G
Guest
Guest
Hope you enjoy the book, Fred.
Interesting to hear about the stay bar issues experienced and discussed above. However I don't think this is a unique RF issue as it has been experienced on GTDs too. Not that our dizzies hit the bulkhead! Although I did once put my dizzie through the bulkhead window once when removing the engine, but I digress....
An experience often found when going from a cable gear change to a solid bar system was that the natural movement of the engine and box package (remember they are rubber bush mounted) lead to odd things happening in the gear selection department. The front of the system is solidly fixed to the chassis and the rear part fixed to the gear box. hence room for movement. Not an issue with cables as these allow for movement in the same vein as bicylce brake cables. Solid rods transmitted the movement and in effect the result was that the gear stick would move a little and the gate positions were variable! Under braking or hard acceleration the effect is quite off putting in telling you whether or not you have selected the gear fully. This causes real problems at the Brighton Speed Trials and other heavy useage venues, basically competition or track work.
My thought for anyone designing their own solid rod system would be to keep the gear box end as tight to the centre line of the car as practically possible. Think of pivot points and levers. A little movement here equals bigger movement further out.
As a result a longitudinal brace is often fitted from the belly of the gear box going backwards to the rear most chassis member. This stops or greatly reduces the fore and aft tendancies of the engine/box package. On my car I use a direct brace ie no rubber bushes. By being on the centre line of the gear box any rotational forces are unchanged.
This is easy to make and fit on Renault boxes due to its longitudinal bolt pattern down the centre of the box. Hah, there had to be a benefit to this "design flaw" one day!!!! Just teasing, guys. Can't be too difficult on other makes of boxes though.
A few guys have gone further and have fitted braces to reduce the rotational motion of the engine. These are normally taken from the cylinder heads to the chassis but I am sure other ways of acheiving the same goal are out there.
I would suggest that for road and some track work a longitudinal brace is a very good idea but the rotational braces could be left for balls out racers? After all, don't race cars have the engine as part of the stressed chassis package nowadays?
Malcolm
Interesting to hear about the stay bar issues experienced and discussed above. However I don't think this is a unique RF issue as it has been experienced on GTDs too. Not that our dizzies hit the bulkhead! Although I did once put my dizzie through the bulkhead window once when removing the engine, but I digress....
An experience often found when going from a cable gear change to a solid bar system was that the natural movement of the engine and box package (remember they are rubber bush mounted) lead to odd things happening in the gear selection department. The front of the system is solidly fixed to the chassis and the rear part fixed to the gear box. hence room for movement. Not an issue with cables as these allow for movement in the same vein as bicylce brake cables. Solid rods transmitted the movement and in effect the result was that the gear stick would move a little and the gate positions were variable! Under braking or hard acceleration the effect is quite off putting in telling you whether or not you have selected the gear fully. This causes real problems at the Brighton Speed Trials and other heavy useage venues, basically competition or track work.
My thought for anyone designing their own solid rod system would be to keep the gear box end as tight to the centre line of the car as practically possible. Think of pivot points and levers. A little movement here equals bigger movement further out.
As a result a longitudinal brace is often fitted from the belly of the gear box going backwards to the rear most chassis member. This stops or greatly reduces the fore and aft tendancies of the engine/box package. On my car I use a direct brace ie no rubber bushes. By being on the centre line of the gear box any rotational forces are unchanged.
This is easy to make and fit on Renault boxes due to its longitudinal bolt pattern down the centre of the box. Hah, there had to be a benefit to this "design flaw" one day!!!! Just teasing, guys. Can't be too difficult on other makes of boxes though.
A few guys have gone further and have fitted braces to reduce the rotational motion of the engine. These are normally taken from the cylinder heads to the chassis but I am sure other ways of acheiving the same goal are out there.
I would suggest that for road and some track work a longitudinal brace is a very good idea but the rotational braces could be left for balls out racers? After all, don't race cars have the engine as part of the stressed chassis package nowadays?
Malcolm
