Inductive pickup to drive a tachometer.. - page 2 - FAQ/Tech Tips/Please Read First - VWDiesel.net The IDI, TDI, and mTDI source.

• #15 by maxfax on 28 Nov, 2011 21:15
• Quote from: Toby on 27 Nov, 2011 18:41

  I think I will try TIGing a couple of tabs to the inside circumference of the pulley where they should not interfere with the cover.
  

  
  I found that to work quite well.. I didn't even bother to try welding additional metal tabs to the pulley, just put a couple blobs of bubble gum on there, and ground them to look nice..
  
  Kevin, if you can;t get your current sensor mounted sturdy enough, next trip to the junk yards look for one of the trans speed sensors as used in late model Fords. They are a little less bulky (easy to be broken) than the one from the 4.0..   I used one from a 4R70w out of a late 90's F-150..  It worked well enough that all I needed to do was bolt a piece of angle to the back of the block with a hole for the sensor to slide though, and a small hole for a bolt to hold it..
  
   I have found that the signal isn't quite strong enough from some aftermarket tachs, mainly the cheapo ones, but may factory tach works fine with it..
• #16 by R.O.R-2.0 on 29 Nov, 2011 07:51
• well gentleman, and lady (if you are reading )
  
  i have a working tach drive system on my diesel..
  
  it idles @ 900
  
  it brings the needle off the 0 peg of the boost gauge @ 1500
  
  it makes full boost a little before 3000..
  
  .060-.070 air gap.. more is better, unless your pickup isnt strong enough to drive the tach.. i have a GOOD autometer tach, so i have no issues.. i really want to see if i can drive a stock VW gasser tach tho..
  
  bracket is made from 1/4" aluminum. its bolted to the block with 2 grade 8.8 bolts. it DOES NOT vibrate.. you can hold the engine at whatever speed you want, and the sensor doesnt even WIGGLE..
  
  this is another one of those builds that makes me want to bang my head on the wall.. ive had all these parts laying around, just not the knowledge to use al of them in a way that works..
  
  anyway, pics to come later.
  
  and NO, there were no issues with triangulation 
  
  and people can criticize my build all they want, im not going to change it for anyone.. i will actually welcome criticism, because i am VERY CONFIDENT in my build skills..
  
  i may have not done it the best way possible, big deal.. i made it functional, and transferable to another engine if need be. it IS ADJUSTABLE, and it is very easily removed to gain access to the main drive belt..
• #17 by ORCoaster on 29 Nov, 2011 13:08
• i may have not done it the best way possible, big deal.. i made it functional, and transferable to another engine if need be. it IS ADJUSTABLE, and it is very easily removed to gain access to the main drive belt..
  
  Gee what more can a guy (or gal if your reading this) want?  Cost is low, it is out of the way when needed service comes calling, it is above all functional and you can use it other places.  
  
  Can't wait for the pictures, I may be following suit here as my ride really could use the tach.  I just like em.
  
  
  
  Oh I had to come back and thank ya for sperminting for the rest of us.  Gasser tachs are a dime a doz but to find a diesel tach and not have the W terminal is like pulling hens teeth.
• #18 by R.O.R-2.0 on 29 Nov, 2011 13:18
• Quote from: ORCoaster on 29 Nov, 2011 13:08

  i may have not done it the best way possible, big deal.. i made it functional, and transferable to another engine if need be. it IS ADJUSTABLE, and it is very easily removed to gain access to the main drive belt..
  
  Gee what more can a guy (or gal if your reading this) want?  Cost is low, it is out of the way when needed service comes calling, it is above all functional and you can use it other places. 
  
  Can't wait for the pictures, I may be following suit here as my ride really could use the tach.  I just like em.
  

  
  im with you on this one. a tachometer is my favorite gauge hands down.
• #19 by maxfax on 29 Nov, 2011 13:41
• Quote from: R.O.R-2.0 on 29 Nov, 2011 07:51

  i really want to see if i can drive a stock VW gasser tach tho..
  

  
  It should.. The only thing I noticed is that the gasser tach seemed slow to respond to RPM increases.. Could have just been my tach too as it did eventually die alltogether...
• #20 by RabbitJockey on 30 Nov, 2011 04:31
• thumbs up this is cool, simple and cheap with out having to question accuracy at all.  i've done quite a few of the gas tach conversions for myself and other peope, and it works great, how ever i think this method is a bit easier assuming someone has the ability to make a mount for the sensor
• #21 by theman53 on 30 Nov, 2011 05:10
• Yes. This is nice I would love to do this, show me pictures so I can copy it. I may have to buy a gauge pod from that guy as I am out of room in my center consol.
• #22 by ORCoaster on 30 Nov, 2011 06:35
• In order for us to really do a good job copying this setup we would like AutoCad drawings please.  But a napkin and felt pen will work as well. 
• #23 by R.O.R-2.0 on 30 Nov, 2011 08:18
• Quote from: ORCoaster on 30 Nov, 2011 06:35

  In order for us to really do a good job copying this setup we would like AutoCad drawings please.  But a napkin and felt pen will work as well. 
  

  
  if you want auto-cad drawings form me, you may have a better chance of seeing god..
  
  im not gonna completely design this for you guys.. i dont want anyone to COPY my setup. i wanna see who can come up with a better setup in all actuality..
• #24 by R.O.R-2.0 on 30 Nov, 2011 10:54
• Also, i didnt use a crank angle sensor in the final build.. i used a cam position sensor off of a different ford engine..
  
  its a more low profile pickup, kinda looks like a wheel speed sensor.
  
  and you dont HAVE TO use the same pickup as me. or even one from a ford. any 2 wire magnetic pickup SHOULD work  as long as it can put out a strong enough signal..
  
  if you have a newer GM wheel speed sensor, dont use it, they dont work.. there really small, and fit nicely anywhere, but dont make enough juice to drive a tach..
  
  anyways, pics as promised.
  
  
• #25 by ORCoaster on 30 Nov, 2011 13:33
• The gautlet has been thrown, better this!  OK, let's see how good we can make it.  Over the next year or so we should have quite a few folks that can try their hand at this.  I for one am putting it on the things to do list.  Might end up as a major mod in the future.  like the governor mod. 
  
  Thanks so much for the work and I know you will be tweaking on this as time goes by.  It is just in our nature to do so.  That is why we are here in the first place, NO?
• #26 by theman53 on 30 Nov, 2011 16:53
• I see red marker...one of my favorite tools since I seemed to always break my crayons    
  I didn't realize that this was all that had to be done. The nuts are just steel and since they are welded off the steel pulley it only reads the nuts? Also, why 2? How does this work electrically speaking as I don't know this end of the spectrum well.
• #27 by R.O.R-2.0 on 30 Nov, 2011 17:06
• Quote from: theman53 on 30 Nov, 2011 16:53

  I see red marker...one of my favorite tools since I seemed to always break my crayons    
  I didn't realize that this was all that had to be done. The nuts are just steel and since they are welded off the steel pulley it only reads the nuts? Also, why 2? How does this work electrically speaking as I don't know this end of the spectrum well.
  

  
  the nuts simulate the 2 cylinders firing per revolution of the crank. remember, im trying to duplicate a gasser tach signal. and a gasser coil fires twice per revolution of the crank.
  
  the nuts are just a chunk of metal to excite the magnetic coil in the pickup. since its an inductive pickup, it carries its magnets inside it, and requires no external magnets to make a current..
  
  yes, i love sharpies, i have a bucket of them in my shop. most of them being red.. 
• #28 by 81 vw pu on 01 Dec, 2011 18:36
• Heres one I put on my caddy today, did'nt want to copy yours so heres a little different version.
  Sensor is 92 F-250 rear anti-lock. No welder needed for those without one. Works great even with a cheapo tach.
  
  
   
• #29 by R.O.R-2.0 on 02 Dec, 2011 05:58
• i used my smaller pulley specifically so you guys couldnt copy it to a TEE.. unless you figured out what pulley i was running, and that i had to make a spacer to run it also.. so, it CAN be copied, but you gotta go thru the same hassle i did  
  
  if you weld nuts on the outter lip of the pulley like i did, and you are running a stock diesel pulley set, then the nuts will hit the water pump pulley BAD.
  
  most diesels have the bigger pulley setup, i used a small crank pulley with a small water pump pulley.. (underdrive)
  
  i dont know if the pullies on my engine were stock to it (vanagon) or if they were rabbit pullies. i know the crank pulley on there now is off an OLD 1.5D... (like, really old.. the engine i got the small pulley from, originally had manual brakes, just to give you an idea)
  
  i like the setup tho. it takes alot of the guess work out of making the trigger wheel.. only problem i could see, is that the bolts holding the bracket together may vibrate out.. these engines have ONE HELL of a harmonic vibration @ 3k rpms..