any new ideas on ford conv. Tach transmitters ?

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any new ideas on ford conv. Tach transmitters ?

Postby jethro » Sun Jan 10, 2016 10:21 pm

I have been trying to think of how to do an alternate Tach transmitter scheme-
I keep thinking about mounting a small steel sprocket in the the front of the serpentine idler pulley.
I am thinking that since the surface of the belt is going the same linear speed everywhere - If I can determine the teeth per second that the harmonic balancer type gives- which should be the same teeth per inch of sprocket circumference-
I should be able to replicate that with any diameter of sprocket (might have to make a sprocket to get it just right)
Then I should have the pick-up where I can get at it better in stead of crammed in a tiny crack between the harmonic balancer and the radiator shroud. Anyone tried this ?
Anyone know how the sensor pulse frequency corresponds to read engine RPM ? I guess I could feed it square waves from a
pulse generator and tell that way. I assume it is a hall probe..... have to remember how those work internally to guess what
voltage and current it is looking for .......

Anyone tried to make a better mouse trap ?
Cant see paying 400$ for the "store-bought" rig to do this .........

Tim
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Re: any new ideas on ford conv. Tach transmitters ?

Postby ihredneck » Mon Jan 11, 2016 7:13 am

Can't say that I've ever messed with this stuff.

It'd be nice to have a cheaper option, as I know my neighbor who has destroked his 6.0 wasn't too excited about paying for the tach mechanism.
1992 W350 RCLB 5 Speed Locking 3.54s Flatbed completely stock it's whole life (for now) 117K on the clock (In the middle of a frame off restoration)
1992 W350 RCLB Rag Locking 4.10s Flatbed basket case - All the spare parts left from the other W350 & I still have a whole truck left...
1999 RCSB 1500 24v NV5600
2000 VW Jetta TDI
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Re: any new ideas on ford conv. Tach transmitters ?

Postby Gots_a_sol » Mon Jan 11, 2016 4:29 pm

I made my own tone wheel and the stock ford crank sensor.


Printed off a wheel with marks every 1 degree. The V10 uses a 40 tooth tone ring originally, so that works out to 9 degrees between teeth.

Image

Half of the teeth marked. I rotated the wheel 5 degrees and marked all the way around again after this.

Image

And cut out. They aren't all EXACTLY the same, but should be close enough. I hadn't cut off the minus one tooth yet.

Image

Bolted on

Image


It works great so far other than the occasional jumpiness as the air gap to the crank trigger is a little too big.
-Joe

00 Excursion - 12v/nv4500, he351cw, 5x12s, 366 spring, THD piston pump, 4" intake/exhaust
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Re: any new ideas on ford conv. Tach transmitters ?

Postby jethro » Tue Jan 12, 2016 8:26 pm

Be nice to chuck it up in a lathe and take a little cut off the outer edge of the teeth to uniform the dimensions. You could get your sensor nice and close that way.....

Does the missing tooth tell the computer where TDC is for advancing and retarding ? If so I would think I wouldn't need the missing tooth since the first gen cant vary its timing on the fly.

Nice job- I bet that took some patience to cut out so nice and uniform. Nice.

Tim
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Re: any new ideas on ford conv. Tach transmitters ?

Postby Gots_a_sol » Tue Jan 12, 2016 8:42 pm

I tried it without removing the -1 tooth and the tach didn't work at all. Cut it off and it immediately worked afterwards.

I spent a lot more time doing it than I would have liked, but it was much more cost effective than the aftermarket option. $20 worth of steel drops off ebay that were already perfectly round and the right diameter, just had to cut the notches and drill a bunch of holes (there is a stack of spacers behind the wheel to get the spacing right)
-Joe

00 Excursion - 12v/nv4500, he351cw, 5x12s, 366 spring, THD piston pump, 4" intake/exhaust
Gots_a_sol
fuel screw!!!!
 
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Joined: Fri May 28, 2010 11:45 pm
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