17 replies to this topic

[Minigman]

I’ve posted quite a bit on here already about this issue and having had a new gearbox case and rebuild and transfer case replaced due to a collapsed idler gear bearing on the last box, I’ve finally got the whole lot bolted together and back in the car today.

Whilst I had the whole thing out and apart I replaced the thrust bearings - the old ones had only done 1200 miles and looked like new but hey ho replace them anyway.

I bolted the new box on, idler bearing clearance sorted and then the transfer case on and checked primary gear end float as all was within tolerance.

So having bolted it all back together and put it back in the car it fired up fine with good oil pressure and no noises.

The clutch throw and stop clearance checked before the engine was run and all good.

Fired straight up and then once ticking over nicely and warmed up everything settled down as it should.

BUT then I pressed the clutch and the revs dropped a lot and you can’t select a gear. In fact you have to release the clutch or the engine will just stall.

So everything is good in neutral but no clutch and can’t select any gears.

The clutch is an orange diaphragm, running a lightened flywheel and 276 cam.

The had a newly built 1330 engine, gearbox etc 1200 miles before the idler bearing obliterated.

Any ideas where I start on this please?

[Benoit_Dupont]

Hi,

 

so, I'm not the expert and there are definitely people more able than me in this matter here.

But from what I can say: A lightened flywheel does exactly what it is supposed to do: it's light, so it does not have much momentum: when you decouple the engine from the gearbox, this momentum is what keeps the engine from stalling. 

that's why lightened flywheel are mostly for race use where you're in fact always reving. on the street, that does not work.

 

what you can do however is to have the idle rev set higher and see if it does not stall: higher iddle will mean that you will conserve more energy in the flywheel in form of rotation speed to compensate for lack of mass.

[blacktulip]

Something isn't right. Am i right in saying it didn't do this before on the same spec?

[Stevie W]

Hi,

Did you check the crank end float after fitting the new thrust washers and has the clutch been correctly adjusted?

It sounds like ths clutch is placing immense pressure on the crank thrusts, or there's too much end float. Could you ask a friend to push the clutch pedal right to the floor with the engine off so you can look at the Frank pulley for any movement?

No visble movement shows whilst the end float might not be within spec, it isn't excessive. If there's no movement try re-adjusting the clutch.

Cheers, Steve.

Edited by Stevie W, 17 April 2020 - 01:00 PM.

[Minigman]

Hi,

so, I'm not the expert and there are definitely people more able than me in this matter here.
But from what I can say: A lightened flywheel does exactly what it is supposed to do: it's light, so it does not have much momentum: when you decouple the engine from the gearbox, this momentum is what keeps the engine from stalling.
that's why lightened flywheel are mostly for race use where you're in fact always reving. on the street, that does not work.

what you can do however is to have the idle rev set higher and see if it does not stall: higher iddle will mean that you will conserve more energy in the flywheel in form of rotation speed to compensate for lack of mass.

I understand what you’re saying but the engine ran very sweetly for the first 1200 miles before completely out of the blue the idler gear bearing obliterated.

I don’t think it would have run at all from the off had the components not been compatible.

[Minigman]

Something isn't right. Am i right in saying it didn't do this before on the same spec?

Yes you’re right in saying it was all fine for 1200 miles until suddenly the idler gear bearing obliterated.

Edited by Minigman, 17 April 2020 - 02:00 PM.

[Minigman]

Hi,

Did you check the crank end float after fitting the new thrust washers and has the clutch been correctly adjusted?

It sounds like ths clutch is placing immense pressure on the crank thrusts, or there's too much end float. Could you ask a friend to push the clutch pedal right to the floor with the engine off so you can look at the Frank pulley for any movement?

No visble movement shows whilst the end float might not be within spec, it isn't excessive. If there's no movement try re-adjusting the clutch.

Cheers, Steve.

When I installed the thrust washers I checked the end float albeit with a feeler gauge and I got 4-5 thou. 4 went in but 5 was a squeeze.

I’m with you on the clutch thing. On closer inspection The arm is bent and the rod which goes into the slave cylinder appears to be at a slight angle. The clutch was bled and the 20 thou gap to the stop was done along with the throw out.

I’ve now ordered a new arm, clevis pins, plunger, rod and slave cylinder (all a lot cheaper than another gearbox build).

As things are a bit slow currently it’s going to be 7-10 days before I have another bash.

Do you know how long can you store DOT4 fluid in its original container before it becomes too old to use? I’m wondering if the fluid is being compressed reducing the clutch action - just an overnight thought.

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Edited by Minigman, 17 April 2020 - 02:13 PM.

[Stevie W]

Ok, so no issues with endfloat then!

The clutch arm being bent like that was an old trick to give more "movement" to give the clutch more disengagement. It used to make up for any wear on the ball on the other end of that arm. With regard to DOT 4 brake fluid storage it seems the general concencus (google search) is that a couple of months in an air tight container that's already been opened then had the lid refitted tightly, is ok.

If you've got a while to wait for your new parts, you could remove the "wok" dismantle the clutch arm clevis pin and plunger in readiness and see if anything's amiss.

Cheers, Steve.

[Minigman]

Ok, so no issues with endfloat then!

The clutch arm being bent like that was an old trick to give more "movement" to give the clutch more disengagement. It used to make up for any wear on the ball on the other end of that arm. With regard to DOT 4 brake fluid storage it seems the general concencus (google search) is that a couple of months in an air tight container that's already been opened then had the lid refitted tightly, is ok.

If you've got a while to wait for your new parts, you could remove the "wok" dismantle the clutch arm clevis pin and plunger in readiness and see if anything's amiss.

Cheers, Steve.

In order to remove the wok can I do this in the car by just removing the wok engine mount and engine steady and jacking it up a little? I guess the starter solenoid needs dropping of flies the inner wing too. Anything else?

[imack]

I've just had the wok and flywheel off my '72 and didn't take anything off other than the fresh air intake elbow. You'll need to remove the starter motor if it's a standard one, you'll probably get away with it if you're using a high torque type.

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[Stevie W]

Yes absolutely!

 

Place a block of wood across the "wok" side of the gearbox bottom and gently raise the jack to support the weight of the engine/gearbox on that side. Unbolt the stabiliser from the engine block-end, this will allow the engine to be raised slightly later on.

 

Undo and remove the engine mount bolts that hold the mount to the subframe (easier said than done)! The jack will stop the engine/gearbox dropping.

 

In the boot, disconnect the battery positive terminal (will prevent possible shorting of the wok to the "live" terminal of the solenoid). You can remove the solenoid mounting bolts and move it slightly to gain more space when removing the "wok".

 

Remove the return spring on the clutch arm so that the "wok" can easily be moved later. Now remove all the bolts holding the wok on. Two of the lower bolts are a pain to reach due to being close to the subframe web. Jacking up the engine/gearbox slightly can give you a little more space, but make absolutely sure the engine can't slip off the wood/jack otherwise you'll end up with the weight of these crushing your fingers! At this point it's a good idea to loosen the clutch throw-out stop lock-nuts!

 

You might want to remove the starter motor and air inlet elbow as imack above did.

 

Once these bolts are off, the "wok" should be easy to remove but might need a gentle tab with a wooden mallet if it's been fitted for a long time. Once the wok is off, you'll be able to remove the loosened clutch throw-out lock nuts & dismantle the arm, clevis pin and plunger. If there's anything obviously broken or worn (clutch arm ball for example).

 

It depends on what you find and how far you want to go with further dismantling, whilst you've got it all apart it would seem sensible to change the clutch release bearing. ....!

 

Cheers, Steve.   

Edited by Stevie W, 17 April 2020 - 05:51 PM.

[Minigman]

Yes absolutely!

Place a block of wood across the "wok" side of the gearbox bottom and gently raise the jack to support the weight of the engine/gearbox on that side. Unbolt the stabiliser from the engine block-end, this will allow the engine to be raised slightly later on.

Undo and remove the engine mount bolts that hold the mount to the subframe (easier said than done)! The jack will stop the engine/gearbox dropping.

In the boot, disconnect the battery positive terminal (will prevent possible shorting of the wok to the "live" terminal of the solenoid). You can remove the solenoid mounting bolts and move it slightly to gain more space when removing the "wok".

Remove the return spring on the clutch arm so that the "wok" can easily be moved later. Now remove all the bolts holding the wok on. Two of the lower bolts are a pain to reach due to being close to the subframe web. Jacking up the engine/gearbox slightly can give you a little more space, but make absolutely sure the engine can't slip off the wood/jack otherwise you'll end up with the weight of these crushing your fingers! At this point it's a good idea to loosen the clutch throw-out stop lock-nuts!

You might want to remove the starter motor and air inlet elbow as imack above did.

Once these bolts are off, the "wok" should be easy to remove but might need a gentle tab with a wooden mallet if it's been fitted for a long time. Once the wok is off, you'll be able to remove the loosened clutch throw-out lock nuts & dismantle the arm, clevis pin and plunger. If there's anything obviously broken or worn (clutch arm ball for example).

It depends on what you find and how far you want to go with further dismantling, whilst you've got it all apart it would seem sensible to change the clutch release bearing. ....!

Cheers, Steve.

I can get all that apart quite easily as I only bolted the whole engine, box transfer case etc. together and dropped it back in the car earlier this week. A new thing for me to do on my own during lock down. I shortened 3 of the ‘wok’ bolts by 1/4” where they sit near the subframe just in case I ever needed to remove it again as I’d read this would help things. Sounds quite straight forward and relatively simple. Thanks.

[Stevie W]

Ah ok, fair enough,

No worries, good luck and let us know how you get on and if you find anything!

Cheers, Steve.

Edited by Stevie W, 17 April 2020 - 06:58 PM.

[Steve220]

Is the primary gear thrust washer on the right way round?

[Minigman]

Is the primary gear thrust washer on the right way round?

Yep, taper side in. If it wasn’t I’m pretty sure you can’t measure the end float it as the C washer won’t seat correctly.