trigger wheel thoughts
Turbo Mini Forums

Just been laid in the bath enjoying my hang over, thinking about trigger wheel brackets and what a PITA they are.

My simplistic understanding (correct me if I'm wrong) is that you have a sensor that reads the gaps between the teeth and tells the ecu when it gets a big gap/missing tooth. The size of the teeth and the gaps is not that important, but they must be spaced precisely every 10 degrees ( in a 36-1 scenario), with the missing tooth passing the sensor 90 degrees BTC.

Then I thought about the injection verto flywheel, which has the 'teeth' machined into the back and the sensor hidden away in the transfer case. Something like this:



So... could I stick my CPS through the wok/transfer case and make the appropriate markings on the flywheel? Maybe drill and tap some holes and put some cap head bolts in or something along those lines.

The first negatives that sprung to mind where movement in the flywheel making the readings inaccurate and the gaps being too big.

Looking at my flywheel, I would need to put the 'teeth' on the face of the ring gear.




Thoughts please.

yep, your bang on,

also you should end up with a more accurate signal, because 1) the triger wheel is bigger and 2) you wont be measuring the whip in the crank.

dunno how your going to manage it though!

Easiest way would be a lasercut trigger plate bolted between the flywheel and the strap spacer. Modify the spacer whatever the trigger plate thickness is

Good idea!

smashing. Was just giving that some more thought. Shouldn't be too hard for my local talented machinist to spin me up a ring with the teeth machined into it and just bolt it on the outside of the wheel.

It increases the rotating mass, but in alu it shouldn't be too heavy...

http://www.jbperf.com/

lasercut would be cheaper..........
1mm mildsteel and bend the ends 'teeth' over at the ends. Weight wise, wouldn't be alot that you'll notice.

Edited by Jason G on 12th Mar, 2011.

Beet me to it Jason! good plan for fastening it.

EDIT: Thanks Jean. Steel it is

Edited by apbellamy on 12th Mar, 2011.

remember the ford ones are just pressed tin.

I have these moments of clarity

I think I'm going to dig out an old flywheel and ruin a transfer case tomorrow

actually I think the wok may be easier to get the sensor in, maybe in the timing hole at 12 o clock.

another use for the ring that holds down the diaphragm spring ,on a verto ring type ?

Edited by robert on 12th Mar, 2011.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

That's what I was thinking too, but I'd either need to get the sensor in it at an angle to the wok or have the teeth cut with an angled face so that they where close enough to each other. Poking through the side of the transfer case might be easier - depends on the length of the sensor.

Also need to be careful of the old pre engaged starters as the head bit needs to clear it. Fortunately I have a modified modern starter from Wil's friend.

Is the size of teeth important?

the tooth size isnt that critical, if it looks right it'll work

Now you got the ball rolling...why not tack weld a trigger wheel plate to the washer on the big bolt that holds the clutch assembly. It would then fit any clutch arrangement.............

Edited by Jason G on 12th Mar, 2011.

I'm going to have a play tomorrow. I feel some CAD coming on

Either way....its got to be cheaper than some of the flash trigger pullies. Only issue, is dust from the clutch going to cocking up the signal. Would this be a problem?

On 12th Mar, 2011 apbellamy said:
I'm going to have a play tomorrow. I feel some CAD coming on

Edited by Jason G on 12th Mar, 2011.

there are enough production cars running sensor in the flywheel housing, shoud be fine.

Create a dxf file using CAD...I'll knock one up in 1mm mildsteel for you.

Nice! Only issue is the size of teeth. Trying to bend them over on a curve will be abit of a mare.

On 12th Mar, 2011 Joe C said: