Spinning the Rods

imageI took the crank out at the same time as I had to take the bolts out, and decided to “spin the rods” which is something I should have done before. I wasn’t too concerned though, because SBD had measured my crank when  they keyed it and supplied bearings to suit. However, it is good practice.


One by one, the rod is attached (with lots of assembly lube) and screwed up ‘ratchet tight’ so not torqued up to any great torque. The rods should move smoothly and without any slap. Then dismantle and put a piece of newspaper in there as a buffer between the bearing and the rod and tighten again. It should jam up pretty quickly (which it did).

If it doesn’t jam then you have too much clearance between the rod big-end and the crank. It’s a little bit ‘rule of thumb’ but a safe test. All mine passed, so at this point I decided to commit. I used my sharpie to write the piston number on the top of each piston and coloured a pattern (again in sharpie) on only one side of each rod, over the joint between the top and bottom of the big end. Thus after I’ve torqued everything up and I need to take it apart then everything can go back together in just the same position as before.

Taking the crank out meant I had to remove the flywheel, which had been bolted up with thread-lock. This meant I had to chase the threads clean again. I bought a set of thread-chasers to clean down the threads. However, it turns out (along with a lot of things in this duratec) that they’re 12×0.75 threads, not 12×1 which is the standard size for 12mm. Thread chasers are quite a lot like a tap, but slightly easier on the thread. It’s not a big deal, so I borrowed a 12x.75 tap and cleaned out the threads. It’s a slightly tedious job – you just keep going in and out until the crap stops falling out the end and the tap moves easily through the thread. So, tomorrow, I should be putting it all back together.

Feed the attention-whore