My 1996 E350 (460ci) makes a valve clattering noise while accelerating. Any time a load is placed on the engine. I had a few cars from the 70s that had the same symptoms and the only cure was to use premium gasoline, 93 octane. I did the same thing with the van and it does reduce the clatter considerably but not completely. I would like to use regular grade gasoline because of the price difference. In my area premium grade is at least 50 cents more per gallon. My understanding is that the van's engine is calibrated to use regular grade gas so I don't know what is going on.
I would appreciate your help diagnose this problem and save a few bucks while at it.
Thank you

 

You could have too much slack in the timing chain. Whens the last time you did a tune up? Fuel filter/ fuel pressure test? Checked vacuum hoses? Pinging is detonation which is usually 2 things. Timing or a lean condition. (fuel pre burning)

 

While the van is 22 years old it only has 60k miles which I think would eliminate the timing chain slack. I have not changed the spark plugs, wires, distributor cap and rotor since I got the van two and a half years ago. I did replace all fluids and filters at that time.I am replacing all those parts now..Will check timing while I am at it.
If I understand you correctly , my van should run fine on regular grade gasoline with no valve clatter?
Thanks