UTfball68
Well-Known Member
- Joined
- Jul 18, 2008
- Location
- Granite Quarry
Howdy fellas...I got to pulling the Bronco apart this weekend to throw the cam in. I pull the most rearward plug on the passenger side and it wasn't pretty. The head of the plug was smashed flat. As of 4 months ago, those were new plugs, and the Bronco ran perfectly fine until it died about a month ago. No knocks, no pings, no nothing. Anyway, I pulled the head and found a bent exhaust valve on that same cylinder...not terribly bent...but enough to where half the valve wouldn't seal in it's seat. So I sent the heads off for a quick valve job.
Then I saw there was part of the diode and ceramic from the plug morphed in to a ball, resting on top of the piston. The top of the piston had a little scarring on it, but not something I'd be afraid of using again. The cylinder was just fine as well, no scoring at all.
I rotated the engine, and the piston is stopping where it's supposed to. I didn't notice an rod play at all either.
So can someone help me out as to what smashed up that spark plug? For a little history, that engine jumped time about 6 months ago, I replaced the timing set. Then it was acting like it jumped time again, but the timing set was fine and I replaced the distributor with a Motorcraft reman unit. And it hasn't run right for the few minutes it ran after the new dizzy went in.
Any ideas, thoughts, questions would be greatly appreciated.
More info...pulled the cam, and there were two lobes that were way more worn than the others, but the others weren't too terribly bad. The lifters had zero radii left and were worn flat. The pushrods all looked good, but one was covered in rust, it looked like there was a little head gasket leak.
And one more tid bit, the bad valve was a single groove valve and the rest were all multi-groove, as if this were a problem valve in the past and has been replaced once already.
Then I saw there was part of the diode and ceramic from the plug morphed in to a ball, resting on top of the piston. The top of the piston had a little scarring on it, but not something I'd be afraid of using again. The cylinder was just fine as well, no scoring at all.
I rotated the engine, and the piston is stopping where it's supposed to. I didn't notice an rod play at all either.
So can someone help me out as to what smashed up that spark plug? For a little history, that engine jumped time about 6 months ago, I replaced the timing set. Then it was acting like it jumped time again, but the timing set was fine and I replaced the distributor with a Motorcraft reman unit. And it hasn't run right for the few minutes it ran after the new dizzy went in.
Any ideas, thoughts, questions would be greatly appreciated.
More info...pulled the cam, and there were two lobes that were way more worn than the others, but the others weren't too terribly bad. The lifters had zero radii left and were worn flat. The pushrods all looked good, but one was covered in rust, it looked like there was a little head gasket leak.
And one more tid bit, the bad valve was a single groove valve and the rest were all multi-groove, as if this were a problem valve in the past and has been replaced once already.
