Inconcinnity

So I’ve just finished putting a Hyundai G4CP engine into my CB GSR and I thought I’d get some information written down for anyone who might need it in the future, as knowledge was a little sparse for me going in.

I started out with a fully reconditioned bare long motor that I got from engine builder HM Gem, who were selling them on eBay for $500 because they’re old stock and who the hell is going to fork out to put a reco motor into their 20 year old Hyundai. If I remember correctly, they had about a half dozen of the things they were trying to get rid of, so keep your eyes peeled on eBay if you want one because it’s entirely possible they still have some left.

Right, so the old motor came out and I started swapping bits. A note in advance, if you’re doing the reco motor route, you’re either going to need a Sonata with a dead motor in it or a trip or 5 to the wreckers. If you’ve got a running Sonata to donate a motor, then you’re set. If you’ve just got a good second hand motor, you’ll probably need to see a wreckers for an engine pipe and maybe some other bits.

The list:

- Inlet manifold: Straight off the 4G61. Port size was identical (double check this as I have heard otherwise, so maybe some aren’t), throttle body size was identical.

- Exhaust manifold: This is where having a Sonata for bits comes in. There are two options here. You can use the manifold off the 4G61 (same port size), but the outlet is goddamn tiny (I think my old Hyundai Excel had a bigger manifold outlet diameter). Also, the 2.0lt block is a tiny bit taller than the 1.6, so when you put the 1.6lt manifold and engine pipe on, the engine pipe is probably going to contact your sump (I didn’t try this, but I’m sure I’ve read this same bit of information on a forum somewhere). Your other option is to do what I did and use the Sonata manifold and engine pipe. You’ll need to grab the little bracket above the power steering pump for hooking the motor too, the 4G61 bracket hits the bigger manifold. Before the motor goes in, I’d give the heat shielding at the bottom of the manifold a few taps with a hammer, because it’s suuuuuuper close to the air con fan.

- Timing cover: The top inner timing covers (two little tin plates behind the cam gears) swap straight over. The one on the inlet side doesn’t meet up with the bottom section but instead leaves a gap (presumably because of the difference in block height). I left it as-is because it’s in a remote place and timing covers aren’t truly sealed anyway. If it bugs you, you can just fill the gap with silicon or something. The plastic outer timing cover I grabbed off the Sonata because the one off the Lancer was broken. I put one on top of the other and couldn’t spot a difference, but I think the difference in block height has to have been squeezed in somewhere. Safer just to use the sonata one.

- Injectors: From the Sonata (no brainer). I got reco injectors for mine from AzNew fuel injectors and used the 4G61 fuel rail.

- Coil: Never came off the inlet manifold, but either one will do.

- Water pipes: For some nonsensical reason the bolt hole for the water pipes is ~70mm closer to the water pump on the G4CP. I took a piece of what used to be a cargo barrier bracket, drilled two holes in it and attached it to the water pipes with a bolt and nut. That extended over the distance to the bolt hole in the block. This is probably a bit easier to do with the gearbox bolted on so you can bolt the pipes to the gearbox and not be trying to guess how high they are meant to sit. I didn’t use the sonata water pipes because the ends of them are still stuck in the hoses they were so corroded. I also had the pipes side by side and the outlet for the radiator hose is moved across a little bit on the sonata pipes, so you could be stretching the hose a fair bit to try to get it on.

- Water outlets and thermostat housing: Straight off the 4G61

- Cam sensor: Straight off the 4G61. It looked like it was possible to get the cam sensor 180 degrees out of whack, so be careful. I might be wrong about that, but I matched the timing marks on both motors before swapping the sensor to be sure.

- Flywheel: Straight off the 4G61. All G4CPs are 6-bolt crank apparently, so there should be no nasty surprises.

- Clutch: The Lancer one

- Harmonic balancer, water pump & power steering pulleys, aircon idler assembly, aircon compressor and bracket and power steering pump and bracket were all off the 4G61.

- Engine mounts and brackets: 4G61 units must be used

- Throttle cable: The Lancer one (may be different if you used the Sonata inlet manifold and throttle body, I didn’t check)

- Gearbox: The Lancer one

- No Sonata wiring was used, kept the complete Lancer loom.

- Starter, alternator and alternator bracket were off the Lancer

- The Lancer alternator belt was a little too short, presumably because of the extra block height. I used a 4PK1000 instead.

- All hoses were the Lancer ones except for the air intake hose because my Lancer one was close to death. Either can be used, but the Lancer one has a longer hose to the breather on the rocker cover for some reason.

- Air flow meter: The Sonata one, however this may be unnecessary.

- Engine pipe: I used the Sonata one to match up with the manifold. The Sonata engine pipe stops short of the catalytic converter by 30cm or so, so you will need to see an exhaust workshop to make up a little intermediate or something and modify the hanger, which is on the opposite side. I was surprised at just how well it fitted on the car, pretty much perfectly really except for the length. The other thing that needs attention is the oxy sensor. The Sonata oxy sensor is down the back of the engine pipe, instead of in the exhaust manifold like on the Lancer. It’s also 4 pin, instead of 1. I swapped the Lancer oxy sensor in and extended the wire up to its plug under the thermostat housing.

So all that done and I followed instructions from some people and used the sonata ECU. That gives you a check engine light and an exhaust light because of the difference in oxy sensor. Plugged the Lancer ECU back in and it runs perfect and the warning lights are gone. Theoretically this means you could use the Lancer air flow meter too I guess, though I didn’t bother swapping it back.

I should probably give a small warning that HM Gem were often called Hit and Miss Engines, because you didn’t know if you were getting a good motor or a bad one. Mine was a little bit of both I think. The block didn’t seem to have been drained properly after it was acid dipped, so all of the welsch plugs were severely corroded and there was sludge 30mm deep in the water gallery. I had to spend 2 hours scraping at it with oddly shaped tools improvised from old bits of fence and flushing it out with a hose. No other problems aside from that though, but be wary that you should do a thorough check of the motor before you start working on it.

Well, that’s it. I’m pretty sure I’ve covered everything and hopefully at least one of you is going to find it useful. Have fun