Otmars Porch 914 project

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Here are links to giffs of the drawings of the adaptor plate.
1 2 3 4 5 6 7

Ever since the high rents in Sillycone Valley chased me out of my shop space, I drive my machine shop over to the house from the storage yard that it's usually in to work on metal stuff.

A hub slowly forming out of what was a rectangle of 7075 aluminum.
I'm no master machinist, I figure I spent a week designing the plate and two weeks getting aluminum and machining it. This was spread out over several months.

Ever wonder how to put the keyway in a hub? I did. As usual, Bob Schneeveis had the answer. All by arm power. Here I was cutting about .003" per plunge. The tool is a lathe boring bar which I shortened and ground a tool for. The mill head is held from rotating by putting it in back gear and normal at the same time.

Here is the lower hub with pulley for the Goodyear pd belt and the triple disc Tilton Racing clutch on the bottom. JB has put the pd belt in his dual motor 944 conversion and it is very quiet.

Adaptor parts ready to get together. I have some pictures of the tricky rotary table work of making the plates, but I can't seem to find them at the moment. A freind with a CNC helped with the center spacer, I didn't do that one by hand.

The crowbar helped get the lower motor in place against the belt tension. This system does not use a tensioner, just accurate center to center distances.

The cover plate is cut to slip into the Porch transmission bolt pattern.

One of the motors was not advanced and needed new holes in the frame to be advanced. I found that the original threadforming screws can be used if you drill a #1 drill (0.228") and drill a little more than 0.8" deep.

After the rear plate went on, I bolted up the Tilton clutch. The whole assembly seems pretty heavy, but I guess that's the price one pays for performance. I wonder how much of the frame around the field is really necessary? :-)

Next up: Pulling the ICE and putting it in the car.

Last update 5.9.01

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Here are links to giffs of the drawings of the adaptor plate. 1 2 3 4 5 6 7 Ever since the high rents in Sillycone Valley chased me out of my shop space, I drive my machine shop over to the house from the storage yard that it's usually in to work on metal stuff.
A hub slowly forming out of what was a rectangle of 7075 aluminum. I'm no master machinist, I figure I spent a week designing the plate and two weeks getting aluminum and machining it. This was spread out over several months.
Ever wonder how to put the keyway in a hub? I did. As usual, Bob Schneeveis had the answer. All by arm power. Here I was cutting about .003" per plunge. The tool is a lathe boring bar which I shortened and ground a tool for. The mill head is held from rotating by putting it in back gear and normal at the same time.
Here is the lower hub with pulley for the Goodyear pd belt and the triple disc Tilton Racing clutch on the bottom. JB has put the pd belt in his dual motor 944 conversion and it is very quiet.
Adaptor parts ready to get together. I have some pictures of the tricky rotary table work of making the plates, but I can't seem to find them at the moment. A freind with a CNC helped with the center spacer, I didn't do that one by hand.
The crowbar helped get the lower motor in place against the belt tension. This system does not use a tensioner, just accurate center to center distances.
The cover plate is cut to slip into the Porch transmission bolt pattern.
One of the motors was not advanced and needed new holes in the frame to be advanced. I found that the original threadforming screws can be used if you drill a #1 drill (0.228") and drill a little more than 0.8" deep.
After the rear plate went on, I bolted up the Tilton clutch. The whole assembly seems pretty heavy, but I guess that's the price one pays for performance. I wonder how much of the frame around the field is really necessary? :-)
Next up: Pulling the ICE and putting it in the car.