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B20 crank sensor wheel

TR Conn

TR Conn

Member
Joined
Dec 13, 2006
Location
Long Beach, Ca
I'm taking the next step with my B20 Megasquirt install and am working on the ignition.
I've been using the points for the timing so far and I'm looking for ways to install a crank trigger wheel.
Dale (Avalanche) made nice ones, but they were underdrive pulleys and I would like to keep the stock diameter. I have A/C, so its a double pulley.
I'm really limited for space between the pulley and the fan so I'm considering something like this:

picture.php


Does that look to be a viable way to do it?
The metal band between the grooves is 3/8". How large and how deep do the holes need to be to properly activate the sensor? I have both the Bosch (LH 2.4 CPS) and a Cherry GS100502. I could use either sensor. Or is there a better one?

How have others attached the toothed wheel to the stock, cast crankshaft pulley?
 
There are two types of pulleys. The cheap unreliable one that appears to be two stamped steel pulleys welded together. The other, which I have, is a solid & heavy solid steel casting.
I'd be interested in seeing photos of the notched pulley.
 
I made 60-2 pattern on flywheel on my B30, sensor is std Lh2.4. Works wonderfully, even it was bit tricky to manufacture due the dimensions of the flywheel.

Holes were dimensioned with same way as on a Lh2.4 FW. Holes and ridges were on smaller periphery, so they were adjusted accordingly.
 
Isn’t there a way to use a Pertronix breakerless kit with MS like a hall sensor? I have no knowledge of this but I’m pretty sure I read it somewhere and intended to look into it more if I ever sack up and decide to ditch my carbs.
 
yes, crane or pertronix box will do it, but its only a 4 rigger so it just reads 90*-90*-90*-90*. so single coil or possibly wasted spark compatible, but no way to do sequential.

I'd run the DSM CAS if you can, and have minimal space out front. if theres enough room for a Double rib pulley, see of BrickAutosport can work up one with a 36-1 ring, then fab a sensor bracket off the oil pan bolts.
 
I am in the exact same scenario looking for the exact same thing. Curious where this goes.

TR Conn said:
I'm taking the next step with my B20 Megasquirt install and am working on the ignition.
I've been using the points for the timing so far and I'm looking for ways to install a crank trigger wheel.
Dale (Avalanche) made nice ones, but they were underdrive pulleys and I would like to keep the stock diameter. I have A/C, so its a double pulley.
I'm really limited for space between the pulley and the fan so I'm considering something like this:

picture.php


Does that look to be a viable way to do it?
The metal band between the grooves is 3/8". How large and how deep do the holes need to be to properly activate the sensor? I have both the Bosch (LH 2.4 CPS) and a Cherry GS100502. I could use either sensor. Or is there a better one?

How have others attached the toothed wheel to the stock, cast crankshaft pulley?
Click to expand...
 
After quite a bit of computer time searching around the internet and visiting a couple of machine shops It looks as though I'm going to go the Pertronix route.
This seems the easiest and iinexpensive.
It requires modifications to the distributor (lock out the advance and vacuum adv/retard).
It most likely will require distributor rotor phasing.
With the Pertronix there is no way to get sequential injection. Something I'm sure I can live without.
To go even cheaper and easier it seems as though the original points can be used instead of the Pertronix to give the tach. signal to the MSll. It requires the same modifications as using the Pertronix.
 
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I've found another way...
picture.php

The "reluctor wheel" is from a Pertronix I fried a while ago. (Memo: Don't hook up a Pertronix with the leads switched!).
Phasing will just be a matter of drilling 2 holes and extending the notch for aligning the cap.
The sensor is a Cherry #GS100502-168A. It requires a 2.4K ohm pull-up circuit. According to DIYautotune, this provides a "nice square wave so there’s no variable voltage issues".
 
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Nice, I'm using the same thing for my cam sensor, 36-1 on the pulley for crank. If you have an 8 bolt crank, you might be able to use the 60-2 flywheel and work the bellhousing for a crank sensor. If you decide to go sequential later on.

And double your jamb nut on the outside, the inner one is locked in by the radius of the distributor, the one on the outside doesnt have a whole lot to lock on, so adding another jamb nut there will keep it from being able to back off and cause issues like sensor rubbing or sync loss due to a wobbly sensor.
 
Thanks for the tip.
I'm still trying to figure out the jumpers to get this to work.
It should be easy, but the info in the instructions is scattered around and I don't really understand some of the terminology.
The sensor works on the bench, but I'm not getting a tach signal on the stim or the car.

Update: I switched the ignition over to the VR circuit and am now getting a signal.

2nd update: I got it fired up today. Set the base advance and started cleaning up the wiring.
 
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TR Conn said:
There are two types of pulleys. The cheap unreliable one that appears to be two stamped steel pulleys welded together. The other, which I have, is a solid & heavy solid steel casting.
I'd be interested in seeing photos of the notched pulley.
Click to expand...

sorry forgot all about it
dirty weight 1lb 1.7 oz

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