3.2 flywheel - timing ring

[jpnovak]

A 3.2 Motronic flywheel has 130 teeth and a single pin "reference" for TDC. I am considering to interface my EFI setup with a stock flywheel. I do not like the look of a VR sensor mounted by the crank pulley.

How much will the balance be changed by removing one tooth from the 130 tooth total count? I could also remove the reference sensor pin. Do I need to shave the pins opposite of the ones I remove to counter balance the mass loss.

Using the density of steel and an approximate dimension I think a single tooth will weigh in the neighborhood of 0.3- 0.4g. I assumed 1x10x4mm and 7.85 g/cm^3. If you consider that a flywheel weighs more than 10 pounds this means that the missing tooth affects the overall mass <0.008%

I do not see any problems removing a tooth. What do you naysayers say?

[KTL]

It seemss no different than a munged-up starter ring on a dopey person's car who on more than one occasion has accidentally started the car when it's already running? Probably not a big deal. But from a balance standpoint, it wouldn't be hard to rebalance if you ditch a tooth and the sensor's grub screw pin. A properly placed machining spot, like you see on brake rotors or the clutch housing would balance it easily. A machine shop could knock this out for you no problem.

Remember that there are two different 3.2 flywheels. Which one are you using?

[jpnovak]

Kevin, Thanks for the reply. This would be a 915 flywheel. I do not have one yet. Purely academic thoughts at this point.

[racing97]

I believe the tooth count on the Motronic trigger ring is already 129 if it makes a difference to the arrangement you need on your EFI

regards