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LT1 opti-spark alternative ideas??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BigBad75K5, Feb 12, 2002.

  1. BigBad75K5

    BigBad75K5 1/2 ton status

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    I'm swaping an LT1 into my Jimmy. I just wanted to know if anyone has any info on alternative to using the opti-crap and useing a regular EFI dist. ?
    Thanks
     
  2. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    If you're keeping the computer for it, I think you have to stay with the opti. If not you can put a reg distributor in it.

    The lt4 crate motor from gm had an intake to do that. Cant remember the details.

    John

    <font color=blue>"When all else fails, read the instructions, or get a bigger hammer"</font color=blue>
     
  3. BurbinOR

    BurbinOR 3/4 ton status

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  4. mnstr_fx

    mnstr_fx Registered Member

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    If you are keeping the LT1 PCM then you need the Opti-crap. Only other feasable alternative is Electromotive Iginition, (DIS) system. Read $$$$$. If you are stuck using the Opti, I might suggest updating to the 95 and newer "vented" style. I just updated it on my 94' Z28. (oops, wrong board :))

    76-82 Chevy Pickup / Blazer - K5-K10-K30
    90' TBI
    TH 400
    203 / 205 Doubler
    Dana 60, Corp 14 - 4.88'd - Detroit Locked
     
  5. BurbinOR

    BurbinOR 3/4 ton status

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  6. Lonnie

    Lonnie 1/2 ton status

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    94 &amp; up cars are sequential injection.... 93 is batch fire &amp; speed density. The later opti (95 up) is pretty water resistant. The option would be to get an aftermarket computer (Speed Pro/FAST, Accell etc.) &amp; modify the factory intake (rather easy to do) to accept a magnetic pickup distributor. This way you still have computer timing control &amp; a dry distributor) The Electromotive uses a crank trigger, which is also succeptible to being damaged on the bottom of the engine by rocks etc.
    Lonnie

    <P ID="edit"><FONT class="small">Edited by Lonnie on 02/12/02 06:26 PM.</FONT></P>
     
  7. Twiz

    Twiz 1/2 ton status

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    Have you guys ever tried sealing the unit? - should work, maybe figure out how to vent it and it should be a sound unit.

    Worth a shot before ditching it and tring to figure out how to convert it.

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  8. blazer72

    blazer72 1/2 ton status

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    The only time that my Electromotive triger was damaged was when the March belt sytem craped out. With the GM belt system the triger in very protected.

    72 Blazer 400TPI NV4500 NP203/205, 6 bolt FF14
    01 Suburban 8100 2500 4X4
     
  9. BigBad75K5

    BigBad75K5 1/2 ton status

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    It does'nt mater about the fireing order of the injectors if you use a TPI computer, you just plug the TPI harness into the injectors. I had a complete write up found about this and lost it when my lap top crashed about a month ago. I can't seem to find it anywhere on the net again!!
    I'm still looking though, if anyone see's it please send me a link.
    I still don't trust the Opti-Crap in water crossings, with a normal dist u can just pull the cap off and wipe it out if you get it wet and it sets alittle higher up.
     
  10. mnstr_fx

    mnstr_fx Registered Member

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    You can change everything back to a TPI setup and either machine the LT1 intake or use a TPI intake. The big differences between the two engine is in the intakes and the reverse flow cooling. TPI's have much better low end torque than the LT1's. Conversely, the TPI's run out of air in the upper RPM's where as the LT1's are still going.

    NOTE: These are MAJOR generalizations based on STOCK engines. (I can start to feel the heat now)

    As for the Opti's and water. A general rule of thumb on an Opti is that if your water pump goes out, (leaks), better change them both. This applys for the earlier unvented and the vented ones. Believe me, moisture finds a way in there. Also, an unvented Opti will die early anyway due to the corrossive environment inside there. (air with 30-40-50,000 volts). Let alone if you give it a few good water crossings.

    If you are using the factory wiring / PCM setup, go with Electromotive and ditch the opti. The electromotive should be plenty high enough in the chassis and somewhat protected by the damper and crossmember. Otherwise, change over to a TPI setup and use a regular distributor.

    76-82 Chevy Pickup / Blazer - K5-K10-K30
    90' TBI
    TH 400
    203 / 205 Doubler
    Dana 60, Corp 14 - 4.88'd - Detroit Locked
     

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