4.0 distributor not turning

[MaxMan]

I had an earlier post about a 91 xj with a 4.0 that got water in it. Tonight when I was trying to start it, it made a loud clank noise and blew a puff of smoke out of the throttle body. I noticed I had no spark and found that the rotor on the distributor isn't turning. Is this the timing chain, camshaft, distributor gear? Is the motor probably shot? Please give me advice, I'm broke and need this vehicle to get to work.

 

[8Mud]

Pull the valve cover, turn it over by hand, not with the starter and see if all the rocker arms move. If the rocker arms move, the chain is there and probably OK, could be the pin in the distributor gear. If you had hydro lock, strong enough to pop the chain, chances are you have bigger troubles than the chain. But the only way to know for sure, is a visual inspection (make sure everything is functioning) and a compression test.
I´ve learned the hard way, by observation and personal experiance, to pull the plugs anytime the air filter gets wet, and turn the motor over and see if any water squirts out of the cylinders. It´s even possible to bend or break something, just with the starter motor torque, even if the engine doesn´t run.
Trying to start the motor, with a broken chain, can cause more damage.

 

[Pietro]

dont bother taking the valve cover off. you can look into the oil cap while turning the engine to see if the rockers are moving or just remove the distributor and look to see if the cam itself is moving. if not, work your way forward. next is the timing chain. no way to inspect without removing the drive belt, pulley, and cover. if the chain snapped, it can be replaced easily but i dont know if the 4.0 is an interference motor meaning that the valves wil bend against the pistons if the timing chain breaks.

 

[8Mud]

The reason I recommended taking off the valve cover is to check for bent valves. I had number 6 intake bend and jam in the guide. Think it was just the water that, bent it. I´ve never broken a chain, so have no real idea wether the valves will contact the piston top or not.

 

[Pietro]

i dont know if the 4.0 is interference or not, call up a jeep dealer, one of the techs in the shop would probably know, either way, if the cam aint turning, open up your wallet because it is about to become lighter

 

[Dr. Dyno]

I had an earlier post about a 91 xj with a 4.0 that got water in it. Tonight when I was trying to start it, it made a loud clank noise and blew a puff of smoke out of the throttle body. I noticed I had no spark and found that the rotor on the distributor isn't turning. Is this the timing chain, camshaft, distributor gear? Is the motor probably shot? Please give me advice, I'm broke and need this vehicle to get to work.

Remove the plugs and try to turn the engine by hand using a socket wrench on the crank pulley bolt. If it won't budge at all, there's a good chance that you've hydrolocked the engine and bent a couple of rods. The only way to find out for sure is to remove the oil pan and inspect all the rods.
If the crank turns but the distributor rotor doesn't, there are two possibilities; either the timing chain has snapped (highly unlikely) or the distributor drive gear teeth have completely worn away. Remove the distributor and you'll know which one of the two it is.

 

[MaxMan]

Thanks for the help everyone. I just went out and took off the oil cap. The rockers I could see are moving when the engine is turned. I guess tomorrow I can see if the distributor gear is damaged. If it is, would it have been caused by something else that is damaged? Also if the distributor gear is stripped, would the camshaft gear likely be stripped as well?

 

[Pietro]

like the guy said in one of the other posts, there is a pin and gear at the bottom of the distributor, pull the dist. out and check to see if the shaft and gear still moves as one piece.

 

[MJR]

It is possible that the distributor froze up and sheared off the teeth on it's drive gear.

 

[Bloose]

It is possible that the distributor froze up and sheared off the teeth on it's drive gear.

This is exactly what happended to my wifes '01 4.0 (it's not actually a distribtor but a oil pump drive with a cam sensor on it). Unfortunately for me putting in a new OP drive didn't help because when the OP drive gear sheared it took out the cam gears too.

Good luck man, but from my keyboard it doesn't look good.

B-loose

 

[MJR]

This is exactly what happended to my wifes '01 4.0 (it's not actually a distribtor but a oil pump drive with a cam sensor on it). Unfortunately for me putting in a new OP drive didn't help because when the OP drive gear sheared it took out the cam gears too.

Good luck man, but from my keyboard it doesn't look good.

B-loose

Where in the hell have you been?

For the record it's more common on the 00-01's and personally I haven't seen one yet damage the camshaft (the drive gear is part of the camshaft).