Why the 4.0 timing torpedo’s

[Number4]

I understand now why the timing will just let go and torpedo the 4.0 engine.

I pulled my 150k mile engine out and replaced it with my 130k engine, while having the trans swapped.
My sons 4.0 had a spark plug break, so we set forth to look over the 150k engine to swap it in.
Turns out the 150k engine had two broken rear guides. While messing with it, the front tensioner crumbled.

This engine made absolutely no noise. No start up rattle, nothing. So as these guides break, they can stay in place and function. When they let loose finally, it’s complete failure with no warning. Engine toasted.

 

[MakinJeepsWeep!]

This is why from what i have been told and researched that you should always use motorcraft oil. It is said to have special additives to keep the guides conditioned and not crumble. Is it true i dont know. I use motorcraft in all my fords and they all have a ton of miles. The 06 i picked up with bad chain guides i rebuilt and its run like a champ for 3 years now.