350 is locked up - help please! (1 Viewer)

[Scott R]

Long story short, I've been doing a three year frame off rebuild including a 87 350TBI conversion, power steering and disc brakes, 4 speed transmission.

I installed the engine and drive line when the frame was finished two years ago. It's as I said a 75 350TBI with an AA bell housing, 4 speed transmission with a special output shaft that mates to the 72 three speed t-case that came with this 72 FJ40.

When I first installed all of this we did a functional test of the drive train by turning over the engine with an impact gun and walking the gears and testing the clutch, all was well at that time. Fast forward two years to yesterday and I'm completing the Saginaw power steering conversion, in fact I'm installing the belt on the pump and I wanted to move the engine to help slip the belt on. To my surprise it's stuck!

This gets better, I can crank the engine back about 90 deg no problem, then forward 90 deg, and "CLUNK" it's stuck! It won't go more than 90 deg in either direction, clutch in, clutch out, transmission in neutral. I don't know what happened between then and today, and I'm at a bit of a loss. Before I pull the engine again, does anyone have any thoughts on this?

 

[Poser]

Look up inside the flywheel housing and make sure that something is not hitting binding on the flywheel and clutch assembly?


Did you have the TBI conversion on when you were turning the engine over two years ago, or is this something since the last time the engine was rotated?

 

[Scott R]

Look up inside the flywheel housing and make sure that something is not hitting binding on the flywheel and clutch assembly?


Did you have the TBI conversion on when you were turning the engine over two years ago, or is this something since the last time the engine was rotated?

I was under the flywheel yesterday while an assistant moved the motor, I can't see anything binding in there, at least not from that vantage point. Do you think it would be worthwhile to remove the bolts from the pressure plate as a further test? They are completely accessible with the lower bell housing cover off.

Second question on the TBI, it was always there, this is a stick 87' 350 TBI from a GMC Jimmy, at least that's what I removed it from. It was running at the time of purchase, in fact the owner started it for me right before I pulled it. So I suppose the answer is that yes it did have the TBI installed two years ago. The air cleaner has been off a few times for wire routing, but the butterflies have never been opened. The TBI system is not plummed to fuel, or power at this time.

 

[Poser]

I was just concerned that something could have been dropped into the intake manifold and found its way into the engine.


I do not know how the pressure plate bolts would cause this as they thread into a blind hole and should not stick past the flywheel.



When you rotate the engine the other way, does it only go so far and then bind up again?

 

[Scott R]

I was just concerned that something could have been dropped into the intake manifold and found its way into the engine.


I do not know how the pressure plate bolts would cause this as they thread into a blind hole and should not stick past the flywheel.



When you rotate the engine the other way, does it only go so far and then bind up again?

Yes, it moves about 90 to 120 deg in either direction, then it stops. If it was able to father one direction this might be easier to figure out. My fear here is that a push rod is stuck, or a rocker or something. I just can't imagine what could be hanging this up. I can probably borrow a bore scope next weekend to check the cylinders, but it's a long shot.

 

[camcruiser13]

that sucks,

you are going to have to start opening things up and looking. ih8engineproblems

 

[90 Weight]

hmm I had a similar problem with my new 350 crate motor....but since yours is a manual Im not sure...when I mated the auto tranny to the engine...the torque converter wasnt indexted properly and I broke some tranny pump gears, which forced something in the motor to bind up....

 

[Poser]

when I mated the auto tranny to the engine...the torque converter wasnt indexted properly and I broke some tranny pump gears, which forced something in the motor to bind up....

 

[ranger]

Is the tranny and or xfer in neutral?

 

[Fast Eddy]

90 degrees is a weird amount. It goes back and forth? Does it have a mechanical fuel pump? Did you try taking out the distributor? Have the spark plugs been in, or out?

It might have some valves rusted shut.

The bore scope would certainly let you see any rust in there.

 

[Scott R]

90 degrees is a weird amount. It goes back and forth? Does it have a mechanical fuel pump? Did you try taking out the distributor? Have the spark plugs been in, or out?

It might have some valves rusted shut.

The bore scope would certainly let you see any rust in there.

@Ranger: The tranny is in neutral, but I'm pretty sure the t-case is in 4 low, in fact I'm sure I left it in 4 low while we were working out the linkage. I have yet to cut the hole in the floor for the t-case shifter. I can however push the car all around with the transmission in neutral.

@Eddy: It has an external electrical fuel pump since it's TBI, I'll pull the distributor this afternoon, thanks for the suggestion on that, that's at least an area I can start on easily. I suppose after that it's time to start pulling the cover to look for other stuck objects.

 

[peesalot]

moisture got in there and formed rust ridges in the cyl bores just below the rings.
pull dist , put a bar on the crank pulley bolt and turn the thing over. If you want pull the pan and spray some pb blaster up in the cyl bores to loosen those rust rings up. IMO pull pan first, easy and gives you a good look.

 

[Scott R]

moisture got in there and formed rust ridges in the cyl bores just below the rings.
pull dist , put a bar on the crank pulley bolt and turn the thing over. If you want pull the pan and spray some pb blaster up in the cyl bores to loosen those rust rings up. IMO pull pan first, easy and gives you a good look.

I'm no Schwarzennger, but I'm a pretty heavy duty lifter, I'm using a 22" breaker bar and I'm standing on it and nothing more than the 90 deg. Well I'm off to go pull covers. I'll snap some pictures if I find anything.

 

[Scott R]

OK, valve covers are off. I pulled the rockers and checked all of the rods, they are fine. I bumped all of the valves and the have action, the distributor is free as well. So I'll go after the pan next, and if that's good I'm down to the timing chain.

 

[my64fj40]

I was just concerned that something could have been dropped into the intake manifold and found its way into the engine.

That's exactly what I was thinking.

I was doing a SBC rebuild many moons ago, and apparently a little piece of gasket material feel in the intake. Messed up the engine pretty bad, and had to do an entire disassembly.

 

[terrx]

If you haven't already, pull the plugs and squirt some oil in the cylinders. May as well have that in there lubricating things while you're troubleshooting. It might help free up rust if that is the problem. I like marvel mystery oil for something like this - it penetrates and is lighter than a motor oil.

 

[Rice]

Possibles ... not all new ideas.

1. an object is not clearing in the bellhousing. The time this happened to me years ago was me leaving an impact socket on a flywheel bolt. By the way, don't turn an engine using an impact wrench.
2. Something dropped into the motor. If you pulled the valve covers off you have already determined a valve isn't what fell.
3. Hydralock. Does it have any fluids in it and are the plugs out?

 

[Scott R]

Possibles ... not all new ideas.

1. an object is not clearing in the bell housing. The time this happened to me years ago was me leaving an impact socket on a flywheel bolt. By the way, don't turn an engine using an impact wrench.
2. Something dropped into the motor. If you pulled the valve covers off you have already determined a valve isn't what fell.
3. Hydralock. Does it have any fluids in it and are the plugs out?

OK, pulled the engine out yesterday, and it was a bellhousing obstruction. For some reason the clutch was hitting the top of the Advanced Adapters 4 speed bellhousing. The clearance I measured was less than 2MM where it was making contact. So my solution, like so many other solutions I have employed during this conversion was to grind the high spot down.

The engine turns freely now, and this gave me a chance to find out that the timing chain was completely shot, $25 to replace it was good insurance if you ask me. I also replaced the oil pan gasket, checked and adjusted the rockers, replaced the water pump. So it was not a complete loss.

As far as the impact gun goes, I have been cranking motors over like that as far back as I can remember, I just set it on one and pull the plugs. In fact I learned to do that working for GM back in the 90's.

All told it was a five hour job, engine is back in and I'll start the wiring of the motor at this point. I need to search the forums now to figure out how Toyota grounds things, because as of right now I can't figure it out.

 

[Rice]

My main reason for mentioning the impact wrench is because you were talking about a locked up motor. There is nothing in the engine for you to hurt but stripping out crank threads will cause an awful lot of cussing.

Glad you found the problem.
Rice