Prevention of cylinder head damage in pump-injector element TDI engines: Optimum problem solving through 07eins PD injector retainer
Cylinder head damage in TDI engines from the Volkswagen Group (VW, Audi, Skoda and Seat) with pump injector elements ("PDE") built between 1998 and 2010 is often caused by loose PDE seats, which work their way into the cylinder head and can lead to leaks and even cylinder head damage. The ORIGINAL 07eins PD injector retainer (repair holder) solve the problem sustainably and permanently, unlike competitor products. This makes defective cylinder heads in TDI diesel engines a thing of the past. In combination with the 07eins reinforced VITON sealing rings, diesel engines receive maximum protection against fuel mixing into the oil circuit.
A detailed overview of the 07eins PD injector retainers can be found on the Pump nozzle unit PD injector retainer / PDE repair holder for VW, Audi, Seat, Skoda TDI page.
Technical cause of the pump-nozzle problemThe damage (“wear marks”) in the seats of Bosch unit injectors bolted on one side, which occurs in the cylinder head exclusively on the side opposite the fastening bolt, is caused by the original retaining shoes tilting sideways when tightened.
The force caused by the one-sided screwing of the retaining shoes presses the PDEs onto the opposite inside of the PDE seats, because the engagement in the groove on the injector is at some distance next to the screw connection:
Non-optimal cause avoidance by VW for TDI pump injector element engines with higher mileage
VW also took this problem into account from the outset and, on closer inspection, provided the retaining shoes with a protrusion at their upper edge, with which the holder is supported against tilting on the cylinder head. In addition, the bore was widened at the bottom to prevent the bolt from being subjected to a bending moment.
During the development of the PDE TDI engines at that time, it was obviously not possible to correctly estimate the extent of this resulting support force, which always leaves tangible and visible marks on this support surface on every cylinder head, over the service life of the TDI engines:
The injector seats form the counterpart to these worn surfaces and now have to withstand the applied transverse force. During operation, alternating heat and cold and vibration cause the unit injectors to wear further and further into the cylinder head. Over time, this leads to diesel mixing with the oil and the numerous resulting forms of consequential damage and engine running problems, up to complete cylinder head damage.
Non-optimal problem solution of the competitor product for TDI pump-nozzle element engines with higher mileage
If a loose bracket with an extended base is now used on the other side of the injector, it will experience the same tilting moment as the original retaining shoes (the groove and support are still offset to the side of the fastening screw).
Optimum problem solution with the ORIGINAL 07eins PD injector retainer (repair holder) with support plates
To counteract tilting, the screw in a narrow bore must absorb the force that is normally transferred to the cylinder head.
The injector screw, which is already subject to high loads, is not designed for this type of force transmission. This overload can lead to complete cylinder head damage with prolonged running time and additional vibrations and thermal expansion.
During the development of the 07eins PD injector retainers, this problem was taken into account:
By screwing the PD injector retainer to the injector, a frictional connection is created to the pump-nozzle element. As a result, the tilting force is transferred to the body of the injector via the screwed wing.
07eins PD injector retainers (repair holders) eliminate the cause of cylinder head damage in TDI engines with pump-injector elements sustainably and permanently:
As with the original VW design, the stretch bolt hole in the 07eins PD injector retainers is large enough to prevent contact and thus prevent bending forces from being transmitted to the thread.
This technical solution for the connection with the pump-nozzle element is protected by DE utility model DE 20 2020 106 341 U1. For this reason, competitor products CANNOT use this optimum connection of PDE and repair holder.
But that's not all. The transverse force that has now been described several times is prevented with the connection to the PDE body. Nevertheless, there is still "only" a one-sided screw connection without actual centering of the injector (as is also the case with surface-mounted solutions, of course).
Another advantage of using the 07eins PD injector retainers is that additional support plates are used to provide additional support.
Each cylinder head has a known, exact dimension of the side cylinder wall to the center of the PDE seat. The corresponding surface is machined and brought to size on each cylinder. As described above, VW also used these surfaces to support the retaining shoes.
The 07eins PD injector retainers use this precise contact surface and, by placing this support shim on it, create a support connection that accommodates tolerances and centres the PD injector precisely.
Summary
The protected ORIGINAL 07eins PD injector retainers eliminate the problem of TDI engines with pump-injector injectors built between 1998 and 2010 thanks to the friction-locked screw connection with the pump-injector element. Solutions with one-piece PD injector retainers or repair holders do not offer this lasting and permanent protection.
