Another pmag question

[lr172]

I wish it was that easy with the 6cyl engines. I’d rather pickup on the case than the crank….

I chose not to go that route on the 540. My research indicated that there is lots of vibration back there and it causes more issues for the mags than that seen on the 4 cyl variants. Didn't want to take the risk. I believe flywheel pickup (VR or hall effect) is the way to go. Almost all upside and MUCH easier than building a mag hole pickup device.

I don't think it is any harder to build one of the for the 6 cyl engines. The shaft is different, but not really any harder to make.

 

[akschu]

I chose not to go that route on the 540. My research indicated that there is lots of vibration back there and it causes more issues for the mags than that seen on the 4 cyl variants. Didn't want to take the risk. I believe flywheel pickup (VR or hall effect) is the way to go. Almost all upside and MUCH easier than building a mag hole pickup device.

I don't think it is any harder to build one of the for the 6 cyl engines. The shaft is different, but not really any harder to make.

It’s my understanding that the gearing isn’t 1:1 which is why the 6 cylinder pmag has a gear train in it. Gears + harmonics = very hard to make reliable.

 

[lr172]

It’s my understanding that the gearing isn’t 1:1 which is why the 6 cylinder pmag has a gear train in it. Gears + harmonics = very hard to make reliable.

Yes, 540 is 1.5:1 or 1:1.5 (forget at the moment), not 1:1. That can be covered in the megasquirt software (custom trigger wheel), but it is quite uncommon and doubt it is in the megajolt code.

Magnets in the flywheel are 1:1 and easy to deal with and take all the gearing and vibration issues out of the equation.

Pmag apparently chose to use gears to get it back to 1:1, so they could reuse their 4 cyl software. Lazy and poor engineering IMO; Should have modified the code to support the 1.5 speed and avoid another point of mech failure.

 

[bjdecker]

How state of the art is a new YIO-390? Why can’t an engine manufacturer create a reliable means of cam / crank position sensing?
Lightspeed
Electroair
Surefly
Pmag

All have to mechanically interface with the accessory case gears. So the market is trying to retrofit new tech on engines that don’t appear to have changed since the 70s…. A tougher environment to operate in

The Lightspeed have (for some time now +23 years) a sensor board that mounts to the front of the case which detects crank position via magnets that are pressed directly into the flywheel at predetermined positions (TDC and +37/42, etc). This was updated to a smaller pickup (sensor) also mounted to the front of the case, and a carrier ring for the magnets that's screwed into the flywheel.

Lightspeed also has the accy case mounted position sensor. (ed. Not recommended for all the reasons and demonstrated failure modes and general poor reliability)

 

[lr172]

The Lightspeed have (for some time now +23 years) a sensor board that mounts to the front of the case which detects crank position via magnets that are pressed directly into the flywheel at predetermined positions (TDC and +37/42, etc). This was updated to a smaller pickup (sensor) also mounted to the front of the case, and a carrier ring for the magnets that's screwed into the flywheel.

Lightspeed also has the accy case mounted position sensor. (ed. Not recommended for all the reasons and demonstrated failure modes and general poor reliability)

sorry, forgot to mention LS.