Wednesday, December 30, 2009

Motor mount drawings.

I have gotten a request for dimensional drawings of the motor mounts that I came up with. Sorry to say that I don't have any CAD drawings of them. I'm more of a make it by feel person when it comes to one off parts of this nature. I can tell you though that I attached some card stock with spray adhesive to the original Audi mounts, then I used a ball peen hammer to gently punch out the bolt holes, after which I transferred the the card stock to .250" thick plate steel and cut out the rough shape. Once both plates where made I bolted them to the motor. The drivers side mount is more involved because the original mount is z shaped. Making a z shaped mount would have proven difficult for me plus there was an issue with a bolt hole being covered by the support tube. I ended up making the mount from flat stock with a standoff welded to the backside of the mount to compensate for the original z shape. This also eliminated the problem of the support tube covering a bolt hole. How you make the feet will depend on which motor mount you decide to use. I recommend something very hard to really limit movement of the motor, there just isn't enough room around the motor for it to be swinging about without hitting something. After I made the feet and had them mounted where the original Porsche mounts where, I used PVC pipe to quickly develop what the connecting pipe should look like. Once that was done I made a new one in .120" x 1.500" OD tube and welded it into position. I started with the passenger side mount and then the drivers side mount. Things to be aware of are that the motor doesn't' want to hang from the hoist at the right angle. I used a ratchet strap to correct this during mock up. Also repeatedly make sure that your height and lateral positioning are correct during the process. If I remember correctly it was 13.5" from the crank bolt to each frame rail to keep it centered. The height has a very small window in which the pan will not hit the frame, but the hood will still close. I will measure it again, but iirc the bottom of the lowest point of the block needs to be 1" from the cross member, this will leave about .500" for the passenger side of the oil pan and .500" for clearance. Take all this with a grain of salt though as I am in the process of making the pan right now and will make updates as problems arise. I will post pics of the mounts when they are removed for powder coating, that should help out if there is any confusion.

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