lp ??

[mprmn08]

if the only diff. between our lp and a piston lp is the piston size and spring then couldnt some with access to a machine shop, like me, take and bore out the piston hole and make a larger one to put in therefore haveing more volume. isnt that why you go to a piston lp is for more fuel volume?? maybe im just shooting in the dark but to me it would work for more volume.

[Begle1]

Stock first gens have a vane pump that is quite a bit different from a piston lift pump in every detail there is.

If you had a "first gen" piston lift pump, then it probably would be machined, but whether or not it'd be worth it is questionable... How do you make a piston? The pump could be had for what, $200?

[seeker1056]

unless i be mistaken all first gens had a diaphram type lift pump run off the cam.
Second gens had the piston type, early having the smaller of the two, later having the larger ones.

Aftermarket piston pumps are around $120 most places or yuo can buy my used one for forty plus shipping

[mprmn08]

ok i was confused then. but if you dont want to run a regulator with the piston lift pump dont you have to have a low pressure lp? if so is there certain years that had low pressure ones or if i have a piston lp how do i know if it is and how do i make it a low pressure one if it isnt?

[seeker1056]

show me a stock cummins with a regulator on it for the fuel system?

Both piston early and late lift pumps make more pressure than a stock Ve uses

Nobody yet has said unequivocally that either wont work without a regulator, probably because it hasnt been tried, and none have said that they didnt go right to a regulator if they did try

So Even if you do need a regulator and you dont want to spend much money you can put a deadhead regulator on it for like $30.

Lots out there with a range of 4-15 psi for that price, and if you need more pressure, from 15-65 psi, from Holley for about $149, or the aeromotive for $119. that is even boost referenced

- R&D costs money so most of us are skippin right to the top and not spendin on the lower end stuff and is probably why your not gettin the answers you want.

[mprmn08]

so how much pressure does a standard piston lift pump put out and how much will a ve handle without blowing out seals in its stock form?

[PToombs]

I put on the low pressure piston type, no regulator. 15-16 psi most of the time. Most VE front seals will take about 30psi. This varies from pump to pump, age of the seals, etc.

[mprmn08]

so where do i get the low pressure type? what years did these come on and how do i know if it is? sorry bout all the newby questions just tryin to figure this out.

[PToombs]

Cummins part numbers-
# 3936320 lift pump (qty 1)
# 3914753 Fuel Line (qty 1)
# 3931348 Gasket (qty 2)
# 3914284 Spacer (qty1)
# 3918191 Seals (qty 2)

Is there anything else before I go to bed?

[mprmn08]

haha thanks. but i thought you said theres a low pressure and a high pressure piston lp? so is there 2 seperate part numbers or did i not understand you right?

[PToombs]

Yup, there are. That number I gave you is the low pressure LP. I don't know what the high pressure part # is. If you search some of the forums, you may come up with it. I don't remember seeing it.

[mprmn08]

ok sweet. thanks

[PToombs]

No prob!

[DTanklage]

Yup, there are. That number I gave you is the low pressure LP. I don't know what the high pressure part # is. If you search some of the forums, you may come up with it. I don't remember seeing it.

think the high press high volume pump is 4944714

if you are tdr member i did a whole write up on the two pumps (w pix)

all you do (to get the extra volume of the larger piston) is take the high pressure pump and put a low press spring in it

or use a reg

high press pump comes with larger fittings too...

[DTanklage]

ps - prolly woulda been a sticky here

no one there really gave a rats a$$

and it ending up costing me a few hundred to figure out