Here we go again, good ol' engine ping! I have read many of the different threads on this subject already, but I thought I would present my unique circumstances in hopes that someone might have some ideas. Here's a little run-down of the details:

I drive a 1989 Ram D150thatI put a re-built 360 motor in two years ago (roughly 20,000 miles on it).I live in AZ where it tends to be dry and hot.I've had problems with the motor since day one, having to bringit back to the dealer for all kinds of problems from oil leak toworn outlifters. I should mentionthat I haven't hadany overheating issues since I upgraded to a higher capacity radiator with the new motor.Over the last month it has been more humid due to rain. Inoticed a slight pingwhen I was driving up-hill (and at higher RPM's). I figured the dealer probablyleft the old spark plugs and distributor on, so I replaced the wires and the plugs withChampion Platinum plugs @ .35 and Bosch wires. With the new wires, I alsoadjusted the timing, but ended up not changing it much, if at all. I run the highest octane gas that I can get, which is 91. Last year,in an effort to locate and fix an exhaust manifold leak I replaced the thermostat.Since I'm in AZ I'm sure I used no less than a 180, but it could have been the 192 degree model. Also, I recently replaced the fuel filter and ran a fuel cleaner through the tank as well for good measure.

So, based on what I've read, everyone talks about possible spark problems, replacing the thermostat with a 180 degree model, and fuel octane. Given that I've gone over the whole spark plug/distributor set up with a "fine tooth comb", adjusted the timing, and currently use the highest octane fuel available I don't know what to try next. Any suggestions appreciated!!!

 

Have you tried backing off the timing a bit? What are you at now?

 

I don't know what it is specifically set on right now; however, I spent a good amount of time setting it at a point where it doesn't shudder upon ignition and it doesn't knock on regular acceleration. If I back it down any more it just runs rough and sluggish, and just doesn'tfeel right. The ping/knock really only occurs upon heavy acceleration, up hill climbing,orhigh RPM.

 

I'm planning on adding an octane booster to thefuel to see if that has any impact. This way I figure I cantell if the problem is related to the octane or not.

 

The octane boost was nice, but it didn't seem to stop the ping. However, I replaced the PCV valve and so far that seems to be making a difference...

 

Funny howa $3 piece of plastic sometimes gets you more results than the $5000 engine overhaul.

 

you might have a vacuum leak causing the idle shudder at proper timing, and covering it up by setting timing too far advanced. try temporarily disconnecting, labeling, and plugging ALL vac lines. back off timing and see if its any better. also use vac gauge to see what it tells you.

 

I agree. You may be inducing the pre-detonation due to another problem that is masked by your settings. BTW how is your compression?

 

These are logical possibilities. I think I will just replace all of the vacuum lines since most of them are old anyway.A vacuum leak could also explain the louder than normal whistling/squeaking noise that the new PCV valvueis making. Compression should be fine since it is a new motor (2 years old).

 

It's a quick check that shouldn't be overlooked (espically because of a rebuild). Were the heads retorqued after break in?