Re: 352: Light Tic Under Light Load, At 2000-3000 RPM

Posted by Joe Hall On 2014/1/12 10:43:28

Thanks Tom & Packard V8 for the good food for thought.

A few problems with cylinder isolation by removing plug wires: It is silent at idle, and the tic only begins at around 2000 RPM under light throttle, in gear (car moving). Also, I have pacemaker, and the manufacturer specifically cautions against electrical interference, i.e. airport scanners, and I presume plug wires, especially if one accidentally "bites" me :)

In re-checking the math on spring clearance: they are factory set to 1.750" seated length. Coil bind is @1.250", so with .398" valve lift for intake and .388" for exhaust, that leaves .102" and .112" before coil bind. My setting them to around 1.700" left .052" and .062" before coil bind. Modern cam manufacturers recommend a minimum of .060", so re-doing the math may just have revealed the problem.

I am on my way out to the garage, to remove a .030" shim from each spring on that head. Will post results later.

Thanks Again,
Joe