Gentleman,
After combing the archives with the search feature.....I'm stumped.

I recently rebuilt (800 miles ago) the top end of my 84 22R (carb), I installed a dual row timing chain in the process.

In the last 200 miles or so, I've developed a ticking sound coming from the front of the truck when the engine is under load (accelerating) from around 2000-3000 rpm. The sound goes away at 3000+ rpm and does'nt tick at idle.

It sounds like a valve ticking, so I adjusted the valves (for the third time since rebuild) again. The problem is I can't reproduce the sound in my driveway. The engine must be under load, i.e., accelerating from a lower speed relative to the gear the truck happens to be in with the engine at operating temp.

I've poked around the engine with my mechanics stethoscope (the best $10.00 I've spent recently) in the driveway. The valves don't make any unusual noise, same from the block, the oil pump area, water pump area, exaust manifold, etc...can't find any loose heat shields or the like. The dual row timing chain isn't rubbing on the valve cover or the base of the distributer shaft, I looked down the timing chain case, no wear on the guides that I can see with a flashlight.

I can hear the ticking sound with the stethoscope where the downpipe meets the exhaust pipe (although I believe this is just the residual sound coming from somewhere else)

I'm not finding any exhaust leaks and I pulled off the catalytic converter. Nothing loose in there, but I can't see too much daylight coming through it.

The fuel pump is sounding noisy(ticking) and the idler pulley sounds like it's worn(kind of a 'grating' noise).

Both of these sounds are barely audible to the unaided ear (in my driveway), the stethoscope allows you to hear 'under' the general 'white' noise of the engine.

I replaced the fuel filter and checked the hole at the bottom of the fuel pump for obstruction. I cut the old fuel filter in half, nothing unusual.


The sound is a distinct, sharp ticking sound, just like a loose valve, but I adjusted the valves to a 'firm' .008/.012.

The noise is making me crazy! <img src="/forums/images/graemlins/scared.gif" alt="" />


Any ideas? Fuel pump? Idler pulley? A faulty head rebuild?