A change of ratios
My elder son was clearly horrified when I said I was going to take the Van Diemen down to Aldon Automotive to have the ratios changed in the gearbox, so I decided to have a go myself. Now, I know that others can do this job in half an hour under an umbrella in the pouring rain in the paddock but it took me all day and I still haven’t quite finished. Nevertheless, I do feel quite pleased with myself that it’s almost done.
When I bought the Van Diemen from Martin Pickles he kindly demonstrated how to change the ratios and I videoed him doing so. So, with this video and instructions printed off from the classic formula ford website and a diagram in a Hewland Engineering manual I set to work.
Everything went more of less smoothly except I failed to realise I had no 1 ¼ inch A/F socket and had to dash out to Halfords, who miraculously had one in a bargain bin for £1 (Greg, I know you read this – loads of sockets and ratchet parts in Kidderminster Halfords going for a song).
Then I had a moment when all the various bits on the pinion shaft (named, apparently, pinions, needle bearings, clutch rings, thrust washers, tracks and hubs but which I previously thought of as cogs and ‘other parts’) fell apart and I had a pile of junk in front of me in no particular order and not even all the same way up. That took a bit of sorting out but I got it all back together somehow.
I changed the 4th gear ratios from 20/31 to 22/28 so setting the top speed at 105 mph, which according to two helpful fellow HSA members should be about right for the hillclimbs I intend to do. Then I put it all back together. This had taken about four hours!
Then I realised that you could not select any gears! So everything had to come out again and after much head scratching, consulting photos I had taken as I pulled it all apart, the video and the diagrams, I realised I had not matched up the selector forks to the dog rings correctly (or perhaps I had but they had become misplaced as I slotted the stack back into the gearbox casing). I reassembled it and got it back in the car and the selector rods now move nicely. But that is more than enough for one day! I’ll finish the job next weekend.