I was driving my 85 Bronco down the highway at approx.45 mph. Heard a jingling sound coming from the engine compartment.I immediatly pulled on to the shoulder and put it in park. At the same time the engine shut down. I tried to restart but the engine appears to be locked up. I could hear the starter engage but the engine would not turn. Engine was full of oil and cooling system was full. No signs of any type of fluid leak. The engine never sputtered, missed, or made any unusual noise. Any idea what would cause the lock up? The trans(automatic) and transfer case seem to shift gears. I kond of suspect the timing chain but would have expected alot of noise and would not expect that it would cause the engine to lock up.
Additional information:
engine: 1970 429 with elderbrock intake and holly 4 barrel .72 jets
MSD ignition, MSD distributor, Accel coil (long story)
trans: automatic
manual shift transfer case and manual hubs
newly rebuilt ($$$$!) 4 pinion traction lock differential (350 gear)
I would appreciate any ideas or opinions before I start to inspect the timing chain.

 

If the timing chain broke or jumped significantly, the engine would still turn over and in fact would probably turn over very quickly. (Due to valve timing causing the valves to be open resulting in a loss of compression.)

Hopefully your starter just locked up. (Tap it with a hammer and try again. I had to do that myself about 3 months ago) If not, try turning the engine over by the front crack bolt. How does the oil look?

Dave,

'93 White XLT.

 

Thanks for the suggestion Dave, I hadn't thought about checking the starter. I am still wondering what made the jingling sound that prompted me to pull over in the first place. The oil looked fine, I didn't see any metal particles or any evidence of water or gasoline. One other bit of information: Several weeks ago I had added some "RESTORE" engine additive. about two days later I developed a slight lifter tick. It sounded like just one lifter and could only be heard if the radio, blower moter etc. were all off. I hope your hunch is right, that would probably be the cheapest repair. I have already replace the starter once. thanks again. I let you know when I find out what is causing the problem.

Ken,
85 bronco xlt that seems to like riding on a roll back (4 times this year!)

 

take off your belts and see if it will turn. may have been the alt. or powersteering pump locked up.

 

Never heard of an engine lock up while its running, unless you run it in to a lake or something. Some more things to diagnoss the problem would be, as suggested try to turn the engine over by hand. This can be done by placing a socket on the middle harmonic balancer bolt and turning it, if it turn great-that means your engine isnt locked up. What i always do in problems such as this, is try to get the vehicle running again. And in that process you can usually rule out questions by going with the basics. If your engine wont turn, you should start at the bottom and work up: is your starter turning the Flywheel, if not, see if the starter is bad. see if something is interfeering with the movement downthere. Then work up from there. If you can get your engine to turn over but not start than think of the simple stuff. An engine requires fuel and spark to fire. If you have a fuel pressure release valve, you can check on the pressure there if you cant hear your fuel pump pressurize the lines. Than check to see if you have spark, pull the #1 wire off the plug and ground it out, and if it sparks than you are good-if not diagnoss that problem with the distributer and the ignition. Then see if your injectors are firing.(dont remember what year your truck was so this may not apply) if you have injectors, and you have a screwdriver or a socket extension, place one end on the exposed top of the injector and the other end on your ear and this well transfer the clicking of the injectors to your ear easily.

Something else to check may sound stupid and easy but could cause consequences such as this. Your battery. If your alternator wasnt putting out properly than your truck will depend on your battery to carry the load, therefore draining your battery at an incredible rate. And a vehicle depending on the battery to run will shut down eventually, and in short time too. And when it does you will loose everything and in somecases it will make a few jolts and noises cause your truck is depending on the battery to run the spark and when it fails, your truck is sufficating cause there is no energy to keep the engine spinning.
Well good luck and i hope at least some of this garble makes sense and helps you.

Gary
95 Bronco 351W 6"Jackstand lift!

 

Kinda sounds like a broken flywheel to me...

 

In what little time that I have had to do some troubleshooting, this is what I have done so far. Tested battery and solenoid -OK. Removed starter (loose)and had starter tested -OK. Attempted to rotate engine manually. I was able to turn the engine backward at least 1/4 turn. I could then turn the engine forward but it came to a stop a little shy of the TDC mark on the harmonic balancer. As soon as I get a chance, I am going to remove the spark plugs and see if I can manually turn the engine over. It may just be the compression keeping it from turning further. I checked the flywheel as best as I could when I removed the starter. I also verified that the power steering pump and the alternator were not locked. I appreciate all of the help. I will continue to update as I do more troubleshooting. I am sure I will have more questions as I go.

Ken

 

Did you look for smoke? Hate to bring bad neews, but it sounds like something might have gone down the carb, bounced off the valve a little, and went in a cylinder. Just a guess.

Jared

 

I finally got a chance to work on the Bronco again. Here is what I have done since the last post. I removed all of the belts and all of the spark plugs. Using a socket on the harmonic balancer I am able to rotate the engine approx. 260 degrees before it stops. I haven't tried to force it further - don't want to risk causing more problems. I used some dowels placed in the sparkplug holes to verify that all of the pistons moved as the crankshaft was moved through 45 degrees of rotation. I checked the distributor and verified that it moved as the crankshaft was rotated. The rotation seems to be smooth and quiet. I have also removed and the battery and starter. My question is what should I check next? The timing chain or valves and lifters. I don't have much experience with working on the internal parts of an engine. Any advice would be greatly appreciated.

 

Get a Haynes manual - you need one anyway, and it'll save you time having all the info right there.

 

I appreciate the suggestion. I have the Haynes repair manual for 1980-1996 Ford pickup and Bronco. Unfortunately the engine in my Bronco (429) supposedly came from a 1970 Ford LTD. I haven't been able to locate this manual locally. What I am looking for now is troubleshooting and\or diagnostic information. The information in the manuals is very helpful for assembly and disassembly but lacking in the kind of diagnostic help that I need. I am trying to determine why I can not get the engine to make a complete revolution. I am trying to find the problem area by doing minimal disassembly, even though I may end up having to do a total disassembly and rebuild. The manual will be a gerat help in any disassembly. Right now I am trying to determine the next logical area to investigate. Thanks again!
- Ken