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250 Posts
Discussion Starter #1
So I got an itch to take my old 4.6l apart to try to figure out what happened... before I swapped motors it had a minor mis one day and the next day it started having a terrible metal to metal slapping sound.. I turned it off immediatly, tried to fire it up and the motor would turn but not fire over (minor sparkles in the oil which reeked of gas when i drained it)..hmm... So when I'm taking the motor apart I looked at the timing gear on the crankshaft..well it had sheared off the piece of metal on the crankshaft that holds it in place...which allowed the gear to spin on the crankshaft a 1/4 of a turn...ouch!... talk about timing issues... so anyways I couldn't help but wonder what it looked like in the cylinders..pulled off both heads.. and on all eight cylinders there is fresh marks from the valves hitting the pistons... and of course the valves are just a little cadywompus...

Has anyone ever heard of something like this happening on a 4.6 or any motor for that matter, I would think that the a chain would have popped first or something. And what would 'cause so much resistance on either the crankshaft or the timing gear for the timing gear to shear off that metal??? The motor was rebuilt 20k miles ago. I was dumbfounded, never seen anything like this.
 

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02 Explorer Pioneer
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2,880 Posts
Yes we have heard of this before....that is why ford redesigned the crank gear to be one piece instead of two. The same thing hapened to Dr Frankencougie at high RPM....piston to valve contact and now he has some nice pretty bent valves to decorate with :)
 

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Overkill Fetish Freak
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2,458 Posts

When the woodruff key cracks, bad things happen...



I heard a strange noise and cought it before it totally let go... Ford should cover that issue since it was a poor design and they knew it since they went with the one piece later on.



The high RPM chain breaking blowup was when I decided to install the PI head that was damaged in shipping... (they were on serious backorder way back when I did my swap). Little did I know the cam was bent... and bad things happend.

-Scott
 

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Baby Huey
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3,210 Posts
FunktasticLucky said:
holy crap... did someone beat that box up or WHAT?!! shouldn't those have been shipped in something that isn't so flimsy... like a crate.

You should have seen how mine got to me, one of the heads was hanging out the side of the box. UPS!!!!!
 
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