Instruments That Had Not Caught Up with the Car
The owner bought this car four or five years ago and has been rebuilding it ever since. New transmission, new brakes, and a Toyota inline six in place of the original engine, which on current numbers should be making north of 700 horsepower. A great deal of time and money has gone into it.
The gauges arrived in reasonable condition, with one exception worth telling. The owner had taken the front lens off to deal with a dead spider inside the cluster, and while cleaning it he broke the tachometer pointer and moved the oil temperature pointer, which left him unsure whether that gauge worked at all.
His two real complaints were about numbers. The speedometer reads to 85 miles per hour, which is what the early eighties did: the gas crisis put a ceiling on what a speedometer was allowed to show, and this car has one. He wanted to know whether it could be made to read higher. And the tachometer runs to 7,000, while the redline on what he has built now sits somewhere around 7,200 to 7,400.
Both can be changed. We sent a mock-up of the finished gauges before anything was touched, so he could see it rather than imagine it, then rescreened every face in the set.
The Tachometer
A new pointer to replace the broken one, a new circuit board, and the whole thing recalibrated for six cylinders across a 1,000 to 8,000 RPM sweep.
The Combination Gauge
The face was rescreened with the rest of the set, and the oil temperature coil was tested afterwards. It was good.
The Speedometer
Stripped, cleaned and lubricated, with a new hairspring so it could be calibrated to the new scale.
The scale was not the only thing that had moved. The differential ratio had changed during the rebuild and so had the tire size, which means the relationship between the wheels turning and the needle moving is no longer the one the factory set. That had to be calculated before anything could be calibrated against it. The finished speedometer reads 0 to 180 miles per hour, and it is accurate on the car as it is now rather than on the car it left the factory as.
This is a BMW, and the rest of our BMW instrument work sits on our European classics page.
This is one of the jobs that has come through our bench. More on how we approach this work: how we design and screen custom gauge dials. You can also see more of our BMW instrument work, or send us an inquiry about your own gauges.