Thread: Gudgeons - 4.0/4.6 V8

Best to press them out Garry, but even the engine re-conditioner has warned me in the past, that sometimes the piston gets damaged,

Cheers Charlie

Originally Posted by chazza

Best to press them out Garry, but even the engine re-conditioner has warned me in the past, that sometimes the piston gets damaged,

Cheers Charlie

Yes - I asked my reconditioner about doing it for me but he did not want to do it in case he damages a piston. However the gudgeon is loose in the pistons so the only way it can be damaged is when the press pushes the conrod small end against the casting inside the the piston.

I will make a up a wooden jig to support the piston and the conrod and a drift that has a protrusion that goes inside the gudgeon to stop the drift moving when being pressed. I will need two of these as the inside diameter of the 4.0 and 4.6 gudgeons are different as the 4.6 gudgeons are thicker. (another little known difference between the 4.0 and 4.6 engines).

Cheers

Garry

I used to press out P76 piston pins using a 6 inch bench vice. Lubricate the screw and slides well and it'll handle it. The main thing is to make sure that there are no heavy varnish deposits on the piston pin to jam in the piston. The tool I used to support the piston was a piece of 1" water pipe just long enough to contain the pin after it had been pressed out of the rod. I ground away one part of it so it gave proper support to the piston and clearance at the lower ring groove land. Now I have a press but the tool remains basically the same.