Welding onto a gearbox input shaft
Discussion
My Noble uses a mildly breathed on ford mondeo ST220 gearbox, its held up very well with 580+ftlb torque but there is an issue with it.
Basically the input shaft is a floating design, it comes within 20mm of the crank but doesnt actually locate in it... There is room in the crank for a bearing (Jaguar version of the engine has a different box were the input shaft locates in a bearing in the crank).
The issue I have is that the huge torque of the engine vibrates the input shaft by over 1mm and thus my clutch plates catches on the inner casing of the clutch basket.
I wish to eliminate this by machinging up a 2mm section that will locate 5mm into the input shaft and then into the crank bearing... question is can I weld onto the end of an input shaft?
Basically the input shaft is a floating design, it comes within 20mm of the crank but doesnt actually locate in it... There is room in the crank for a bearing (Jaguar version of the engine has a different box were the input shaft locates in a bearing in the crank).
The issue I have is that the huge torque of the engine vibrates the input shaft by over 1mm and thus my clutch plates catches on the inner casing of the clutch basket.
I wish to eliminate this by machinging up a 2mm section that will locate 5mm into the input shaft and then into the crank bearing... question is can I weld onto the end of an input shaft?
Cheers for the responses
To give a little more detail,
The box is designed for 200ftlb I'm running 3 times that although I suspect it's not the torque that causes the deflection in the input shaft.
All upgraded nobles do this when they have an upgraded clutch, probably due to the extra clamping force, mine is worse as I have a triple plate and thus higher clamping force, it reduces when I put the lesser clutch in and wasn't there at all when the car was stock.
The noise that's clearly this deflection happens on downshift or pulling away, never on up shift.
The other easier option is to machine 1mm from my end friction disc as I will still have plenty of clamping force... It just seemed like a bit of a patch it for the real issue?
To give a little more detail,
The box is designed for 200ftlb I'm running 3 times that although I suspect it's not the torque that causes the deflection in the input shaft.
All upgraded nobles do this when they have an upgraded clutch, probably due to the extra clamping force, mine is worse as I have a triple plate and thus higher clamping force, it reduces when I put the lesser clutch in and wasn't there at all when the car was stock.
The noise that's clearly this deflection happens on downshift or pulling away, never on up shift.
The other easier option is to machine 1mm from my end friction disc as I will still have plenty of clamping force... It just seemed like a bit of a patch it for the real issue?
The input shaft isn't loose when removed, in fact it has the same defer election as when it was built.
Wear marks on the clutch plates show the friction plate nearest the engine has deflected off center 1mm and touched the inside of the clutch basket and the friction plate itself has chips, the middle plate has deflected just over half and the gearbox side plate hardly at all.
I can't do pictures as I'm not home, but the wear marks are clear as to what's happening.... I am the only one running a tripple plate and this has tighter tolerances to the single plate unit which has more clearance in the same areas hence the noise is louder when using the tripple over the single.
The noise heard on down shift is clearly this contact and it's as though the shaft vibrates then centralises as the noise is brief on initial clutch engagement and goes on full engagement. So the clutch must center properly.
Must admit I hadn't considered that the gearbox may have this deflection built into in... I'm now leaning towards machining down the end friction plate to allow more clearance.
Wear marks on the clutch plates show the friction plate nearest the engine has deflected off center 1mm and touched the inside of the clutch basket and the friction plate itself has chips, the middle plate has deflected just over half and the gearbox side plate hardly at all.
I can't do pictures as I'm not home, but the wear marks are clear as to what's happening.... I am the only one running a tripple plate and this has tighter tolerances to the single plate unit which has more clearance in the same areas hence the noise is louder when using the tripple over the single.
The noise heard on down shift is clearly this contact and it's as though the shaft vibrates then centralises as the noise is brief on initial clutch engagement and goes on full engagement. So the clutch must center properly.
Must admit I hadn't considered that the gearbox may have this deflection built into in... I'm now leaning towards machining down the end friction plate to allow more clearance.
The discs are a tightish fit to the input shaft, there isnt any chance it could move by 1mm.... the clutch basket cant be moving as its the friction plate at the flywheel end thats touching and so it cant flex there as its clamped to the flywheel with a return.
the friction plates splines have 100% engagement on the input shaft splines in both instances, its close but I have checked carefully many times so there is no chance they are falling off slightly.
Also the stock clutch does this if you upgrade it (they reinforce the springs and fit a more abrasive friction plate). so its not unique to mine, only more prevalent due to tighter tolorences IMO
For reference the exact same clutch is used in mid engined cars with a different box and massive V8's with similar torque and they are silent in those cars.... the box's they use DO have a spiggot bearing that teh input shaft registers into (like most cars).
the friction plates splines have 100% engagement on the input shaft splines in both instances, its close but I have checked carefully many times so there is no chance they are falling off slightly.
Also the stock clutch does this if you upgrade it (they reinforce the springs and fit a more abrasive friction plate). so its not unique to mine, only more prevalent due to tighter tolorences IMO
For reference the exact same clutch is used in mid engined cars with a different box and massive V8's with similar torque and they are silent in those cars.... the box's they use DO have a spiggot bearing that teh input shaft registers into (like most cars).
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