Hi guys, a friend of mine has a '95 Bronco 5.0. I know it's not the same exact thing, but this is more of a question for the mechanically inclined.
Here's the background:
Replaced valve cover gaskets, etc, one day. A few days later, there's an oil leak, and it's from the back drivers side valve cover gasket. We remove the upper intake, the valve covers, replaced with the rubber style, re-tightened the rockers, put it all back together, try to start, cranks but doesn't start. We then remembered that during the removal/install we disconnected 2 of the spark plug wires from the dizzy, and thought maybe they were backwards, so we switched them.. cranked again, nothing. So we check for spark at the coil, there is none. We go back over everything, and realize we left a connector from the dizzy unplugged. So we plug it back in, crank it, and it runs great for like 15 seconds, then idle starts dropping, and runs REALLY bad for a few seconds (knocking, deiseling, etc,) til he shuts it off.
We think ok maybe those wires were actually correct, so we switch the 2 plug wires around on the dizzy, and it starts back up, but runs TERRIBLE for a few seconds, this time it sounds like there's some serious detonation or knocking, so he shuts it off. We then decide to double check the plug wires. Well, it's all messed up somehow, but it ran fine before, the way he had it. So, we go back through the manual, set it all back to the correct way, etc, and crank it. This time it doesn't start at all.
So, and lastly, we remove all the wires, and the cap, then crank it by hand to #1 TDC, check where the rotor is pointing, set all the wires back correctly. Try it again, no start. This time, I bump the motor by hand with the key, trying to spin the crank back to the 10* mark. It cranks over once, he says to crank it again, so I crank again, this time the crank doesn't move. Try it again, crank doesn't move (motor not spinning.) We use a prybar to back the crank up a little, and try again, crank doesn't move. Starter is fine, not slipping, etc.
It seems the motor is locked up or something now. We can't figure out what in the heck happened. I think when it was running real bad and knocking, perhaps a valve got bent, or we broke a connecting rod or something somehow. He thinks it has nothing to do with the internals, and that something else is preventing the motor from turning over.
The way I understand engines, there's got to be a serious internal problem in order for the motor to not crank over if the starter is fine. He asked me if I tightened the rockers too tight.. I don't think I did.. did it the way I always do, wiggle the push-rod while tightening until it stops wiggling, then give another half turn.
So basically I'm asking, what would cause the engine to seize up like that? Would over tightening the rockers do this? (I still stand by my belief that I didn't overtighten.) What would that deiseling noise have been, and would the 2 spark plug wires being backwards have caused that??
And the kicker is, after all this, we checked the oil level for gee whiz, and it was a quart overfilled.. apparently he had just got the oil changed a few days ago. Could overfilled oil cause a problem like this??
Here's the background:
Replaced valve cover gaskets, etc, one day. A few days later, there's an oil leak, and it's from the back drivers side valve cover gasket. We remove the upper intake, the valve covers, replaced with the rubber style, re-tightened the rockers, put it all back together, try to start, cranks but doesn't start. We then remembered that during the removal/install we disconnected 2 of the spark plug wires from the dizzy, and thought maybe they were backwards, so we switched them.. cranked again, nothing. So we check for spark at the coil, there is none. We go back over everything, and realize we left a connector from the dizzy unplugged. So we plug it back in, crank it, and it runs great for like 15 seconds, then idle starts dropping, and runs REALLY bad for a few seconds (knocking, deiseling, etc,) til he shuts it off.
We think ok maybe those wires were actually correct, so we switch the 2 plug wires around on the dizzy, and it starts back up, but runs TERRIBLE for a few seconds, this time it sounds like there's some serious detonation or knocking, so he shuts it off. We then decide to double check the plug wires. Well, it's all messed up somehow, but it ran fine before, the way he had it. So, we go back through the manual, set it all back to the correct way, etc, and crank it. This time it doesn't start at all.
So, and lastly, we remove all the wires, and the cap, then crank it by hand to #1 TDC, check where the rotor is pointing, set all the wires back correctly. Try it again, no start. This time, I bump the motor by hand with the key, trying to spin the crank back to the 10* mark. It cranks over once, he says to crank it again, so I crank again, this time the crank doesn't move. Try it again, crank doesn't move (motor not spinning.) We use a prybar to back the crank up a little, and try again, crank doesn't move. Starter is fine, not slipping, etc.
It seems the motor is locked up or something now. We can't figure out what in the heck happened. I think when it was running real bad and knocking, perhaps a valve got bent, or we broke a connecting rod or something somehow. He thinks it has nothing to do with the internals, and that something else is preventing the motor from turning over.
The way I understand engines, there's got to be a serious internal problem in order for the motor to not crank over if the starter is fine. He asked me if I tightened the rockers too tight.. I don't think I did.. did it the way I always do, wiggle the push-rod while tightening until it stops wiggling, then give another half turn.
So basically I'm asking, what would cause the engine to seize up like that? Would over tightening the rockers do this? (I still stand by my belief that I didn't overtighten.) What would that deiseling noise have been, and would the 2 spark plug wires being backwards have caused that??
And the kicker is, after all this, we checked the oil level for gee whiz, and it was a quart overfilled.. apparently he had just got the oil changed a few days ago. Could overfilled oil cause a problem like this??
(J/K) but I would remove all the plugs and see if the motor will now turn over. If it wont, I wonder if something didnt fall and get jammed up, which is keeping the motor from rotating, albeit from an external mechanism.
