Z6 Mini-Me Swap
How to Swap a Z6 92-95 Civic Si/Ex SOHC VTEC Head onto your 88-91 CRX Si Block.

xtensive - Website

Here is what you need before starting your Z6 swap project:

    Z6 head from a 92-95 Civic Si/Ex
    Head gasket, intake gasket, and exaust gasket from 92-95 Civic Si/Ex
    Timing belt from 92-95 Civic Si/Ex
    Valve cover gasket for a 92-95 Civic Si/Ex
    RPM Activated switch, or Vtec controller (such as Fields, or APEXi)
    Adjustable Fuel Pressure Regulator, or FPR from 92-95 Civic Si/Ex
    Timing light
    Lots of VTEC Stickers, and Powered by Honda stickers

Recommended things to pick up (but not totally necessary):

    Change of oil/oil filter
    New Anti-freeze
    Impact Wrench (this could very well be a necessity!)
    New set of head-bolts
    New Spark-plugs, dist. cap, and rotor

Starting the saga:
Pull that baby in the Garage, and drain the oil, and coolant. The Coolant pet-cock is located at the bottom of the radiator on the passenger side. Disconnect the battery. Unbolt the Intake manifold, and pull it away from the head. There is a bracket that bolts to the underside of the throttle body, so if it ain't moving, that is why. Unbolt the exaust manifold. Unbolt the downpipe from the hanger under the engine, and this should alow enough play to pull the exaust manifold away from the head.


Pull the spark plug wires, noting where each one went. Take out the spark plugs. Unbolt the valve cover, and pull it off. Unbolt the Dist. from the head. Loosen the alternator bracket, and move the alternator up enough to get the fan belt loose. Do this with the AC compressor if your car is so equipt. You will need to loose the bolt facing the drivers side of fender, and then loosen the bolt on top of that bracket to get the AC compressor to loosen. If your lost, go get a friggin' helms manual.


Next, jack the car up, and take off the driver's side front wheel. There is a kick panel that you can remove inside the wheel well. Take if off. Unbolt the Timing belt cover (all the way down to the drive pulley. Line up the drive pulley to the timing mark on the timing belt cover. There should be 4 marks on the drive pulley. One all by itself, and a set of three to the left of that mark. Line it up to the middle mark in the set of three (18 BTDC). Slide off the alternator belt, and AC belt if so equipt.


Now comes the hard part...unbolt the drive pulley. This is very very hard to do. I would HIGHLY recommend a nice big strong impact wrench for this. You can ghetto rig anything you want, from a 6 foot pry bar to a 5 pound sledge, but from personal experience that baby ain't gonna come off without a nice impact wrench...besides, you've always wanted one of those anyways, right? Mine broke two Husky sockets, 1 Craftsmen socket, and a socket reducer to get the pulley off, so good luck. Now remove the timing belt cover. Loosen the Timing belt tensioner (The idler pulley the timing belt curves around...it has a 12mm bolt on it...), and loosen the timing belt enough to pull it off the cam, and then finally off the engine.


Unbolt the head in this sequence: . Remove the oil control jet from the block using a small pin or screwdriver. It should just pop off, and requires no screwing, etc. BE CAREFUL! Where's the oil control jet? Click here. If you fail to remove the oil control jet, the oil pressure in the head will be too high, as it already has it's own oil control jet, and VTEC will never actuate. Clean off the pistons, and scrap the head gasket remains off your block. Be careful with this, and don't use anything hard such as a putty knife, as it will leave scratches, and destoy the integrity of the headgasket seal. All clean and purty now? Good. Lets go to the install...

Installation:
Take your newly aquired VTEC head (make sure to have all the stickers handy!) and make sure it's clean. Now would be an excellent time to get a valve job done if this head came off a high mileage engine...that's your call. Basically reverse the order of disassembly. Using the new head gasket bolt the head on using your new head bolts (hint, hint) in the correct order. If you don't have a HELM's manual, e-mail me and I'll tell ya the order, but you ***REALLY*** should have a HELM's Manual by now... Torque them down to the correct LBS/SQ IN (HELM's anyone?). Turn the cam gear until the mark "top" is at the top. Slide the drive pulley back on to maker sure the middle timing mark is still lined up. Take the drive pulley back off.


Slide the new timing belt (you did get one didn't you???) over the timing gear, and work it around the water pump, and T-belt tensioner, and finally around the timing gear off the crankshaft. The belt is probably going to be TiiiTE, so it may require a bit of elbow grease, and some creative welding (just kidding). If the tensioner pulley is all the way loose, you should be able to get the belt on without *TOO* much effort. When the belt is on, tighten the tensioner pulley back up. The belt is gonna be TiiiiTE but I wouldn't worry too much about that. (Did I mention a disclaimer yet?)


Bolt the T-Belt cover back on, and then bolt the drive pulley back on using the impact wrench (you did have to get one didn't you? I knew it!) Slide the Alternator belt, and AC belt back on the drive pulley. Tighten them back up respectively. Bolt the Dist. back on. The A6 Dist. is NOT going to line up to the Z6 head, so you have several options here...either use the two side bolts with large washers to hold the assembly on, or do some creative metal fabrication to make it look better. This is entirely up to you. A suggestion would be to bolt it down with the same amount of room on either side of the bolts, incase you need to advance or retard yor timing a bit.


Bolt the intake manifold back on using the new intake gasket. Bolt the exaust manifold back on using the new exaust gasket. Re-bolt the down pipe hanger, and don't forget the intake manifold bracket that bolts to the underside of the throttle body. Bolt the valve cover back on, using the new valve cover gasket. Put in the new spark plugs, and re-connect the spark plug wires. Fill the car back up with oil, and coolant. re-connect the battery. You are now ready to see if she'll start...cross your fingers. Tripple check to make sure everything is back where it should be.

Hooking up the VTEC RPM switch:


If you opted for the VTEC controller like you should have then follow the instructions that came with it. If you're cheap like me and got the RPM switch, start saving your money for a VTEC controller, 'cause you'll probably end up buying one later...(I did).


I bought a Summit Racing RPM activating switch from Summit Racing for like $40, so I am assuming you did the same. If you got a different RPM switch then I'm not sure it this will be the same, but I can't imagine why not. Just letting ya know. The Summit RPM switch actually throws a ground signal when the desired RPM is met, so you will have to wire up a relay to change that negative graound to a +12 volts. Here is how to do it:


Go down to your local radio shack and pick up a standard auto relay. I believe they only carry one, so you can't go wrong. It'll cost ya about $5. Here is a schematic of how to wire it:



Now on a side note here, when you set the RPM with the dip switches, you must remember that Summit Racing tends to cater to 'Merican made auomobiles, and V8's are the SH*T, so they have also assumed that you too own an 'Merican made automobile with a big fuel sucking V8 under the hood, and have designed the RPM switch to work that way. Since you only have four lonely cylinders, you will need to divide the number you want the RPM to kick in at by 2.


    Example: you want it to kick in at 4400 RPM, then set it to 2200 RPM with the dip switches...get the idea?


Installing the FPR
If you went with the 92-95 Civic Si/Ex Fuel Pressure Regulator, then simply swap out your old FPR with the one you picked up. If you went with the adjustable one, then follow the directions it came with. The FPR is located on the drivers side of your fuel rail...Here's a pic...


Check out my site for a bunch more pics of what you can expect to encounter...and if you find any incorrect info here, please let me know!


Enjoy VTEC.

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