Weird clutch problem: Kills engine

Dr_Grip

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So now i got my engine back in the Kadett, it runs just fine, but...

When i press the clutch, the engine cuts out. I can start the engine in neutral and, while on a platform, with the wheels in the air, i can also start the engine with a gear engaged. The drive shaft and one wheel then turn just as expected. But when i press the clutch pedal, the engine cuts out. When i press the pedal i can literally feel how something stars braking the engine, bringing revs down. When pressing the pedal fully, the engine just cuts out.

I already took the clutch assembly apart and checked that the clutch disk is in the right way round, which is is. I can't see any scratches or stress marks on the outside of the plate spring or on the clutch lever....
 
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D-Fence

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Engine running in neutral is normally excluding typical stuff like idle speed sensor etc.....does your engine even have that stuff or is it manual idle speed? Does it start with clutch depressed?
Did you check if the clutch seperates properly? Car on lift, press clutch, wheels still turning? Does the car run well in neutral? It all sounds like a borked idle speed sensor/setup....typically it would happen if revs drop to idle, not if you start in neutral....does it switch off when you rev it in neutral and lift?
 
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Dr_Grip

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Engine running in neutral is normally excluding typical stuff like idle speed sensor etc.....does your engine even have that stuff or is it manual idle speed?
The engine has no sensors at all. Idle speed is controlled by a) a screw on the carburettor and b) the adjustment of the throttle linkage.

Does it start with clutch depressed?
Yep. No problem at all. Both in neutral and in gear.
When pressing the clutch, on the other hand, even my brand new starter motor can hardly turn the engine at all, let alone bring it up to speed.

Did you check if the clutch seperates properly? Car on lift, press clutch, wheels still turning?
You mean, with the engine stopped? Nope, didn't check that.

I gave the whole mess another thought:
Clutch_illustration.jpg

If we look at this illustration, the flywheel, clutch disk, pressure plate and drive shaft all spin at engine speed. Even if there's unwanted contact between any of these parts when the clutch is engaged, it would not stop the engine as they are all spinning at roughly the same speed.
Thus the single point of failure is the thrust bearing. I was able to turn it effortlessly with the gearbox out of the car, but that does not say too much on if it locks up under pressure or not.
 
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D-Fence

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Theoretically speaking, your clutch assembly should have no connection whatsoever to the engine like cables, sensors, vacuum lines etc, right? So there is no way the pressing of the clutch pedal sets anything else in motion but the movement in the clutch itself?

I got a completely bonkers idea, could it be that your mass-points are not connected correctly? So if you disengage the clutch you kill mass from engine, so the ignition stops? Try measuring system voltage when pressing clutch..
 
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Dr_Grip

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Correct. I've checked if the clutch cable gets into the way anywhere. It does not. There are no sensors or whatsoever. The only thing the cable does is pull a lever that pushes the thrust bearing against the plate spring.
 

D-Fence

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Check my bonkers idea I edited in above :)
On second thought, car wouldn't start with clutch depressed......

When pressing the clutch, on the other hand, even my brand new starter motor can hardly turn the engine at all, let alone bring it up to speed.

Might explain that though, not enough juice.....
 
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Dr_Grip

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Check my bonkers idea I edited in above :)
On second thought, car wouldn't start with clutch depressed......

I thought about this, too - but then the starter motor (which has it's own mass cable) should be able to easily turn the engine, it just would never start. But it is blocked...

The longer I think of it, the more it looks like the thrust bearing works as a big brake for the crankshaft.
 
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D-Fence

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Well, might be. If it isn't the bearing, I am out of ideas, so let's hope it is :). I forwarded your problem to the Touri Forum guys, they are quite good at troubleshooting cars :)
 

Dr_Grip

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Well, might be. If it isn't the bearing, I am out of ideas, so let's hope it is :). I forwarded your problem to the Touri Forum guys, they are quite good at troubleshooting cars :)
Together with the Kadett C Forum this is three forums troubleshooting my clutch. Maybe I should bring OHF into it, too.
 

D-Fence

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The internet to the rescue ;)
 

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I once had a similar problem when one of the springs came loose and turned around 90 degrees, but since you've taken it apart already it can't be that.

Did you install the old parts or did you change something?
 

Dr_Grip

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It's the old clutch, no new part there - so far. If no one convinces me otherwise, I'll get me a new thrust bearing on tuesday...
 

D-Fence

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I was told to tell you you own a very rare prototype of the Opel Start-Stop automatic, sadly it is only a prototype with only Stop function :p
 

Dr_Grip

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I was told to tell you you own a very rare prototype of the Opel Start-Stop automatic, sadly it is only a prototype with only Stop function :p
*laughs* My dad said the same thing, pointing out that that's why he's a VW man.
 

D-Fence

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Touri:
Press clutch and check if the driveshaft is moving (at the belt drive in front), maybe the bearings are gone and the driveshaft moves when pressure is engaged to flywheel.

Could this maybe have happened while you removed the pulley of doom?
 
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Dr_Grip

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I'll check this tomorrow... which bearing would this be if it's them?
 

D-Fence

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Crankshaft bearings? :)
 

Pedrocas

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You know what they say, "it's better to have ran and stop than to have never ran anyway".
 
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