Sunday, July 22, 2012

Restoration tip: Indexing the flywheel to increase ring gear life

In life you never stop learning and this little tip is an example of that. Recently a very experienced mechanic clued me in that the flywheel on a 6 cylinder engine will always stop on one of 3 approximate places when the engine is turned off. As a result every time you go to start the engine, the gear on the starter motor engages the ring gear not randomly on the flywheel but on one of three areas. Once we removed our flywheel this was perfectly visible. There was engagement wear on the flywheel in exactly three locations and everywhere else the teeth were factory fresh and like new.

Now for the money saving tip. If you find excessive wear on your ring gear it can be removed and turned by a sixth of a turn (or turned one bolt on the crank if re-balancing the engine) exposing brand new teeth to the starter motor. In our case the wear was so minimal that it was not necessary but if you ever priced out a ring gear from Ferrari you will know how useful this tip can be.

On another note the butcher mechanic of the previous owner showed his colours again. This time it was in the form of Grade 8.8 bolts that were used to hold the flywheel in place. For those not familiar with bolt grading, using these bolts in this application ranks up with using wooden tooth pics as nails in the framing of a house. Way too weak and we were lucky to catch the fault before a catastrophic failure. Needless to say appropriate new bolts have been purchased and they will be going  on.

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