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Tach Hookup: Simple, please help!

Discussion in 'The Garage' started by BowtieRed, Jul 19, 2003.

  1. BowtieRed

    BowtieRed 1/2 ton status Author

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    Two questions:
    I have a tach I got from a friend, and just wanted to know how to hook it up, I think it will fit in the empty spot below my oil pressure gauge. That's not what I'm asking though, I just want to know where the wires go. It has red, black, green, white and two little posts that look like ground posts on a starter motor. Any help?

    #2: What's the max recommended RPM for a GM Goodwrench 350 260hp/350ft/lbs?

    Thanks,
    Henry
     
  2. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    White= Ignition Hot 12v
    Red= Dimmer switch (so you can dim the tach light with your gauges)- (Cluster feed on my fusebox)
    Green= Neg. - side of coil or Tach terminal on HEI.
    Black= Ground.

    /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif
     
  3. BowtieRed

    BowtieRed 1/2 ton status Author

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    thankya!

    could i take the white straight to the battery? or does it need to be the red wire in my ignition (hot 12v) both would be easy as i have a push button start and you need no key to turn truck on. . . but you need a key to get it out of gear /forums/images/graemlins/grin.gif
     
  4. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Sure thing! /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif

    ...And I have no idea, but my dads GM crate engine only goes to about 5K...
    Ive heard people say thats because of the factory cam that comes in the crate engines... with a cam swap you can get some more rpms outta them.
     
  5. BowtieRed

    BowtieRed 1/2 ton status Author

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    any help on question #2?
    thanks a lot

    oops, i missed the second one.
     
  6. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I ran the white to a terminal on my fuse box that is hot when the key is on, like whats powering the stereo or heater.
    ... You wounldn't want to run that straight to the battery, because it would then be hot all the time... not just when the key is on...
    /forums/images/graemlins/grin.gif
     
  7. BowtieRed

    BowtieRed 1/2 ton status Author

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    alright, not related, but does the crate engine block need retor fit roller lifters if a roller camshaft is installed? or since it is new can regular roller lifters work? i just though about this when i noticed the engine has a hydraulic cam while lookin for max RPM. it has to be over 5k- it makes max power at 5k.
     
  8. BowtieRed

    BowtieRed 1/2 ton status Author

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    oooooooooooook. . .. now. . .say. . . umm, where exactly on the distributor does the green wire go- i found the thing that says "TACH BAT" i'm guessing somewhere around there?
     
  9. Confedneck

    Confedneck 3/4 ton status

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    if its not hei it doesnt go to the distributor, if it is HEI it goes to where it says "TACH" on the distributor, where it says "batt" there should be a white(mine is) plug plugged in, and you need a spade connector on the end of the green wire, and stick it up under "tach"...someone really should do a tech write up on tach install, ive seen at least 4 threads about it recently...
     
  10. SF87K5

    SF87K5 1/2 ton status

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    It plugs in were it says tach.
     
  11. fortcollinsram

    fortcollinsram 1/2 ton status

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    [ QUOTE ]
    alright, not related, but does the crate engine block need retor fit roller lifters if a roller camshaft is installed? or since it is new can regular roller lifters work? i just though about this when i noticed the engine has a hydraulic cam while lookin for max RPM. it has to be over 5k- it makes max power at 5k.


    [/ QUOTE ]


    well it depends...is it a roller-ready block or not? In 1987, they started using "roller block", even through most of these blocks didn't get roller cams until much later (unless it was in a car) Have you had the intake off the block? the roller-ready block have the lifter bosses machined flat and there are 3 "nubs" that are equally spaced that that line the center of the lifter valley...The machined surface on the lifter bosses is where the guide plate goes and the nubs in the lifter vally are where the "spider" guide-plate retainer bolts in...In my 87 350, the lifter bosses were machined flat and it has the nubs, but the nubs were not yet drilled and tapped to accept bolts for the guideplate retainer...
    /forums/images/graemlins/eek.gif


    Does you engine have a 1-piece rear main or a 2-piece? I don't know for sure, but I taht may give you an idea if it has a roller ready block /forums/images/graemlins/smirk.gif

    Or pull a casting number and thrw it up for one of the guys to let you know the vintage of the block...

    If you have a factory roller-ready block , I would go that way as you don't have the vertical linkage bar between roller...I have just noticed that the vert. link on the retro rollers wear over time (as should be expected) and can cause some lifter slop...

    Chris
     
  12. BowtieRed

    BowtieRed 1/2 ton status Author

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    [​IMG]
    [​IMG]
    [​IMG]

    tell me now. . . i can't find nothin. . . /forums/images/graemlins/laugh.gif
     
  13. BowtieRed

    BowtieRed 1/2 ton status Author

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  14. fortcollinsram

    fortcollinsram 1/2 ton status

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    the heavier AWG wire should be the hot 12V+...What color are the other 3 ?
     
  15. Confedneck

    Confedneck 3/4 ton status

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    the green wire is going to go on that corner between the 2 connectors that go in, where it's labeled "tach"
     
  16. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    You're getting warmer....

    Not the best picture, but this should show you where.
    My tach wire is the yellow one, to the left of the fat Red + wire.
    [​IMG]
    If you crimp on a female spade connector you should be able to find where it hooks up next to the red wire going to BAT on the dist.
     
  17. santana

    santana 1/2 ton status

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    [ QUOTE ]
    White= Ignition Hot 12v
    Red= Dimmer switch (so you can dim the tach light with your gauges)- (Cluster feed on my fusebox)
    Green= Neg. - side of coil or Tach terminal on HEI.
    Black= Ground.

    /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif

    [/ QUOTE ]




    I'm sorry, Imay be wrong here but I did mine on Fri. Its a Sunpro type but its the same wire colors and they went like this:

    Red= 12v fused constant+
    Black=Chassis ground-
    White=lighting circuit/dimmer
    Green=Tach terminal on dist.

    I dont know if its different for different tachs. /forums/images/graemlins/thumb.gif
     
  18. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    My tach was the same...white was for the back lighting and was patched into the panel light circuit so if you dimmed the panel the tach would dim as well. Red was keyed hot, black was ground, and green went to the 'tach' terminal on the HEI.

    Rene
     
  19. 79Jimmy

    79Jimmy 1/2 ton status

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    That's how my Auto Meter is wired as well. /forums/images/graemlins/thumb.gif
     
  20. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Maybe i shoulda put a disclaimer that i might have the red and white backwards.. /forums/images/graemlins/grin.gif
     

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