The feeling that some people in the motor trade are subhuman often arises when you have been “done-in” by an unscrupulous workshop manager.
Certainly, when I was still at the bench there were times that I wished I was an ape, because their long arms can get in everywhere and their long fingers are perfect for assembling some of the more fiddly bits.
Perhaps more primitive creatures will do as they are told and not think they know better to such an extent that they ignore accepted wisdom, the way older mechanics often do. This is the only explanation I can think of why Josie de Bruin, a recent retiree to our town, suffered a wrecked engine.
The engine of her 2001 Ford Mondeo 2,0-litre had recently been overhauled by a respected engine machining shop that has done some work for us in the past, but, two weeks later it put a “leg out of bed”, as we say in the trade.
We towed in the car, and Syd started stripping it. A broken con-rod, severed just below the small end, had poked a hole in the crankcase. The cause of the break was immediately obvious, so the mystery was not why it happened, but why the machine shop made such a basic mistake.
The top part of every con-rod was dark blue, denoting excessive heat, but the pistons showed no sign of overheating.
This could only be due to some mechanic using a blowtorch to heat the small-ends prior to pushing the gudgeon pins through.
The correct method is to use a temperature-controlled oven to ensure the small-end gets hot enough to expand, but not so hot that the strength of the metal is affected.
Hennie ‘phoned the machine shop to tell them about the failure and to find out why they installed gudgeon pins that way.
He was rewarded with a shamefaced admittance from the foreman that they had started doing it to save time, but had never had a failure up until then.
Hennie replied that the blowtorch would work most of the time but was very risky because the temperature could not be controlled.
However, the foreman assured Hennie that they would honour their warranty and supply and fit another reconditioned engine.
Why didn’t the other ´rods fail? There’s always one that goes first, and with the unscientific heating there’s bound to be a huge spread in temperature- induced weakening between the four ´rods.