DOHC ZC swap into 1988-19991 RT4wd

I have searched and have found a lot of info on this swap, but id really like to hear it from members on here that have *actually* done the swap themselves. I know it will fit, i know you use the RT trans and all that, but i do want to clarify some things.

I have a 1989 RT that is in need of a new engine. Instead of trying to fuss with the mini me in there now, and rebuild, im planning on just getting a hmotorsonline ZC swap and calling it a day. Looking to replace the water pump, tensioner and belt, seals/gaskets, and replace with aFidanza flywheel and Exedy stage 1 clutch. Then just drop it in.

Few questions just to clarify and so that others can also see this as a source for actual answers.

Im panning on getting the 88-92 OBD0 swap...

Exhaust manifold. Must i use my RT one or will the ZC one work? Also heard that an OBX 4-1 header will work without modification, but have yet to confirm or find otherwise (chime in if you know!)

Oilpan. I know the A6 one for the RT's in the states is specific to make way for the transfercase. I have also heard that the ZC one will clear. Id love to run the 4-1 header and not mess with the oilpan, but again, i havent found anything to confirm this..

Mounts. I have just picked up a set of D-series Innovative mounts for the RT, and id assume they will work. Need to clarify this though!

Axles and halfshafts. Id assume i can use the ones that are currently in the car, but havent a clue...

Clutch and transmission. Being that the trans is an 89, i should be able to use the same flywheel and clutch as the regular RT takes, but again i have yet to find anything to confirm...

Other than that, i guess the dizzy plug needs to be repinned but that's it. Is there anything else i should know? It should just plug n play from there?!?!

Not planning on doing this right now, but within the next two months....

Cheers guys, i appreciate it!
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Comments

  • CharbCharb Administrator
    Been quite some time since I did mine... but there wasn't jack for info at the time. I'll do my best to fill in the blanks that I can remember....

    exhaust mani- reuse the RT. Supposedly the ports are off just a little. And I'm sure you could port them to match. But I never did. And don't remember hearing anyone doing it. ALL aftermarket mani's require modification.

    oilpan- reuse the RT A6 or use your ZC if it's in good shape. I personally (among others) reused the ZC. It cleared just fine for me reusing the RT e-mani
    /\/\edit/\/\--- make sure you use matching oil pickups! And, RT A6 and other A6 are NOT the same!

    mounts- RT mounts are different. But can't remember specifics. I personally just reused my stock mounts. But there are aftermarket RT mounts out there... I just can't remember the difference

    axels/halfshafts- just reuse.

    clutch and tranny- buy for the year of the tranny. The throwout bearing is the only difference in RT/fwd when buying a kit

    dizzy- will need to be repinned. But not a big deal. I used http://www.thezcr.com when getting my wiring info. Not sure where to find it now. It's been like 7/8 years since I did mine.

    I'm secretly planning to do this swap again. Provided I can find a goddamn RT... hopefully I'll do a full/detailed write-up.

    If you have any more questions, keep em coming. Hopefully this will refresh my memory some more lol
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    Charb, you're a boss!


    Thanks man.

    Anyone else with any moarrr info to add?!
  • woodiwoodi Wagonist
    ZC Oil Pan and RT D16A6 oilpan are identical. I just rebuilt my ZC and used my A6 oil pan because it was in better shape.

    Exhaust problems are the same as with any other RT4WD. Use the stock manifold or get one modified to fit. If I remember correctly though the SOHC ZC manifold is a better design and will fit and clear the transfer case but good luck finding one. I used my new exhaust gasket to trace out the ZC Ports and port matched my manifold with a die grinder. I'm using an aftermarket 4-2-1 modified to clear the transfer case now and the ports on that were oversized so no grinding was necessary.

    axles, mounts, flywheel, everything bolts right up. As charb said just order a clutch kit for your year RT4wd and you'll be good to go

    My dizzy plugs were a different type one was square one round so I had to swap plug bodies in addition to moving wires. It's quite easy though just pop the pins out and push them into the correct body. Match color to color it's easy. You also have to pull two wires out and extend them to the CPS on the exhaust camshaft.

    There is also one plug on the D16A6 harness that is not used. I think it goes into the intake manifold but I can't remember what it is at the moment.

    Trying to think what else you need. Radiator hoses are different than the A6. Check thezcr.com for that info.

    Swapping into the RT and the other civics really isn't much different so read up on thezcr.com for anything we may have forgot to mention.
  • HaydzHaydz Moderator
    Because you are keeping the transmission the same then anything relating to the transmission needs to stay RT specific, which is why the trans mounts, axles, cups etc. all work - because they were designed to. You're not shifting the position or mounting of this at all.

    The power steering pump is DOHC ZC specific, and I used the top half of the DOHC ZC manifold and the bottom half of the SOHC ZC manifold (the lower collector 'collects' earlier to clear the transfer case).

    viewtopic.php?f=7&t=10

    Have a read of my original post. Take note of the date though...
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    so i think im set. just put in an order for all new exterior gaskets, timing belt, pump and so on (use the CRX SI tensioner, i suppose?!), and other bits to install before i drop it in. now here's the question: anywhere else to get a longblock?

    hmotors has one in stock, and steve is awesome, but if anyone else knows of a good distributor, lemme know.

    ZC+ Jakers CF driveshaft+GC/Illuminas= fulltime4wd fun prospect!


    thanks for everyones reply! i really appreciate it!
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    Ohhhh yeah, also, anyone know for a fact that the OBX 4-1 header will clear?

    found this one, but unsure if it's the right one....


    http://www.ebay.com/itm/88-00-92-95-Hon ... 2020wt_931


    again, cheerss!
  • CharbCharb Administrator
    I've used Foreign Engines up here in Couer D' Alene, Idaho a couple of times. Not sure if they ship or not. But that's where I got mine back in the day. And where I'll likely get my new motor when the time comes.

    Worth checking out at least. I think the DOHC ZC's were $800 last time I checked...
  • CharbCharb Administrator
    FakeJDMEF8 wrote:
    Ohhhh yeah, also, anyone know for a fact that the OBX 4-1 header will clear?

    found this one, but unsure if it's the right one....


    http://www.ebay.com/itm/88-00-92-95-Hon ... 2020wt_931


    again, cheerss!


    Who ever said it would?

    I know that's not what I said.
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    I'll find the posts, but a member (from years ago) on here and another build on some French forum, said it would....


    I know you didn't say it would!
  • CharbCharb Administrator
    FakeJDMEF8 wrote:
    I'll find the posts, but a member (from years ago) on here and another build on some French forum, said it would....


    I know you didn't say it would!


    So you don't believe me? :(

    Only $100... I say buy it, and let us know how much hacking it will take...
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    I believe everythinggg you say:)

    and yeah, for $100, i may as well.... keep you posted!
  • Modifying my 4-2-1 to fit my DOHC ZC in my RT wasn't all that bad. I went a bit further with mine and I can't see the 4-1 requiring as much modification.

    489.jpg
  • CharbCharb Administrator
    We're gonna go ahead and make this the official DOHC ZC RT thread...

    I'm contemplating doing this swap again. And it's been many years since I did it last. I'm going to do my best to help compile useful information for myself and others.

    I stole these from thezcr.com
  • FakeJDMEF8FakeJDMEF8 Senior Wagonist
    Charb, you're the man!

    I picked up a JG rebuilt ZC head, bisimoto IM gasket, OEM pump, belt and tensioner, and Exedy stg 1 clutch and fidanza fly. Now just need a complete block and I'm set!

    Picked up a 4-2-1 eBay header and will update on fitment
  • DRMORTYDRMORTY Council Member
    O.k.

    I am thinking of this swap too.. I would be putting it into my 91 RT4WD Automatic ( Cause, Dailies should be AUTO )

    I have the chance to get a ZC that was Re-built & built, has everything, just needs a car..

    Few questions?

    1. What ECU to use?
    2. Will a JRSC Fit?
    3. RT Auto Trans Mounting? Anyone ever tried?

    1. Looks like I will have to change the Dizzy Plug
    2. Keep either Oil pan
    3. Keep RT exhaust mani
    4. RT Axles

    Am I missing anything????

    I will then call her the JRSC-ZC-RT4WD-Auto or SCZCRTAT for short ;)
  • slo88crxslo88crx Senior Wagonist
    DRMORTY wrote:
    O.k.

    I am thinking of this swap too.. I would be putting it into my 91 RT4WD Automatic ( Cause, Dailies should be AUTO )

    I have the chance to get a ZC that was Re-built & built, has everything, just needs a car..

    Few questions?

    1. What ECU to use? You can use your stock ECU or a 89 teg one will work! Unless you want obd1 That's a different story
    2. Will a JRSC Fit? It will if you can find a jrsc for dohc zc (diff mani bolt patter then a sohc) They made adapter plates a while ago but haven't seen any in a long time.
    3. RT Auto Trans Mounting? Anyone ever tried? Im sure it would mount the same as all sohc

    1. Looks like I will have to change the Dizzy Plug
    2. Keep either Oil pan
    3. Keep RT exhaust mani
    4. RT Axles

    Am I missing anything????
    Cant think of anything but if you have any ?? don't be scared to ask!

    I will then call her the JRSC-ZC-RT4WD-Auto or SCZCRTAT ( say that tens times fast! Suonds russian lol)for short ;)
  • CharbCharb Administrator
    I ran an A1 ECU in mine the first time. Hopefully find a stock JDM one next time.

    One thing I remember doing, which is easy, was swapping the boards in the ECU. Reason being- the mounts. My wagon's stock A6 ECU had different mounts than the A1 I purchased to use. So I just took them apart and swapped the boards. Very straight forward. Much cleaner install having it mounted in it's stock form.... just something else to tackle :)
  • woodiwoodi Wagonist
    Before I got my chipped ECU I was running a PG7 out of a teg and as charb says the mounts definitely aren't the same. The teg mounts are on the sides of the ECU and the Civic are top and bottom. I just stuffed it in the same location and tightened the bolts down through the civic cover plate. It wasn't perfect but still seemed to hold it tightly under the carpet without rattling around and got the job done. The PG7 ecu light is also in a different location so I had to pull the cover off if I needed to read ECU codes. I've got the PG7 sitting in a pile of stuff I've been meaning to sell if anyone wants it.
  • Why would you want a JDM ecu when you can get an EDM ECU :mrgreen: Can get them ALL day long here :wink:

    Just in case anybody needs to know, if you run a DOHC ZC, the adapter plate, and a JRSC, the belt will hit the frame. You will also need a custom belt as the one I was provided was too short. I ended up using a custom 6 rib belt and carefully cutting it in two. Also the JRSC crank pulley is a three rib, three belt pulley where the stock wagon crank pulley is a two three rib and one v-belt pulley. So my power steering pump currently has no belt as it is v-belt and not a ribbed pulley. Trying to figure out if I can get a pulley to interchange to work and give me power steering.

    Here is the notch I put in the frame:
    307.jpg

    Some pics of the DOHC ZC with the supercharger attached:
    936.jpg
    111.jpg

    Adapter has been said to be discontinued as well. Here is the picture of the one I have:
    65.jpg

    Other than the couple of problems I posted above it went in super smooth and both of the problems I encountered were both due to the JRSC and not the DOHC ZC itself.
  • DRMORTYDRMORTY Council Member
    Good stuff to know... I am gonna go work the deal on the zc...
  • HaydzHaydz Moderator
    Trust me when I say you want the PM7 over the PM6 ECU. I have no personal experience with the PG7 so cannot comment on that one.
  • if i am not mistaken the dohc zc uses a Bseries intake . cause i had a jdm Dohc Zc in my 95 Civic Vi-Rs..and i swapped out the intake with one from a 97 ctr B16
  • Does anyone have pictures of the power steering pump and brackets? Maybe AC?

    Going to do a zc swap in the upcoming months and would like to keep ps and rehook up my ac since I will have more power when I turn on the ac
  • A/C I never had so that I can't help with, however I used the stock D16A6 pump bracket and modified it to work. I don't have pics of it right now as the wagon is in storage but once you get the ZC you will see what you need to cut off the A6 bracket to make it work.
  • DRMORTYDRMORTY Council Member
    Just got a Full JDM DOHC ZC Swap.
    With A/C & PS.. Because you gotta have it in FL or your stupid.
    Selling off the tranny stuff. Gonna be doing my ZCJRSCRT4WD w/Automatic Trans!
    Talking to ZC Speed Guy today about getting adapter for my JRSC... Can't wait!

    Gonna try to pull the old A6 this week..

    Excited!
  • I'm going to put a zif socket in my PM6 since I have an external eprom ecu and the I'm going to use a slightly modified PM7 map from a guy off d-series.org supposedly works very good. And I won't have to mess with and obd1 conversion
  • Quick question I just bought a Zc and want to replace water pump and timing belt does D16a1 work
  • d16a6 water pump and 88-91 prelude timing belt
  • For all your parts inquiries for those who don't want to search. :mrgreen:

    http://www.d-series.org/forums/dohc-zc/ ... -list.html
  • imdbuiimdbui New Wagonist
    ragenasian wrote:
    A/C I never had so that I can't help with, however I used the stock D16A6 pump bracket and modified it to work. I don't have pics of it right now as the wagon is in storage but once you get the ZC you will see what you need to cut off the A6 bracket to make it work.

    Anymore details on the PS bracket mod you made? Im holding the bracket and looking at my DOHC ZC and can't picture what I'd need to cut to make it work. Thanks!
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