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wdTom
11-30-2004 17:18:07
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Re: WD Allis Chalmers in reply to bennie, 11-30-2004 11:06:27
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There is a LOT more than just putting in shims. You need to maintain proper crush, which is the bearing shells adding up to a couple thousnads more diameter than the bearing housing, rod, or main in the block. I put the bearing shells in position in a CLEAN rod or main (whatever) and finger tighten the cap. When starting put all upper mains in the block and rest the crank in them. Put just a little oil on the crank and crank side of the shell as you will be turning the crank in these shells for a while. A couple of drops is enoght, you you don't want it getting between the bearing and the block. Measure the gap between the cap and main body of the bearing, get each side even by adjusting bolt tension (with fingers or VERRY LITTLE more force) Now say you have a reading with your feeler gauge of .010". To maintain crush you would put in .008' shims. This makes the bearings a tight, but not too tight fit. I am not sure about the amount of crush, .002" may not be right, the book will correct me here, but that is the idea. Next you put the bearing together with the proper shims for crush, but you put a strip of plasti gauge on the bearing before you put it together, torque the bearing to near final, take it apart and check the plasti gauge with the package it came in and read the clearance you have. If it isn't right you have to file the bearing shells to bring it down. You have to file them evenly. This is important. Especially end to end so they will maintain even crush. I use a flat surface and a dial indicator to measure the bearing before andwhile fileing. With the bearing shell ends on the flat surface the dial indicator will read the "height" of the round "top" of the bearing. You can keep track of of how much and how evenly you are fileing this way. If you needed to remove say .002" you must also remove .002" in shims to maintain your crush. Do all this with the bearing shells nearly dry. Don't lube until you are done. Do not put any lube between the bearing shell and their housings. Put lube on the crank and shell the last thing you do before you assemble it for the last time after the proper fit and crush is established. Turn the crank after each bearing is done. When doing the rods it will get harder and harder to turn as you have to drag the pistons along, but it should always turn when you are done. To do this right takes a long time, it isn't a 45 min job. Don't rush it. If you don't want to do all this you can have your machine shop machine the rods and block so they will fit the bearings without shims and giveproper clearance, like modern engines. WD-45 and maybe some later WDs were like this I think.
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