WHYDIYGTE...gearbox mount
Discussion
Thanks Adrian this was how Ferhurst Set it before i bought the car ????? Will change there are no washers or spacers on the alloy bracket at all i will pop the car down to my local MB garage and put on the ramp there as my new toy is not level the alloy bracket is just sitting on the chassis rail there are also two spacer washers between the rubber bracket and the gear box i guess they put them there to get it level instead of on the alloy bracket i guess these would also pop through or are they supposed to be there?
Rally design do a nice new heavy duty ford Mount.
OP. The reason for spacers generally is to place the driveline in Phase to allow the U/J's to work in perfect harmony with each other which eliminates any harmonic vibration through the driveline.
The angle that the tailshaft of the gearbox and the pinion of the Diff should add up to 180 degrees. the offsets and relative heights are not critical but the driveline should always be in phase
IE. if gearbox is say 3 degrees down from horizontal then the pinion flange should be 3 degrees up etc etc.
On a solid mounted rear axle this is critical..The science differs on a live axle which flexes.
Before you do anything check your driveline is in Phase. Rabone do an inexpensice magnetic based angle setter to make the job easy.
N.
OP. The reason for spacers generally is to place the driveline in Phase to allow the U/J's to work in perfect harmony with each other which eliminates any harmonic vibration through the driveline.
The angle that the tailshaft of the gearbox and the pinion of the Diff should add up to 180 degrees. the offsets and relative heights are not critical but the driveline should always be in phase
IE. if gearbox is say 3 degrees down from horizontal then the pinion flange should be 3 degrees up etc etc.
On a solid mounted rear axle this is critical..The science differs on a live axle which flexes.
Before you do anything check your driveline is in Phase. Rabone do an inexpensice magnetic based angle setter to make the job easy.
N.
heightswitch said:
Rally design do a nice new heavy duty ford Mount.
OP. The reason for spacers generally is to place the driveline in Phase to allow the U/J's to work in perfect harmony with each other which eliminates any harmonic vibration through the driveline.
The angle that the tailshaft of the gearbox and the pinion of the Diff should add up to 180 degrees. the offsets and relative heights are not critical but the driveline should always be in phase
IE. if gearbox is say 3 degrees down from horizontal then the pinion flange should be 3 degrees up etc etc.
On a solid mounted rear axle this is critical..The science differs on a live axle which flexes.
Before you do anything check your driveline is in Phase. Rabone do an inexpensice magnetic based angle setter to make the job easy.
N.
The comments about the box output and diff input needing to be parallel in order to create equal UJ angles are correct. However, where there is combination of horizontal and vertical offsets, between these two, it can have a large impact on the installed joint angle. OP. The reason for spacers generally is to place the driveline in Phase to allow the U/J's to work in perfect harmony with each other which eliminates any harmonic vibration through the driveline.
The angle that the tailshaft of the gearbox and the pinion of the Diff should add up to 180 degrees. the offsets and relative heights are not critical but the driveline should always be in phase
IE. if gearbox is say 3 degrees down from horizontal then the pinion flange should be 3 degrees up etc etc.
On a solid mounted rear axle this is critical..The science differs on a live axle which flexes.
Before you do anything check your driveline is in Phase. Rabone do an inexpensice magnetic based angle setter to make the job easy.
N.
The angle the prop shaft joints see is a combination of both the offsets. If one offset is zero then it is very easy to calculate the installed angle if you can accurately measure the remaining offset. But if both are present it is a bit more complex as the two cause the shaft to sit in a compound angle. This compound angle is calculated using the 'cosine rule' for those interested in doing the trigonometry.
To put this in perspective, my engine/gearbox line is delibrately set 32mm over to the nearside of the chassis, and also has a vertical offset between it and the diff input. When calculating the installed angle, in order to remain within the manufacturer's maximum joint angles, I had to set the diff input in a position that leaves unequal drive shaft lengths. Without doing the sums this would not have been obvious.
Colin.
Thanks for all the advice 
i was just amazed when i checked it that Ferhurst had done it that way when i looked at it even i thaught there was something wrong it lasted 3000 miles until the washers they put on started to push through.
Yes some of the replys are somewhere over my head but realy interesting to see and learn nice thing about not knowing to much is the learning curb is all uphill Everest here i come?
Cheers
i was just amazed when i checked it that Ferhurst had done it that way when i looked at it even i thaught there was something wrong it lasted 3000 miles until the washers they put on started to push through.Yes some of the replys are somewhere over my head but realy interesting to see and learn nice thing about not knowing to much is the learning curb is all uphill Everest here i come?
Cheers
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