30-01-2018, 10:55 PM
Grieg, although it is not obvious from the pictures of my casting rig; there is sufficient clearance between the con rod/cap and the sides of the jig for a white metal coating of about 3/16 inch. Thus the need for the exhaust putty string to stop the white metal "running away". I have also sent Ruairidh a picture of "the Newton Big End Boring Bar" I doubt you will find another one, but it does show how the sides are machined, together with profiles of the cutters. So you could adapt a lathe jig to suit. Incidentally, I have made up right angled cutting tool from good quality Allen keys. They are hard enough to cut aluminum and white metal with no problems, and are ideal for the side thrust radia. John(25-01-2018, 08:05 PM)Greig Smith Wrote: Hello Chaps
Firstly thank you all for your valued input on this subject, I need to have the rods sorted in a short-ish space of time as I've offered the car to a friend to drive and the rods need to be sorted out rather urgently, so I'm now on a steep learning curve.....
The pictures of the jigs are invaluable, I too am curious about how to cast the white metal so as to get the thrust face on the side of the cap...... I've been considering how to do this and hold the rod in the dead centre, your collective jigs show this clearly, however I just can't see how the white metal will be able to 'cast' around the edges of the caps, hopefully the picture below will highlight this more clearly.
The rods are all that's stopping us from rebuilding the motor, we've bored out the oil pump and done the double oil jet conversion a-la Mike Forrest, so hopefully this shouldn't happen again. Quite a few of the tips and tricks in the 750 Bulletins from the '50's have been incorporated into this car and the supercharged sister car we're busy building...
Cheers
Greig