Flying magnet cam position sensor
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- Helpful MS/Extra'er
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Flying magnet cam position sensor
I'm in the process of going from an optispark ignition to a 36-1 crank trigger and a 1x cam signal. I've got the diyautotune 36-1 wheel and hall effect sensor for the crank signal. Planning on using the base of the opti and drive mechanism to make a flying magnet trigger for the cam signal. I've got an msd 2346 2 wire VR sensor. Here's my question, can I use the digital high frequency input on the cam VR sensor? When originally terminating the harness I had to use DHF2 for the high res signal on the optispark and ended up using the CMP wiring on the VSS. Now that I'm switching I was hoping to not have to redo anymore wiring than necessary.
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Re: Flying magnet cam position sensor
VR sensors are not intended for use with flying magnets. I can't say it won't work, but I would sure be checking out the wave-form with a scope before relying on it. the high frequency input should be fine.
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Re: Flying magnet cam position sensor
I may be wrong about it being a vr sensor. It's marketed as a "DIY cam sync" kit. It's a 2 wire sensor, green and violet, which I believe on the MSD distributors is a VR sensor. I will double check though. Thanks for the replybillr wrote:VR sensors are not intended for use with flying magnets. I can't say it won't work, but I would sure be checking out the wave-form with a scope before relying on it. the high frequency input should be fine.
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- Super MS/Extra'er
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Re: Flying magnet cam position sensor
Did the kit include that round magnet with the sensor? If so, it is probably OK. That may be a "VR" sensor with no internal magnet, just a coil and pole pieces. That is not as convenient or nearly as common as a VR with an internal magnet, but it should work the same. I guess that it isn't technically a VR, doesn't operate on change in field reluctance; it's more of a small AC generator. I know, too much info...
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Re: Flying magnet cam position sensor
These days I'd rather have too much info than not enough! It was a complete kit with the magnet. I got it assembled tonight and was able to get it started. The instructions for the kit said that depending on how the magnet was installed would determine how the switch operated. I didn't have any way of checking it's polarity so I had to wing it. After getting it assembled I temporarily wired it and cranked the engine over while running a composite log. I seemed to get a better signal using the CMP wiring vs the digital high frequency input. I ended up having the cam trigger set to falling edge and it started up on the first hit. Out of curiosity I switched back to the DHF2 input and it still started but had a cam sync error. Keep in mind that none of that wiring is shielded, so it may still work, but I may just try to figure out how to make the vss run on the high frequency input since it's not as critical. Here's a picture of the finished product. I need to make a more rigid bracket to hold the crank sensor but it works for now. Thanks for all your help.billr wrote:Did the kit include that round magnet with the sensor? If so, it is probably OK. That may be a "VR" sensor with no internal magnet, just a coil and pole pieces. That is not as convenient or nearly as common as a VR with an internal magnet, but it should work the same. I guess that it isn't technically a VR, doesn't operate on change in field reluctance; it's more of a small AC generator. I know, too much info...