I had a problem with my 2.0l Pinto cylinder head and bought another as a less-cost option to reconditioning mine. The head is unleaded with new valves and guides and has been skimmed “for maximum compression ratio”. I thought it a good opportunity to fit a cam that is better than the standard Cortina one. My Robin Hood S7 is only used for road and I’m considering the Kent FR31. However, I am concerned that there will be sufficient clearance between valves and top of piston.
The engine is a 2.0l Pinto from a 1980 Ford Cortina. The block was skimmed when I built the car some 22 years ago. The engine uses a standard Weber downdraught twin venturi 2V carburettor, throttle barrel diameter 32/36 mm and an after-market 4 branch exhaust.
Comparing the head with my old one, it looks like it has been skimmed by about 2.5mm. I note that the spark plug electrode will foul the piston unless it is inserted with the electrode at the top. Is it possible to tell from the following measurements if the valves will also foul the pistons? I asked Kent Cams but they weren’t really interested in helping.
Cylinder head thickness, rocker cover to face: 91.95mm
With valve closed and measuring from the edge of the valve closest to the face of the cylinder head:
distance from exhaust valve to face: 6.68 mm
distance from inlet valve to face: 5.84 mm
With piston at TDC, and measuring from top of piston to face of block: 0.2mm
Inlet valve diameter: 40.6 mm
Exhaust valve diameter: 35.9mm
I think the problem, if any, will be when the piston is rising and the exhaust valve closing but without knowing the cam profile I can’t predict this (not sure I could do the maths anyway). I could do a trial build and check for contact using Plastercine on the piston top, but that means buying the cam first which is a costly gamble.
I would also appreciate opinions as to whether the Kent FR31 would be suitable or if there is a better option for my set-up.
RHOCaR Member
