VE pump- figuring out loud

[ford69557ci]

Going to big on the cam plate will cause the pump to lose flow atleast it did in my test pump. If ya want more timing push the pump to the head and wire the ksb up to a switch.

[CaptainChrysler]

How much case pressure can a VE handle and not blow apart?

[seeker1056]

in our testing wiring the ksb lost fuel cc's

We went to a 2.8 cam plate from a 3.2 and picked up better performance but not cc's if that makes sense, if i understood Giles correclty.

it has been said on more than a few forums that the 4mm cam plate uncovers the spill port on the 14mm prematurely and loses fuel, rather than gaining fuel

I am thinking that if one could make a fuel supply setup similar to the common rail and feed the head rotor alone, that you might get the fuel and rpm you are looking for.

ie a gear driven mechanical fuel pump so fuel supply is linear with rpm, and open the ports in the 14 mm head rotor assembly and feed directly int othe old shutoff port

[ford69557ci]

The 4mm plate does just that. I think the reason the factory plate works better is due to the way it is ground just for the cummins 6bt. I dont think the other plates are really made for our specific pump

[dragrdan]

@seeker- you got better performance from a 2.8 than from a 3.2? If I am reading that correctly, tho it was with the 14mm H&R? By better performance, do you mean across the board, or just upper rpm's?



Does the 4mm(or the 3.2mm) camplate uncover the spill port on the 12mm also?

[Farmboy]

Not to hi-jack your thread but... Dragrdan, you are about 20 minutes away from me! It is cool to have someone close to me! Finally!

[GLHS]

We tried 4 different cam plates in mine and the stocker delivered the most fuel. Unfortunately, it wants to give it all to you at 1100 rpm and slowly trail off from there.

[seeker1056]

If i understand Giles correctly the smaller camplate allowed the cc's to remain more for longer in the upper rpm range

for example the 14 with the 3.2 plate made like 435 ccs to about 2900 rpm then fell off drastically to like 220 cc's from there on up to 3800 rpm

with the 14mm and the 2.8 cam plate cc's were 335 to 3200 rpm or so and held 260 cc's to 2900 rpm

so you seeing fill time here i think

[ford69557ci]

That is whats happening so maybe the larger plate would work good if the head was being feed through the shutoff?

[dragrdan]

what camplates are available? I know of the factory(2.8 ) and the 4mm.
Are any of them Bosch or are they all custom?
If they are custom where are they available from?

[dragrdan]

Could the higher rpm/lower cc's be a problem with "float" where the rollers are not staying in contact with the camplate at all times? Similar to valve float?

[ford69557ci]

There is also a 3.2 available I think. I got all my stuff from rocken tech. I dont think it is a problem of float, I think the passages in the pump, the vane pum, and the passages in the H&R are just no large enough to support high rpm fueling.

[dragrdan]

Back to the 4mm camplate, if it uncovers the spill port, is it at the beginning or end of the stroke? Could something else be adjusted/machined in the pump to keep it covered? IE... if it is at the end of the stroke, could the camplate be machined deeper where the rotor engages the bore by (x) mm would that keep the spill port covered? Or could a rotor be machined with the spill port moved by (x)mm?
Not sure where the 4mm camplate is compared to the 2.8, if the base or lowest point of the cams are in the same position, and only the lift is increased by 1.2mm, or if the midway point of the lift is the same, and the lobe and base are just moved by .6mm.

[dragrdan]

@seeker and ford: Do either of you have a graph, or chart showing the relationship of rpm vs fuel. I am thinking that if it were a drastic drop it would be due to float(suddenly reducing the stroke), as fill time should be a steady decline(as rpm increases, fill time decreases proportionately).

Do the VW and Cummins pump use the same rotor return springs? If so, it may explain why the VW's can rev higher. Less weight of the 9mm rotor would drastically increase the rpms at which float would occur.

[fergavs]

In my pump I run upgraded return springs and solid roller bearing so I doubt float is an issue in my pump but it still loses fuel as RPM increases. I also agree that it is an issue of fill time. The faster the pump spins the less time you have to fill up the fuel. Just seems to make sense.