Originally Posted by
pitpop
I had a PM and wanted to share it with everyone here. It was asking about the dots machined into the head button, and he asked if they go towatd the exhaust side of the engine. Yes, they do go toward the exhaust side of the engine.. extra credit for anyone who can tell me why they do that.
Originally Posted by
pitpop
..............The big answer is... it is marked where the plug coil is SUPPOSED to be attached to the plug housing. This cold spot is best arranged near the exhaust port. It probably doesn't mean nearly as much with the turbo plugs these days, but back when everyone was running standard plugs, I imagine it could make quite a difference. I say it's "supposed" to reflect the location because occasionally it is mis-marked. You would be better served to screw a plug in and look at it from the inside, then put the button on.
Thanks for sharing that
I've been checking this out on a few of my engines. I found out the position where the coil is attached to the housing relative to the headbutton differs with every glowplug. This means that the markings will be right in a new engine but
can be wrong when you use a new plug. Not that i think it matters that much but i you want every % of power out of your engine you should check.
Out of 3 engines, all 3 engines had the markings to the exhaust (always install them like that) but 2 engines had the point where the glowplug coil attaches to the body at an 90 degree angle to the exhaust, instead of pointing towards the exhaust. All 3 had their plugs replaced in the past.