(Have) DHKs (re)fitted/modified

Hello everyone!

Is there a distribution channel to obtain the individual components of nozzle holder assemblies?
Has anyone here ever modified their own DHKs (Deutsches Hilfskommando - German Auxiliary Units) themselves? What difficulties arise in this process?
Does anyone know of a specialized workshop that is capable of checking and adjusting the opening pressures of the first and second stages (!!!) after replacing the injectors (on the common rail)?
Based on my experience, Bosch service centers are not capable of repairing TDI diesel high-pressure pumps themselves. They can only measure the opening pressure of the injectors. Check level.

In the US, it seems there are more qualified businesses that perform such modifications on direct-drive hubs.

Thank you for the information.

Regards,
Alex.

Hi Donalexo,

I suspect this is related to my post.
It might also be because you can buy parts in the USA that you can't get here. For example, .216 nozzles. I'm just going to take a chance and try to modify my spare DHK, but I can't even get the nozzles.

How is the opening pressure adjusted on these things? Are different springs used? Below the needle, there's only the needle itself - and there's nothing adjustable on it.

The same applies to the ESP's 12-hole injector. I would now feel confident enough to replace it myself (with a spare pump). And then have it tested on a dynamometer at Bosch. Checking is reasonably priced.

@garth.brooks

To measure the first opening pressure, essentially only a test stand with test oil and a pressure gauge is required. Measuring the second opening pressure, however, requires significantly more sophisticated measurement technology, as the second opening pressure is electronically evaluated. The cost of such a testing facility would be far too high.

The initial opening pressure is set using a pressure pin. The longer the pressure pin, the higher the Pdoe 1. If the line pressure, which acts on the needle seat, is higher than the spring force of the lower spring, the needle lifts out of its seat. The actuation is performed via the aforementioned pressure pin. With higher line pressure, the nozzle needle is lifted further out of its seat. This causes the upper spring to be activated via the cartridge case and the pressure equalization disc.
The second opening pressure is adjusted via this small pressure equalization disc. By unscrewing the nozzle tensioning nut and removing the nozzle assembly (nozzle + spacer + stop sleeve), you can see the disc. The thicker the disc, the higher the Pdoe 2 value.
Depending on the engine type, the first pressure setting is 191-201 bar or 221-231 bar, and the second is... Opening pressure: 301-315 bar.

Best regards.
zodiac

@garth.brooks


"If you need anything from the US, let me know. I have an American contact who needs things (especially when the dollar is at a rate where they can exchange it for euros), and he can get anything available there."
Currently, the prospects for us to make a purchase from American companies look very promising.

Okay, if you need anything, just let me know. I can then find out the price, and the shipping costs are reasonable.

Hello everyone!

Regarding the topic of "modifying the nozzles on the DHK itself," I found the following link.

... [no longer relevant]

However, I wonder if the nozzles offered there are of comparable quality to those manufactured directly by Bosch.
Generally speaking, the matter would be interesting, especially considering the price .

If anyone knows of any other sources, please post them!

Regards,
Alex.