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  • Non 3rd gen (DOHC)engine into 3rd gen (SOHC) car

    Just finished up swapping a 01 block/98 head into an 02 SL1 and I figure since there are only 3 years worth of engines that are a direct drop in fit I would document my findings.

    Applies to manual trans only, could almost certainly be made to work with an auto trans.
    01 block
    98 DOHC head
    01 SL2 manual PCM (although any 00-02 DOHC manual PCM should work) this shouldn't be necessary if you're doing DOHC/DOHC
    98 Intake Manifold, fuel rail and injectors
    92 OEM 4-2-1 exhaust manifold (any 5 bolt should be just fine, I was at the JY looking for one and happened to find one of these for the same price so I used it)
    02 SOHC Throttle body (DOHC would probably work if you had the bolts for the 98 intake manifold, I base this on the 02 SOHC TB also having 4 bolts on it and the IAC/TPS part #s being the same) (update 6/2/2017 as I'm doing another one of these - stick with the SOHC TB if the car was a DOHC with vertical manifold before as the throttle cable lengths are slightly different)

    Remove original engine (I remove engine/trans as one) and AIR system
    Install 3rd gen knock sensor
    Remove the 3rd gen injector clips and wire in the older bosch style from your 98 fuel rail, the colors match up nearly perfectly so this should be rather easy... especially with the engine already out of the way) *I could never get 100% confirmation that the 02 injectors wouldn't fit the 98 rail but they didn't look like they fit in far enough so I didn't want to take any chances plus BOSCH pigtails give you more options
    Swap clip off the back of the block where the vacuum line from the TB goes to on the 3rd gen engine
    Reuse 3rd gen flywheel/clutch or change the hydraulics to the earlier design
    If SOHC/DOHC swap get DOHC AC brackets as they are different
    If SOHC/DOHC get new plugs/wires

    Do PCM relearn sequence for your DOHC computer and you should be good to go

    Other observations:
    The air system won't work with the older 5 bolt head.. but I'm not throwing a code for it on this car..
    This may apply to the DOHC to DOHC as well as SOHC to SOHC as long as fuel lines will plug in.

    Comments 2 Comments
    1. paintballmaniac's Avatar
      paintballmaniac -
      What is the PCM relearn procedure when swapping from a SOHC to a DOHC 3rd gen ECU?
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