Measuring End-Float Using A Telescoping Gage
If you are the owner of a car that may have a history of excessive thrust washer wear, you should make crankshaft end-float measurements a regular part of your routine maintenance checks. It is very simple, and once you become proficient at it, it only takes five or ten minutes of your time.
There are various ways to check crankshaft end-float, and below is one method to use for a quick check on a Triumph TR6. You must find a method that works best for you.
1) Carefully place a sturdy wooden board (1 inch x 4 inch x 4 feet) between the crankshaft pulley face and the bottom of the radiator. While using the board for prying, gently but firmly force the crankshaft toward the rear of the car by pushing squarely against the end of the crankshaft pulley (not against the fan blades). This does not take much force, and you may even feel the crankshaft move slightly. This action will force the crankshaft toward the rear of the car.
2) Take a telescoping gage (sometimes called a snap gage) and place it between the face of the radiator and the face of the crankshaft pulley. This is a crude measurement, but after some experience and always measuring between the same two points, this method becomes fairly accurate for an initial check. Once you have a good feel between the two surfaces and the gage ends are squarely positioned between the two measured surface points, carefully lock the snap gage in place while making sure it doesn't move in the process. Using a dial caliper or vernier caliper, measure the distance (from end to end) of the telescoping gage ends and write this number down on a piece of paper. If you are new at this, take two or three measurements until you feel confident that your measurements are accurate.
3) Get into the drivers seat of the car and press the clutch pedal to the floor, and then release. This action will force the crankshaft toward the front of the car (opposite direction as in No. 1). Take another accurate reading just as you did in No. 2, and subtract the second reading from the first reading. The difference between readings is your end-float measurement. If you are new at taking this measurement, do it again for practice and good measure.
4) If your end-float reading is .010" and you would like to end up with .005" after you install your new thrust washers, you'll want to order a rear thrust washer that is .005" thicker than the one that is currently in your engine. In normal circumstances, the front thrust washer will remain the same thickness as what came out of the engine which is typically .092". It is believed that all Triumphs had standard thickness (.092") thrust washers installed in the front position when new. The end-float is adjusted by changing the thickness of the rear thrust washer only.
Important note: No matter what type of thrust washer you have installed in your Triumph engine, it is imperative that you make engine crankshaft end-float checks a regular maintenance routine. Driving style and overall engine condition will greatly affect the longevity of your engine thrust washers.
These methods are for checking end-float without removing any parts from the engine. With the oil pan removed, you can use feeler gages (shim stock) to measure the gap between the crankshaft surface and thrust washer surface.
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