Help! She died today and won't turn over -UPDATE it's a spun bearing

[Cgn1976]

Man, none of this computes with me. The fact that is stops in both directions has me at a loss. I previously thought foreign object in a cylinder - that would cause a hard stop in one direction at contact, and would also have to be something odd shaped to get through a valve and yet be large enough to stop a piston’s upward travel. Then you’d need two of them in separate cylinders to stop motion in the opposite direction. Not impossible, but astronomically unlikely?

Thought about something coming loose in the timing gear housing, but also would only likely cause a stop in a one direction. As well as something like a hex nut caught on the back side of a cam lobe. Would stop in one direction, but ought to be rollable in the opposite. And in any of these cases, while running and driving would have produced an unmistakable “bang” or “pop”.
Wish I could be more help, but I’m sitting by holding the popcorn bowl, awaiting to see what this boils down to.

Lol. seems my journey into pig land is clearly going the path less traveled. Between my throw out bearing mess with the clutch last year, my brake job disaster that was fixed after a month only with a 2nd new booster (City Racer swears the other one is fine and I'm stupid ) and now this?
Squeal like a pig, boy!!! Reeeeeeeet!!! Reeieieitit!

I agree about something in the cylinder seeming like it would back out by turning the other way and thought the same thing that both cylinders would have to have something in them, but considering the flywheel goes only 2 teeth, I don't think there's enough travel for both of them to have something in them and hit. I'm not up on gear ratio, but two teeth on the fly wheel isn't very much of the full engine's revolution. Looking at pics of the engine in the manual today my thought was timing gear jammed up with a nut or cracked maybe and something jammed in there?. I can see the cam from underneath and it looks good from what i can see anyway. Not broken. Is getting at those timing gears easy or I probably have to pull the radiator, right?

That thought brought me to a search where I found this thread, that's eerily familiar. Dies out, ground and starter stuff, realizes the engine is locked but moves a little bit..starts going towards cam and timing gears and......the thread ends like the Sopranos! Come on!!!!!!!!!!!!!!

Bizarre Issue with a '76 FJ40 - Help is appreciated!

So I have a 76 FJ40 that I am having an issue with. I can't get it to turn over. I have checked and replaced the following: - Starter has been bench tested and is good working order. The Solenoid engages and the motor turns when bench tested. The solenoid engages but the motor does NOT turn...

forum.ih8mud.com

 

[gonzopancho]

Agree it’s unlikely to be in a cylinder/combustion chamber. Only thing I can think of there is a broken piston ring that’s limiting one of the remaining two pistons, since the rod journal would move away from the rod in one of the two directions. Pulling the head is unlikely to show a broken ring; but maybe it scored the cylinder before things locked up.

According to cnzjzy.com, the F/2F flywheel ring gear is 349.7mm OD 319.3mm ID and has 136 teeth. This means the circumference of the ring gear is 1098.61mm, so each tooth is about 8.08mm or 0.318”, which is just over 5/16” for those of us who are old.

More importantly, if the flywheel is moving 2 teeth, that’s 2/136 * 360 degrees. About 5.3 degrees. At/around TDC (and BDC) the piston doesn’t change position much as the crank rotates. I don’t know the center to center length of the rods, or I’d calculate it.

Since #3 and #4 are near TDC the pistons aren’t moving very far with 5.3 deg of crank rotation.

I can’t think of how a follower (“lifter”) would break to bind in both directions. Same thing with the crank/cam gears.

One thing to note: the F engine oil system allows oil from the pan into the engine. There is a tee where the oil flows both to the filter housing and the oil galley that feeds the main journals. If something broke and passed to a point far enough to block the galley on one journal, you might still see oil everywhere on the rods, if you got lucky.



My guess is still a main bearing.

 

[gonzopancho]

For reference, here is the 2F (and "1.5F" (9/73 changeover) oiling diagram. Here the oil is forced through the filter before supplying oil to the galley that feeds the crank main journals.

The only other thought that occurs is that somehow the thrust surface for the crank shaft has broken, and is allowing the camshaft gear to 'walk' in and out far enough to get enough out of time that everything stops. It's just a theory. Yes, you'll have to take the timing cover off the front of the engine, which means pulling the crank pulley. The other thing that occurs is that the cam gear can fail, esp if it's been replaced. I'm not crazy... 3fe cam gear slipped 10 degrees - https://forum.ih8mud.com/threads/im-not-crazy-3fe-cam-gear-slipped-10-degrees.907062/#post-10205630. If this occurred, it might have allowed the valve train timing to be completely 'out' .vs where it should be.

Might call @FJ40Jim About Us - https://tlcperformance.com/pages/about-us and run what you know by him.

 

[RUSH55]

My bet is on something causing a mechanical stop. Could be wrong, but if a bearing seized up
A) There wouldn’t be smooth motion for 5* and then a clunk
B) It would be either immovable or continuously movable with a lot of force

That being said, since it’s open, I’d still check them all one at a time. If nothing, then I’d pull the head.

 

[Cgn1976]

For reference, here is the 2F (and "1.5F" (9/73 changeover) oiling diagram. Here the oil is forced through the filter before supplying oil to the galley that feeds the crank main journals.

The only other thought that occurs is that somehow the thrust surface for the crank shaft has broken, and is allowing the camshaft gear to 'walk' in and out far enough to get enough out of time that everything stops. It's just a theory. Yes, you'll have to take the timing cover off the front of the engine, which means pulling the crank pulley. The other thing that occurs is that the cam gear can fail, esp if it's been replaced. I'm not crazy... 3fe cam gear slipped 10 degrees - https://forum.ih8mud.com/threads/im-not-crazy-3fe-cam-gear-slipped-10-degrees.907062/#post-10205630. If this occurred, it might have allowed the valve train timing to be completely 'out' .vs where it should be.

Might call @FJ40Jim About Us - https://tlcperformance.com/pages/about-us and run what you know by him.

After reading this and thinking a bit I was convinced of a cam or timing gear issue and then I remembered I pulled the rocker off and the lock in both directions was still there. Tells me it's not a valve timing issue, right? With the rocker off, wouldn't the lifters and rods just freely follow the cam shaft regardless of anything else? I can also confirm the lifters are all free and moving. Now could the timing gears still be the problem? I suppose so. Now feeling like a fly wheel bolt issue. I have about 45 min now and then again at lunch today to see how much further I can get. I just remembered I have a little USB ear/nose camera I can wrap in plastic wrap and tape to a coat hanger to scope the spark plug holes and maybe up inside the clutch/flywheel, which I'm about to do. Not sure how much I'll be able to see on 3 and 4 being at the top of the stroke, but I'm gonna try anyway.

More later and again...THANK YOU TO EVERYONE!

 

[onemanarmy]

is it in gear?!

haha. I sure hope not.

 

[Pighead]

Tells me it's not a valve timing issue, right?

It's not a valve timing issue now, with the rocker shaft off. But it could have been. With the rocker shaft off all your valves should be closed and their stems all at the same height with all springs looking uniform. Go back and hit each valve stem with a hammer again, see if they all sound and act the same.
I'm thinking you might want to look under your timing cover before you pull the head, pending your scoping...
That bonded cam gear can do wierd things if it unbonds. I can't think of exactly how it could jam an engine, but pulling that cover easier than pulling the head.

 

[MacDaddyRabbit]

is it in gear?!

haha. I sure hope not.

This is gonna sound goofy I think but …

Take a paper towel cardboard tube and use it as a stethoscope on your bell housing when moving the flywheel back and forth.
Listen for the clunk. I know so little compared to everyone but like ok yeller I once had a clutch assembly failure years ago.

 

[MacDaddyRabbit]

This is gonna sound goofy I think but …

Take a paper towel cardboard tube and use it as a stethoscope on your bell housing when moving the flywheel back and forth.
Listen for the clunk. I know so little compared to everyone but like ok yeller I once had a clutch assembly failure years ago.

My hunch is a bearing, which it very well may be , won’t clunk.
A bolt that has loosened enough to stop the spin will I think. And hopefully would clunk at both rotational stop points.

But you can place my mechanical skills in a thimble compared to most others.

 

[Pighead]

There are those 2 bolts that hold the camshft down, you access those through the holes in the cam gear. If one of those backed out...

 

[Cgn1976]

is it in gear?!

haha. I sure hope not.

lol. that's another one I can confirm

 

[Cgn1976]

This is gonna sound goofy I think but …

Take a paper towel cardboard tube and use it as a stethoscope on your bell housing when moving the flywheel back and forth.
Listen for the clunk. I know so little compared to everyone but like ok yeller I once had a clutch assembly failure years ago.

I just scoped behind and above the flywheel with my little camera and light and can confirm the 4 large bolts that are visible and might back out and hit the fly wheel are definitely tightened all the way down and not touching the flywheel. Didn't find anything else in there. The fly wheel looks free of visible blockage.

 

[Cgn1976]

I just scoped behind and above the flywheel with my little camera and light just now and can confirm the 4 large bolts that are visible and might back out and hit the fly wheel are definitely tightened all the way down and not touching the flywheel. Didn't find anything else in there. The fly wheel looks free of visible blockage.

 

[Cgn1976]

My hunch is a bearing, which it very well may be , won’t clunk.
A bolt that has loosened enough to stop the spin will I think. And hopefully would clunk at both rotational stop points.

But you can place my mechanical skills in a thimble compared to most others.

Mine must fit in a doll's thimble then!

 

[Cgn1976]

It's not a valve timing issue now, with the rocker shaft off. But it could have been. With the rocker shaft off all your valves should be closed and their stems all at the same height with all springs looking uniform. Go back and hit each valve stem with a hammer again, see if they all sound and act the same.
I'm thinking you might want to look under your timing cover before you pull the head, pending your scoping...
That bonded cam gear can do wierd things if it unbonds. I can't think of exactly how it could jam an engine, but pulling that cover easier than pulling the head.

Good to hear, as that's where I heading. I just scoped all the cylinders and they are all clear and show no signs of an impact. With the rocker off, all valves were fully sprung (not sure the right term for this). I hit them with a mallet and they all sprung open and popped back...they all acted exactly the same and felt just like they did when I did the valve stem seals a while back. Again I'm no expert, but they felt right.

I tried to get the connector rod caps off 3 and 4 again but I'm gonna need just the right size plier/channel lock to get a good enough grip to wiggle it off, with all the stuff in the way.

Also I undid the bolts and in the front main cap but can't seem to get that off. 2 long 19mm bolts on the bottom, and 2 14mm from the front of the timing cover under the pulley. There was aslo little 10mm on the driver side under there on the timing cover that looked like it was bolting into the that front main cap as well. Am I missing something else or does it need a little persuasion? I'm very hesitant to force anything here. About to dig through the manual now to see if that helps me here.

 

[Pighead]

Since your other conn rod bearings looked good, probably let those other 2 rods alone.
I wonder if you just loosened the other main caps, 2 or 3 turns maybe, and allowed the crank to come down just a bit, maybe if it was a seized bearing, it might free up? But if the conn rod bearings look good, i might look under the timing cover and the pressure plate first.

 

[Pighead]

Mine must fit in a doll's thimble then!

I think you're doing a fine job of ruling things out.
I'm thinking you could power through a slow-speed main bearing seizure with your crowbar, think I'd be looking for a hard interference, like behind your timing cover.

 

[gonzopancho]

The manual shows how to use the main cap bolts to apply a little leverage to crack the caps loose.

Maybe loosen them one at a time (back the bolt heads on each cap out 1/4”) and try to turn the crankshaft after each is loosened. If there is Babbitt transfer to the main journal(s), this should allow it to pass.

 

[gonzopancho]

Actually, maybe, If you have the means, drop the transmission before you go much further.

 

[elroberds]

is it in gear?!

haha. I sure hope not.

I asked the same thing.