AS AN AUTOMOTIVE apprentice, you often do stupid stuff. I was reminded of this recently when I was told a story about two apprentices while I was involved in the overhaul of a preselector gearbox.
Never heard of a pre-selector gearbox?
Well, this particular massive unit is out of a 1954 Daimler Conquest sedan, which has been going through a full resto after sitting in pieces for years, and naturally the owner wanted this gearbox looked at. Seals and stuff.
This English upmarket unit was fitted to lots of posh Pommy cars, and is the forerunner of the eventual introduction by Americans of the fully automatic gearbox.
Manual cogboxes were still primitive back in the 1950s, so Wilson, among others, devised what is basically a mechanical version of a semi-automatic transmission. Got fitted to cars and buses by Daimler, and the way it works is pretty clever. You still have three pedals – accelerator, brake and clutch – but the latter operates a spring-loaded bus bar inside the gearbox. At the top of the steering column is a short lever-operated quadrant, which has positions for four forward gears and reverse.
So when you want to go anywhere, you select low, stomp on the bus bar pedal and that engages the gear. Move off, select second with the lever and stomp on the bus bar pedal again, and so on through the rest of the gears. It’s all done through four epicyclic geartrains and one top-gear clutch, locked by brake bands as in an auto, but instead of a full hydraulic control, the brake bands and top-gear clutch are clamped tight by springs and levers. It’s ti all very ingenious, down to the self-adjusting bands, which are automatically re-positioned by nuts on screws, turned by little springs as you stomp on that bus bar pedal.
I had seen these ’boxes before; years ago I worked for a Jaguar and Daimler dealership, and one out of a Lanchester (made by Daimler) came in from a western sheep property and had to be rebuilt. The problem was that parts for this had to be ordered out of the UK, and they took months to arrive by a slow-sailing ship, so by then we had forgotten how it all fitted together.
But we got there. They don’t make these weird transmissions anymore, effective though they were, with almost no internal drag.
Anyway, this was a mongrel thing to overhaul, and I had to borrow the use of a large press at a friendly downtown auto shop, so I could pressfit the internals, which took two attempts before we finally got it right. That’s when the guy at this auto repair shop told us this apprentice story.
Seems these two were sitting around with not much work on, and decided to use the press that I had been involved with, to squash down a coil spring that had been pulled out from the front of a customer car. It was a slow-working giant of a press, so they stuffed this spring under the hydraulic ram. They were having a bit of a giggle as they cranked down the ram, severely squashing the spring, until it suddenly let go, as it disliked being compressed. Jumped out from between the oil-soaked ram and the footplate, went Kapow! through the closed glass window behind the press, hit the deck outside, and, still full of venom, rebounded off the tar in the yard and went straight for the front of an expensive Mercedes. Bounced again, and luckily ended its ll i i d t th lf dj ti rant against a concrete-block fence. Those two won’t try that again!
Another mate of mine wandered into an engine reconditioning shop, and recognised what he knew was an upside-down short engine out of a Pommy-built Range Rover. He had owned and overhauled one of these, so he knew what he was looking at, and this one was minus its sump, and the nose of the crankshaft was missing, although the rest of the shaft was still attached to the engine.
“What happened to that?” he asked one of the guys running the shop.
The answer came that the bloke who owned this English chariot had decided to rebuild his own engine, and lifted the alloy-blocked V8 out of the engine bay and began to strip it. Heads and manifolds off, pistons and rods out, just the crank to go. Undid the vertical bolts, and the main caps wouldn’t move. Removed the auto drive plate, looked for more bolts locking in the caps, and decided that they were just plain tight. Gave the crank and caps a few exploratory taps with a hammer, and nothing even looked like moving. So he got a fit of the shits, pulled a short-handled mash hammer out of his toolbox, into the front of the crank with a few solid belts, then got real mad at this mongrel thing and let go with a full-force underarm whack. And the nose of the crank fell off!
What he didn’t know was when Rover’s design engineers reworked the Buick-origin alloy engine they had bought with all patterns and jigs out of America, it was decided to cross-bolt the main bearing caps. And this amateur engine builder had only undone half the bolts! s t i