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Original Lister Cs Engines / Re: 1940 CS 5/1
« on: February 21, 2021, 06:47:00 AM »To the best of my knowledge only the very early engines had a smaller diameter crank pin, actually the very first engines had 1 7/8 mains and two piece main bearing housings borrowed from the parent engine, the model L gas, oops petrol engine. All were recalled best I have read. Past the early versions, which you do not have. A 5/1 only differs from a 6/1 in the operating RPM and HP rating the crank, bearings and rod are same part number. Good luck with your gib keys, my current shop project took me about 20 hours to remove one key and flywheel die to a botched attempt to cut the key out with a torch. If the decide to drill the key as Gary suggested it is best to make a drill guide which is a short piece of the proper sized key with a hole drilled thought it exactly on center and square.
Thanks for that input... I have been inside a few of the early 3/1 and 5/1 engines. Here is what I found... 2" main bearings and the smaller rod journals in my specimens. It was very easy to assume that the 3/1 and 5/1 were direct predecessors of the 6/1 and 8/1 and they differ mainly in bore size (which they certainly do). Taking a look at the part numbers I can see that 3/1 and 5/1 use the same crankshaft part number. Operating speeds - same as later engines.? There are certainly a lot of variants and subtle changes to be seen in the early engines and replacement parts may have been swapped in over the years as well. It does not help that minimal published data remains for the early versions of these... they also reference a 3 1/2 - 1 in some of the documentation, variants all I would bet. I did find margin notes saying the 3 1/2 and 3/1 vary only in rated speeds... 5/1 and 6/1 however have different bore sizes? Plenty of room for confusion. Check your individual engine it may vary from the published specs.