During a recent chat about tapers and keyways, I advocated using engineers blue to indicate the need to remove metal from the boss of the flywheel to stop it from being tightened against the rear main bearing. The removal of metal, if necessary, is also advocated in Doug Woodrow's "Austin 7 Manual". I am indebted to Glyn Llewellyn who pointed out some possible weaknesses with this basic technique and concerns the operation of the oil thrower.

For the oil thrower plate to do its job, it needs to be pinched between the flywheel boss and the rear main inner journal. Two types of oil thrower exist - the original pattern has a swaged ring around its inner diameter and the other has three or four heavy dimples in the same area. The situation we are trying to achieve is where the flywheel is hard on its taper with the oil thrower pinched between the flywheel boss and the rear main. This can best be gauged by tightening the flywheel, without the key in place, on the crankshaft on the bench before engine assembly takes place.

However, if you don't have this luxury, i.e. you are not rebuilding the engine, the oil thrower can be dimpled with a punch and the flywheel tightened on its taper (having already been lapped on) without the key in place. It should require the use of a puller to remove and the dimples on the thrower should show signs of compression.

If this is the case, all is well. If, however, the flywheel requires only a little effort to remove it, this indicates that the boss is hard against the rear main. This should also be evident from flattening the oil thrower. In this case, it will be necessary to remove some metal from the boss to achieve the correct clearance which still pinches the oil thrower but does not make it solid against the rear main bearing.

Finally, put the flywheel back with the key in place and make sure it tightens to the same place. I must stress the need to check clearances on woodruff keys - I noted three examples of damage on the Euro Tour due to poorly fitted keys - original Austin spares are too valuable to make mistakes which damage them or render them unusable!