R69US Autopsy
 

 The clutch was removed and found to have good remaining thickness. The slipping of the clutch, experienced once at high speed, could have been caused by a glazed surface and an old, weak diaphragm spring. The clutch can be beadblasted, and the spring replaced.

Here a puller is being used to remove the flywheel.

 

 Removal of the flywheel showed a rather clean clutch housing and a dry seal. The seal appeared to be a non-original replacement, and was not leaking at all.

This seal is usually leaky, and often tthe whole clutch housing is a black mess from leaked oil that catches dirt.

   With the clutch and flywheel removed, the items on the front of the block are removed next. The generator is at the bottom, the centrifugal advance in the middle, and the coil at the top. This coil is an original coil, remanufactured by Huggett GmbH.
   The electrics have been removed, and the cast timing cover removed, exposing the gears. The oil pump gear is at the bottom, the crank gear in the middle, and the cam gear at the top.
   The oil pump gear is held by a nut which is removed. Here a puller is being used to remove the crank gear.

 

Motor block being heated for removal of cam gear and crankshaft
  Having served their purpose in steadying the motor during removal of the clutch, flywheel, and crank gear, the oil pan, heads and cylinders were removed. The seats were good and the valves still had thick edges, but one exhaust valve stem was worn below factory specs and the hardchrome peeled
off on one spot, and the exhaust guides were worn out of tolerance. The rings were worn (oil ring gap too large).The cylinders were a little scored, and one cylinder had been pitted by rust where piston had been stored for many years at bottom center. Finally, the amount of metal worn off the pistons and cylinders, as determined by measurements and a generally accepted wear rate of .01 mm per 10,000 km, indicated the motor had run about 50,000 km (30,000 mi.)
 

 With the block heated to around 250 F, the cam gear, cam bearing and cam can be lifted out.

Here the front oil slinger can be seen, screwed to the cheek of crankshaft.

While still hot, the block is turned over and the rear bearing is removed by prying with two screwdrivers, or by using a puller. The crank is then withdrawn from the rear, using a downward twist.

   Here is the crank and one of the two oil slingers. The large hole in the slinger goes over the end of the crank pin, which is seen just above the crankshaft here. The crank pin has a tiny hole which connects to the con rod bearing. Oil is centrifuged to the outer rim of the slinger, where some of it escapes into the littlle hole to feed the con rod bearing. Both slingers were filled up.
 

 Here a blue Tee-handle screwdriver is stuck into the little oil hole in the crank pin. When outer edge of a slinger gets filled with sludge after thousands of miles, the sludge travels with the oil into the little hole. The con rod bearing gets dirty oil, and then may begin to get less oil if the hole starts to become plugged. This wears out the bearing and the crank pin. This can only be repaired by taking the crank apart, which few shops can do.

Guenther pressed the crank apart, measured the wear, and determined that the con rod bearings and crank pins were worn and needed replacement.

   This is the rear main bearing of the R69S. It uses barrels instead of balls, which allows the crank to flex at high RPM. The crank will never need to flex 90 degrees as shown here. This bearing costs about $150 and could have been reused, but I decided to put in a fresh one.

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