12-04-2022, 08:59 AM
I have found that none of the newly made crankshafts I have fitted are symmetrical in this area.
The best that can be achieved is a central position that misses both troughs, statically. Austin cranks are perfectly symmetrical in this area and jets line up on both sides. Even with the asymmetrical positioning on the new cranks, little problem is ever reported, this includes the several hundred I have fitted and makes me think that lubrication at revs come more from mist than a little low pressure oil jet.
There does seem to be an issue with longevity on 1.5” splash cranks using shell bearings, I have no experience in using such but have seen and heard of the problem from many.
Something else to consider is that original Austin rods have oil escape holes drilled at the top of the bearing so fresh cool oil is constantly circulating through, many of the new shell bearing rods do not have these escape holes and I would be interested to hear from others if this may be part of the cause.
You can retain the three bearing jets happily or fit the earlier (and larger) two bearing ones - the change of design raised the pressure to accommodate feed to the centre main bearing - which you no longer have.
The best that can be achieved is a central position that misses both troughs, statically. Austin cranks are perfectly symmetrical in this area and jets line up on both sides. Even with the asymmetrical positioning on the new cranks, little problem is ever reported, this includes the several hundred I have fitted and makes me think that lubrication at revs come more from mist than a little low pressure oil jet.
There does seem to be an issue with longevity on 1.5” splash cranks using shell bearings, I have no experience in using such but have seen and heard of the problem from many.
Something else to consider is that original Austin rods have oil escape holes drilled at the top of the bearing so fresh cool oil is constantly circulating through, many of the new shell bearing rods do not have these escape holes and I would be interested to hear from others if this may be part of the cause.
You can retain the three bearing jets happily or fit the earlier (and larger) two bearing ones - the change of design raised the pressure to accommodate feed to the centre main bearing - which you no longer have.