Saturday, April 8, 2017

Engine Rebuild Part III - Crankshaft Rebuild

The Royal Enfield Interceptor crankshaft is a heavy duty assembly. It is dynamically balanced which was not common for its day. The rods are substantial and the bearings are well designed for their job. The Interceptors are known as smooth running machines due to the attention paid to this assembly.

The crankshaft is out....time to rebuild. 

One thing I was a little concerned about was the sludge trap as the caps can be difficult to remove on most British motorcycles. I have heard many people drill and use an EZ out to overcome the stubborn little buggers. I was hoping I would not have to resort to that.

So what is the sludge trap? It is a cylindrical cavity in the crank center that collects the tiny metal shavings that flow through the oil ways. I did not expect to get much out of the RE as the engine looked pretty good inside. I was wrong about that as sizable chunks of rusted steel particles were found. This reaffirms the notion that cleaning the sludge trap is a "must do" when the crank is out. My RE has only logged 12,993 miles yet the collection of metal bits was pretty substantial. My BSA Hornet, which had a severe life, also had blobs of steel wool looking material inside the crank. After thoroughly cleaning the trap the caps were reinstalled, staked into place, and secured with Locktite.

The Allen wrench wouldn't budge manual impact driver didn't move it......

The air impact easily popped both plugs out with minimal damage to them. 

Well this doesn't look like something I need in my crank....little metal bits rusted back into a solid.

Cleaning out the sludge trap with a 12 gauge bore brush.  

The bearings looked good but while I had the engine apart I decided to replace them. 

The crankshaft journals measured within spec and were not ground. The connecting rods were bead blasted and reinstalled with new "nominal" sized bearings in the caps. The small end bearings also measured within spec and will run on new wrist pins. The rod cap bolts were torqued and safety wired into place. Loctite was used for additional insurance. 

Safety wiring the rod bolts with stainless aircraft safety wire.  

Reassembled, wired, and ready to go into the cases...time to build up the lower engine unit. 

Grandpa Ken in England  in the early 40's. He is second from the left in front of a bomber with a very politically incorrect name. 

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