Anyone swapped a R18Z1 into an 8th Gen?
Just picked up an 06 sedan with cracked block. It's out of the timeframe for recall so I'll be replacing the engine myself. It seems the Z1 swaps are a lot cheaper and more abundant, so I was considering this engine as an option. Would it bolt right in and run off the stock ecu? Any input would be greatly appreciated. Thanks
As far as motor specs, they appear to be almost identical:
R18A1
Found in:
2006–2016 Honda Civic (Thailand/Indonesia/Japanese/Pakistani-market FD1, American/Canadian-market FA1 and FG1)
2007–9 Honda FR-V (European-market BE1)
R18Z1
R18Z1 Engine on a Honda Civic FB2
Found in:
2012–2016 Honda Civic (Southeast Asian FB2)
2016– Honda Civic (FC1)
What I think will be questionable is mounts and harness plugs and pinouts etc.
If you can get all that dialed, the ECU should probably run it without too much problem.
The other questions needing to be answered are, are the vtec's the same, and do the motors use the same sensors and systems?
I'm unfortunately very ignorant on these newer motors and cars. I do however remember reading about the K24 and not all of them have the same vtec mechanism with each other it seems. Very well could be the same issue with the R18 motors and I am pretty sure that would cause a bit of trouble for the stock ECU.
R18A1
Found in:
2006–2016 Honda Civic (Thailand/Indonesia/Japanese/Pakistani-market FD1, American/Canadian-market FA1 and FG1)
2007–9 Honda FR-V (European-market BE1)
- Displacement: 1,799 cc (109.8 cu in)
- Compression: 10.5:1
- Bore & stroke: 81.0 mm × 87.3 mm (3.19 in × 3.44 in)
- Power: 141 PS (104 kW; 139 bhp) @ 6300 rpm (Japanese Spec)
- Torque: 17.7 kgf·m (174 N·m (128 ft·lbf)) @ 4,300 rpm
- Fuel Cut Off: 6900 rpm
- Redline: 6800rpm
R18Z1
R18Z1 Engine on a Honda Civic FB2
Found in:
2012–2016 Honda Civic (Southeast Asian FB2)
2016– Honda Civic (FC1)
- Displacement: 1,799 cc (109.8 cu in)
- Compression: 10.6:1
- Bore & stroke: 81.0 mm × 87.3 mm (3.19 in × 3.44 in)
- Power: 141 PS (104 kW; 139 bhp) @ 6,500 rpm
- Torque: 17.7 kgf·m (174 N·m (128 ft·lbf)) @ 4,300 rpm
What I think will be questionable is mounts and harness plugs and pinouts etc.
If you can get all that dialed, the ECU should probably run it without too much problem.
The other questions needing to be answered are, are the vtec's the same, and do the motors use the same sensors and systems?
I'm unfortunately very ignorant on these newer motors and cars. I do however remember reading about the K24 and not all of them have the same vtec mechanism with each other it seems. Very well could be the same issue with the R18 motors and I am pretty sure that would cause a bit of trouble for the stock ECU.
Why wouldn't you just put the stock motor back in? I think that regardless of price difference, the less hassle of swapping the stock engine back in will be worth it. Unless it truly it plug and play.
The stock A1 engine was prone to engine block cracks. Plus they're about 4-500 more than the Z1. If I can get away with putting in a more reliable engine for cheaper I'm all about it
You can reduce some of the challenges if you only use the block and head of the Z1. Keeping your intake/fuel and exhaust.
There might be a sensor challenge but less likely over the complete engine. That will likely only leave mounts being the issue.
There might be a sensor challenge but less likely over the complete engine. That will likely only leave mounts being the issue.
Just picked up an 06 sedan with cracked block. It's out of the timeframe for recall so I'll be replacing the engine myself. It seems the Z1 swaps are a lot cheaper and more abundant, so I was considering this engine as an option. Would it bolt right in and run off the stock ecu? Any input would be greatly appreciated. Thanks
All well and good, just get the ECM for that engine when you buy the engine. No worries then.
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All imagery and OEM part numbers ( to the best that I can find online ) show me that there is virtually no difference in the mounts between the A1 and the Z1 blocks. Note that the Z1 is usually found in the RHD Civic from the Asian and Australian markets so there might be a clearance issue with the dog bone stay at the top of the engine RH side. This is where the brake booster/ master cylinder and clutch master cylinder ( for manual transmission cars ) would be located on RHD cars. I have been wrong before, but I found the USDM part numbers at Majestic Honda online and the R18Z1 parts images online using the block code as a search reference.
The engines R18A and R18Z have a different operating principle of i-vtec. You will have to replace the ECU (but not the fact that the ECU 9th is compatible with the 8th) or replace the camshaft or cylinder head completely.
As I had stated above, get the ECM from that specific engine ( as in the one that was in the car when the car was manufactured ). The serial numbers of both engine and ECM would be available through a dealer information access check.
Hello!? Did you finally get the R18Z1 to work and what did you do about the crankshaft position sensor!? I accidentally bought one R18Z1 for my 06 Civic, I tried to route an extra harness to get to the back since the original had the sensor at the front of the block. Changed knock sensor, Vtec sensor, but when I tried starting it brought a P0339 code . Saying crankshaft sensor circuit A intermittent. Got tired and started looking for answer and found this forum. So did it work for anyone, please let me know thanks
Hello!? Did you finally get the R18Z1 to work and what did you do about the crankshaft position sensor!? I accidentally bought one R18Z1 for my 06 Civic, I tried to route an extra harness to get to the back since the original had the sensor at the front of the block. Changed knock sensor, Vtec sensor, but when I tried starting it brought a P0339 code . Saying crankshaft sensor circuit A intermittent. Got tired and started looking for answer and found this forum. So did it work for anyone, please let me know thanks
I got a civic 2008 that the cylinder bloc as crack, so I needed to swap the engine for an other, but the R18A1 was 1000$ and the Z1 was 400$. So I decide to give an try to the Z1, even if I know that it will need a little more work to make it work juste fine in a 8th gen civic.
You need to know that the cylinder BLOCK of both engines are exacly the same. So all the sensors and brakets of the A1 will fit on the Z1. You have two major trade to work on to make the Z1 work in a 8th gen civic.
First of all, the crank sensor(ckp) on the Z1 is not located on the front underneat the oil pressure switch like the A1, but on the back under the starter. Also, the signal plate for the crankshaft sensor is not the same on the Z1 and the A1. To fix that part, you'll need to trade the ckp signal plate from the crankshaft of the A1 to the Z1, then, trade the upper oil pan/crankcase from the A1 to the Z1 to get the sensor on the right place.
secondly, the camshaft signal gear is not the same on a A1 and a Z1, again, you need to take the one from the A1 to put it in the Z1, cuz the gear itself on the Z1 camshaft is integrated on the camshaft, so you need to take it all off the cylinder head and replace it by the A1 camshaft. (At this stade, i recomand you to make an intake and exhaust valve clearance check/adjustement). After this two steps, the rest is pretty easy. The Vtec selenoid assembly, the thermostat assembly and EGR assembly can be trade from the A1 to the Z1. Take the A1 knock sensor to put it on the Z1 cuz its not the same and personnaly, I also trade the air intake along with the throttle body to be sure it will work fine. If your new Z1 didn't come with the ignition coil, the A1 ignition coil can work, but they're too long to sit tight and seal the sparkplug chanel.
With all this work done, you DONT need a new cumputer or harnest, it will be plug and play!!!
I hope it will help some of you wondering if its possible to trade from A1 to Z1!
of anybody have questions, ask me and I will try my best to awnser you as quick as possible!
PS: i'm sorry for the sentence error, english is not my first language

Last edited by BennyWise; Feb 11, 2025 at 07:02 PM.
Hey BennyWise, I'm attempting to swap out my R18A1 for the R18z1. I haven't pulled the crankcase on the z1 yet, but noticed in the illustrated parts break down the bearings appear to be different. Did the bearings essentially look identical when swapping out the crankcase?
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Drsexiestboy
Honda Civic / Del Sol (1992 - 2000)
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Feb 18, 2009 10:47 PM







