22 replies to this topic

[Colakurt]

I have just completed a total engine and gearbox rebuild. Which also means replacing all bearings and thrust washers.

 

The engine is a 1380cc A+ with orange clutch diagraph and ultra light steel flywheel and Minispares Evo001 cam.

The crank thrust washers that was in before the rebuild was a standard set on the fan side and +3thou on the clutch side. After replacing them with standard thrust washers on both sides, I measured the end float to about 3 thou. I would like to check this again, hopefully without having to take the engine out of the car? Method?

 

Here is the problem. The engine runs as it should in idle at about 1000rpm but when I press the clutch the revs lowers and in some cases the engine stops. I have done some reading and found people mentioning a possible reason can be crank end float being too low. But here is where my issue is different.

When I press the clutch it seems like the clutch cover or wok is giving in or warping as the pedal is pressed. If I look at the fan belt pulley I can also see it move but it is only barely notable, like almost nothing. The pedal feels really heavy and must be pushed all the way to the floor before the clutch is fully engaged. To me it seems like something is not working right in the clutch region, but the question is what?

 

I have checked the assembly order of the clutch and it is correct, all components in the clutch was reused from before the rebuild, except the release bearing, plunger, clutch arm and slave cylinder, which is all new.

 

Any ideas of what I can do before I have to take the engine out and apart again?

[nicklouse]

How have you set the clutch arm? Stop and nuts.

[Colakurt]

I would say so, but not sure how the stop and nuts should be set. My understanding is that they are not supposed to touch the diaphragm under normal use but only work as a safety measure in case the return valve on the master cylinder fails?

[sonscar]

Read the manual and follow it carefully.The stops adjustment is reasonably critical.I would have to read how to adjust it too,Steve..

[nicklouse]

I would say so, but not sure how the stop and nuts should be set. My understanding is that they are not supposed to touch the diaphragm under normal use but only work as a safety measure in case the return valve on the master cylinder fails?

Nope nope and nope.

 

read the manual. You may have overloaded the thrust bearings. If you have then the engine needs pulling.

[imack]

Thrust bearings fitted the rightwards around?

[Lplus]

I have just completed a total engine and gearbox rebuild. Which also means replacing all bearings and thrust washers.

 

The engine is a 1380cc A+ with orange clutch diagraph and ultra light steel flywheel and Minispares Evo001 cam.

The crank thrust washers that was in before the rebuild was a standard set on the fan side and +3thou on the clutch side. After replacing them with standard thrust washers on both sides, I measured the end float to about 3 thou. I would like to check this again, hopefully without having to take the engine out of the car? Method?

 

Here is the problem. The engine runs as it should in idle at about 1000rpm but when I press the clutch the revs lowers and in some cases the engine stops. I have done some reading and found people mentioning a possible reason can be crank end float being too low. But here is where my issue is different.

When I press the clutch it seems like the clutch cover or wok is giving in or warping as the pedal is pressed. If I look at the fan belt pulley I can also see it move but it is only barely notable, like almost nothing. The pedal feels really heavy and must be pushed all the way to the floor before the clutch is fully engaged. To me it seems like something is not working right in the clutch region, but the question is what?

 

I have checked the assembly order of the clutch and it is correct, all components in the clutch was reused from before the rebuild, except the release bearing, plunger, clutch arm and slave cylinder, which is all new.

 

Any ideas of what I can do before I have to take the engine out and apart again?

I presume you mean fully disengaged.   Will the car go into gear when the pedal is fully down?  Is the clutch arm or the ball bent?  I had a sort of similar problem with a new clutch fitted with a new standard diaphragm.  The clutch refused to disengage and if the pedal was pushed hard enough the engine slowed down.  The engine would rev freely with the clutch pedal up.  The ball on the end of the arm was bent due to the pressure I exerted.  Removing the clutch and fitting the old diaphragm cured the problem completely.  My only tentative explanation for the problem is the new diaphragm slipped sideways off the ridge it is supposed to sit on and jammed the clutch mechanism.  Not sure if this helps but it seems similar.
 

Edited by Lplus, 31 May 2023 - 10:22 AM.

[Colakurt]

The clutch arm and stops is adjusted according to every guide I have been able to find. So I am quote confident the stops is set correctly. The screw on the clutch cover is adjusted by removing the spring and pulling the clutch arm out as far as I can, and then adjusted untill it barely touched the arm, and then one half turn further in, so there is free movement of the arm. The end stop nuts is adjusted so there is about 1mm of Freeplay when the pedal is pressed fully down. That is the guides I have found both here, on YouTube and from minimania. So that should be set correctly.

I have considered if my clutch diaphragm is correct as I can see others having the same issue with the orange clutch as I do. For me it seems like something is being pushed further than intended and that may put excessive strain on the thrust bearings. Also because it seems like clutch over is giving in when the pedal is pressed.

I can put the car into gear with the clutch pedal all the way down and the engine is running. So the clutch does work but the rpm drops significantly and sometimes enough to stall the engine.

I have not driven the car yet, only had it in idle, so hopefully there is no permanent damage to any things.

I do aim for just under 100hp for a fast street setup so I don't know if I need the orange diaphragm or if I can do with a standard?

[Colakurt]

Also there is no visible damage to the clutch arm or plunger, they are both new as well.

[sonscar]

According to my ancient manual you are describing the classic symptoms of overthrow.Undo the big nuts,press in the clutch and hold.Tighten to the wok,release clutch and then screw towards the wok one flat.Steve...

[Colakurt]

Okay sounds good. But will that not risk bending the arm?
And what can I do to make the clutch disengage earlier when I press the pedal? I don't feel too confident that the clutch is released unless the pedal is all the way down.

[sonscar]

Do not overthink things,try adjusting it properly first.A mini will not feel like a modern car.Steve..

[coopertaz]

remove cluch assembly and double check components, if you have an ultralight flywheel are the spacers the correct size? whilst out check crank end float with dti on crank end and push on other end of crank. easy to do with engine still in.

[GraemeC]

The clutch arm and stops is adjusted according to every guide I have been able to find. So I am quote confident the stops is set correctly. The screw on the clutch cover is adjusted by removing the spring and pulling the clutch arm out as far as I can, and then adjusted untill it barely touched the arm, and then one half turn further in, so there is free movement of the arm. The end stop nuts is adjusted so there is about 1mm of Freeplay when the pedal is pressed fully down. That is the guides I have found both here, on YouTube and from minimania. So that should be set correctly.

 

Either you've mis-read those guides or you've explained badly here what you've done.

 

For the arm stop:

1) Remove the spring

2) Lightly pull the arm out until you feel some resistance (this is the release bearing touching the thrust plate in the centre of the diapragm)

3) Wind the bolt out until it touches the arm

4) Wind the bolt back in until you have approx 0.5mm (0.020") clearance from the arm and lock off

5) Re-attach spring

 

For the Throw Out nuts:

1) Back the nuts well clear of the flywheel cover

2) Have an assistant press the clutch pedal hard to the floor ***

3) Wind the top-hat throw out nut in until it contacts the flywheel cover

4) release the pedal

5) wind the top-hat throw out nut in one 'flat' and lock with its lock nut.  There should be NO free play with the clutch at rest.

 

*** The fully correct way is to use a piece of metal tube over the clutch arm to give lots of leverage and then pull the arm out as far as you can by hand. However using the pedal gives a 'safe' alternative to prevent overthrow

Edited by GraemeC, 01 June 2023 - 02:07 PM.

[Colakurt]

Crazy About Mini's - For the arm stop, that is the procedure I have done, so that should be set correctly. For the Throw Out Nuts, that is also what I have done, although the plunger ran out of threat when I was winding the nuts in while the pedal was pressed, it did end up flush to the casing and I could turn it a bit more after the pedal was released, but not a full flat.

 

After doing the adjustment I have noticed that I have to press the pedal firmly to the floor of the car for the clutch to be fully disengaged. To me it seems like there is something in the clutch mechanism that stopping or preventing the release mechanism of the clutch, resulting in increased pressure on the thrust bearing.

If I put the car in gear it will start to roll as soon as I lift the pedal a nanometer from the floor. So I am simply not confident the clutch is releasing correctly, while it also seems like it will over-throw if the plunger is pushed further in.

 

Is there any possibility of the diaphragm to be over tightened or pre loaded too tightly? its almost like the clutch mechanism doesn't allow the pressure plate to travel far enough before the load is being transferred directly to the crank.

 

I have two sets of straps between the flywheel and pressure plate, and the bolts connecting them is tightened with 22nm as per Haynes manual. The straps have not been dethatched from the flywheel during the rebuild. So they should be in the same location as before.