6 mo. problem chase finally ends. now how do i fix it? (CAM chain)

[Blank-Disk]

Okay, I've been hearing this tapping noise since i got my 93 ATX two years ago, could NEVER find out where it was comming from. It's gotten louder and louder over the years. I've spent months chasing after a powerloss/engine jolting/hesitation problem. Today, i went out to do the ol' "listen to the screw driver on the fuel injectors test", and after finding them to be okay, I decided to make sure everything else sounded good just for the **** of it. I put it on the timming belt cover in various spot, alternator, anythign that has spinnign stuff inside. Then, i put it on thr front valve cover over the chain ont eh driver's side. Clear as freakin' day, i could feel and hear something knocking inside. I checked everywhere else, on both valve covers. the ONLY place where i can hear it is on the **** on the front valve cover that houses the CAM chain and tensioner.

The tapping is about 4-6 quick taps (maybe 1 second durration), about every 3-5 seconds, at idle anyway. But that's all the tapping i need to hear to know I need to fix it. I was thinking the tensioner could be going bad, and causing slack int eh chain, which hits the case. But that's just my theory. Any idea would be GREATLY appreciated.

Note: I already replaced the valve cover gaskets and plug seals, and when i did the tensioner seemed fine, but i wasn't having the powerloss issues then.

 

[Slo-Sho]

Time to open her up!

 

[Yamaha V6]

The chain's stretched, put money on it. Replace the chain, you may find the tensioner gone or just clogged up on the piston vent. Make sure the one you've got moves freely with a little resistance, and has a good nylon insulator left.

 

[Blank-Disk]

is it at all possible that the tensioner is flexing in and out intermittently. i noticed the knocking noise doesn't jsut stop, it fades away

 

[Yamaha V6]

Anything's possible, you'll need to open it up to see for sure, but the lack of power coupled with a chain tensioner failing causes a "snapping" of the chain timed with the firing pulse, which aggravates the stretching (no tension, FIRE, snap into place, repeat thousands of times on your way to work).

The further the chain's stretched, the farther out of time the exhaust cam will be, resulting in lost power, poor running, etc. If you put a better tensioner in with a stretched chain, the exhaust cam will still be out of time. By the same token, replace a chain without replacing a failed tensioner, won't be too long before you're hearing the tick again.

 

[Howdy_Doody]

Are these parts (tensioner, chain) still available from Ford? I got spooked when I heard the oil pump had been discontinued.

 

[Slo-Sho]

Prepare yourself for another spook.

 

[jelloslug]

The chain's stretched, put money on it.

I'm with Yamaha V6 on this one. Out of all the engines that I have opened up that had "bad tensioners" all of them really had bad (streched) chains and clogged up tensioners. Disassemble and clean the tensioner and replace the chains and that should fix it.

 

[Blank-Disk]

I read that the sprockets WILL be bad too, and should be replaced. How true is this?

also, thanks to everyone for the advice so far.

 

[jelloslug]

I have never seen a bad sprocket (nor have I ever heard of such)