Hello all,
Well I was out driving the GT on Monday night and I managed to break my gearbox input shaft again for the second time, this time it was the second motion shaft that has let go.
The gearbox itself is a Renault 21 Turbo UN1 – 13 and the engine it’s hooked up to is a Chevy 355 putting out around 430 HP and 430 TQ (has not been on the dyno yet), and at present I have three options open to me.
1) – Replace the broke second motion with a standard Renault one, but this is not fixing the problem and it’s only a matter of time before it happens again.
2) - Replace the main input motion shafts with an upgrade one piece shaft that is available from GTO / Derek Bell or Chris Cole, but to be honest I cannot justify the cost.
3) - My third option and the one that is most appealing to me is to make my own one piece shaft, I have been talking to a company that can make me one for a fraction of the cost that I can buy one of the other kits for, but this would only have the standard gear ratios and not the taller 1st and 2nd that the other kits have, but this is no big deal for me also I can have it made to the length I require and the right spline for my clutch plates.
I’m looking at making the shaft from EN36 steel and case hardening it to 0.030” the main idea when getting this shaft machined is to eliminate any weak points that exist on the original Renault shaft i.e. the collar that joins the first & second motion shafts & also to reduce the depth of the oil grove on the five gear as well eliminating the step just before the fifth gear spline, I have marked these on the picture below.
I would appreciate any ideas and advice that anyone could give me on any further bits that I may have over looked.
Best Regards,
Chris.
Well I was out driving the GT on Monday night and I managed to break my gearbox input shaft again for the second time, this time it was the second motion shaft that has let go.
The gearbox itself is a Renault 21 Turbo UN1 – 13 and the engine it’s hooked up to is a Chevy 355 putting out around 430 HP and 430 TQ (has not been on the dyno yet), and at present I have three options open to me.
1) – Replace the broke second motion with a standard Renault one, but this is not fixing the problem and it’s only a matter of time before it happens again.
2) - Replace the main input motion shafts with an upgrade one piece shaft that is available from GTO / Derek Bell or Chris Cole, but to be honest I cannot justify the cost.
3) - My third option and the one that is most appealing to me is to make my own one piece shaft, I have been talking to a company that can make me one for a fraction of the cost that I can buy one of the other kits for, but this would only have the standard gear ratios and not the taller 1st and 2nd that the other kits have, but this is no big deal for me also I can have it made to the length I require and the right spline for my clutch plates.
I’m looking at making the shaft from EN36 steel and case hardening it to 0.030” the main idea when getting this shaft machined is to eliminate any weak points that exist on the original Renault shaft i.e. the collar that joins the first & second motion shafts & also to reduce the depth of the oil grove on the five gear as well eliminating the step just before the fifth gear spline, I have marked these on the picture below.
I would appreciate any ideas and advice that anyone could give me on any further bits that I may have over looked.
Best Regards,
Chris.