Case question for possible location for crank trigger Options

[technicalninja]

What was the original use for the large hole on the flywheel side of the right (passenger) engine case?

Looks like it could have been a good flywheel lock location.

To me it looks like very good spot for a crankshaft position sensor...

What was its original reason for being there?

[technicalninja]

Eric, thanks for the tips!

My first ideas for cam/crank triggers involved getting 2 4 cylinder mag pick up assemblies, fixing them into a distributor housing and chopping 3 of the teeth off of one of them. This would do it. You would have to delete the mechanical advance.

Most of the OEMs have moved to directly on whatever is rotating. Cam sensors are directly on the cam (usually the gear) and the crank sensor is directly on the crank.

The crank sensor looks super easy to me but there is limited access on the cam in a type 4 installation. It has to go on the distributor drive IMO.

I don't like sensors depending on a mechanical drive as any play in that drive may cause "jitter" and create problems where a directly sensing element would not.

I can easily see the simplicity of using a distributor as both, especially for the DIY crowd.

I am a fabricator/technician/designer and like to come up with my own way.

Separating the sensors also gives me a bit of adjustability regarding the "phase" between the two. This might or might not be important in the future.

One thing I will have to make that you might be interested it is a flange for the intake which places a modern injector exactly where the original ones are and then can be used for ITB or Plenum manifold. Plenum manifolds may well be the way I go.
Just look at the 964 motor in the classifieds or the Ferrari motor that is being installed in the forums for ideas. If I can get a plenum to work, I can easily control it with an ETB like this one.

https://www.summitracing.com/parts/bch-0280750151

That critter is cost effective and 60mm bodies can easily support a 200hp motor.
You add complete throttle control and electronic cruise control as well.
Most folks don't realize that the air pump has completely been replaced by the electronic throttle body and the decel valve (that so many have trouble with) is included in the Tbody. So, complete throttle mapping, electronic cruise, and a variety of emission controls can be utilized with ease.

The dubshops crank trigger looks very nice but it appears to be a PIA to get to with the engine in the car and I may need the room it occupies.

I spoke with my MS3 guru about my ideas and an MS3 Pro has the ability to run a PWM AC compressor in tandem with the engine.
A PWM compressor (especially if I use R12 which is legal in any 914) will have almost no drag on the engine at idle and is the path to sub 32 degree AC...
They made the compressors more efficient for fuel economy reasons but with the fine control this enables you can go sub-artic if you want.

My all-time record car for temps was a 12 BMX X5 that has an "intense" button on the AC control head. This was an R134 system that could hold 32.8 F on a 105 degree day.
It would do it at ANY speed including sitting still in direct sunlight.
Bad Assed!

[ogdougy]

Most of the OEMs have moved to directly on whatever is rotating. Cam sensors are directly on the cam (usually the gear) and the crank sensor is directly on the crank.

The crank sensor looks super easy to me but there is limited access on the cam in a type 4 installation. It has to go on the distributor drive IMO.

I don't like sensors depending on a mechanical drive as any play in that drive may cause "jitter" and create problems where a directly sensing element would not.

I can easily see the simplicity of using a distributor as both, especially for the DIY crowd.

I am a fabricator/technician/designer and like to come up with my own way.

Separating the sensors also gives me a bit of adjustability regarding the "phase" between the two. This might or might not be important in the future.

I think you are over estimating the "jitter" that is caused and it is really a non-issue. Look at the OEMs in the 90s before they had all their tooling switched over to make those directly connected sensors.

Nissan, Toyota, Mitsubishi all had their CAS systems (getting their cam and crank positions) running off of the exhaust camshaft (directly connected or through a gear) driven by a rubber timing belt. This adds about all possibilities of error and they worked perfectly fine. The only time they would fail to keep accurate timing is when the motor made gobs of power and the torque would stretch the belt.

As for the phase relationship between the senors there is no need to adjust that ever mechanically. Only if the original design got it wrong, even then you just adjust it with software.

Im all for the do it yourself idea. There are plenty of projects I have made that cost me a lot more than just buying an off the shelf product. But it still doesn't stop me from poking holes in mine or someone elses idea. It all helps in the design process