Hi,
For the engine I and restoring we are are about to have new cast iron pistons blanks machined up to replicate the original pistons, I supplied the old ones to the machinist and they have measured them up found some discrepancies and asked question which at this stage don't have a good answer.
1, The original front piston was found to have 2mm offset in Gudgeon pin to skirt, i.e. piston pin not drilled through dead centre of the piston , offset is to non-thrust side. Is this correct. The two old cast ones I have at home the pin is dead centre but I am not sure if they are both front or rear or front and rear. Possibly one of them was not machined the same originally by accident.
Q, Are the gudgeon pins machined in to the piston offset or in the centre?
2, Can you also recommend a piston to bore clearance i.e. front cylinder vs rear cylinder. I suspected 0.0015" would not be far off and did read model T ford has 0.0025".
Q, recommended piston to bore clearance for cast-iron pistons, front cylinder/rear cylinder.
3, The top ring land is smaller on the rear piston than same land on the front piston, possibly due ring groves being machined out for new rings from time to time.
Q, Does any one have a match set of pistons who can measure up the dimensions from the top of the piston down to the lower ring so we can make ours the same?
Thanks in advance.
David.