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MG TD TF 1500 - Engine failure 51TD

I'm starting a new thread for this because it began under the title St. Patricks day parade, and that isn't an appropriate title for the subject at this point. Long story short: the engine shut down near the end of a grueling hour of crawling along at 1/2 mph in the hot sun. The water temp never got too high, about 220 degrees or a little over halfway on my meter; no steam. I tried to rev the engine to keep oil pressure up when possible.... but anyway.
Symptoms: the engine was running fine when it revved slightly and then conked out. No explosions or terrible noise. Restarting it it ran for a second then conked again. Then we pushed it to where we could jump it and it was clearly not the battery. The engine no longer wanted to move more than half a turn before stalling.
I got it home and pulled the head. Using the starter I could see that the pistons all moved, and no apparent damage visible from the top.
This morning, I engaged a makeshift starter handle and found I could turn the engine maybe 1/7 rev before there was a clicking noise and suddenly I could not turn it. Turning it backwards, same issue.
Not looking good, is it? I'm assuming crankshaft or bearing failure at this point.
Thoughts? I have yet to drain the oil and pull the sump.
Geoffrey M Baker

pull the dizzy to start with.

hope you get it sorted easy
mog

I would bet that the throw-out bearing has an issue.

Riding it like you needed to do in the parade was stressful.
I don't know exactly how or were but I bet its dislodged from the fork.

Jim B.
JA Benjamin

Just pulled both starter and distributor. No change, same symptoms.
So what's the betting? Broken crank? What other possibilities are there at this point?
Geoffrey M Baker

Folks, here is where I admit I am now out of my comfort zone; the most I've ever done is remove an engine head before. So Jim, where is the throw-out bearing and fork? Thanks!
Geoffrey M Baker

Throw out bearing and fork are part of the clutch,,, I'm doubting that would be the problem,,,, does your clutch seem to operate OK,, can you depress the clutch,,

SPW
Steve Wincze

For an idea where the clutch parts are, go to Dave's great picture site

http://www.dbraun99.com/mgtd15470/Gearbox%20and%20Clutch/Clutch%20Refurbishment/Index.html
Steve Wincze

Throw out bearing is the thing that disengages the clutch. The forks on the back of the clutch's pressure plate ride on it and it (the throw-out bearing) takes a beating in parades, as does the clutch.

It is slightly possible that the bearing has suffered a near catastrophic demise and is causing the symptoms of an engine bearing biting the dust - BUT, it should allow the engine to turn when there isn't any pressure on the clutch peddle.

Good thing is, throw-out bearings are cheap and pretty easy to replace - if you can slide the trans back and out of the car. Do the clutch too while you're at it if needed.

I don't know the TD trans well, is there an inspection cover?

......
MAndrus

is the clicking noise from the front or rear of the engine?


I would pull the timing cover next.
mog

Watch the pistons as you turn the engine. For that 1/7 turn are they moving completely in sync? And smoothly-- no jerking or one piston making a shudder when hitting the "stops?"

If so, I'd go with a clutch issue. It is possible the clutch cover has broken and is interfering with a rotation of the engine. Or the throwout bearing has disintegrated as others suggest or some other item has broken off.

There is an inspection cover; you might be able to look in there and spot debris or something broken.
David Littlefield

Sounds like a crankshaft to me. Mine ran a mile after she broke then nothing. I hope that is not it in your case. only way to tell is pull the sump and look closely at the front journel.
T Maine

My first guess would have been a seized valve. Easy enough to have happen when really heated up with bronze guides on the exhaust. That wouldn't explain the half turn only unless you had a high lift set up cam.

I'm sure you would have seen that when you pulled the head. There is an inspection plate on the bell housing but since it's on top..good luck with removing it to have a peek inside. If you were depressing the clutch while creeping or standing still, there is a good chance you wore the graphite away on the throw out but I would imagine you would have heard some rather nasty noises as it became metal to metal contact.

Broken crank is a possibility.. I'd put the car in gear and set the hand brake. Turn the engine with your hand crank or better yet a socket with extensions. If you can't turn it I'd guess the crank is still in one piece. If you can..look and see if all of the pistons are moving up and down. That's where I would start if it were me.
MG LaVerne

Are all the teeth still completely intact on the distributor gear? Probably, but it is right there to inspect.

Since the head is off already, pull the pushrods and the lifters (keeping track of their order). Inspect the lifters' surfaces and peer down the lifter holes to examine the lobes. You can also watch to see if the cam moves in perfect sync with the crank to evaluate the timing chain & sprockets (bear in mind, if you only rotate a few degrees back and forth, there's a bit of chain slop that can produce a touch of lag in cam rotatation).
JRN JIM

So far I can't find anything definitive. I've pulled the sump and everything looks like it was well oiled. I can rotate the flywheel a bit either way and the crank moves with it.
I also pulled the timing chain cover and could see nothing wrong there.
Soooo... it's either move back towards the clutch and look at the throwout or pull the journals to look at the bearings on the crank.
JIM, the teeth are fine on the distributor. I could see nothing wrong with the cam either, although again, I really am not sure I would see the problem if it was staring at me. Again, looks like oil was getting where it needed to be, no water/oil mixture, no problems like that.
Laverne, I put the car in gear and could move the crank with a set of socket extensions only the same amount, just enough to move the pistons up and down one inch.
The ONLY thing I have seen that makes me think it might be a broken crank is that the two lobes in the center of the crank are not absolutely symmetrical, i.e. looking identical to each other; one looks to be slightly moved out of sync from the other, no more than 1/8 of an inch. But if the break was on the middle journal, I would think I could detect some play where the front of the crank wasn't moving when the rear was... and I don't see that. So maybe the lobes look slightly different just because of balancing in manufacturing? Not sure....
Geoffrey M Baker

Look at the oil pump drive gear and cam gear if you can see it. There were some circlip problems some years back that would cause the drive gear to pop loose and jam. George
George Butz

Goeff,
Again, referring to Dave excellent pictures,, go to

http://www.dbraun99.com/mgtd15470/Engine/Teardown/slides/crankcase%20with%20gasket.html

to see a pic of the crank,, the center lobes kinda look symmetrical
Steve Wincze

Steve, looking at that pic (which I can't see from your link, but I do have his website bookmarked) there looks like as much variation in his as on mine, so I don't think that's a problem, I just thought I would mention it. I guess I am going to pull the journals and see if there is anything visible underneath.... if that looks good, guess I'm pulling the transmission (ouch!)
Geoffrey M Baker

Going back to the original post, there has to be a hint in this statement,,,,
>>the water temp got to about 220, nothing bad, and then suddenly at the last corner it raced a little bit, and then cut out.<<

Why would the engine race a little bit????? something in the timing??

SPW
Steve Wincze

SPW, I don't know. To redescribe it, it was idling along and there was literally just a second where it seemed to pick up to a faster idle, then it cut out.
Geoffrey M Baker

Geoff, don't forget that if it is a broken crank the break will most likely be at the front side on the #1 connectiong rod journal. Therefore when you move the flywheel the whole crank except for the front throw will move in unison. How about getting someone to rotate the front of the crank back and forth and see if the rear of the crank follows this motion.
Hugh
H.D. Pite

I'll do that Hugh, thanks.
I reengaged the starter and was able to turn it, about a quarter turn at a time, and again, everything moved together.
As nobody is here to help me right now, I did observe one thing: I removed the starter again and pointed a torch at the hole where the starter engages the flywheel, so I could see the flywheel clearly. Then I rotated the front of the crank back and forth with the starter handle and observed that the flywheel moved in perfect unison, back and forth, no visible play at all. Again, only about an inch either way before it locks up. I also noticed that while it turns easily either way for an inch, as soon as it locks, the whole engine is trying to turn with it.
Geoffrey M Baker

Correct me if I've read this wrong...

Engine running fine, no noises, oil pressure okay, then it raced a second and stopped.

You were able to restart it with the starter motor - which means at that time the motor would make a full revolution or more.

The next time you tried to start it you said the engine no longer would move more than half a turn before stalling. Did it actually fire and stop or just stop turning with the starter?

You pulled the head and can watch the pistons move up and down for about a 7th of a turn. You pulled the sump and it appears that the counterbalances for #'s 2 and 3 are about an 1/8" out of alignment...but you're not sure. Have you removed the center main bearing to look for a crack in the crankshaft there?

Have you tried jacking up the back of the car (one side), putting the transmission in neutral and turning the rear wheel? Then put car in 4th gear and try turning the wheel - will the engine rotate? If not, have someone push on the clutch and see if it wheel will rotate. That should eliminate the transmission and the clutch assembly if the rear wheel turns.

Gene Gillam

I recently took a running engine out of a car, took all the bits out bar the camshaft, which I found impossible to turn but for a few deg, it had run its journal. needed a lot of force to pull.


why not remove the timing chain to see if the cam turns or the crank turns?

mog

I think you have a broken rod or the small end cinch bolt has broken or come loose so that the rod end is jamming somewhere

At high speed it usually comes thru the block!

But it could keep you from rotating mor than a few degrees

Don Harmer

Mog might be on to something,,, before you drop the bearings check to see if the cam is free to turn.. you already have the cover off,,

SPW
Steve Wincze

I have now checked all bearing surfaces (journals and pistons) and nothing is visibly broken or damaged. All three journals look immaculate and the pistons look fine although there is some scoring on two of the piston bearings, there are no marks on the crankshaft at all.
I'll pull off the timing chain tomorrow.
Long day..... I need a beer...
Geoffrey M Baker

The car rolls free in nuetral, right? That's how it made it into the garage, correct?

Trans didn't come loose and back away from engine? This happened to me 50 years ago with symptoms much like you descibed.

situation at the time- hot engine; stop & go driving; idling long periods with clutch in; throw-out bushing spinning genereating heat from friction; force from throwout bearing forcing crank against crank thrust bearing...

If the trans input shaft siezed in the crank pilot bushing , the clutch won't disengage and things act crazy, but you'd still have nuetral and the engine would still roll, unless there was a serious trans failure.

Inspect the thrust surfaces of the center bearing insert and the mating crank surfaces for galling.
The symptoms you described could be explained by a spun bearing, but hopefully, your inspection has eliminated this nightmare.
JRN JIM

Before removing chain, make sure you are absolutely familiar with the orientation of the sprockets and the shiny chain links, if you have them. You might make a sketch so you can reinstall it correctly. You don't want bent valves or another mystery on how to get it running agian.
JRN JIM

Thanks Jim, that's the plan!!!
This morning I removed the radiator, and that was not easy. All bolts came out without damage though.
Only damage so far is that two of the four bolts securing the fan blades to the water pump snapped off. I was able to take the pump and put it in a vise and apply heat to the front end and was then able to grab the remaining thread nubbins with a vice grip and unscrew them... saving a lot of time drilling out and retapping!
Now ... onto the timing chain...
I've carefully studied the diagram in the workshop manual (a15) of the orientation of the sprockets and the chain.
But here's the problem: the timing mark on the cam sprocket correctly matches a white link in the chain. But the timing mark on the crank sprocket does not match to a white link (there is only one white link as far as I can see) but in fact matches to a section BETWEEN two links.
Is this OK??? See photo...

Geoffrey M Baker

The timing chain marks will only line up correctly when the #1 piston is TDC on the compression stroke so this isn't really telling you anything except where you are at this time in the present crank/cam relationship.

Don't worry about where your marks are now...set 'em correctly after you find the cause of your problem.
Gene Gillam

Gene is correct, also the "white links" on some of the new chains are not the correct number of links apart anyway. George
George Butz

Ladies and gentlemen... I give you... THE CAMSHAFT!!!
As soon as I removed the timing chain I was able to spin the engine freely!

Woohoo!
(Much money saved!!)
Geoffrey M Baker

Is it just the camshaft or a lifter seized up?

Bill,
TD24570

Bill Brown

With all this information my guess would be the oil pump internal (pump) gears or possibly the bushings.
Hugh Pite
H.D. Pite

I'm with Hugh..sort of...Points now lead to the oil pump or the dizzy. Could be the gears to the cam on either. The momentary increase in engine speed kinda says distributor but we shall see soon enough.
MG LaVerne

Distributor has already been pulled and the gear supposedly looks OK. The engine still wouldn't move with dist. out.
We know there's history on the cam/oil pump gears and catastrophies. Let's hope that didn't occur. Fortunately, bearings didn't get fed shrapnel from tooth decay.
My thoughts turn to the split center cam bearing, as if it wasn't secured right and spun/siezed.
Also, recall the note from Moss, "New front cam bearings must be fitted each time the cylinder block is hot-tanked, as the caustic solution will destroy the thin wall bearing shell and must be line-reamed after installation. This procedure must be entrusted to a competent automotive machine shop."

JRN JIM

It's the camshaft, probably the center bearing. So far, I cannot extract it. I've removed the oil pump and the bearing retainer dowel screws, and I can pull it out about 3/8 of an inch and that is it.
I'll spend some more time on it tomorrow...
(Oil pump gears etc all look OK).
Geoffrey M Baker

The center and rear bearings must be oriented correctly so that the oil holes line up with the delivery holes in the block. Otherwise the bearing will run dry and rapid failure will occur. Same goes for the front bearing, but that one is easy to eyeball. The center and rear are not easy to see, and are easily installed the wrong way around.

Moss is now carrying a front cam bearing that fits properly. I've just fitted one a few days ago. The old County bearing was the troublesome one, and good riddance to it.

If your oil pump is still installed and it has seized, then it may also prevent the cam from coming out easily.
Steve S

Geoff, I had some trouble removing my centre camshaft bearing so I made a puller. See the thread in the archive "Replacing the camshaft" which gives my blow by blow & some very useful pics & detail on the removal & installation process. Cheers
Peter TD 5801
P Hehir

its a pain to pull, plenty of silicone spray and pushing back and front as well as turning to try and flatten the metal to allow it to free seemed to work, the spun material was not uniform in its deposits on the cam face. its a 2 beer job.
mog

This thread was discussed between 16/03/2015 and 18/03/2015

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