125E Crankshaft

Does anyone know anything about a 125E casting crankshaft, four bolt flange? I can’t find any information on it anywhere, it came with a TC motor I picked up. I know the 125E rods are talked about a lot but not the 125E crank. Thanks in advance.

Hi

The 125E crankshaft you have is a Lotus crankshaft , as fitted to all Lotus Twin Cam engines pre1967 and as you say runs with a 4 bolt flywheel. A similar crankshaft, the 116E has the same stroke (72.75mm) and this is used in the 1500 Pre Crossflow engine . Although dimensionally ldentical in terms of journal sizes and stroke to the 125E crankshaft, the Lotus crankshaft has larger counterweights. They are both referred to as ?Rope Seal? crankshafts and can be interchanged within the same early blocks.
Your full engine that this crankshaft came with may be a later model and if so would have a 6 bolt ?Lip Seal? crankshaft (3020E).

Nick

Ok, makes sense. The engine is date coded 1963 if I remember right. It is a 120E block, billet main caps were added at some point, and it came with a dry sump pan as well as a baffled pan. Block would need to be checked, but I am pondering a 85mm route on it, have a set of Cosworth steel rods.

This is a pic of a genuine Lotus fitment 4 bolt crank.

That is the one! Thanks Guys.