Boxerworks.com

Hi, new here, I'm in the process of rebuilding a 1982 r100 engine. It's torn down to the block, (minus the crank, need to make a puller to get the bearing carrier out) and I'm now making a list of parts to buy so I can rebuild it.

The engine will be modified a bit for performance and reliability, and I was wondering, aside from gaskets, seals, stretch bolts, valve lap/guides, Rings... Are there any internal parts that people make a habit of replacing for safety and peace of mind? I.e, bearings, timing chain/tensioner, cam followers, pushrods..? Assuming all the components look fine (visually), which are a good idea to always replace while the engine is apart anyway? Engine will be seeing higher rpm due to the cam.

Some info on what engine will have:

336 cam
dual plugged heads
9.5 Pistons
Oil pan spacer
Keihin FCR flatslides

I've re-built a lot of Airheads in my day but have never had to touch crankshaft bearings so good for you for going that far.

In my experience, the timing chain should always be serviced. Everything else should be mic'd out to see what needs replacing.

My short list of measurements would be:

Rod bearings and freeplay (Installed on the crank journals)
lifters
Pushrods for out of roundness and wear on the tips
Rocker arm diameter
Pistons to cylinder clearance
Rings end gaps and float (If you have Nikasil barrels, you won't be doing any boring, etc. Others can chime in here about what limitations you have with those barrels but they're almost as hard as diamond)
oil pump clerances
camshaft front bearing measurement
camshaft lobe measurements
crankshaft front pulley teeth, check for wear



Hope that helps,

jimmy

Thanks a lot Jimmy, i'll start measuring