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Crankshaft Pulley - Fitting Difficulties and Persistent Oil Leakage

Re-fitting the Crankshaft Pulley to all variants of the 'A' series engine can often be a problem which can be classified into the following two distinct groups:

  1. The pulley is difficult to refit and locate correctly over the crankshaft
  2. There is a persistent oil leak from the front timing chain cover seal after re-fitting the pulley

Problem 1

This is often caused by the Woodruff key, it's locating slot in the crank pulley, or the pulley bore becoming damaged or burred during removal of the pulley. This often happens when the crankshaft pulley is removed whilst the engine is in place as, due to the restricted space, a puller is impossible to fit and the pulley must be 'levered' off with a 'rocking' motion. In addition, if the pulley nut has become loose, due to incorrect locking, then the key groove in the pulley can become widened, and the bore damaged by the key as, with the engine running, the pulley works its way off the crank. Before refitting a pulley always check the pulley and crankshaft as follows:

If the engine is removed from the car and is re-assembled to a point prior to fitting the timing sprockets to the crank and camshaft, the following additional procedure will ensure a good fit of the crankshaft pulley and also ease the fitting of the crankshaft timing gear and chain:

Problem 2

Oil leaking from the around the pulley is most often due to the timing case cover being fitted and secured prior to fitting the pulley to the crank. (As detailed in the Haynes Book of Lies.) Due to tolerances in the fixing holes in the cover, this invariably means that the cover is not centered directly around the crankshaft, resulting in the pulley seal not being centered on the pulley. This allows oil to escape around the gap on one side of the seal whilst the opposite side is damaged due to it being pressed too hard against the pulley shaft.

Oil leaks may also occur due to the seal being damaged by sharp burrs on the pulley shaft as the pulley is fitted, or by the seal lips locating in a groove that the previous seal has worn in the crank pulley shaft.

Both these problems can be resolved by fitting the seal, timing case cover and crank pulley as follows:

Pete Kay (ERA Mini Turbo)


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