Jaguar piston clearance problem

[Wichid]

Hi Gergo,

like you, I am rebuilding my XK 140 engine (3.4 litre) and recently purchased some Mahle pistons. I was equally surprised that they advocate a running clearance of 0.1mm (0.004 inches). I would have expected a running clearance for a cast piston of this bore size in a road car to be 0.0020 to 0.0025 inches. What did you do in the end, did you bore with a 0.1mm clearance? Does it rattle and smoke, or did you bore smaller and risk seizure? Would appreciate your feedback! Regards, Dick.

[packman10_4]

Ive always gone with 3-4 thou piston to bore ... i know it can change slightly with forged pistons Arias being one of them expansion times and material hardness ...