Since it appears that the 8mm elements are not consistently available, I am making calculations for the more common 10mm ones.

I agree that in order for the 10mm elements to work properly the entire system must be set up for them as the system is currently set up for the 5.5mm elements.

Simple volumetric calculations show that I only need .050 inches of plunger lift past fill port closure to get the max delivery quantity I am looking for, (90cc per 1000 strokes), @ 75 to 80% of useable rack travel.

I do not see any reason for the plunger to travel any further than is necessary to insure that the desired fuel quantity can be delivered, and as such, I will be re-grinding the cam to reduce the total plunger travel to that which is needed while retaining the deceleration geometry of the lobe. This will reduce loads on the cam, reduce turbulence in the IP fuel cavity, allow increased time that the fill port is open which will help barrel refilling, and allow for an increased RPM limit.

I am also going to have some nozzles extrude honed to open up the dia significantly in an effort to allow an increased volume of fuel to pass through as tight of a gap as possible. With the larger dia the pintle will not have to lift as much to pass a given volume of fuel over a given period of time. This combined with the pop pressure set to 200 bar should produce a very fine fuel fog. I think it is critical that because the fuel will be delivered over such a short period of time that it should be delivered as burnable as possible. Some initial tests I have done and have seen of increased fuel volume or same volume delivered in a reduced time have shown that the initial spray pattern is made up of a fine mist, but quickly turns into a stream when the pinte lifts too much.

I have made a couple different Prechambers and I want to eliminate the ball all together in the next generation. If I can get a fine fog out of the nozzles, I don't think I will need the ball to brake up the fuel stream, but that is for a different thread.

I only mention it because as with the delivery time being reduced so reduced is the amount of time that is allotted for the pressures to equalize after ignition of the fuel. The stock Prechambers breath very slowly and because the 5.5mm elements take so long to deliver the fuel in any quantity, there is time for the pressures to come close to equal, but this is only in the very concretive stock fueling quantity and slow speed.

Also it is my thinking the timing advance needs to go away. I do not see any need for it with the 10mm elements.

The only thing that I am still kicking around are the Delivery Valves. I will want to either change the springs, or the valves and springs, to work with the 200 bar pop pressure. They are easily changed so I am not overly concerned about them at the present.

I have quotes for 10mm elements from 2 different China companies, both sell them for about $13.00 ea, the third charge about $70.00ea, so I am going to try the least expensive options first. I will order 5 from each company for a total of 10 elements.

I was going to order them last week, but money was tighter than I wanted so they are on hold for a week or so.