Checking Flywheel Rim Faces

After nut has been turned fairly tight, install flywheel assembly in truing device as shown in Illus. 53, and true according to indicators (see "Truing Flywheels)."

Remove wheels from truing device, again hold in vise as before and securely tighten crank pin nut. Pull this nut very tight. Now check the sideplay of female (forked) rod between flywheels (see Illus. 52). Sideplay should be .006" to .010". Check with thickness gauge. Push the rod end tight against one wheel and insert thickness gauge between rod and other flywheel. If it is found that there is too much sideplay, probably all or most of the excess play can be taken up by pulling crank pin nuts a little tighter. If there is not enough play, it is due to one of the following conditions: Flywheels and crank pin assembled with oil on tapers and nuts over-tightened (crank pin nuts must be pulled very tight but, of course, tightening can be overdone); new flywheel washers installed and not fully seated (see "Servicing Flywheels and Installing Crank Pin, ta pered holes enlarged as a result of flywheels having been taken apart and reassembled several times in connection with previous overhauling; a flywheel cracked at tapered hole.

In a case like this, the first thing to do is recheck flywheel washers. If these washers are found fully seated and secured in flywheels, the next best thing to do is determine which flywheel seats farthest on crank pin taper, due to enlarged tapered hole or crack, and replace that wheel with a new one. Another thing that can be tried is exchanging crank pin for another new one. However, there is ordinarily very slight variation in length of crank pins. As a last resort, side faces of forked rod lower end can be ground off as necessary to gain required sideplay. If this is done, backs of retainers may also need to be ground off slightly as retainer assembly must, in every case, be narrower than female (forked) rod.

After rod sideplay has been checked and adjusted, crank pin nut pulled very tight and nut lock washer installed, again install wheel assembly in truing device and recheck for trueness.

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