Motor mount prototypes

After installing the M400 gearbox and the motor in the car and modifying the tunnel, I can start building the motor mounts. Die original Volvo Amazon motor mounts are too big because the Siemens motor is wider than the B20.

motorsteun   optie

Perhaps mounts from a Volvo 140, 240, 740 of even a Penta (boat) can be handy combined with a frame at the sides of the motor to connect them to. That will however require quite some measuring and “trial and error”.

Therefor I started with my initial idea for the mount. A 10mm thick steel plate mounted on the front side of the motor with ‘flaps’ on which the motor rubbers can be mounted. First I created a mockup of wood to get a first idea of the angles and distances.

motorsteun   prototype   hout

Next created a prototype using steel.

motorsteun   prototype   hoeklijn

Quite nice for a first attempt. Must be mounted a little higher because the free space between the subframe is only 5 mm.

bodemvrijheid   motor

In the end it will be build using thicker material of course. For the record, the motor weighs 90 kg and can deliver 300 Nm of torque.


In the meantime I have taken some measurements from the first steel prototype and aligned some angles and lengths. Building on that I created a new prototype.

schets   en   nog   een   prototype   motorsteun

While test fitting in the car it turned out that the “flaps” are not symmetrical. There is a 10 mm difference. After checking it turned out the original B20 left and right motor mounts are different too and also the mounts on the subframe are not centered. Something you would not easily notice. Now the motor is level, 10 mm of clearance at the motor while on his weight.

bodemspeling   motor   1cm

Using this prototype and the pdf icon CAD drawing of the Siemens 1PV5135 motor I am going to have it fabricated using a 8 to 10 mm steel panel. Similar to how New Electric did it in their Jeep CJ-5 conversion.

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Foto: New Electric

In that case the ‘flaps’ look even longer and horizontal. Building on that my design will be able to handle the weight and torque as well.

Update 2

I have extended the prototype to make it representative for the final form factor.

mockup   plaat   kopse   kant

Added some ribs and larger contact areas for the rubbers.

versterkte   ribben   motorsteun

Update 3

I also created a supporting cardboard model to see how we can fold/create it from one piece as much as possible.

mockup   motorsteun   karton

So this is the kind of shape that needs to be lasercut.

uitslag   tekening   motorsteun

The outer flap can be bend and only the inner rib needs to be welded. Next week contact some workshops to discuss planning and costs.

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OldVolvo is a classic Volvo hobby blog by Lars Rengersen.

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