After finally seizing up my 14mm head and rotor after 2.5 years of countless 3500-4000 rpm pulls, races, and dynos, I have come back to the drawing board. I'm pretty sure my 14mm seized from crappy watery fuel though and not from rpm and abuse after finding rust in my pump and what didn't look like fuel coming from my airdog. The rotor seized in the head, had to tap it out with punch, broke the cam plate ears, coupler, and pump shaft ears, and thats as far as I dug into it before I threw it all in a box for a rainy day.
So...I got my old original ic 12mm pump back out and went into it a little. After finding a broken return spring (it still ran). I ended up putting a non ic head and rotor in it (originally from my 14mm pump) since it has much deeper cuts in the rotor. Also my old 12mm always idled low after the truck got warm which i was always told was from a worn out head and rotor. This picture is probably old news to most people but may be useful to some.
Intercooled rotor on the left, non intercooled rotor in the middle, and 14mm rotor on the right. To me the non intercooled rotor seems to have just as deep of cuts as the 14mm rotor does.
After putting my 12mm back together along with non ic delivery valves (they are a deeper cut, but not by much) and adjusting the regulator valve quite a bit, it took me quite a few runaways before I finally got it dialed back in. Main cause was throttle indexing. Cuz my fuel screw feels like its bottomed out and it won't runaway. I've had this happen on many other intercooled pumps/trucks. Once I got it dialed in, this 12mm pump flat out rips, and I almost like it as much or more than my 14mm pump, and it seems to run just as good or better. It has no afc and spools my big single much easier than my 14mm pump did with a tight afc setup. The 14mm did fuel much much harder down low though. I still need to get a case pressure gauge installed....
Going back to rotor comparison, in my thinking, the 14mm rotor is bigger, which would allow more time or duration in between ports to fill the ports with more fuel, which in higher rpm would benefit? Maybe I'm thinking of this wrong, but in my head it made sense. I'm not afraid to try the 14mm pump again, as I had good luck with it even with high rpms. I've already got another under the shelf waiting for a rainy day and extra coin. I've still debated on trying the 4mm camplate with it as well even though I haven't heard many good things.
Most people say the problem with VE pumps is that the vane pump can't keep up. I tried doing some research on vane pumps a while back to see if modifying the one in the ve would benefit (more vanes, bigger vanes, etc.) but didn't come up with assuring answers. I remember reading once about a guy using a power steering pump to supply the VE pump with its high pressure, but then never heard much of it again. I've heard many different theories and even the the theory of cavitation causing these pumps to fail which is highly believable at high rpm.
We are all in this for something a little different, for me its mostly just for curiosity, and I'd love to gain much higher rpms with a VE and compete more with the looked down upon pump. I know there is a lot left on the table and much more trial and error to be had.
Things I've already thought of include:
-running an external pump and possibly dual feed through the timing check port in middle of head. Could have it rpm or boost controlled so that it didn't affect low rpm timing.
-lightening up the flyweights for more rpm, (heard of p pump guys doing this and got me curious)
-tractor/ag governors, are they different? would they better?
-delivery valve options, could there be more options out there, or would custom made ones be worth it?
-an even bigger head and rotor, would more than 14mm be worth it?
I'm just as curious as the rest of you but I seem to learn things best with trial and error.
op: