Re: mikes 1948 super 8

Posted by Owen_Dyneto On 2014/12/31 18:34:18

Very unusual to crack at an intake valve seat; from my own experience 99% of internal cracks occur starting at the exhaust valve seat and if not properly repaired, slowly progressing to the cylinder bore and then down the bore. Cracks of this sort are primarily the result of severe and constant overheating, perhaps exaggerated by adding cold water to an overheated engine. A plugged water distribution tube can also be a contributor.

As to hardened valve seats, never on the intakes. If you plan a steady diet of keeping up with traffic on Interstates at 70 or higher speeds, you should think about hardened exhaust valve seats or stainless steel exhaust valves. Otherwise no.