gearbox/clutch difficulties
Discussion
My car runs a AS 550hp SBC factory supplied adapter, flywheel, Brand new HD clutch & spring supplied by factory and a G50/00 gearbox with new release fork and shaft.
The clutch will not disengage fully making it seriously difficult to select gears. However the release fork is hitting the clutch pressure plate and therefore cannot travel any further!
I have already machined 1mm from the back of the pressure plate which helped but did not cure the problem.
Today I loosened the gear box and rammed some penny washers in the gap between adapter and gearbox. The clutch now disengages perfectly.
I obviously cannot leave it like this and so I have options: reduce flywheel thickness by the thickness of the washers or machine more from the pressure plate.
Both of these would give the desired result. However taking material off the back of the pressure plate will leave the clutch/fork relationship as is and reducing the thickness of the flywheel will reduce the ability of the fork to take up clutch wear.
The old clutch package also suffered from the same problem as the release fork had been heavily ground to try to stop it hitting the pressure plate.
Interestingly the new pressure plate actually hit the back of the bellhousing case hence the requirement to machine 1mm from it.
Firstly does anybody have a dimensional drawing or list of the correct thicknesses for the relevent parts so that I can check once again that nothing is wrong?
Secondly does anybody know if G50/00 has different dimensions in the bell housing which may cause my problem?
Thirdly could anything else be causing this?
Any other bright ideas?
The clutch will not disengage fully making it seriously difficult to select gears. However the release fork is hitting the clutch pressure plate and therefore cannot travel any further!
I have already machined 1mm from the back of the pressure plate which helped but did not cure the problem.
Today I loosened the gear box and rammed some penny washers in the gap between adapter and gearbox. The clutch now disengages perfectly.
I obviously cannot leave it like this and so I have options: reduce flywheel thickness by the thickness of the washers or machine more from the pressure plate.
Both of these would give the desired result. However taking material off the back of the pressure plate will leave the clutch/fork relationship as is and reducing the thickness of the flywheel will reduce the ability of the fork to take up clutch wear.
The old clutch package also suffered from the same problem as the release fork had been heavily ground to try to stop it hitting the pressure plate.
Interestingly the new pressure plate actually hit the back of the bellhousing case hence the requirement to machine 1mm from it.
Firstly does anybody have a dimensional drawing or list of the correct thicknesses for the relevent parts so that I can check once again that nothing is wrong?
Secondly does anybody know if G50/00 has different dimensions in the bell housing which may cause my problem?
Thirdly could anything else be causing this?
Any other bright ideas?
Mark
No idea of the cause but if the washers worked how about getting a piece of aluminium the same thickness, cut to the shape of the bell housing rim. Then cut it in half so that each piece has two bolt holes in each piece. You could then slacken/remove two bolts on the transmission and fit the "shim". Tighten up when both are fitted and job done.
The fix is cheap and you know it will works because the penny washers did.
Paul
No idea of the cause but if the washers worked how about getting a piece of aluminium the same thickness, cut to the shape of the bell housing rim. Then cut it in half so that each piece has two bolt holes in each piece. You could then slacken/remove two bolts on the transmission and fit the "shim". Tighten up when both are fitted and job done.
The fix is cheap and you know it will works because the penny washers did.
Paul
Mark I assume from your text above that this is a traditional small block chevy? The reason I ask is that some L.S. motors have about .070 worth of materiel on the rear cover that if not milled off can cause the bellhousing to come short about .070 from mating to the block on install. It would be very easy to miss this on assembly and just tighten the bellhousing bolts until it all came together. but I think this could interfere with the mate up of the clutch and flywheel. I don't know that to be a fact I caught the problem the first time I mated the engine and transaxel together. I did call Kennedy Engineering in Palmdale Ca who build the adapter for Ultima and they confirmed that this is a problem in many 5% of the L.S. motors. Lee
MarkWebb said:
Morning Steve.
Indeed it could however clutch was factory supplied.
Also note original install suffered same problem and was butchered to try to resolve it.
Different question for you
Do you know the input shaft size and spline spec?
Not to hand.Indeed it could however clutch was factory supplied.
Also note original install suffered same problem and was butchered to try to resolve it.
Different question for you
Do you know the input shaft size and spline spec?
This from AP catalogue shows 3 different spline sizes and of particular note the different thickness plates.
Can look at mine tonight if needs be.
PORSCHE
911 80 on Competition Standard OE CP5354-22 Use OE Bearing Ø215mm sprung centre cerametallic driven plate 0.87" x 20 spline 8.00mm thick.
911 Competition Standard OE CP6454-2 Ø228mm sprung centre cerametallic driven plate 0.87" x 20 spline 7.37mm thick.
911 2.0i, S 87 on Competition Standard OE CP5354-33 Ø215mm sprung centre cerametallic driven plate 0.80" x 24 spline 8.00mm thick
911 2.0i, S 87 on Competition Standard OE CP5354-22 Ø215mm sprung centre cerametallic driven plate 0.87" x 20 spline 8.00mm thick.
924 Turbo 84 on Competition Standard OE CP5346-1 Ø215mm rigid centre cerametallic driven plate 1.00" x 23 spline 8.38mm thick.
Steve
it should not be forgotten that the porsche "ausrückgabel" is actually reducing the force of the pedal, since it is not hinged in the center there is let us say a 2:1 ratio to reduce the pedal force. If you go for a central cylinder there is no such thing and I cannot imagine how hard it then would be with a turbo clutch cover.
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