Aargh ! - help: changed flexplate - now engine wont turn !!
Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
Aargh ! - help: changed flexplate - now engine wont turn !!
Have "enjoyed" changing the battered flexplate on my 74 over the last few days and was looking to get it finished today ... BUT... have discovered that the engine wont turn over (by hand).
All was fine before I hooked up the Torque converter: rotated the crank thru 360 to fit the flexplate bolts, but now it doesnt want to budge. As far as I can tell the plate is the right way in (humps towards the t/c),so have had a good look round and I cant see any obstructions around the plate, but I physically cant wind the engine over to tighten the last T/C bolt - WHAT GIVES !!.
The car feels like the transmission is in park i.e. locked - when its currently in neutral.
WHAT THE HELL HAVE I DONE GUYS !!!!!!
Cheers,
Laurence
What have I done (or not done as the case may be !!!)
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Remove the bolts you have in and see if the engine turns. Then see if the torque converter turns when its not bolted to the flexplate. If both turn when not bolted together, its the bolts.
Burning Brakes
Joined: Mar 1999
Posts: 1,047
Likes: 3
From: CA
Sounds strange. I would take out the flywheel/converter bolts that you installed and then try again to see what is locking up. With the bolts out the torque converter should turn freely by hand and the flywheel should turn with a flywheel wrench or by turning the front crank bolt.
Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
Thanks for the quick replies fellas.
Yep, totally get what youre saying guys - all bolts that have gone in - came out originally !!. Is there some way the transmission itself can lock?
But, I can only get to two of the three t/c bolts as one is way up at the top of the plate at the moment. Now how the ... do I get to this bolt if I cant rotate the engine to bring it down as it were.
I'm learning all the time - just sometimes its painful !
Cheers all
Yep, totally get what youre saying guys - all bolts that have gone in - came out originally !!. Is there some way the transmission itself can lock?
But, I can only get to two of the three t/c bolts as one is way up at the top of the plate at the moment. Now how the ... do I get to this bolt if I cant rotate the engine to bring it down as it were.
I'm learning all the time - just sometimes its painful !
Cheers all
Le Mans Master
Joined: Aug 2006
Posts: 7,427
Likes: 1,560
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
When you install the converter into the transmission you have to turn the converter so the two tabs on the converter go into the two tabs on the transmission input shaft.
Loosten the transmission at the bell housing and see if it turns.
Loosten the transmission at the bell housing and see if it turns.
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
When you unbolted the old flex plate from the torque converter did the torque converter slid back into transmission easily (it should)? When the flex plate was out did you move the torque converter forward? When placing a torque converter on to the transmission shaft It has three “Clicks” to seat properly if you moved it forward (without a flex plate to stop it) you may not be seated properly which will cause it to bind up when trying to bolt it up to the flex plate. Although with the transmission bolted up to the block it would be a very tight space between the flex plate and the converter. Does the flex plate still look flat or a little out of shape? This just a thought but I do know that when a transmission is out and being bolted back up to the block and the torque converter is not fully seated it will bind up and not turn.
This just a thought without seeing it.
Scott
This just a thought without seeing it.
Scott
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Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
Cheers guys - this is all really helpful stuff.
The t/c slid back off the old plate when unbolted very easily and that's where it stayed until I needed to bring it forward again (to the new plate).
It also rotated very easily.
I think Im just gonna have to unbolt the bell housing and see if I can get any movement of any kind.
Cheers all
Laurence
The t/c slid back off the old plate when unbolted very easily and that's where it stayed until I needed to bring it forward again (to the new plate).
It also rotated very easily.
I think Im just gonna have to unbolt the bell housing and see if I can get any movement of any kind.
Cheers all
Laurence
Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
Was your old flex plate 168 teeth or 153?
If it spun over fine before you mated the trans back to the block then it has to be something with bring the two back together again.
However, I believe you said you got 2 of the converter bolts on before it locked up? But where those bolts easy to get to and you didn't have to rotate the engine until you got those on first?
Was the flex plate easy to spin over with the trans bolted to the block before you bolted the converter to it?
If it spun over fine before you mated the trans back to the block then it has to be something with bring the two back together again.
However, I believe you said you got 2 of the converter bolts on before it locked up? But where those bolts easy to get to and you didn't have to rotate the engine until you got those on first?
Was the flex plate easy to spin over with the trans bolted to the block before you bolted the converter to it?
Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
Thanks fella's.
The flex is a 168 tooth, and I can confirm it is flat against the crank.
Lying in bed thinking about this as ya do ( or is it just me ?) - I think I must have rotated the engine initially to get the 3 flex-to-convertor bolts in and started, but not by any great amount. This makes me think that the prob is the T/C and I ve taken up "the slack" as it were and now that has been taken up the two wont budge as something has wedged.
Thinking about the convertor and how its mounted on the tranny: when it slides back against these mounts mentioned previously - is it a perceptible feeling, as I would need to check that its mounted OK and I don't know what I'm looking for in reality.
Cheers for all your thoughts
Laurence
The flex is a 168 tooth, and I can confirm it is flat against the crank.
Lying in bed thinking about this as ya do ( or is it just me ?) - I think I must have rotated the engine initially to get the 3 flex-to-convertor bolts in and started, but not by any great amount. This makes me think that the prob is the T/C and I ve taken up "the slack" as it were and now that has been taken up the two wont budge as something has wedged.
Thinking about the convertor and how its mounted on the tranny: when it slides back against these mounts mentioned previously - is it a perceptible feeling, as I would need to check that its mounted OK and I don't know what I'm looking for in reality.
Cheers for all your thoughts
Laurence
Pro
Joined: Oct 2006
Posts: 734
Likes: 0
From: Bryan Texas
I'd pull the tc bolts out and see if things move as they should. If the flexplate and tc spin as they should, you know the tc bolts are hitting something. Do the tc bolts tread into the tc or do they have nuts? Nuts go on the tc side.
Last edited by myk7; Apr 6, 2010 at 08:12 PM.
Advanced
Joined: Dec 2008
Posts: 52
Likes: 0
From: Medina Ohio
After reading all the post here I'm going to toss my 2 cents in.
I think one of two things have happened.
1. You put the flex plate bolts in backwards and they are hitting something.
2. You did not get the torque converter all the way into the pump and it is binding and keeping the motor from running.
I hope it's the first because of it's the second and you have gotten the transmission to tighten all the way against the block you more than likely trashed the pump.
Again this is only my 2 cents worth. See if you can loosen the transmission bolts some and try to turn the motor over. If that works then you know the torque converter isn't in all the way.
I think one of two things have happened.
1. You put the flex plate bolts in backwards and they are hitting something.
2. You did not get the torque converter all the way into the pump and it is binding and keeping the motor from running.
I hope it's the first because of it's the second and you have gotten the transmission to tighten all the way against the block you more than likely trashed the pump.
Again this is only my 2 cents worth. See if you can loosen the transmission bolts some and try to turn the motor over. If that works then you know the torque converter isn't in all the way.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Start over again and ask questions here when in doubt. I once put my motor back in without the clutch throwout bearing. Had to pull the motor again to put the bearing in. I was fine a month or so later 
Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
- start again ??? - only as a last resort !!!.The question of whether the plate is in the right way round did cross my mind - like straight away ! - cos it is the sort of dumbass thing I would do - but it is in correctly thank goodness.
Having read everyones comments on here and from other sources, I reckon the problem is in the trueness of the t/c on its spline in that it is on slightly "pissed" and needs reworking.
Thanks to everyone for their posts/replies - I'll have a look at the w/end as work just gets in the way during the week !!
Cheers guys
Laurence
Thread Starter
Cruising
Joined: Apr 2010
Posts: 11
Likes: 1
From: Newport
Bit of a P.S to the post relating to my flex plate woes - IT'S SORTED !!.
Am major league delighted to report that the prob was indeed the T/C binding after being attached to the flex plate. Cured simply enough with the loosening of the tranny mount bolts to start with (as suggested thru the forum), and backing out the flexplate bolts. When disconnected both engine and T/C revolved easily (sweet moment !!).
Avoided the problem reoccurring by tightening the flex plate bolts gradually and in stages, just checking as we went. Car now turn's over a treat on the starter.
Thanks to all for their input and suggestions.
Cheers
Laurence
Am major league delighted to report that the prob was indeed the T/C binding after being attached to the flex plate. Cured simply enough with the loosening of the tranny mount bolts to start with (as suggested thru the forum), and backing out the flexplate bolts. When disconnected both engine and T/C revolved easily (sweet moment !!).
Avoided the problem reoccurring by tightening the flex plate bolts gradually and in stages, just checking as we went. Car now turn's over a treat on the starter.
Thanks to all for their input and suggestions.
Cheers
Laurence