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Have you cleaned your crankshaft lately?

By Chris McPheat, May 9 2019 04:57PM

I spent some time stripping the Rolls-Royce 20hp crankshaft down today, the oil way drilling plugs and main and big-end bearing journal sludge trap caps had to be removed. The plugs were easy enough but the caps are always a bit of a fiddle, cotter pins are used to secure castellated nuts on thin bolts that run through both caps. As the crankshaft (and damper) work as a centrifugal oil filter dirt in the oil builds up in the big-end journal (see photo). At this level it starts to seriously impede the flow of oil, the 20hp only has direct oil feed to the front, middle and rear main bearings, the other 4 get their oil from that which is flowing through the crankshaft. I have heard that when these cars were new they had a top end decoke every 2 years and every 4 years the bottom end was cleaned out. Needless to say this procedure is no longer so tightly observed, hence the question at the top, when was the last time you cleaned the sludge out of your crank?

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