Classic Mini Cooper S 1275cc short block assembly | Redline Update - Hagerty Media
These days, not much surprises Davin when it comes to events in the engine assembly room. Elements outside his control, however, can provide an entertaining change of pace. Take for instance the incorrect bearing size setback he discovered last week. His plan was to pivot to the transmission, but instead he got something unexpected. A surprise, but not such an unpleasant one.
The first set of bearings that were ordered ended up being too small for the finished machined crankshaft, but a replacement set arrived faster than expected and allowed progress to roll forward (almost) without a hiccup. We say “almost” because Davin might have had the proper bearings, but he lacked the proper tool to check the oil clearance on those bearings. Without micrometer that will do the job, he had to resort to a very basic tool that he doesn’t use often—Plastigauge.
“It’s not that Plastigauge is bad; it’s not,” said Davin about the measuring material. “It’s more that I find it to be a little inconsistent and I don’t have any way of confirming what it tells me with hard numbers.” No matter; it will have to do for this engine, since there is a bit of a deadline looming. Instructions for using this tool are simple: assemble the connecting rods to the crankshaft with a small piece of Plastigauge between the bearing cap and the crankshaft, torque everything down, then disassemble and use the Plastigauge package to determine the clearance. Davin first thought this engine to be a bit tight, but then he remembered that the journals on this crank are much smaller than he is used to.
With a few other parts already installed, the Mini engine is effectively sitting now at the short-block phase. The cylinder head is next, and if the rotating assembly was any indication that will come together quick. Or maybe there will be another odd hurdle? We don’t know, but regardless we will be back next week with another Redline Update. Be sure to subscribe to the Hagerty YouTube channel to never miss an oil-soaked minute.
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