18rc to 2Xr swap on 1974 Chinook questions

Discussion in 'Pre-1975 Build-Up/Project Threads' started by northoak, Jan 30, 2023.

  1. northoak

    northoak Member

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    Hey y'all, the 18rc on my Chinook is real tired. It runs but I'm not really confident taking it on trips with the current motor. It has tons of blow by and compression was around 120 on all cylinders last time I checked. A good friend has a lift, engine hoist, experience etc and is down to hang out and swap in a 20 or 22r with me.

    I'm trying to figure out what all I need to throw a 20 or 22r in there. I can live with the 4 speed since I'm not really trying to blast in this little rv.

    I've seen some posts say you can just bolt a 22r right in, I've seen others that say you need the motor mounts from a 75 that had a 20r in it.

    My understanding is that the frame rails are slightly thinner on these pre 75 trucks. When did it switch over? I'm wonder if 75 is the only year I can use mounts from or if mounts from a 75-78 would work.

    I'm trying to get together all the parts before hand so we don't pull my motor and then have a dead rv sitting in his garage for months. Any tips are appreciated!
     
    Last edited: Feb 1, 2023
  2. jetas

    jetas Grand Toyotaholic

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    Mine had a 20R swapped in when i got it(has a 22R block now), still not sure what it came out of but i can only assume it was from truck. The oil pan needs to be a mid-sump pan otherwise it will come in contact with the crossmember or steering linkage.

    The motor mount brackets i assume were from the donor vehicle, the rubber mounts i used generic 20R/22R mounts.

    the frames were allegedly narrower on the pre-75 trucks but the 20x engines fit just fine assuming you have the correct mount brackets.

    if you dont have emissions testing where you live then wiring and plumbing is EXTREMELY simple
     
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  3. northoak

    northoak Member

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    Thank you for the info. Luckily I don't need to smog this thing here in California since it is pre 1975. I saw from your profile that your truck is a late 1972 with a 22r? Sounds like I do in fact need to track down motor mount brackets from a70s truck with a 20r.

    I am confused about one thing. if the frames got thicker in 75 and folks report successfully using mounts from a 75 wouldn't that mean newer reproductions meant for a 79-83 could work?

    Also great info about the oil pan running into the og steering setup!
     
  4. jetas

    jetas Grand Toyotaholic

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    I'll tell you this much, the motor mount brackets for a 83 didnt work for me. I still have them sitting in a corner of the garage. I honestly have no clue what the parts i have came out of, i only reused them because they were a confirmed fit.

    Hell for all I know the brackets are the stocks for the 18R.

    i can say this about the wider frame rails, its not by a lot because the control arms are identical from what i saw, i had a complete subframe from a 75+ that i got the brakes from. One thing that was a different width was the sway bar
     
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  5. northoak

    northoak Member

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    Can anyone confirm if the 75 thru 78 frames all use the same width rails/motor mounts?

    When researching I've only read about direct bolt in swaps using mounts from a 75 but I'm thinking they should be the same mounts thru 78?
     
    Last edited: Feb 1, 2023
  6. jetas

    jetas Grand Toyotaholic

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    20R was the only engine available in the 75-78 models in the US i believe
     
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  7. northoak

    northoak Member

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    bumping for confirmation. There is a 76 at the pick n pull 45min away. It is probably picked clean but I was going to check out to see if it has the mounts left. Any idea if the 76 frame would be the same width and mounts as a 75?

    I'm assuming 75 to 78 should all be the same and thus motor mounts from any would work for putting a 22r in my 18rc 74.
     
  8. northoak

    northoak Member

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  9. jetas

    jetas Grand Toyotaholic

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    The rubber portion isnt your issue, its the actually metal brackets bolted to the block. There are a few different variations
     

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