Just finished replacing the head gasket on my '71 850 Spider (903cc). Had brought the head to a local machine shop recommended by Tim Rooney; shop determined the head was warped and they milled it about .015" (I think that's what the man said, it wasn't written on the receipt). I then installed a "reinforced" head gasket from Chris Obert, in the belief that the bit of extra thickness might compensate for the material removed from the head.
Finished reassembly yesterday and started the car, it fired right up and seemed to be running normally, but within a couple of minutes the coolant temp had already hit 130C and was still climbing, so I shut 'er down. There was the beginning of coolant boiling in the plastic reservoir.
Why isn't the new head gasket sealing on a freshly-milled head? I did everything by the book, torqued the head bolts very carefully to a final value of 39.6 ft.-lbs. (the highest value I've got in any of my service manuals; some show a lower final value of 36 ft.-lbs.).
Did I make a poor choice of head gaskets? I'm wondering if the one I bought might be intended for racing and needs stronger head bolts and higher torque.
For now the plan is to start over again, but use a standard OEM-type head gasket of Italian manufacturer I've had in my parts bin for a while. Thoughts and recommendations? Grazie.
Finished reassembly yesterday and started the car, it fired right up and seemed to be running normally, but within a couple of minutes the coolant temp had already hit 130C and was still climbing, so I shut 'er down. There was the beginning of coolant boiling in the plastic reservoir.
Why isn't the new head gasket sealing on a freshly-milled head? I did everything by the book, torqued the head bolts very carefully to a final value of 39.6 ft.-lbs. (the highest value I've got in any of my service manuals; some show a lower final value of 36 ft.-lbs.).
Did I make a poor choice of head gaskets? I'm wondering if the one I bought might be intended for racing and needs stronger head bolts and higher torque.
For now the plan is to start over again, but use a standard OEM-type head gasket of Italian manufacturer I've had in my parts bin for a while. Thoughts and recommendations? Grazie.