30-09-2018, 07:48 PM
(This post was last modified: 30-09-2018, 07:58 PM by Bob Culver.)
The hole is not in the squish area so not caused by a stone etc.
When this occurs in pre computer moderns it is attributed to continuous detonation under load, often not audible in a soundproofed car. But with the harshness of Sevens with advance it is difficult to imagine such a conditon escaping notice.
(the only pinging I ever observed was fleeting on flooring the throttle after overrun with a very hot engine).
The bum advice in the early Ruby book, widely repeated in other publications, to set auto advance at 2 inches has led t a lot of troubles.
Perhaps the casting was flawed.
i once spent hours trying to get an outboard motor to run and found a similar hole. With a bolt and nut it ran perfectly!
In the days before Seven owners were wealthy and firms did work cheaply, could contemplate welding. Or a rivet!
PS the head seems to have barely covered the gasket.
When this occurs in pre computer moderns it is attributed to continuous detonation under load, often not audible in a soundproofed car. But with the harshness of Sevens with advance it is difficult to imagine such a conditon escaping notice.
(the only pinging I ever observed was fleeting on flooring the throttle after overrun with a very hot engine).
The bum advice in the early Ruby book, widely repeated in other publications, to set auto advance at 2 inches has led t a lot of troubles.
Perhaps the casting was flawed.
i once spent hours trying to get an outboard motor to run and found a similar hole. With a bolt and nut it ran perfectly!
In the days before Seven owners were wealthy and firms did work cheaply, could contemplate welding. Or a rivet!
PS the head seems to have barely covered the gasket.