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I fixed a timing chain that was making an awful racket and the engine seemed very sluggish, My brother in-law and I thought a possible chain replacement and possible engine rebuild was in order. On one of the forums I read that the chain tensioner is a known problem. When the spring is properly tensioned there is quite a bit of travel available in the plunger.
I removed the tensioner assembly and disassembled it completely (much against the instructions on the forum that I was following).
When disassembling the tensioner there is a snap ring that holds a keyed washer on the inboard side of the tensioner housing, slide this snap ring up the shaft of the housing toward the the mounting flange do not take it off!! It will be much easier slide it back into position for reassembly later. You can now pull the plunger, shaft, and spring from the housing. That is when I discovered that the end of the spring was broke off and there was absolutely no tension on the timing chain what so ever!! I grabbed my handy needle nose pliers and bent a new 90* end on the spring using the broken piece as a reference. The plunger is two pieces, the first, a shaft with about an 1 1/4" of threads on one end and a deep slot on the other end, the second piece is the plunger that is visible and sticks out of the tensioner housing it has a matching threaded hole for the shaft, the outside of the plunger has a flat keyed surface that is mated to a keyed washer (this allows for the plunger to move in and out of the tensioner housing and prevents it from rotating. To expand on the spring design, it is a coil spring (sort of like a mini slinky) on the outboard end of the spring there is finger that is bent at a 90* towards the center of the coil of the spring, this is where the slot of the tensioner shaft engages the spring, the inboard end of the spring has a 90* bend to the outside of the coil, this finger engages into the slot in the bore of the tensioner housing and prevents the spring from rotating in the housing and it allows the spring to be wound like a clock, (this is the end that was broke off in my big red). Reassembly... make sure that the plug screw on the outboard side of the tensioner housing is removed, insert the spring with 90* finger pointing towards the center end in first make sure the finger pointing out engages into the slot in the housing bore, now insert the threaded shaft slot first!! Rotate the shaft, the slot should catch the spring finger and drop another 1/8" or so. Hold your finger on the end of the shaft, now take a small regular screw driver and insert it into the small hole in the outboard side of the tensoiner, rotate the screw driver clock wise like tightening a screw, you should feel the screw driver drop into the slot of the shaft, now rotate the shaft about ten turns or so, pay close attention to the spring do not over stress the spring (feel binding). With the spring tensioned hold the screw driver and housing in one hand to prevent the spring from unwinding now thread the plunger in as far as it can go but do not tighten it to the shaft (the shaft has to be able to unscrew and push the plunger against the timing chain tensioner "shoe". While still holding the screw driver in the housing (don't let the spring unwind!!!!) Match up the keyed washer with the end of the tensioner housing and slide the snap ring back into place. Still holding the screw driver and tensioner assembly reinstall the assembly, and a new gasket into the engine block and tighten the mounting bolts. Once tighten you can let go of the screw driver the spring should should rotate the screw driver counter clock wise a few turns until there timing chain has tension, remove the screw driver and replace the plug screw on the end of the tensioner housing. If by chance you lost grip on the screw driver after the snap ring was put back in place, and the plunger had fully extended, simply re-tighten the spring (and retract the plunger) by reinserting the screw driver into the tensioner assembly and turn the screw driver counter clockwise until the plunger is retracted. You should be able to start the engine and the noise will be gone. You may also notice a much snappier throttle.
I removed the tensioner assembly and disassembled it completely (much against the instructions on the forum that I was following).
When disassembling the tensioner there is a snap ring that holds a keyed washer on the inboard side of the tensioner housing, slide this snap ring up the shaft of the housing toward the the mounting flange do not take it off!! It will be much easier slide it back into position for reassembly later. You can now pull the plunger, shaft, and spring from the housing. That is when I discovered that the end of the spring was broke off and there was absolutely no tension on the timing chain what so ever!! I grabbed my handy needle nose pliers and bent a new 90* end on the spring using the broken piece as a reference. The plunger is two pieces, the first, a shaft with about an 1 1/4" of threads on one end and a deep slot on the other end, the second piece is the plunger that is visible and sticks out of the tensioner housing it has a matching threaded hole for the shaft, the outside of the plunger has a flat keyed surface that is mated to a keyed washer (this allows for the plunger to move in and out of the tensioner housing and prevents it from rotating. To expand on the spring design, it is a coil spring (sort of like a mini slinky) on the outboard end of the spring there is finger that is bent at a 90* towards the center of the coil of the spring, this is where the slot of the tensioner shaft engages the spring, the inboard end of the spring has a 90* bend to the outside of the coil, this finger engages into the slot in the bore of the tensioner housing and prevents the spring from rotating in the housing and it allows the spring to be wound like a clock, (this is the end that was broke off in my big red). Reassembly... make sure that the plug screw on the outboard side of the tensioner housing is removed, insert the spring with 90* finger pointing towards the center end in first make sure the finger pointing out engages into the slot in the housing bore, now insert the threaded shaft slot first!! Rotate the shaft, the slot should catch the spring finger and drop another 1/8" or so. Hold your finger on the end of the shaft, now take a small regular screw driver and insert it into the small hole in the outboard side of the tensoiner, rotate the screw driver clock wise like tightening a screw, you should feel the screw driver drop into the slot of the shaft, now rotate the shaft about ten turns or so, pay close attention to the spring do not over stress the spring (feel binding). With the spring tensioned hold the screw driver and housing in one hand to prevent the spring from unwinding now thread the plunger in as far as it can go but do not tighten it to the shaft (the shaft has to be able to unscrew and push the plunger against the timing chain tensioner "shoe". While still holding the screw driver in the housing (don't let the spring unwind!!!!) Match up the keyed washer with the end of the tensioner housing and slide the snap ring back into place. Still holding the screw driver and tensioner assembly reinstall the assembly, and a new gasket into the engine block and tighten the mounting bolts. Once tighten you can let go of the screw driver the spring should should rotate the screw driver counter clock wise a few turns until there timing chain has tension, remove the screw driver and replace the plug screw on the end of the tensioner housing. If by chance you lost grip on the screw driver after the snap ring was put back in place, and the plunger had fully extended, simply re-tighten the spring (and retract the plunger) by reinserting the screw driver into the tensioner assembly and turn the screw driver counter clockwise until the plunger is retracted. You should be able to start the engine and the noise will be gone. You may also notice a much snappier throttle.
