12-09-2018, 12:28 PM
(12-09-2018, 11:21 AM)Michael D Wrote:(12-09-2018, 10:05 AM)Chris KC Wrote: For what it's worth I tried quite a few heads in the past and the Speedex was the one I kept on the car. Ultimately though I felt the compression ratio was rather high, so I reverted to the standard '37 type, which is a good all-round head for road use. Aluminium heads are more prone to warping / distortion, worth considering too.
I am aware of the fact that some people fear warping of an aluminium head but then again AlfaRomeos's had alloy heads as had the great Hillman Imp..... its a matter of treating them right methinks. Torqueing (or is it torquing?) them down properly (not meaning ham fisted) and allowing block and head to warm up.. which is not the same as 'water temperature at 80 degrees centigrade'. I'm used to that. And I'll be carrying a head gasket in case things do go pear shaped....
Side valve heads are more vulnerable to warping as they have little torsional stiffness. But yes careful management of torque and temperature is appropriate. It depends what you plan to do with the car Michael; I warped an alloy head when I burst two radiator hoses going over the Petit St. Bernard pass, and had to get home with water weeing into the cylinders every time I stopped the engine. This was inconvenient and since then I have stuck to cast iron, for trips further afield at least.