Re: 1954 359 L8 / Iridium spark plug in place of Autolite copper resistor 308 spark plug
Posted by HH56 On 2022/3/28 11:12:05
As O_D said, you definitely want to do a quick measurement with the valves fully open before using any longer reach plugs. The plug hole is directly over a valve (exhaust I believe) and with the valve fully open there may not be enough room for anything longer than what you have.
The valve clearance to the head is so small issues with valve edges hitting the head have also been found when heads were slightly milled to clean up the surface. In some cases people had bolted a freshly cleaned head down without checking clearance and then cranked the engine and did substantial damage.
Attach file:
clearance.jpg (89.66 KB)
The valve clearance to the head is so small issues with valve edges hitting the head have also been found when heads were slightly milled to clean up the surface. In some cases people had bolted a freshly cleaned head down without checking clearance and then cranked the engine and did substantial damage.
Attach file:
clearance.jpg (89.66 KB)
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