2nd Gen CRX Motor Swapping 101
A primer for anyone who is thinking about going hybrid.


Before you do an engine swap, it will pay to do your research. Things like power output, availability, cost, and complexity should be considered. Another big one is buying an engine from a legitimate seller. Check the VIN against your states DMV to verify itís not stolen, if possible. Buying an engine thatís stolen may be a good deal dollar wise but if the police get wind, your motor can be confiscated, even if you didnít know. Plus somebodyís car got stripped for that engine and I hate to see people support criminal activity by purchasing ripped off goods. There is such a thing as karmaÖ

There are many shops that sell imported Japanese domestic motors (JDM). They almost all universally say less than 40k. But you have no way of telling. They quote 40k because Japanese cars get a lot less miles because (a) being on an island (b) cars are more expensive to operate and the public transportation system is used more and(c) something about insurance and taxes getting higher on older cars. So a perfectly good car gets disassembled for scrap because no one wants to pay higher premiums. Consider these engines can be 10+ years old and you have no way to verify mileage, caution is best exercised.

On any older engine, it would be wise to do some preventative maintenance, considering you have no idea what its history is.

    1. Timing belt, water pump and possibly tensioner.
    2. New seals. ALL new seals. Main seals, cam seals, valve cover gasket, spark plug grommets, etc. You can replace them now while itís easy or wait to spring a leak because the 10 year old rubber deteriorated.
    3. Engine mounts if youíre smart. Often, people put heavier engines in and using the mounts that have been in there and worn out will make for headaches later. The engine will sag, or move too much when the throttle is mashed
    4. Check any hoses that came on the engine carefully, if possible replace.
    5. Do the equivalent of a good tune up. Spark plugs, oil filter/oil, valve adjustment etc.

Okay, now which engine do you choose? Well, believe it or not, thereís quite a bit to choose from. Iíll start from cheapest/easiest and go from there. Also to consider, are partial replacements like heads and transmissions. A note to DX owners, all of these swaps will require swapping from your engines DPFI (dual point fuel inj) system to the more common MPFI (multi-point fuel inj).

D series

  • The D16A6. The 88-91 CRX si and Civic si or ex.
    SOHC 1.6 non VTEC. All the si owners out there know this is a good solid engine.
    The 88 made 105 hp and the 89-91 made 108 hp and 100 ft/lbs. tq. You can pick up a running engine for about $500, usually with some kind of short-term warranty and a motor needing a rebuild shouldnít be anymore than $150.
    This is engine is especially something for DX and HF owners to consider. All for about the same price as the basic bolt-ons (like intake, header, and exhaust.) Especially the HF, at 62 Hp those bolt-ons would only get you, maybe, 12-15 Hp if youíre lucky. A stock si engine increases the output 43-46 hp. Does this logic appeal to anyone? Also consider picking up the SI transmission, itís geared for acceleration vs. the DX cruising and definitely the HF fuel economy gearing.

  • The JDM ZC. The term ZC covers several different engines. The types Iím aware of are:

      DOHC 1.6 Non VTEC, Black valve cover. When people say ZC, this is the engine most of them will be referring to. It's rated at 130 PS(that's 128 hp) and 108 ft/lbs. of torque. Very similar to the US Acura Integra for 88-89(D16A1) but with different mounts and head. This engine is called the D16A8 and A9 in European markets. It was available in the Japanese market CRX from 88-91, remained available in a lower end Integra until 93 and is still in use in several models of Rover hatchback in England. So that means there are new ZCs out there but chances of you getting one of the older ones is more likely. This engine will bolt right in, no fabrication of mounts and no wiring problems. If you’re on a budget, you can even use your old si ecu, exhaust manifold and transmission, but these will choke the factory quoted hp number to less.

      DOHC 1.6 Non VTEC, Olive/Brown valve cover. Easily confused with the 86-87 D16a1. These make great engines for earlier Civics/CRXs. But because the mounts require some fabrication to go into the 88-91, skip this one in favor of the black valve cover. As the predecessor, power output on the fuel injected version is 135 PS. That's right, 5 more then the newer black valve cover. There is also a carb'd version making 115 PS.

      SOHC 1.6 Non VTEC. This one has become more common with time. It's price(typically sub $450) makes it very attractive. It has a more aggressive cam and ecu that rates it at 118 hp. Aside from the cam and ecu, this is basically a D16a6.

      I like the ZC. It’s DOHC design makes it rev high smoother than the SOHC Honda engines. And with adjustable cam gears, the DOHC engines are easier to tune, with better results. Many people get them expecting a drastic difference but are disappointed with the results. This could stem from several reasons. Age, worn out engine, mismatched components etc. Get a healthy engine, the ZC ecu, the short-geared transmission, and an adequate header and it will run circles around the stock si engine BUT if you remove one of those things from the equation, it will slow the ZC down. It has a little more torque than the D16A6, but not much. Where you really notice the difference is 4000 RPMs and higher and at freeway speeds.

      After many years of being the cheap and easy swap, it appears supply is dwindling. Prices are up and quality is down. Quite frequently there's a wait for the next shipment to come in. But if you can find one in good shape, they're a great choice.

  • The D16Z6. From the 92-95 Civic SI and EX
    SOHC 1.6 VTEC. 125 hp and 106 ft/lbs tq
    The D16y8. From the 96-00 Civic EX
    SOHC 1.6 VTEC. 127 hp and 107 ft/lbs tq
    A lot of people compare this and the black valve cover ZC when thinking about swapping engines because the price and power output are similar. Itís available domestically, which makes it easier to find and verify actual miles on an engine. There are quite a few engines floating around because people swap them out for Integra engines. There is generous aftermarket support for this model as well. And the VTEC switch over is a blast to drive through.
    The block does bolt right in physically if you use your si tranny but there are a few changes to be made in the wiring.
    The VTEC needs a way to be activated. Easiest thing to do is wire up a RPM sensitive switch to have it activate the VTEC at a preset RPM, like 4400. While easy, it has some drawbacks. Normally, this engineís ecu would be used for this and when VTEC comes on, it gives the engine a richer fuel curve and makes sure oil pressure is adequate. So there is your other option, convert to the entire D16Z6 wiring harness and ecu.

B series

    Big brother to the D series, you get plenty of choices. Unfortunately, they are all more expensive than the D series. And as in most cases, you get what you pay for. Most of these engines are larger displacement and the least powerful B series engine is a match for the best the D series has to offer.

    Up until recently, the only way to get one of these bad boys in your car was to have custom mounts fabricated or turning your car over to a guy with a welding torch *cringe*. Well, there being a public demand for these engines, somebody was sure to come up with something to solve the problem. Enter Hasport and Place Racing. Both came out with a bolt in mounting kit for a reasonable amount of money. These kits will put any of the B series engines into a 4th gen civic or 2nd gen CRX.
    That solves the physical installation. Now comes wiring. And it gets ugly. You have to switch your car to whatever ecu and wiring harness that came with the engine you get. On top of that youíre going to need the transmission and axles to pull this off. All these things add up and are what make the B series a more expensive swap.

  • The B18A and B18B. From 90-current Integra LS/ GS
    DOHC 1.8 Non VTEC. Hp from 130-142 and tq from 121-127 ft/lbs, all depending on the year of the engine. As with the some of the D series, these engines are available domestically and this makes finding one for a decent price and verifying the miles by VIN code a little easier. And when you consider, that most of the Integras sold here are with this type of engine, it only helps availability/ price. The larger displacement and lightweight of the CRX make these engines torque something to smile about. As far as the drag racing/performance import world is concerned, the Integra is king but these low-end model engines get no respect. Which makes them cheap. Iíve seen blocks go for $700 at the local salvage yards.

  • The B16x. 90-91 JDM and Euro CRX/Civic, various JDM Integras, 94-97 Del Sol vtec, and 99-current Civic si.
    DOHC 1.6 VTEC. This little gem has been around for awhile. Itís actually has several different configurations, like the B16A, B16B, B16A4, etc. Hp varies slightly but you can count on 160 hp, 111 ft/lbs of tq and an engine that loves to rev. Each configuration requires a little something different to make it work so itís worth your time to do the homework.
    Personally, I think this is one of the ideal engines to put in the CRX. It was designed for the car but never made it to the U.S. shores, so finding a complete package to swap (engine, tranny, ecu, axles etc) should start around $1600. The newer the engine, the more expensive its going to be though. Iíve seen complete swaps out of the newer Civic si going for 3500. Those people in Europe, Australia, Japan etc have no idea how lucky they are to be able to pick one of these up stock. The morons at Honda really blew it by not getting these to the U.S. and replacing the CRX with the Del Sol. *sigh* But I digress

  • The B20B. 1997-98 CRV
    DOHC 2.0 Non VTEC. 126 hp and 122 ft/lbs. (9.1:1 compression ratio)
    The B20Z. 1999-00 CRV
    DOHC 2.0 Non VTEC. 146 hp and 133 ft/lbs. (9.6:1 compression ratio)
    Want big displacement(for a Honda, anyway) without abandoning the tried and true B-series? This is your answer. Note the difference in the B20B and Z models. The B20B is usually the cheaper of the two, being older and having less power. A lot of tuners usually don't care which one they get because they are going to custom build to their own specs. But if you're staying relatively stock, 20 hp and 11 ft/lbs is a big enough difference to warrant some extra attention.

  • The B17. 92-93 Integra GSR
    DOHC 1.7 VTEC. Hp is similar to the B16 at 160 but tq is better at 117. A predecessor to the B18C1, there arenít many out there. If you do find one, they are typically with higher miles but they are significantly cheaper than the newer GSR engines

  • The B18C1. 94-present Integra GSR
    DOHC 1.8 VTEC. What can I say, this is the storm trooper of the Honda performance invasion. It makes 170 hp and 128 ft/lbs. Itís being swapped into all manner of civics, lower end integras, and of course, the CRX. Itís power output and closer gear ratio tranny make it quite a motivating force in propelling the CRX down the street. Because of its reputation and the lesser numbers of GSRs sold, this engine is a tad on the expensive side. You can count on spending 2800-4000 for a complete swap. There is also a JDM version of this engine simply called B18C that gets imported in small numbers.

  • The B18C5 97-98, 00 Integra Type R
    DOHC 1.8 VTEC. Imagine the GSR on steroids. Power has been massaged up to 185 hp. The tranny is even more closely geared than the GSR and comes standard with Limited Slip Differential to manage wheel spin. Very rare piece of engineering marvel. Expect to spend 4500-6000 for this complete setup. As with the GSR, there is a JDM counterpart called B18C spec R that finds itís way to the US occasionally.

H series

  • The H22x 92-00 Preludes
    DOHC 2.2 or 2.3 VTEC. With a special mount kit, like the B series, this monster can go in your CRX. I wouldnít consider this combination unless you are going to do nothing but ľ mile this car because your handling will be shot. If you want to get an idea of what I mean, have a hefty friend sit on your hood and try driving around. Too much weight on the front will cause your car to have massive understeer. But if thatís all right, you wonít be disappointed. The most torque that you can shake a stick at.

Other Go Fast alternatives

Transmissions, mix and match for your application/taste. There are different gear ratio trannys for both D and B series engines. If you take an engine with same power and try it with a close ratio tranny and then the longer gear ratio tranny, youíll see the shorter the gears, the faster the car will accelerate. You go thru shifting 1-5 sooner too. Problem with this is you end up in 5th gear by 45 mph and have to cruise on the highway at 4500 rpms. So the trick is to find the right balance between acceleration and cruising at highway speeds.

Head Swapping. Okay, why? Well, itís easier than an actual engine swaps and is a good option if only your head goes bad and your bottom end is fine. While itís fairly inexpensive to just strap a new head on an engine, it really pays to do the research on whatever your attempting.

D series
D16A6 block with D16Z6 or D16Y8 head. Referred to as a Mini-Me, you get to keep your stock block and bolt on a VTEC head. Hp is about 130 and tq is about 108. I say ďaboutĒ because there are so many small variables that will affect results. You basically unbolt everything from the stock head, remove it and then drop in the new one and bolt everything back up. The Y8 head is the easiest and the Z6 requires some fiddling with the distributor. At this point youíve got a stock si engine but the compression is higher, between 10.4- 11.1 vs the stock 9.1. That means youíre probably going to have to run premium unleaded or face detonation problems. There are ways to get the compression ratio down. Switch to a thicker head gasket and try aftermarket turbo pistons (expensive) or use D16Z6 pistons, that will lower it .6-1.0.
Now youíre faced with wiring up the VTEC to work. Itís either the switch mentioned in the D16Z6 swap above, a Field Vtec controller or a programmed ecu from Zdyne. Typically a VTEC head will go for $175-250

B series
B18B block with B18C1 or B16 head. Referred to as a LS/VTEC, you take a stock LS block and put the GSR or B16 head on it. The reason for this? The LS is actually a slightly larger block than a GSR, this makes more torque, but it doesnít rev as freely as a VTEC head. So youíre getting the best of both worlds. One of the drawbacks is now you have a top end thatís rev happy but a bottom end that wasnít designed to rev that high, so many people bulletproof the bottom end before tackling this.

Thank you daven, for your patience and hard work in this nessecary article.