DIY Ignition switch

[essmeier]

I recently acquired my 2800CS and it has an add on ignition switch using a secondary key. I wanted to get the original key working and was planning to use the original switch as a template to create an alternate. Unfortunately, my car apparently did not come with the original. I've tried to get started by making sample parts of differing sizes but Im at a point where real dimensions would be helpful. I have a switch that does fit and turns but its sloppy and some items like the set screw tab I can't easily size. So, I'm coming here to ask if someone can provide dimensions for the ignition switch. Besides the dimensions I also have a few questions. When I turn my key I don't get any tactile feed back like a click for each position and a spring push back for the starter position. Are these provided by the switch or do I have something else defective or missing? The steering lock where the switch mounts does exist in my car so my assumption is that the switch needs detents and a spring.

These are the dimentions I'm looking for.

A. Body diameter
B. Smaller diameter containing the key
C. Length of the body
D. Length of the smaller diameter with key
E. Height of the pin
F. Height of the set screw flange
G. Width of the set screw flange
H. Diameter of the pin
I. Diameter of the key hole
J. Width of the key hole
K. Width of the small side of key hole
L. Width of the larger side of key hole
M. Depth of the set screw flange
N. Distance from outside switch to pin
O. Distance from outside switch to set screw flange
P. Diameter of center key hole
Q. Distance to set screw
Theta. Angle from center pin to center set screw flange

Here are my experiments so far. I also have a circuit ready but I need to finish the boards. The switch works by using magnets to trigger the 4 positions. Then an external board with 4 relays will provide the power like the original switch.

 

[ScottAndrews]

Not an expert on E9 switches, but most automotive switches of the era used ball detents to provide the tactile feedback you mentioned. ALmost all of them use sliding contacts for the electrical connections. In addition, these cars have several power modes that are controlled by the switch: Off, Accessory, Start, and Run. I am sure you are familiar with these. In the E12/E24 switch (which I AM familiar with), the power modes are controlled by a stepped contact plate inside the switch. As the switch rotates, that plate rotates, and springy wipers sucessively contact different parts of the plate (as shown below). The plate connects the battery line (always hot) sequentially to the Accessory bus, and then the Run bus, and in a momentary fashion to the Start bus. Each of these buses is actually controlled by a relay that is actuated by the switch (to limit the current that the switch needs to handle).

 

[ScottAndrews]

Real OEM says that the switch is actually available ($US 200+) as part number 61321355148. Here is the RealOEM pic (Switch1.jpg)

I also took some photos of the E12/E24 switch. Looks to be about the same, but plastic instead of metal. This switch is also available from BMW (somewhat expensive) as part number 61321355701. The entire assembly is somewhat complex. There is a lock tumbler (6 in the diagram below) that is where the key goes. This has the spring for the momentary start position. It has a small flat shaft onthe end that engages a mating slot onthe end of the switch (3 in the diagram). the set screw (8 inthe diagram) goes into the tab on the switch. The switch has the ball detents for the various positions.

As for dimensions. Here is what the E12/E24 switch has (very likely the same or similar)

A: 27.25 mm (the black end cap on the switch is 31.8 mm, but that dimension is not very relevant, since it doesn't fit into anything.
B: 15.6 mm
C: 17 mm (the dimension to the end of the black end cap is 23 mm, but again that is not a critical dimension)
D: 5.5 mm
E: 3.2 mm
F: 6.7 mm
G: 5.8 mm
Phi: 90 degrees
H: 2.8 mm
J: 7.2 mm
K: 2mm
L: 3 mm
M: 2 mm
N: 1 mm
O: 1.7 mm
P: 5 mm (seems to be the same dimesion as I in your drawing)
Q: 3.2 (the hole is 2 mm)

 

[ScottAndrews]

Did a little more sleuthing. The entire set of parts is available. Key, lock tumbler, switch, etc. Pretty expensive, but probably much easier and more reliable than making your own. The is from Maximillian Importing company, which is a BMW Mobile Tradition retailer. You can probably also find this at any dealer. They will need to order it from Germany. Walloth-Nesch may also carry it.

 

[essmeier]

Thank you Scott for the dimensions and the extra info. I was not aware the part still existed. I saw a replacement on ebay for $600 which is why Im going the diy route. I'm fairly far along with the switch so I'll probably finish it. I am a bit disappointed to learn that the spring is in another portion of the assembly. I may add this into my switch since mine doesn't work and make it removable for anyone that has a working spring.

 

[sfdon]

Realoem pricing is meaningless and unusable. As is any indication of availability.

Out of date by a decade.

The same goes for Maximillian.

Just because they show an item does not mean they can get it.

Walloth does not have the 61321355148 switch.


The 61321355701 switch is the smart move. Under $200.00 from dealer
and €140.00 from Walloth.

it is the e24 switch and is metal.

Suchergebnisse für: "61321355701" | Wallothesch

www.wallothnesch.com

Genuine BMW 61-32-1-355-701 | Ignition Switch H61310 | FREE Shipping on Most Orders $499+ OEMG! | getBMWparts

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[ScottAndrews]

Realoem pricing is meaningless and unusable. As is any indication of availability.

Out of date by a decade.

The same goes for Maximillian.

Just because they show an item does not mean they can get it.

Walloth does not have the 61321355148 switch.


The 61321355701 switch is the smart move. Under $200.00 from dealer
and €140.00 from Walloth.

it is the e24 switch and is metal.

Yeah, I have found that about 30% of the parts, (usually the more oddball ones) on Maximillian are listed as available, but aren't. I just use RealOEM as a part number guide.

Also not exactly sure what the plastic switch I photographed is. I thought it was the one from my E24, but I just replaced that with the '701 switch from the dealer, and that too was metal. The plastic one may have been from a later 635. In any event, these all appear to be the same dimensionally, and I would assume from an electrical perspective. They are surprisingly flimsy!

 

[Stevehose]

Thank you Scott for the dimensions and the extra info. I was not aware the part still existed. I saw a replacement on ebay for $600 which is why Im going the diy route. I'm fairly far along with the switch so I'll probably finish it. I am a bit disappointed to learn that the spring is in another portion of the assembly. I may add this into my switch since mine doesn't work and make it removable for anyone that has a working spring.

You saw the one Dickie has been listing for years at $600.