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4bt Tach / Rpm reference or crank sensor

40K views 47 replies 12 participants last post by  fitty 
#1 ·
Anybody have any CHEAP ideas to get an rpm/tach reference for tach and stand alone trans controller? I was thinking crank trigger wheel..cut with a water jet (or bought on ebay) and magnet sensor from MSD.. any ideas? Alternator signal? Anything I'm overlooking? I saw that there is an available crank sensor for 4bt's for marine apps but can't find any part numbers! Chris
 
#40 · (Edited)
if you try SAA 85920008 (saa-separated) it looks like a Freightliner number. On the web I can only find Russian sites selling it? I'll have to check it out. Any pics? Does it have a steel body or plastic? What does your setup look like?

LincTex: You have any pics of yours? No such luck of a whole on the Chevy Bell. Is your sensor perpendicular to the flywheel teeth? Also, my worry was that the Dakota Digital translator box wouldn't put the correct square wave DC signals the TCI trans controller is looking for.
 
#41 · (Edited)
1) LincTex: You have any pics of yours?
2) No such luck of a whole on the Chevy Bell.
3) Is your sensor perpendicular to the flywheel teeth?
4) Also, my worry was that the Dakota Digital translator box wouldn't put the correct square wave DC signals the TCI trans controller is looking for.
1) Don't have a camera handy right now but it looks just like this:

2) The Ford small block adapter has the correct 3/4" - 16 hole about 6 inches above the starter on the pass side
3) Yes
4) Maybe Dakota Digital could answer that
 
#45 ·
more in the same vein as the mopar igniton idea, i needed an extra sensor a while ago for an add on odometer. the pos car's speed sensor wasn't compatible. ( most are. ) i ended up using an aftermarket cruise control pickup. these put out a sine wave. they come with 2 magnets. if you mounted the magnet 180 deg. from each other and hooked them up to a mopar ignition module using the ceramic resistor instead of the coil. it would have to work. either that or hook it up to a gm efi module that was made to convert from sine to square for efi. ( not sure what got this setup in the states. i have seen some accel ones, so they must be reasonably common. ) something to think about anyway.
 
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