I think I have a Timing issue?

[dlutz1983]

I have a 2002 Explorer with 4.0L V6 with 79000 miles. Last year I started to hear a bearing kind of sound only when I accelerate hard passed 2500 rpms when I drive coming from the right passenger's side front of the engine. As soon as I let off it goes away. I have power braked it and accelerated, I have accelerated with it in park, and I can not repeat the sound.
My question is, If this were a timing chain issue would I hear it all the time no matter how I accelerate. Or could this be something totally different?
I would appreciate any help that you guys can give.

Or if someone can explain what a bad timing chain sounds like.

 

[MGG]

I have a 2002 Explorer with 4.0L V6 with 79000 miles. Last year I started to hear a bearing kind of sound only when I accelerate hard passed 2500 rpms when I drive coming from the right passenger's side front of the engine. As soon as I let off it goes away. I have power braked it and accelerated, I have accelerated with it in park, and I can not repeat the sound.
My question is, If this were a timing chain issue would I hear it all the time no matter how I accelerate. Or could this be something totally different?
I would appreciate any help that you guys can give.

Or if someone can explain what a bad timing chain sounds like.

That sounds like its pinging because of bad fuel.

 

[dlutz1983]

Can you explain what pinging is? I am at a loss. Also what are your suggestions on getting rid of the pinging?

 

[MGG]

Can you explain what pinging is? I am at a loss. Also what are your suggestions on getting rid of the pinging?

Pinging or knocking could be any number of things, unfortunately. Experienced car folks can usually tell serious problems from minor ones just by listening.
Number one problem is low grade (low octane) or cheap gas. It doesn't ignite as well as the others and may lag behind the spark just a bit to allow you to hear the combustion from the cylinder from the open valve.
Secondly is ignition timing. Retarded or advanced timing could accomplish the same problem. Burning the compressed air/fuel vapor at the wrong time resulting in a ping. My experience in California is that the manufacturer's "smog test" suggested timing makes my car run really bad. Every time they test it, I have to set my timing at the mfgrs setting for the test (or else they wont do it). It passes but runs like heck.... pinging and no power. I just set the timing back to what runs well and doesn't ping after the test passes. Kind of a joke really.
The two above are usually diagnosed as a rattle or "ping" from the valve train (top of the engine) and occurs typically when the engine is under load. Going uphill, starting out from a stoplight or accelerating quickly. Both of these will build up carbon in the valves and pistons when associated with stop and go city driving. If the carbon stays hot, it acts like a spark pulg and lites the compressed fuel/air vapor and will cause the car to run-on (dieseling) after you shut it off.

Taken from a simple search on the webs...

Try some premium fuel for a week or two... Wouldn't hurt then you can narrow it down to if that may even be the prob or not. My 0.02