Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Temp sending unit ?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Stroked72Blazer, Mar 27, 2003.

  1. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

    Joined:
    Nov 9, 2002
    Posts:
    352
    Likes Received:
    0
    Location:
    Little Rock, AR
    I am putting an engine with Vortec heads in my 72. The Vortec heads have a smaller hole for the temp sending unit. I want to use the factory guages. Has any one done this? Is there a late model sending unit that is calibrated the same as the 72 ?
     
  2. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

    Joined:
    Nov 9, 2002
    Posts:
    352
    Likes Received:
    0
    Location:
    Little Rock, AR
    I really don't want to use the intake hole. Please help.
     
  3. Blazer1970

    Blazer1970 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,600
    Likes Received:
    0
    Location:
    Old Mission, MI
    I looked for one with the same resistance, but with no luck. I think the one I got was for an '88 and up truck. If your parts store is any good, they will bring out the catalog which will show the resistance of the senders that they sell. You need a 3/8 NPT sender - original was 1/2 NPT. The original sender is 72 - 88 ohms at 220 degrees. The new style sender I got is 138 - 156 ohms at 220 degrees. The higher resistance sender will not move your gauge at all. I played around with a spare gauge cluster that I have, and I found that paralleling about 150 ohms across the sender (from the terminal where the sender wire hooks up to the gauge, to ground) will make it work right. You have to use at least 1 watt resistors, Radio Shack sells 10 watt wire wound resistors that will work good. I used a 100 ohm, and a 50 ohm in series. This made my guage read kind of high, so I need to play a little more, but at least the gauge is semi-usable once you learn where it is supposed to run (which is about all they ever were).
     
  4. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

    Joined:
    Nov 9, 2002
    Posts:
    352
    Likes Received:
    0
    Location:
    Little Rock, AR
    Is the factory sending unit mounted in the drivers or passenger side head?
     
  5. Blazer1970

    Blazer1970 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,600
    Likes Received:
    0
    Location:
    Old Mission, MI
    Drivers
     
  6. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

    Joined:
    Nov 9, 2002
    Posts:
    352
    Likes Received:
    0
    Location:
    Little Rock, AR
    Cool I must have the correct wire hooked up then.
     
  7. Blazer1970

    Blazer1970 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,600
    Likes Received:
    0
    Location:
    Old Mission, MI
    The dark green wire.
     
  8. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

    Joined:
    Nov 9, 2002
    Posts:
    352
    Likes Received:
    0
    Location:
    Little Rock, AR
    Are you talking about the one that comes through the firewall at the block or the one that comes through with the speedo cable.
     

Share This Page