All U.S. 86-89 integra’s (RS, LS, GS) all have the same initial D16A1 engine design. Only slight engine changes were made between the 86-87 and 88-89 Integra models. The biggest difference between the two isÂ wiring/ecu/& ignition. Remember I mentionedÂ Vacuum Advance IgnitionÂ earlier? Well among Integra’s, only the 86-87 Integra’s use thisÂ Vacuum Advance IgnitionÂ system (just like the the 86-87 Civic/CRX Si models do). This is a big reason why 86-87 D16A1’s electronics & wiring are compatible (plug n play) with 86-87 Si’s. Whereas 88-89 D16A1’s electronics are not — youÂ cannotÂ carry over & use (plug n play) the OBD-0 ecu/wiring/ignition system that 88-89 Integra’s have into an 86-87 Si. It’s just not compatible. But, you technically can convert an Si to OBD-0, but it’s an enormous pain in the ass and I don’t suggest doing it unless you’re the adventurous type and love playing with wiring.Â
Normally, theÂ browtopÂ ZC & D16A1 engines are a dead ringer for havingÂ Vacuum Advance IgntionÂ (VAI) systems, which wereÂ preÂ OBD-0 engines; blacktop’s being OBD-0. So, when purchasing a motor for your 84-87 civ/crx (especially for an Si model), a rule of thumb would be to look for a browntop ZC/ D16A1 engine if you don’t want to run into ignition & wiring incompatibilities. Of course, it is possible to convert an OBD-0 blacktop ZC/D16A1 to a VAI system by simply removing the OBD-0 components and replacing them with VAI components. Doing this will allow you to take advantage of an updated and slightly more powerful ZC/D16A1 engine.
There areÂ 3 continental versionsÂ of this 1.6 DOHC engine:
- ZCÂ (JDM)
- D16A1Â (US)
- D16A/9Â (EDM)
Â Rover Coupe 416 GTI engineÂ (pics stolen from an ebay ad)
Pretty weird eh? Kinda reminiscent of a an 84-87 Si’s SOHC valve cover! I’m not sure how long the Rover coupe lifespan series lasted.Â Â
Rover had other coupe models that shared Honda SOHC D-series engines as well. A fella by the screen name ofÂ Ben_KÂ on theÂ D-series.orgÂ forum has kind enough to share some detailed info on the Rover SOHC & DOHC coupes. Here’s what he told me:
The first generation of this 1.6L DOHC engine (JDM/US/EDM) all had aÂ 4-boltÂ brownÂ colored valve cover, which overtime has been nicknamed “browntop” by Honda enthusiasts. TheÂ browntopÂ ran for about 3 years in Japan and 2 years in the US and ?? in Europe.Â
Â Browntop valve cover(s) ZC & D16A8/9
Â Browntop valve cover U.S. D16A1
Browntop ZC/D16A1 engine specs:
- TheÂ program fuel injectedÂ (PGMFi) JDM ZC was rated @Â 135psÂ / US D16A1 was rated @Â 113hp.
There was a dual-carbureted version of the JDM ZC engine which wasn’t performance minded, rated at about 108ps. There’s also discrepencies in the Honda performance scene as to why the JDM ZC puts out more power than the US D16A1. Japan’s “PS” horsepower rating sytsem seems to be a bit overated imo, but the biggest differences lie within theÂ ECU programmingÂ &Â camshaft profilesÂ between the JDM & US browntop engine, but its hard to believe there’s almost aÂ 22hpÂ difference between the two types from just an ecu & camshaft change!
- The compression ratio is rated @Â 9.3Â for both ZC & D16A1 engines due to the flat top pistons.
- Both share a squareÂ toilet bowl shaped intake manifoldÂ design.
- Both shared the same ignition system which was known as a “vacuum advance” and used an external coil:
Vaccum Advance Distributor
- Nicknames of this JDM ZC version included: “JDM browntop” “browntop ZC“, “1st gen ZC“
- Nicknames of the US 86-87 D16A1: “US browntop“, “browntop D16A1“, “1st gen D16A1“
Changes made to the US D16A1 engine in 1988-89:
- The valve cover color was changed to black and became known as the “blacktop” [retained 4-bolt valve cover style]:
Blacktop D16A1 Valve Cover
- The pistons were upgraded from a flat top to domed piston increasing the compression ratio fromÂ 9.3Â toÂ 9.5.1:
- TheÂ connecting rodsÂ were slightlyÂ lightenedÂ up.
- TheÂ ignition systemÂ was upgraded to the more widely known “OBD-0” wiring/ecu/and internal coil ignition system.
- TheÂ intake manifoldÂ design changed to a better flowing design:
US 88-89 D16A1 I/M
- With the update to OBD-0 ecu/ignition system and higher compression pistons, theÂ 88-89 D16A1 gained 5hp making a total of 118hp.
- Nicknames of the 88-89 D16A1 included: “US blacktop“, “blacktop D16A1“, and “2nd gen D16A1“
- 1989Â would be theÂ last yearÂ Honda would produce the 1.6 DOHC D16A1 engine in America.
Changes made to the JDM ZC engine in 1988-91 and 92-95 ZC:
- Overall, received the same changes as the blacktop D16A1, but with a slight twist …
- The head, block, & tranny design were revamped to accommodate the newer 88-91 EF civic/crx & 92-95 EG engine compartment & chassis.
[The US wouldÂ neverÂ see this version of the ZC engine, only from used engine importers]
- The slight head & valve cover redesign changed to aÂ blackÂ 8-bolt valve coverÂ dubbed “blacktop” as well:
JDM blacktop ZC [8-bolt] Valve Cover
- Received the same exact domed pistons & slightly lighter connecting rods as theÂ blacktop D16A1.
- The intake manifold design changed to a more smoother and better flowing design, different than the US blacktop:Â
JDM 89-91 ZC I/M
JDM 92-95 ZC I/M
- Also received theÂ OBD-0Â wiring/ecu/and ignition system update.
TheÂ 92-95 ZCÂ was upgraded toÂ OBD-1Â wiring/ecu/and ignition type.
- Nicknames of the 89-91 JDM blacktop included: “2nd gen ZC” / “blacktop ZC” / “JDM blacktop“
- Nicknames of the 92-95 JDM blacktop included: “OBD-1 ZC” / “hydro ZC” / “3rd gen ZC”
This OBD-1 ZC engine was only found in the JDMÂ EG-5Â model.
Only minor changes were made to the OBD-1 ZC – mostly theÂ change to OBD-1Â and aÂ hydraulic transmission.Â
The overall look of the engine remains the same as the 2nd gen ZC. The intake manifold has light cosmetic changes as seen above.
- 92-95Â would be the last year(s) Honda of Japan would produce the 1.6 DOHC ZC engine — R.I.P. DOHC ZC!!