13 replies to this topic

[Thelimes79mini]

just finished my engine / gearbox rebuild the problem i have is that the clutch when depressed
slows the engine down about 200 to 300 rpm I have replaced the slave cylinder with a new one
at first i could not get any gears at all so a made a longer push rod and now i can drive the car
but the idle still slows down and the dredded 3rd to 2nd crunch is still there and all syncro rings were replaced as this condition existed before a rebuilt the box
Any ideas or advice

Thanks in advance

The Lime in Canada

[The Principal]

Did you adjust the clutch when installed? the two large nuts on the end of the operating shaft govern how much throw or travel the thrust bearing can go. In effect sounds like you have too much travel and are forcing the crankshaft hard against the thrusts at the opposite end of the engine this will cause long term problems. Check the gap between the nuts and the clutch cover, by making a longer push rod you will only make the problem worse.

Do you mean the baulk rings have been replaced in the gearbox? or the syncro hub? or both?

[Thelimes79mini]

Did you adjust the clutch when installed? the two large nuts on the end of the operating shaft govern how much throw or travel the thrust bearing can go. In effect sounds like you have too much travel and are forcing the crankshaft hard against the thrusts at the opposite end of the engine this will cause long term problems. Check the gap between the nuts and the clutch cover, by making a longer push rod you will only make the problem worse.

Do you mean the baulk rings have been replaced in the gearbox? or the syncro hub? or both?

I changed the baulk rings,main shaft, second gear
The engine slows down with the standered push rod and i'm not able to get any gears with that set up
I am pulling my hair out
Thanks for the reply

The Lime

[cooperrodeo]

Is the crankshaft endfloat OK?

[Thelimes79mini]

Is the crankshaft endfloat OK?

yes as far as i know
I did'nt have this problem before i rebuilt only changed the main thrust bearings

[tiger99]

There is something very contradictory here. Pushing the clutch slows the engine, yet making the push rod longer, to push it more, does not?

I actually think that the primary gear may be partially siezing on the crankshaft, so even if the clutch plate is fully disengaged, the drive is not. I have seen that once.

Surprisingly, no-one has asked you if it is a Verto or pre-Verto clutch. That makes a very big difference, the pre-Verto should have a stop bolt near the slave cylinder which must be correctly adjusted, and if that was missing it could explain why you had to extend the push rod.

[Thelimes79mini]

There is something very contradictory here. Pushing the clutch slows the engine, yet making the push rod longer, to push it more, does not?

I actually think that the primary gear may be partially siezing on the crankshaft, so even if the clutch plate is fully disengaged, the drive is not. I have seen that once.

Surprisingly, no-one has asked you if it is a Verto or pre-Verto clutch. That makes a very big difference, the pre-Verto should have a stop bolt near the slave cylinder which must be correctly adjusted, and if that was missing it could explain why you had to extend the push rod.

Its a pre verto clutch it has the bolt/stop which ive adjusted as per the haynes manual
and the rpms were dropping when i had the shorter push rod in
When I took it for its first test run everthing worked just like it should
Went for petrol an hour later coudnt get any gears atall
had to start it while in gear and was able to get home but coudnt change down
put the longer push rod in now i can drive it change down exept from 3rd to 2nd and ive change all the baulk rings

at a total loss

Thanks The Lime

[bmcecosse]

The gap to the little 'stop' is best at 15 thou, with the arm held away by hand (return spring removed). Then i suggest you bleed out the hydraulics. Did you ONLY change the baulk rings - or did you also fit a NEW 2nd gear?

[Thelimes79mini]

The gap to the little 'stop' is best at 15 thou, with the arm held away by hand (return spring removed). Then i suggest you bleed out the hydraulics. Did you ONLY change the baulk rings - or did you also fit a NEW 2nd gear?

Fitted a new second gear , main shaft and baulk rings

Thanks The Lime in canada

[tiger99]

This is beginning to make sense. If you make the push rod longer you need to reset the stop bolt to get the correct clearance again, and you are in EXACTLY the same situation as before, EXCEPT that the slave piston is more fully retracted, so the volume of fluid in the slave cylinder is less. Fluid is incompressible, so again, no difference, but if it is not fluid, but partly air, that matters. I concur with bmcecosse, bleed it.

But you still have another problem.

[Cooperman]

Undo the two large nuts in the centre of the clutch cover. These are the overthrow stop nut & locknut.
Set the stop bolt clearance to 0.015" when pulling the clutch arm by hand witht he spring removed.
re-fit the spring and check that the top of the clutch arm has a linear movement of 0.55" +/0.050" from clutch pedal full up to clutch pedal fully down. If it does not move this amount then there is a hydraulic problem or a problem with the pedal linkage.
If that movement exists, push the clutch pedal fully down and screw in the inner overthrow stop nut until it just touches the cover. release the pedal and turn that nut a further 1/2 a flat. Use the locknut to lock it in that position.
The clutch is now correctly set. If there are still problems with selecting gears come back on here.

[bmcecosse]

Did you fit an 'original' baulk ring - or a pattern item? But could just be air in the system - not freeing the clutch properly, hence the crunch. Does it double-de-clutch ok without crunch?

[Thelimes79mini]

Did you fit an 'original' baulk ring - or a pattern item? But could just be air in the system - not freeing the clutch properly, hence the crunch. Does it double-de-clutch ok without crunch?

I did fit original baulk rings but why did it work fine on the first test run and now it crunchs from 3rd to 2nd
double clutching does not work either

[Thelimes79mini]

Undo the two large nuts in the centre of the clutch cover. These are the overthrow stop nut & locknut.
Set the stop bolt clearance to 0.015" when pulling the clutch arm by hand witht he spring removed.
re-fit the spring and check that the top of the clutch arm has a linear movement of 0.55" +/0.050" from clutch pedal full up to clutch pedal fully down. If it does not move this amount then there is a hydraulic problem or a problem with the pedal linkage.
If that movement exists, push the clutch pedal fully down and screw in the inner overthrow stop nut until it just touches the cover. release the pedal and turn that nut a further 1/2 a flat. Use the locknut to lock it in that position.
The clutch is now correctly set. If there are still problems with selecting gears come back on here.

I've set the clutch as you suggested and i can select gears no problem when changing up the box and down untill it comes to
changing down from 3rd to 2nd thats why i changed the baulk rings in the first place
Thanks the Lime in Canada