photos of conversion

status

The 88 Integra D16A1 engine into my 86 CRX DX project is now more or less complete... there are still plenty of small details to be worked out, but the car is essentially running. It works reliably, and I've put about 1000 miles on it already. Below are my notes on the conversion.

engine

Though it had 100k miles on it, the integra engine was in decent shape, so I didn't bother with a bottom end rebuild. The valve clearances were set, I changed the oil, and did a general tune up - spark plugs, wires, timing belt, gaskets, etc. There is a slight rod knock when the engine is cold, I'll probably get new crankshaft bearings soon. The engine drops in with basically no modification, except that you need to use the driver's side engine mount from the CRX. You also need to grind that engine mount slightly to clear the plastic timing belt cover. Some people have claimed that the engine will interfere with the hood, I didn't find this to be true. I used the radiator from the CRX, and used either hoses from the integra which I cut to fit, or the old CRX ones. I got the exhaust system done by a local shop... they fit on 2.25" pipe, with catalytic converter, resonator, and muffler. Braided stainless steel flex-pipe runs from the exhaust manifold to the rear part of the exhaust.

transmission

The integra transmission goes right in as well... use the shift linkage from the integra, as they're slightly different lengths. I had to replace mine, since 5th gear looked like it had been in a blender. I bought a new 5th gear, but the problem was somehow that it was always engaged, even though everything seemed fine with the selector fork... I put new driveshaft seals on my junkyard transmission. Also, the old clutch was worn away, so I replaced that as well.

vacuum system

The vacuum system basically drops in as well... I bolted the little row of solenoid gadgets in the same place they were in the integra engine compartment. I had to plug the largest line coming out of the charcoal canister, the integra had no such matching line. There's also a line that goes to the air cleaner box (#8, I believe), the CRX didn't have this. I sawed a plastic fitting off a random vacuum valve I had lying around, and crazy glued it on to the air box, which worked amazingly well. Also, I plugged the cruise control vacuum line, since I didn't bother swapping that over.

electrical system

The electric system was probably the greatest challenge... first off, the CRX DX doesn't have the Vehicle Speed Sensor (VSS) in the speedometer unit in the instrument cluster. I bought an HF cluster, which does have it, and swapped the speedometer into my cluster. While I was at it, I took the shift indicator light from the HF and put it in my cluster as a check engine light, since the DX doesn't have that, either. Also, there's the Electronic Load Detector (ELD), which raises the idle to compensate for the load on the alternator. I swapped over the whole integra fuse box, which included the ELD, buried deep inside. This wasn't as bad as it sounds - you just take the 3 positive leads from the old CRX fuse box, and attach them to the 3 terminals on the integra fuse box. The rest of the electric was tackled one device at a time... I'd recommend getting the wiring diagrams for each car, it would have been impossible without them. Essentially, I took the wiring out of the integra whole, and then carefully clipped off everything that was not needed. Then I put this into the CRX, hooking up hot wires and grounds as appropriate. Then I cut off all unnecessary CRX wiring in the engine compartment. The tricky parts were interconnecting the things that were necessary, and needed to be hybridized... For the lights on the CRX instrument panel (oil pressure, temperature, etc.) I just cut the wires within the engine compartment and soldered them to the appropriate wire on the integra harness. Usually, the colors matched.

fuel system

The CRX DX uses a 3-4 psi fuel system, driven by a mechanical pump in the engine compartment, while the integra uses a 35-40 psi system with the pump next to the fuel tank. I wound up using the fuel pump off an 88 CRX SI, which more or less bolted into place, with some sawing-off of the metal fittings. The original system used screw fitted metal lines, I replaced them with rubber lines with hose clamps, which seems to work fine. I also ran the wires from the fuel pump to ground and the main relay. I put a small fuel filter before the pump, and a larger (generic) one within the engine compartment, dangling clamped in the middle of the fuel line. The liquid and gas fuel return lines work basically the same as in the CRX. One lesson learned is that UV light will dissolve the fuel injector seals in the course of a few months. If you're working on your car outside, at least put the hood back on when you're not working!

steering / suspension

I used the crossmember, steering rack, and steering knuckles from the integra. The main perk of this is power steering. Everything bolts right in, without modification. The power steering reservoir even has the appropriate holes to bolt in, even though it doesn't exist on the CRX. One small catch was the power steering cooler - it's made for the longer integra engine compartment. Eventually, I'll get one fitted up, but bypassing it works fine for now.

brake system

Using the integra steering knuckles allows you to also use the larger rotors, and calipers with larger piston diameter. I saved the rear axle from the integra, and plan to put the rear discs on as well, eventually. The disc e-brake is another motivation for also swapping the rear. I used the old master cylinder and proportioning valve, at first this worried me, since the integra calipers are much larger than the CRX ones, but the car stops fine.