delivery valves?

[cummins12club]

What kind of vlokswagen pump did the delivery valves come from

[turboram]

The valves came from a 1.5 or 1.6 pump

[cummins12club]

What year/modle vehicle

[oldestof11]

78-88 I believe are the 1.5/1.6L model years.

[turboram]

Vw used the ve up untill the mid 90s IIRC

[BC847]

I'm trying to figure out what that nic in the side of the DV plunger is doing with the injection event.

Delivery valve
The delivery valve closes off the high-pressure line from the pump. It has the job of relieving the pressure in the line by removing a defined volume of fuel upon completion of the delivery phase. This ensures precise closing of the injection nozzle at the end of the injection process. At the same time, stable pressure conditions between injection pulses are created in the high-pressure lines, regardless of the quantity of fuel being injected at a particular time. The delivery valve is a plunger-type valve. It is opened by the injection pressure and closed by its return spring. Between the plunger’s individual delivery strokes for a given cylinder, the delivery valve in question remains closed. This separates the high-pressure line and the distributor head’s outlet-port passage. During delivery, the pressure generated in the high-pressure chamber above the plunger causes the delivery valve to open. Fuel then flows via longitudinal slots, into a ring-shaped groove and through the delivery-valve holder, the high-pressure line and the nozzle holder to the injection nozzle. As soon as delivery ceases (transverse cutoff bore opened), the pressure in the high-pressure chamber above the plunger and in the high-pressure lines drops to that of the pump interior, and the delivery-valve spring together with the static pressure in the line force the delivery- valve plunger back onto its seat again (Fig. 11).

From what I've seen, the DVs can be had with various mods that alter how the DV controls residual fuel pressure in the high-pressure line on the completion of the injection event, that which can be influenced by a bunch of stuff.

For example:

Delivery valve with return-flow restriction
Precise pressure relief in the lines is necessary at the end of injection. This though generates pressure waves which are reflected at the delivery valve. These cause the delivery valve to open again, or cause vacuum phases in the high-pressure line. These processes result in post-injection of fuel with attendant increases in exhaust emissions or cavitation and wear in the injection line or at the nozzle. To prevent such harmful reflections, the delivery valve is provided with a restriction bore which is only effective in the direction of return flow.

Constant-pressure valve
With high-speed direct-injection (Dl) engines, it is often the case that the “retraction volume” resulting from the retraction piston on the delivery-valve plunger does not suffice to reliably prevent cavitation, secondary injection, and combustion-gas blow-back into the nozzle-and-holder assembly. Here, constant-pressure valves are fitted which relieve the high-pressure system (injection line and nozzle-and-holder assembly) by means of a single-acting non-return valve which can be set to a given pressure, e.g., 60 bar (Fig. 13).

** Our stock/OEM DVs don't have a "Retraction Piston" as mentioned above. They are "Full-Cuts" if you will. (As is shown in that image turboram posted above).

I can't help but think those nics are an attempt to equalize the high-pressure lines and nozzle-holders with that between the H/R and DV such as the Constant-Pressure Valve mentioned above.

[RCCUMMINS89]

When I read it, that's how I took it. So in my understanding, if one to swap out dvs to the ones without the nics, it would cause a somewhat erratic idle... something to a mild lope? Which IMO would sound similar to a set up which has very large injectors and oversized plungers (p-pump or 14mm h/r)..... so yes I would see how it would sound like a sled puller. Which because it would want to keep the injection lines in a state of high pressure would also allow additional fuel into the cylnder, at the expense of efficiency and being in control of the excess fuel.

[turboram]

: All I know is there is a guy locally that builds the hardest fueling vp pumps on the market and he builds his pumps with delivery valves that dont allow fuel back to the pump head like the stock vp ones... and he says that his valves make it fuel harder.
Boy I cant wait to get my hands on another ve and try these with my dual feed and 14mm head and rotor on the puller

[RCCUMMINS89]

One thing I wasn't thinking about yesterday... It should in theory increase fuel simply because the pump doesn't have to re pressurize the high pressure line (not that it doesn't still have pressure). So you should get an increase in initial fuel, thus also a minor advancing in timing. This might be even more noticeable at higher rpms..... hence why you gain allot of rpms with this mod.

[Hansen01]

Another thing for your website RCCUMMINS89?

[RCCUMMINS89]

OH.... I have thought about it. I am interested in trying a set. I'm not convinced if they are the answer though. I could see where excessive injector where would come into play, I might be wrong on that though.

[91bluecummins]

sounds like something to try

[RCCUMMINS89]

Ok, someone send me a set.... LOL

[turboram]

Send me some vw delivery valves and I'll cut them for ya..... I'm. Sure there are other valves that will work too

[turboram]

going to the dyno on sat to test out the difference in the delivery valves