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Discussion Starter #1
Ok so I have been told before that the clicking/ tapping sound from the engine bay is normal on a 4.7L on accel and decel and that the lifters are hydraulic, but my rattle is getting worse and frankly im tired of listening to it, its embarrasing and annoying that I hear it over my exhaust. I think its more of a valve adjustment than a lifter, and im hard pressed to believe that a hydro lifter would have this problem if it wasnt bad. Does anyone have a spec/maintenance book? or know where I can get one. I didnt see any at autozone or advanced.

also since im sitting on 110K Im going to inspect the T-belt as im not sure when it was last done, and maybe experiment with a homemade snorkel idea that I have :devil:
 

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ManVan37,

There is no timing belt.....these cams are chain driven and no service is called for.
Although the 4.7's generally have a slightly audible valve train, mostly noticable at idle, your description makes me think you have a exaust manifold leak where it meets the cylinder head.
The reason I am thinking along these lines is because the valve noise may increase in speed, but there should be no change in volume regardless of throttle position.
A exaust leak, on the other hand, will increase in volume with throttle position.
This is due to a bit of back pressure, forcing the exaust out of one or more port connections.

Many members have had the exaust manifold bolts break their heads off, resulting in the sound/leak I am describing....that is a rather sharp ticking sound, not unlike a valve noise.
So, before you go looking too far in the wrong direction, look at the manifolds (you can pull rivets out of the inner fender and draw the panel back to see) for any missing bolts or telltale carbon buildup around the outside of the exaust ports.

Good luck,
Rob
 

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Discussion Starter #3
just had the manifolds repaired on both sides not 6k ago. this is the second time too....also it is audible only at idle, and very loud under decel and when you let off the throttle to coast untill the revs drop to idle. Its unaudible after 2500rpm due to the magnaflow. its very loud due to echo when you pass buildings or cars at close distances and this volume is where I notice the increase in sound. also with the exhaust leak there is a distinctively different tick and it can be heard at all times even with the magnaflow, plus there is the smell of fuel. I will be leak checking my manifolds again soon, but there is an extremely limited chance of it being them again...

reguardless of what service interval states no timeing belt or chain lasts forever. chains stretch over time, with 110k its possible to be stretched very far. but more so what im looking to know is if there are any specs on the valve lash. because this type of tick is common from excessive gap between the rockers and valve.

im pulling my valve covers tomorrow to check my cold clearances and to investigate further.
 

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Discussion Starter #4
Upon further investigation...its worse than a few bad lifters.....I found one lifter that was a tad weak, but when I put it back together and got out my stethoscope...I found the ticking sound is actually more of a clunk sound and it is comming from around the 4/8 cylinder area. So since my oil is due for a change it looks like now I will be dropping the pan to check my rods...ugh I t hink I was happier hopeing it to be a few bad valve adjusters lol
 

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Upon further investigation...its worse than a few bad lifters.....I found one lifter that was a tad weak, but when I put it back together and got out my stethoscope...I found the ticking sound is actually more of a clunk sound and it is comming from around the 4/8 cylinder area. So since my oil is due for a change it looks like now I will be dropping the pan to check my rods...ugh I t hink I was happier hopeing it to be a few bad valve adjusters lol
Just out of curiosity, did you find that there is NO way to adjust the valve train clearance? That is the case with most valve train with hydrualic lifters, but NOT all. That was what I was going to guess, since you were asking for valve train clearance figures, there are none, there is no way to make adjustments, the hydrualic lifters do it all.

Have you considered its just bad lifters, maybe replacing them?

I hope its NOT a spun bearing, they can make that kind of noise.
 

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Discussion Starter #6
yeah this type of rocker setup doesn't have adjustments, unlike some more modern setups. I was partially shocked that they would still use a setup from the late 70's early 80's. The concept is simple and works but demanding as the lifters have to take all the abuse, not just keep the clearances tight. I have also looked deeper and found that the noise is eminateing from within the block, and loudest under the engine. I plan to pull the pan asap if not this week then in Aug when I get home from being TDY.
 
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