HF turbo gearbox / clutch problem

[martin smith]

hi. im on my 3rd recon gearbox due to hard driving and racing the 1/4 mile. the problem is my clutch release bearing doesnt fully leave the plate and eventually wears out the teeth. ive fitted a new cable the last time it happened but its still doing it and ive stuck on some extra spacers to help but it doesnt. this problem started after i changed the first gearbox. i cant see a way of adjusting at the peddal just at the gearbox. when i first fit the clutch it seems fine but after a few months i get a hissing/grinding noise when in nutral, this stops when i lift the peddal with my foot. i thought maybe the release bearing arm may sit in a slightly different position in gearboxes of models of different years. can anyone help or give me any new ideas?