The fabrication of the motor mount brackets is one of the most important parts of the 335i conversion.  It is a pivotal part of many safety inspections and will contribute greatly to the safety and proper future operation of the vehicle.

Making Your Own Motor Mount Brackets
Aside from the many possibilities of buying the motor mounts, they could of course be made.  First a plate that can be screwed to the engine block must be manufactured.  From a suitable flat bar of steel the part to extend from the block to the attachment point in the engine bay is to be made.  The engine is then lifted into its desired position and a few spot welds are made, to hold the parts together.  At this time steel bars are welded in to hold the engine in place.  This will later be dismantled.  The motor mount brackets are removed and strengthened with an appropriate grade steel.  They are then reinstalled and the provisional bars are removed.

The motor mount brackets should be made from ST37-2 (high-grade steel).  This can later be sealed.  Plastic coatings are ideal for this application as they will keep out dirt and road debris among other things that are potentially harmful to the brackets.
 

A "home-made" motor mount bracket could look something like this. The left one, nearest the exhaust, is not designed for the use of headers, however it could later be adapted for their use.   Here you also see that the brackets are made to have a slight angle.  This serves to put the engine further behind the front axle. Thus the engine does not sit centered directly over the front axle.  This shifts the added 60 kg (132Lbs) further back.

Example of my motor mount (Type 1) brackets on a 735i e23 engine **
Example of my motor mount brackets (Type 1) on an M5 Motor (M88) **
Comparison to the aluminum Alpina motor mount brackets **
Example of my motor mount brackets (Type 2) for the e34/e32 engines **

Alpina Motor Mount Brackets
The motor mount brackets of the original B6 can be purchased as yet another alternative.  However, in this case the engine position is fixed, it cannot be modified.  The older versions of the Alpina mount brackets are molded from aluminum. The use of such brackets will position the engine rather far forward (Engine Position I) and require the use of the Alpina radiator. These brackets also break quite easily in an accident and would need to be re-welded or replaced after such damage.  See the left most picture below for an example of the aluminum Alpina brackets. 

The newer versions of the Alpina brackets are made of high-grade steel.  These brackets are seen as more ideal for the 335i project as they are more durable and they position the engine further back (Engine Position II).  These are depicted in the right most picture below.
                                                                                      

Aluminum Alpina brackets (B6 2.8/1 B6 3.5 until 9/87) Alpina part number, left: 11 81 108 Alpina part number, right 11 81 107

Steel Alpina Brackets (B6 3.5 B6 3.5S after 9/87) Alpina part number, left: 11 81 113 Alpina part number, right: 11 81 118

Motor Mounts
Normally the factory e30 motor mounts can be reused (part number: 11 81 1 139 019). If a flatter mount is desired (lower engine position) the motor mounts from a Ford Fiesta Diesel can be used. The motor mounts from the e36 3-Series can also be adapted to work properly.  A piece must be added to the motor mount bracket that extends down into the e36 mount.  This further limits the vibration of the engine on its mounts.

**Available in German Only

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