Most small garages no longer overhaul engines. It’s very time-consuming, and there’s more money to be made from a number of smaller jobs than one big job. We sometimes get our arm twisted to do it, as was the case when Oom Plank Coetzee, the local woodwork teacher, needed to have the engine on his 1995 Toyota Corolla overhauled.
He was entitled to special treatment because Syd married one of his daughters and therefore he did not have much choice in the matter. I was quite happy to let Syd use our equipment because his wife is the best milk tart-baker in town, but he had to work in his own time, just to keep my accountant happy.
The engine was stripped, and the parts were sent to a machine shop. The cylinder block needed a rebore, while the crankshaft needed to be ground undersize so that Syd could fit oversize main and big-end shells.
The parts returned after a few days and Japie was instructed to clean them thoroughly in his lunchtime in exchange for a soft drink and some milk tart. Syd busied himself with the other parts and by the time he went home, everything was ready for the final assembly.
The next morning when I unlocked the workshop I found Syd already inside, cursing and furiously stoking his pipe to get rid of his frustration. “Those idiots,” he shouted. “The machinist didn’t grind any round fillets where the crank journals joined the webs,” he said. I sympathized with him because this would mean the shaft will break after a few thousand kilometres.
Good mechanics know that sharp corners are stress-raisers, and it’s good practice to grind a fillet radius wherever possible, to distribute the stress. It’s certainly essential on a high-stress item like the crankshaft.
Syd had no choice but to take the crankshaft back to the machine shop and demand a replacement. The original crankshaft had to be scrapped because it could not be machined to a further undersize.