07-06-2019, 03:25 PM
Thanks for all the help so far, and apologies if the following is rather long winded.
This morning I had another look at the issue and made some more accurate measurements which makes me think I now know what's wrong but not exactly the best way to resolve it.
Initially I measured the dimension from the bottom if the slots in the thrust race to the face of the gearbox which mates with the engine. As far as I can establish this makes the bottom of the slots (where the toggles bear) 0.182" proud of the gearbox face.
When I had the clutch assembly bolted in position on the flywheel the ends of the toggles were virtually flush with the face of the the casting which mates with the gearbox. As a result the toggles would be compressed by around 0.182" when the gearbox is bolted on which would explain why the clutch is at the point of slipping.
To rectify this and allow for a little free play in the mechanism I was thinking I would adjust the depth of the toggle slots to give me something like 1/16" of clearance. This would mean altering the slot depth so that the ends of the toggles would be around 1/4" below the gearbox mounting face.
There is something like a 3:1 ratio built into the toggle mechanism so to achieve 1/4" of clearance I would need to deepen the toggle slots by around 0.083".
I then measured the depth of the toggle slots in my "new" back plate and although these vary slightly due to wear the average depth is 0.230" so if I were to deepen them by 0.083" they would become 0.333" deep although I suspect the slots were originally 5/16" (0.312") deep because on another Ruby type plate the unworn area seems to be 5/16" deep.
This all seemed fine and I was thinking I'd simply file down the repair pegs in the bottom of the toggle slots by something between 0.062" and 0.083" depending upon whether I based it on the slot depth being 5/16" or the calculated 0.333". This would move the toggle ends by around 1/4" and remove the clutch slip whilst hopefully still giving me good disengagement.
Now the problem. I don't really know how the repair pins were fixed into the bottom of the toggle slots but it looks as though they are actually headed pins pushed in from the slot side and then peened over on the back. The thickness of the head above the bottom of the slot is probably around 0.100 so if I remove 0.062 then there may be only 0.038 of material left and even less if I were to remove 0.083".
Trouble is I just don't know if this will be OK. The alternative is obviously to do as others have suggested and add spacers between the gearbox and engine but these would need to be around 1/4" long which would mean the gearbox flange no longer engaged in the engine casting.
What do you think?
This morning I had another look at the issue and made some more accurate measurements which makes me think I now know what's wrong but not exactly the best way to resolve it.
Initially I measured the dimension from the bottom if the slots in the thrust race to the face of the gearbox which mates with the engine. As far as I can establish this makes the bottom of the slots (where the toggles bear) 0.182" proud of the gearbox face.
When I had the clutch assembly bolted in position on the flywheel the ends of the toggles were virtually flush with the face of the the casting which mates with the gearbox. As a result the toggles would be compressed by around 0.182" when the gearbox is bolted on which would explain why the clutch is at the point of slipping.
To rectify this and allow for a little free play in the mechanism I was thinking I would adjust the depth of the toggle slots to give me something like 1/16" of clearance. This would mean altering the slot depth so that the ends of the toggles would be around 1/4" below the gearbox mounting face.
There is something like a 3:1 ratio built into the toggle mechanism so to achieve 1/4" of clearance I would need to deepen the toggle slots by around 0.083".
I then measured the depth of the toggle slots in my "new" back plate and although these vary slightly due to wear the average depth is 0.230" so if I were to deepen them by 0.083" they would become 0.333" deep although I suspect the slots were originally 5/16" (0.312") deep because on another Ruby type plate the unworn area seems to be 5/16" deep.
This all seemed fine and I was thinking I'd simply file down the repair pegs in the bottom of the toggle slots by something between 0.062" and 0.083" depending upon whether I based it on the slot depth being 5/16" or the calculated 0.333". This would move the toggle ends by around 1/4" and remove the clutch slip whilst hopefully still giving me good disengagement.
Now the problem. I don't really know how the repair pins were fixed into the bottom of the toggle slots but it looks as though they are actually headed pins pushed in from the slot side and then peened over on the back. The thickness of the head above the bottom of the slot is probably around 0.100 so if I remove 0.062 then there may be only 0.038 of material left and even less if I were to remove 0.083".
Trouble is I just don't know if this will be OK. The alternative is obviously to do as others have suggested and add spacers between the gearbox and engine but these would need to be around 1/4" long which would mean the gearbox flange no longer engaged in the engine casting.
What do you think?