jrfox

Hello, I have 97 Explorer 5.0 engine in a old rod. Now it has always ran well, last fall i was having problems with what I thought was a fuel pump locking up. I didnt even think about it this winter, I decided to put a supercharger in now 2 months later I go to start and it wouldnt fire. Very weird good fuel pressure but just wouldnt fire. At first i thought it was the alarm, as you know when they malfunction it could be the problem. I still couldnt get it to fire so I brought it to a electronic shop $300.00 later they finally figured at my expense that the roter was not turning. I knew it sputtered to a stop in my drive going 10mph. So I saw the cam was not turnning so I took off the front cover and my cam chain was in the pan! I freak! Than I pulled the plugs looked great. At first I was going th throw a chain on it and than check the compression. I rolled the cam and the rocker arms were moving fine I eliminated a busted cam. to remove the right rocker the charger needed to come off. When I rolled the cam over I could see something was not correct. The lifters for cylinder 4 was acting real weird it jumped! Well the heads need to come off. Looking at it it looks like the pushrods are all bent a and probably the valves too. Why did this happen? could somebody explain? Im so confused. All the pistons are not marked they look real good. Do I need to check the cam? Lifters? Rockers? What push rods would you recommend? Presently I have a nice small blower cam/ Roller ford rockers/ ported and polished heads/BBK SSI intake all MSD and full syethetic oil. Other than that its vertually stock. Any one have the same experience Why did this happen? Other than the bent valves the head isnt marked at all. One thing you can say is that I was lucky the engine didnt blow sky high, good thing I was doing 10 mph.
Recommendation! Im taking the heads lifters and the push rods to the head shop that have done the original work. Replace the bent valves check all valves lifters check spring tension and height new ford racing chain do I need the 3 piece set if the sprockets are fine. Also I should have stated the engine is a 97 with no miles on it setting 10 years before I purchased. Ive put 3,000 miles on the setup before this happening. Your thoughts. Do I need to replace anything else? Any words of caution! Thanks JOhn Fox
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cepx111

When the timing chain fell off (abrubtly) the valves were out of time with the pistons, hitting the pistons and obvioulsy bending the valves.

Just make sure you have proper spring tension and installed height for your new cam, I imagine you'll have to change the old ones out as years of heat soaking usually weakens them pretty good.

I'd upgrade the OEM pusrods with hardened units from FPP or any aftermarket cam company like CC or Lunati.
If the stock gears arent worn, just stick a chian on there, the OEM sprokets are hardened anyway.
Sounds like you have the rest coverded.

Goodluck, Cp