Tores mailbox VIIC and VIIC/41 operation and technical details

[NZSnowman]

Thanks, again for the great information. It

[tore]

Simon
I`m happy to be able to assist. However don`t make every pipe shiny they were not, most of them were painted grey. The hp pipes from the Bosch fuelpumps to the fuelinjectors were not painted and the indicatorcocks were black steel and with a tendency to have a few rusty spots as they were subject to the exhausttemperatures. Looking forward to be seeing your enginedrawing.
Tore

[NZSnowman]

1. What is this? Is it a small window to check fuel level? What colour should it be?
2. What is this? Is it a small coverplate? It very hard to tell from these pictures as with the paint, but are there two very small screw on each side of the plate?
3. Just noted this reset in the rods this afternoon. I imagine this would illustrate the maximum movement of the rods.

Also just realise I have a major redraw on the fuel pump regulating rods!!! I do not realise that the fuel pump regulating rods are not symmetrical on the aft three heads of the engine, compare to the fore 3 heads. By the way, Tore how did you number the head, from stern to bow.

Thanks, Simon.

[NZSnowman]

Tore, what is the red thing?

[tore]

1. What is this? Is it a small window to check fuel level? What colour should it be?
2. What is this? Is it a small coverplate? It very hard to tell from these pictures as with the paint, but are there two very small screw on each side of the plate?
3. Just noted this reset in the rods this afternoon. I imagine this would illustrate the maximum movement of the rods.

Also just realise I have a major redraw on the fuel pump regulating rods!!! I do not realise that the fuel pump regulating rods are not symmetrical on the aft three heads of the engine, compare to the fore 3 heads. By the way, Tore how did you number the head, from stern to bow.

Thanks, Simon.

Simon
1. This is an "inspection window" where you can check the movement of the fuelplunger in the fuelpump. It should never be painted. Usually the fuelpumps were painted black from the Bosch manufacturer.
2. Honestly I cannot remember this signplate. It could be nameplate for the Bosch factory, as the HP fuelpumps could be moved around it was not a cylinder numberplate.
3.This is a toothed rack entering a toothed rim on the fuelplunger outer sleeve connected to the plunger, regulating the fuelinjection by turning the sleeve and plunger. The movement was strictly horisontal, back and forth and the recess is presumably a guide to prevent it turning.
For the position of the fuelpumprack it was usually an engraved millimeterscale on the rack just before entering the fuelpump. I think you can see marks  on the rigth side of the pumpcasing were the pointer was fitted.
Tore

[tore]

Simon
The cylinders were numbered from forward to aft. The fuelrack linkage is very important. If you look carefully on your pictures you`ll see each individual pump has a linkconnection with an oval slot in the rod and a spring attached, The spring seems to be missing on quite a few pumps on your picture. The system works like this: if one fuelpumpplunger is stuck (scored) the governor or maneouveringhandle should be able to move the rack so the rest of the pumps could be moved to 0 stopping the engine and prevent overspeeding. In drawing the fuelrack don`t forget the governor at the aft end of the rack.
Tore       

[tore]

Tore, what is the red thing?

Simon
This is a small screwvalve for "bleeding" the fuelpump eg to get rid of air in the fuelpump. It is wrongly painted red.
Tore

[tore]

Looking at all the pictures of the fuelpumps it strikes me that every nut and connection is painted. The connection between the HP fuelpump and the fuelinjector in the cylindercover was comparatively often dismantled. The fuelinjectors were sensitive and had to be changed (overhauled) quite frequently. The last thing you wanted to have was paintflakes entering you delicate fuelsystem particulary after the filters. Therefore the connection from the fuelpumps to the fuelinjectors fitted in the cylindercovers should not have any paint and should be clean steel.
Tore

[tore]

Simon
You observation fuelrack is not symmetrical.
The fuelrack is controlled by two means, the maneuovringstand in front of the engine and the governor in the aft. The governor takes care of the stable revs at varying loads and particulary in bad weather is a must. The maneuveringstand overule the governor anytime you want. In order to accommodate the linkage to the governor in the aft end, they reversed the linkage at the center of the engine as you correctly observed.
Tore

[NZSnowman]

1. What is this? Is it a small window to check fuel level? What colour should it be?
2. What is this? Is it a small coverplate? It very hard to tell from these pictures as with the paint, but are there two very small screw on each side of the plate?
3. Just noted this reset in the rods this afternoon. I imagine this would illustrate the maximum movement of the rods.

Also just realise I have a major redraw on the fuel pump regulating rods!!! I do not realise that the fuel pump regulating rods are not symmetrical on the aft three heads of the engine, compare to the fore 3 heads. By the way, Tore how did you number the head, from stern to bow.

Thanks, Simon.

Simon
1. This is an "inspection window" where you can check the movement of the fuelplunger in the fuelpump. It should never be painted. Usually the           fuelpumps were painted black from the Bosch manufacturer.
2. Honestly I cannot remember this signplate. It could be nameplate for the Bosch factory, as the HP fuelpumps could be moved around it was not a cylinder numberplate.
3.This is a toothed rack entering a toothed rim on the fuelplunger sleeve, regulating the fuelinjection by turning the sleeve. The movement was strictly horisontal, back and forth and the recess is presumably a guide to prevent it turning.
For the position of the fuelpumprack it was usually an engraved millimeterscale on the rack just before entering the fuelpump. I think you can see marks  on the rigth side of the pumpcasing were the pointer was fitted.
Tore

Number 2:

Tore, I think you are correct about the Bosch factory name plate 

Could not found any u-boat wartime pictures of this plate So I base the plate below on two wartime Bosch factory name plate from a horn & a magneto They were the only wartime name plate I could found on the net.

[tore]

1. What is this? Is it a small window to check fuel level? What colour should it be?
2. What is this? Is it a small coverplate? It very hard to tell from these pictures as with the paint, but are there two very small screw on each side of the plate?
3. Just noted this reset in the rods this afternoon. I imagine this would illustrate the maximum movement of the rods.

Also just realise I have a major redraw on the fuel pump regulating rods!!! I do not realise that the fuel pump regulating rods are not symmetrical on the aft three heads of the engine, compare to the fore 3 heads. By the way, Tore how did you number the head, from stern to bow.

Thanks, Simon.

Simon
1. This is an "inspection window" where you can check the movement of the fuelplunger in the fuelpump. It should never be painted. Usually the           fuelpumps were painted black from the Bosch manufacturer.
2. Honestly I cannot remember this signplate. It could be nameplate for the Bosch factory, as the HP fuelpumps could be moved around it was not a cylinder numberplate.
3.This is a toothed rack entering a toothed rim on the fuelplunger outer sleeve and , regulating the fuelinjection by turning the outersleeve and then the fuelplunger. The movement was strictly horisontal, back and forth and the recess is presumably a guide to prevent it turning.
For the position of the fuelpumprack it was usually an engraved millimeterscale on the rack just before entering the fuelpump. I think you can see marks  on the rigth side of the pumpcasing were the pointer was fitted.
Tore

Number 2:

Tore, I think you are correct about the Bosch factory name plate 

Could not found any u-boat wartime pictures of this plate So I base the plate below on two wartime Bosch factory name plate from a horn & a magneto They were the only wartime name plate I could found on the net.

Simon
I don`t think there was much difference between the two pumpexecution externally, neither the nameplate. The serialno on the nameplate was not too important, what really matters was the interior parts, plunger and liner, which was lapped together and could be dismantled as a unit from the housing.
Tore

[tore]

Simon
While beeing on the subject of pushrods for the valve rockerarms I realize I have not mentioned a 3rd valvepushrod per cylinder. The red arrow on the picture below indicate the the rod. This is the rod operating the startingvalverockerarm. Normally it is kept free from the camshaft by a spring but when the startinghandle is placed in start position, the rod is pneumatically pushed against the springpressure down to the camshaft which then control the compressed air to the individual cylinders and thus starts the engine by compressed air. As the the other valverods, this should be shiny metallic as well and not painted.
Tore

[NZSnowman]

Fig. 1. New updated fuel pump. Old fuel pump (right).

[tore]

Seems to be fine to me. If you really want details your could put in fuelrack positionmarks 1mm apart as indicated in red below.
Tore

[tore]

The threaded parts on the rack linkageconnection showed on your new drawing was for adjusting the individual pumps fuelinjection in relation to the others, and the fuelrack markings was very useful for that.
Tore