10-12-2018, 01:07 PM
My check for c/m fit with the new -50thou shells to suit the newly machined -50thou c/m journal was to assemble the crank into the case using the c/m bearing only. This allows for the correct installation and clamping strategy of the c/m bearing. I did find that when tightening 'normally' (no torque figures yet, sorry) I achieved a clearance of 2thou (using plastigauge) and a freely rotating crank. If I then tighten further (again no torque figures handy) the c/m housing would then start to become oval - wider and less tall - causing the crank to tighten in the bearing.
I've had some guidance from Chris KC regarding the amount of crush of the c/m shells. I'll hopefully measure this tonight. The shells supplied to me are clearly not originally designed for the 3bearing A7 engine and most liklely are for a 3bearing Reliant sidevalve engine - the tang for one half is on the incorrect side and incorrectly positioned oil feed holes. It seems the c/m housing on a Reliant engine could be ever-so-slightly larger than the A7 engine leading to incorrect crush and this could be why I am seeing the ovality occuring.
Will report back...
I've had some guidance from Chris KC regarding the amount of crush of the c/m shells. I'll hopefully measure this tonight. The shells supplied to me are clearly not originally designed for the 3bearing A7 engine and most liklely are for a 3bearing Reliant sidevalve engine - the tang for one half is on the incorrect side and incorrectly positioned oil feed holes. It seems the c/m housing on a Reliant engine could be ever-so-slightly larger than the A7 engine leading to incorrect crush and this could be why I am seeing the ovality occuring.
Will report back...