Can you convert a obd1 motor to obd2

Discussion in 'Engine Performance + Maintenance' started by HunterC, Nov 29, 2019.

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  1. HunterC

    HunterC Newbie

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    I have a 93 5.7 and a junk 96 obd2 5.7. I am wondering if I can switch the 93 motor to obd2 using the parts off of the the 96 motor.
     
  2. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Your OBD2 PCM is looking to adjust timing based on crank position sensor and not setting the distributor with a timing light as the TBI does. Plus the TBI is firing the throttle body injectors instead of the spyder set up or MPFI.
     
  3. b454rat

    b454rat I'm Awesome

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    The OBDII is the ECM not the motors. But you can make the 96 work in the 93 truck, but will need a tune. You can use the short block for the 97 truck, but not sure if the heads have any compatible intakes to work with the Vortecs fuel/intake.
     
  4. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    ??? Not sure what you are saying.
     
  5. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Maybe we need a little more clarification, are you wanting to take the short block of the 93 and use the top end parts of the 96 AND install it in a 96 truck OR take parts off a 96 and convert a 93 truck to OBD2?
     
  6. HunterC

    HunterC Newbie

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    Do you know if the Tbi blocks and the vortec blocks are the same
     
  7. HunterC

    HunterC Newbie

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    I’m wanting to convert a 93 truck to obd2
     
  8. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    FWIU the blocks should interchange but the internals are different - pistons, cams (roller vs flat tappet), timing chains etc. Not sure if you can use the same crank...

    Then you'll need the entire wiring harness and PCM from the 96, even the 16 pin ALDL connector (instead of the 12 pin) under the dash.
     
  9. Schurkey

    Schurkey I'm Awesome

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    I have a couple of Vortec 5.7L engines in the shop. The block casting number is "880" on them.

    I had a "service replacement" TBI Caprice crate engine in my TBI pickup. The block casting number is also "880".

    I suppose that not all Vortecs are "880" castings, just like not all TBI engines are "880" castings.

    The block casting can be identical between Vortec and TBI. Pistons may be different, camshaft may be different. Heads and intake are absolutely different. The Vortec block may or may not be drilled for an engine-driven fuel pump, and it may or may not be drilled for the pre-Vortec coolant bypass that the TBI water pump needs. I added additional threaded holes for the timing cover, the Vortec block has "missing' holes because the Vortec timing cover uses fewer fasteners. In other words, the block casting can be the same, but it may be machined differently from a TBI block.

    The fuel pump provisions don't mean anything on a TBI, 'cause you're not going to use an engine-driven pump anyway. The coolant bypass drillings DO matter, unless you plumb in some other method of bypassing coolant prior to the thermostat opening.

    The Caprice oil pan was the same as the Vortec pan, and the TBI K1500 pan, except for an added bung in the side of the Caprice pan for an oil-level sensor that had to be plugged.
     
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  10. HunterC

    HunterC Newbie

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    thanks for the info
     

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