I guess I am getting TOO predictable.... LOL
But those holes are a critical interface between all the machinery which causes the pistons to go up and down, squeeze the air, get the fuel to be dispensed at the correct time.... and yet there is an amazingly ( to me ) small amount of discussion / concern for them being clean and open ... etc...
Is this due to the very high cost of the screw out pulling tool ? Or that it seems ' too far inside the engine' to be messed with ... people will do a good job cleaning their injectors and seem to repress any suggestions that the precombustion chambers might should be pulled and at least inspected when they are out.
The Factory Shop manual emphasizes how important it is for them to be clean... perhaps it is a lack of access to the Factory shop manual.... I don't know... but as you can see I have not given up my mission to make people think about them..... LOL