe using Chevron's Techron for a few tankfulls might help.

Tim Rogers
-'93 NX2000 T-top
-'91 NX2000 SCCA ITS racer-to-be
-'75 Silverado tow vehicle