dbagaus

If a non Vtec engine is blown, what all would need to be done to swap for a Vtec. Can the Vtec simply not be connected? are the engines themselves the same? Its difficult to find a non-vtec engine....

mac25

You will need to do further research but I can give you a quick run down.

Since you posted that the displacement is 1.7L i would gather that your engine is from an 01-05 civic.

The non vtec engine should be a d17a1. The vtec engine will be a d17a2.

The lower end, the block, is the same and will bolt up to your transmission. However the head, ECU, and exhaust system are different.

In order to swap to a vtec engine your will need the engine itself, a vtec ECU, the vtec header/down pipe and some wires to relocate the O2 sensors.


I am not sure about your wiring harness. You may have the vtec electrical connection which plugs into the vtec solenoid (located on the head), however you may not; in which case you will need to either run wires from the ecu to the solenoid or find a wiring harness. So do some research on that.

As well I am not sure about the exhaust system. I am not sure if the vtec down pipe lines up with the non vtec exhaust system. So you may need the complete exhaust system (vtec: header, down pipe, mid pipe and muffler. So check that.

dbagaus

To be more specific, you're correct the car is a 2005. I would like to stay with a Non-Vtec, by using a Vtec engine if that is easier.

mac25

It may be possible to drop in a d17a2 with the stock ecu and harness, but I am not sure.

sdaidoji

iTrader: (1)

should be possible - the ecu will not know the vtec is there.

Mac, just to correct, the block also have oil squirters to the pistons and slightly higher compression compared to the non-VTEC engine.
not sure of the differences in the camshaft profiles, though...

what will happen is that one of the exhaust valves will most likely not open (almost) since it is what the VTEC will activate, so it will be a 3-valve engine instead of 4-valve. More low end torque but no power in higher end.

mac25

ahhhh right, thx Sdaidoji.

usajags84

The exhaust will line up if you don't want to change you cat lx has a cat on header design where vtec has a lower cat you can use the engine and harness as long as you run a separate wire for the vtec control there are separate vtec controllers available but it may be cheaper for you to get a vtec harness and ecu but keep in mind when you change the ecu be prepaid to tow it to the dealer to have your key reprogrammed unless you get the key and ignition modal from the doner car
(Cheaper and easier to get a reprogram imo)

jcb111

I just did this my 2005 Civic LX (non VTEC) blew up and replaced it with a 2003 Civic EX VTEC Motor, Trans, wire harness and ECU

Some of the wires are a little different between the 2
There are differences between the Motor harness and the body harness.

All good after flash from Honda
Keys work now with the ECU that matches the motor need to do this if you change the ECU. The motor ran on the LX computer just thew codes for the O2 sensors.
Only code its throwing was the heater on O2 sensor 2 which if you get the harness from the motor there is no place to connect the Downstream O2 sensor as the exhaust is different between the 2 motors. I changed my exhaust also, used a aftermarket LX header back exhaust and just added the 2nd O2 sensor about mid car and left the plug in the header for O2 number 2. You will also need the O2 sensors for the EX motor as they are different between LX and EX
Wired the Black/Yellow wire to pin 5 yel/blu on connector E
Wired all O2 stuff to connector E and all good now, No codes

So just so its cleared up for anyone else doing a LX - EX conversion in a 2001-2005 Civic here is where the wires are landed when using EX Motor, Trans, Wire Harness and ECU

Here is where they are on the stock harness Connector A (31 pins)
25 wht/red Secondary O2
23 brn/yel Logic Ground
14 blk/wht SecondaryO2 sensor heater control
10 grn/yel Sensor ground
Blk/yel Heater acc power

Here is where they go on Connector E (31 pins)

2 wht/red Secondary O2
3 brn/yel Logic Ground (Shield from O2 Sensor)
5 yel/blu Sensor voltage (attach to blk/yel from O2 Sensor)
6 blk/wht SecondaryO2 sensor heater control
Connector A (31 pin)
10 grn/yel Sensor ground

On the wht/red and Blk/wht
I dissected the old harness to get the whole wire with the metal ends that fit into the harness. As you will find out when going from LX to EX there are a few different wires and they are not in both body harnesses the same way. On the other wires I just tapped in and soldered and taped as not to cut the factory wiring.
I hope his helps anyone that might be doing the same swap that I needed to do to get my everyday driver back on the road with a few upgrades.

j_dock69

I've got a d17a2 in my '02 dx sedan, apexii vafc2, stock dx exhaust, ecu, trans, dx wiring harness, no issues at all, out almost 50k KMS on it

jcb111

That's cool, it will run fine that way. The way that I posted is how you get the vtec working and get a little more power out of the motor. In my case where I would shift because power was lacking, it now pulls all the way to redline.
But you need to have the ecu, wiring and have it flashed to work with your key.

RER747

I too am doing the D17a1 to D17a2 swap. The D17a1 thru a rod bearing. I have a full door SI civic that can no longer be registered. I need some clarification.
I have the a2 installed and running off the a1 computer. The car still has the lx exhaust and computer. The car runs.... just not as good as it should.
I need to finish the a1 to a2 swap.
I will be using the donor SI computer and ignition key. Will this avoid having to flash the computer?
Will be using the SI engine harness to replace the LX harness so it vtec can plugged in.
Will be using the full SI exhaust with its 02 sensors. Front 02 sensor should be ok.
Will the only issue be the 02 sensor in the cat? The SI exhaust has the cat under the car rather than by the manifold in the front of the car. There is no place to plug this in once the engine harness is replaced with the SI harness. This 02 sensor is plugged into a different harness on the SI. How can this issue be addressed?

jcb111

My years were 2005 civic LXSE 4 dr. Donor was a 2003 EX 2 dr. I am going to assume that your donor is a 2006 or newer since there is no 2005 - 2001 civic si 4 door. I don't know if the 2006 and up are exactly the same as far as wiring. But as far as using the ecu and key you should be good and not have to flash as long as the parts are mated together. Using the A2 harness will wire in your vtec, but you will have to wire you downstream O2 sensor into your body harness like I did. I poked my downstream O2 wires out at my shifter boot. You will also have to put those into the BODY harness as described in the thread. That has nothing to do with the A2 harness. In the non vtec harness it comes from the front of the car into a completely different plug. I used the wiring from my non vtec harness to wire in the downstream O2. Basically cut back all the loom and tape to keep the factory wiring with the plug and ends to put into the body harness. I used the LX aftermarket exhaust and header with my EX motor. I used the top O2 sensor for the front, plugged the one right below it. Down at my mid pipe I have a nut welded to the exhaust where the downstream O2 sensor is installed using a spark plug spacer to space it out a little further. I have no cat installed. I am using the EX O2 sensors to match up to the ecu and the motor. I no longer have a check engine light on. If the donor car is a 2006+ I am not sure if the exhaust will work with out modification. I will reccoment buying a inexpensive exhaust off the internet if that is the case. I had $200 into my aftermarket exhaust headers and all stainless piping the whole way back. Got it off eBay. Way nicer than expected. Hope this answers your questions. If I can help anymore I will. Let me know. Good luck.
This thread has all the instructions without a lot of the other stuff to scroll through.
https://www.civicforums.com/forums/79-advanced-engine-performance-swaps/364912-wiring-1-7l-sohc-stock-ecu-nonvtec-vtec-swap.html

RER747

JCB111 thanks for the reply.
Drats.... my mistake. I am new to civics. I missed giving some important information and I gave some incorrect information...
LX = 4 door? DX = 2 door? EX = 2door SI?
Donor is a 2002 SI 2dr (EX?). Receiver is a 2003 2 door (non-vtec so it would be a DX?)
A2 harness is the engine harness?
No cat.... interesting. I may have to try that.
I will re-read the attached thread.
I will grab the donor downstream 02 sensor wiring. Then ensure I understand how to connect the downstream 02 sensor wiring.


Thanks again.

jcb111

It's all good
LX DX EX is all trim and usually specifies motor. EX all had the vtec A2 motor LX and DX had the A1 non vtec motor, all came in 4 and 2 door. The 02 SI should work ok. Not sure on the exhaust because of length compared to the the 2 door with trunk the SI was the 3 door or 2 door w hatch. But the O2 sensors from the donor should work along with the wiring and ecu and key assembly. You will still have to modify your body harness to work with the vtec as I stated before. Unless you go through the trouble of doing the body harness from your donor car. Big pain though. If you do get the new aftermarket exhaust get the one for the EX 2 door which should match up to the motor and your car. You won't have to modify as I did for my LX exhaust. Any questions feel free to ask. If I can't answer I'm sure there is someone here that can help. I was new to the motor swap thing too when I started this project. Had not done one in 20 years. Not that hard just be prepared before you start it unless you have a ton of time to do it. Mine took 2 days to swap after work. 1 day to pull the old motor and 1 day to install. I spent a few days before the swap prepping the donor motor. Timing belt, water pump, all seals I could get easily, clutch and all new fluids and body mounts. Install your body mounts after the motor is in the engine bay. It's hard to try and squeeze them by with them installed. I tried. YouTube a few videos if you are questioning what to do. Pretty easy to do if you are mechanically inclined. If your donor has been sitting a while I would also recommend marvel mystery oil in the spark plug holes and let it sit for a couple days to make sure your oil seals are free. Mine were stuck and burned oil a lot till I got them freed up. Google that info, a local performance shop told me to try it and said they do it to all junk yard motors to save time and money.

wingsfan19

Interesting stuff. We are trying to sell my son's 2003 Civic LX coupe that has a bad head gasket and may need an engine swap. We don't have the equipment, time or frankly the expertise or patience to do it ourselves, but I will refer any potential buyers to this and other posts concerning 7th gen engine swaps. How much was your engine?

RER747

I paid $400 for the complete donor car. It was hit in the rear. A total loss. Not repairable. The mileage was high. 240000KM. I did a compression test. all cylinders were 170. I thought that was good.


After selling many of the parts not needed for the swap from the donor, I have about $100 still outstanding... so the A2 engine, transmission, exhaust, wiring, ecu, and keys and locks all for $100. The donor also had a nice touch screen entertainment center instead of the stock cd player.


Another $150 was spent to replace the timing belt, clutch, and all the fluids.....
So l have about $250 into the swap so far.

jcb111

I also paid $400 for my motor trans harness and ecu. Mine had a lot less miles was only 100,000. Whole car for that price is great. I found a crashed LX w 80,000 after I did mine for $800. Would have done that in a heartbeat, but a month after I did mine so my loss. Blown head gasket would not be that bad if you have the time and garage. Really depends on mileage for worth and if any other damage was done. The d17 series motors are the least desirable of all the Honda motors. Especialy the non vtec A1. Most are doing a k swap much better motor that stock has more power than a built D17A2. Mine is my everyday driver, and probably going to be donated to my 16 year old son. So I did not want to make it too fast for him lol.

wingsfan19

Cool. That's a great way to save money! Speaking of parting out, if we can't sell the car for a decent price, that's what we'll end up doing because I'm not selling it for $500 to the dealer -- I'd rather pull EVERYTHING off and sell the remainder to the junkyard. Only thing I can't figure out is how to remove the aftermarket coil overs without having the originals to replace them to hold the car up.

jcb111

If you weren't so far from me I would swap my stock coils for yours lol. Good luck

https://www.civicforums.com/forums/7...vtec-swap.html

Here is another thread I started a while back with instructions for wiring in the ecu if you wanna pass it out so you don't have to scroll through a bunch of bs to get to what you need.

jcb111

Do the water pump and seals as well while you have it out of the car. Pumps cost a little, but seals are cheap

RER747

Too late for the WP and seals. The engine is in the car and running using the non vtec ecu.
JCB111, my only question so far is...The ECU has three connectors/plugs. In your instructions above, what is connector A and connector E? Are these the connectors that plug into the ECU?

jcb111

Yes 1 is the body harness the other is the motor harness that plug into the ecu.

sdaidoji

iTrader: (1)

Since you will match ecu and engine, be careful that 2003+ uses wide band O2 sensors. I think it should work, but that is guess... What does not work is wideband ecu with narrow band sensor.

jcb111

I agree make sure you match the engine, Ecu and sensors to the specific year that they are. I know there was a big price difference between 2003 and 2005 sensors. Not what the car is or you could pull some check engine codes. When I had the non matching Ecu to my engine I was pulling bad O2 sensor codes for both sensors. After the flash of the correct Ecu no more codes. Needs to be wired I. Correctly though as the difference between non vtec and vtec motor placement is different on the body and engine harness.

adonato95

I know this post is old. Doing a swap right now. What do you mean about “wiring”?

310civicEX

will run and wire up just fine....no vtec tho...and i assume 02 sensors are different..

CarmineXI

Ok, so after reading this thread and a few others, I think I have the gist of it, but just to clarify...

2004 Civic LX A/T (D17A1 NA)
Donor engine: 2005 Civic (?) A/T (D17A2 VTEC JDM)

I should be able to install either an A1 or an A2 transmission with the only issues being the O2 sensor, the ECU, and the wiring harness, correct?

After getting stationed in Delaware, bought the car off a used lot. They swapped the good engine/transmission for one they yanked out of a salvage, unbeknownst to me. 2 months later they both blew out. I’m livid. Lemon law says 7 years. FML. Found the engine at a JDM shop in Baltimore. I’ve talked to several JDM shops in the area, but some are saying it doesn’t matter, while others are saying it’ll throw a code for torque, so I ventured to the interwebs for wisdom.

Sound about right?

sdaidoji

iTrader: (1)

Drop engine in, use all the stuff already in the car. ECU, wiring, exhaust, O2, etc.
If you dont wire the VTEC, it will work. You will not have as much power as you would with VTEC working. But it will work.

Auto to manual, not sure, need flywheel, clutch from current engine transferred?

Not connecting the VTEC just means the engine will work with three valves all the time, instead of opening the forth valve at med/high RPM.

Wilson9977.

Hello I'm new to this post I'm have the same question but diffrent motor will a 2002 civic 1.6 sohc fit in a 2003 civic that had a 1.7 sohc I want to buy the car for my girl but don't want to waste all the money if I have to get wireharness diffrent manifolds please help me if you can

sdaidoji

iTrader: (1)

2002 1.6 SOHC? Which country are you in?