JPI RPM sensor

[Rmfriday]

After trying unsuccessfully to install the RPM sensor on my 0-360 C model it appears that the mag needs removed to install the sensor.

The is a vent plug that is very easy to access on the "top" of the mag but it is apparently only for timing and inspection, the vent plug that gives access to the rotating magnet is on the other side of the mag and pretty close to the rear accessory case. Is this in line with what everyone else has experienced?

  

[jetdriven]

Yes, sometimes you have to remove the magneto to install the sensor. We have had fairly good luck avoiding this by using a quarter inch drive ratchet screwdriver which looks like a quarter inch drive ratchet with a flat screwdriver bit which will fit in almost anywhere to turn the screw the back that plug out, and then you can stick to plug in and then turn it with wrench but anyway yes it’s tight

[kortopates]

They’re very fragile so be very careful handling it. And I recall $400! I am sure more these days.


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[DXB]

3 hours ago, Rmfriday said:

After trying unsuccessfully to install the RPM sensor on my 0-360 C model it appears that the mag needs removed to install the sensor.

The is a vent plug that is very easy to access on the "top" of the mag but it is apparently only for timing and inspection, the vent plug that gives access to the rotating magnet is on the other side of the mag and pretty close to the rear accessory case. Is this in line with what everyone else has experienced?

  

Yup.  Put it on the right mag in case you ever want to replace the left with a Surefly.  Also FWIW the connector for my sensor to the harness was incredibly finicky and would give whacked out readings for a long time.  Replacing the sensor via  JPI made no difference. Finally painting the contacts with Stabilant 22, a trivially easy fix, solved the issue. 

[jetdriven]

Those Molex connectors aren’t very tight or robust 

[Rmfriday]

Well we got it working, had to unbolt the mag to get the sensor in.

Jetdriven, thanks for the advice, tried it but in the end it was easiest to just pull the mag.

 

[Rjfanjet]

So quick question. I have the Slick mags and am just finishing the install on my JPI. Does the sensor go where the solid "cap" is or the octagonal shaped plug.

Thanks, finally updating to the 2010's!

[0TreeLemur]

IIRC, it goes in the octagonal aluminum plug that has tiny holes in it.  Typically on the bottom of the left mag.  I had mine installed on the top of the right, and Maxwell moved it to the bottom of the left.  Sure there is a reason, but it worked on the right.

[Acreel264]

I have a JPI RPM Sensor that is essentially brand new. The part # is 420815-2 (Bendix Vent Plug) and list new on Spruce for ~$268. We had to replace our engine and the new engine came with Slick mags. If anyone has a need for it, I'll make you a great deal. 

[bradp]

Without having to totally remove the mag- loosen it.  Rotate upwards so you have access.  Install sensor.  Rotate back.  Do please replace your star washers with new ones.   

[jetdriven]

The GI275 install manual shows it's compatible with the JPI rpm sensor. But it's also compatible with the UMA rpm sender. Which is about half the cost.  They appear the same. 

[carusoam]

Great reminder Brad!

We haven’t discussed star washers in a while.

If anyone is unsure why… star washers don’T work a second time… always replace…

Best regards,

-a-