well im hoping that someone will be able to help me here as i am stumped on this one. i have a 2001 f-150 with a 4.6 with 227,000 on it im used to it blowing the plugs out or them knocking in the head before they break the coil but about a week ago i blew out the 2nd plug on the left side and at the same time the engine picked up what is a very distinct knock, kinda sounds like a rod knock or something to that nature. i have the pan, valve covers and front timing cover off and don't see or feel anything that jumps out at me. ive checked the flex plate and that isn't loose or broke. i took the belt off and the knock never went away either. kinda leaning towards timing chain and tensioner but no really sold on that either. any ideas would be greatly appriciated.

 

anybody?????

 

It helps to use a mechanics stethoscope to help pinpoint a general area of where the noise is coming from. Is the knock consistent with rpm or does it change? Try to pinpoint it.. Could be an exhaust leak, most commonly on the passenger side. Could be a number of things. Tensioners would be in question with those miles. If it is a bottom end bearing, wrist pin or something pertaining to a particular cylinder, you can individually and one at a time unplug the cop/wire and injector to a cylinder and the knock should all but go away on the cylinder that is at fault.

 

anything i should be looking for on the timing chain tensioners? they aren't worn thru

 

k put the oil pan timing cover and valve covers back on and ran the engine. knock changes with the rpm, didn't really hear the knock go away or get quieter when i unplugged the injecters one at a time. im really thinking its a rod bearing or wrist pin that went south but no sure why it happened the same time the plug blew out

 

Any way you can upload a sound clip or video? It really just needs to be heard. Typically with a rod bearing, shutting down the cylinder while it is running will dramatically reduce the noise. Here is a video of mine.. the end result was a bad main bearing and bad tensioners. In the second video If you listen closely, you can hear both sounds. Also an exhaust leak, so there are 3 sounds. The exhaust leak is the ticking sound. I believe the chain tensioner are the clacking sound and the knocking would be the bearing.

 

http://youtu.be/02wS1leN7wg
is a link to a youtube video. i used a stethoscope and def a front end of the engine noise and a lower also hope this will help

 

Weird, sounds consistent with rpms but doesn't stand out as a bearing knock to me. Plus, you said that shutting down each cylinder made no difference in the knock/ticking..and it would. I would have to think wrist pin or chain tensioner. But even with a rist pin, the sound should mostly go away when the cylinder is shut down. And quite doesnt sound like chain chatter to me from a bad tensioner. Did you try the stethoscope on the exhaust manifolds to determine which cylinder?

BTW, to keep from blowing out plugs with these engines, plugs are recommended at 28ft/lbs dry (no anti seize) And when they do, timeserts are the best optoin for a fix, not heli coils.

With any of your blown plugs, were there any pieces to the plug or anything else missing? Sometimes they can bounce around in the plug well and end up breaking pieces off, which make it into the cylinder and can cause damage to the valves or piston.

 

i will try the stethoscope on the exhaust manifold and get back to you, i used the timeserts on the ones ive had issues with so far. never had any pieces missing off the plugs.

 

they all sound the same when i used the stethoscope on the manifolds and i unplugged the fuel injecters one at a time again and didn't hear any less chatter. im clueless to say the least. any possiblity of like a cracked or broken crank? don't really have any abnormal crank end play tho. im kinda to the point now that im just gonna tear the engine out and put it on a stand and for as bad as it rattles i should be able to fine the issue if its castostrophic or not

 

They can knock like that while missing, - it's NORMAL.

It's worse on the passenger side when #3 or #4 isn't firing. Originating from piston slap @ #1.

So, eliminate the misfire and the knock should go away.

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Toyz definitely has a different problem. I think I remember that.

 

yeah i got it taken out of the truck today and tore down, found that the right side bank camshaft must have jumped time from the worn out timing chain, tensioners every piston has marks on it from the valves hitting them.

 

How in the world did you do that ? You must have really hammered on it while it was missing. That usually won't happen with theses engines. If you ran it hard missing, yea, I can see it.

Good Luck.

 

Sounds like it's time for a PI 5.4L swap