4g61t.org

ive searched for hours and cant find a detailed explanation of what all needs to be switched over when swapping a 91+ 4g63. i have an 89 mirage with a 4g61t and i could only find a 6 bolt out of a 92. what problems am i going to run into since its not a 1990 4g63?

Fuel rail from a 4g61t is always best if using the 90 DSM TB or 1989 4g61t TB and throttle body brace bracket, if not, no issue, but check the fuel filter line for proper length as it gets tight.
All sensors need to be swapped back to 90 unless you want to make adapters to wire them up inline and still plug into your 1989 CSM turbo harness (90 DSM style). 2G ISC requries swapping two pins on the ECU.
ECU if kept 90 won't require swapping pins 6 and 14, assuming you are still using the same 90 wiring for a MAF sensor.
Engine is physically the same, if truly 6 bolt.
Check the markings on the cylinder head, passenger side. They indicate what head you "should" have installed. Check front of block near dipstick tube for "4g63" on flat spot of block.
Re-use starter plate from a 1989 Mirage/Colt turbo. I cannot tell you what starter plate works from a DSM, but I assume FWD 4g63 standard transmission combos should all be the same, because the starters and blocks are ... and they swap with the KM210 installed in the 89 Colt/Mirage turbos. All starters are the same ... but see the thread in the archives.
If you have an exhaust system in place that is getting re-used, your cylinder head will now sit higher because the deck height of the 2.0T is physically taller. This could pull your downpipe into the lower portion of the oil pan or north south crossmember, check that clearance as it affected me during my swap. One of the little peculiarities involved in this exact swap!
Check out my build and ask any questions you need to, I can answer to the best of my ability to remember this stuff, or I can link to what I posted years ago. Car is almost back on the road.

I'll be using a 90 ecu... You say swap to all 90 sensors? What sensors exactly? Can the sensors from the 4g61 be used in place sinces its an almost identical head?

I'm just trying to figure out what I can use off the car and what needs to be purchased

Yes, you can reuse all of your 89 Colt/Mirage sensors because they use pigtails just like the 90 DSM sensors did. In fact the 89 CAS on your turbo model is preferable from a pigtail length, to a 90 DSM because there was a difference that may be irrelevant but your setup will transfer. If you ever change, a black top CAS can be used but it requires using your pigtail assembly and an additional connector with pins, to use 91-94 style connectors. While you are in there, research using a black ISC, as they are revised and present less load on the ISC drivers in the ECU. There is a two pin swap to perform and a harness modification like mentioned above because the sensor wiring pigtail became an on sensor/solenoid connector. No really complicated, but I wil be recommending this to anyone who isn't a full on purist looking for 100% original replacement. No point having an ISC that if shorting out, it takes the ECU control side on the ISC down too.

Consider using a 90 DSM throttle body and or have your current TB rebuilt by the throttle body repair guy. If it has never been apart, it needs new seals and cleaning for sure, mark my words. The rebuild guy has options for boring and re sealing the shaft with standard replacement or high boost type seals. The 89/90 TBs use two different sized seals on the shaft, should you be investigating doing it yourself or sourcing your own parts.

Realizing your are using a 92 DSM turbo motor, the 92 TB would require the sensor pigtail swaps or maybe the sensors swap over directly. It has been so long and I have never physically performed the swap just as you have. My motor swap consisted of 4g61t to Galant VR4 red top 4g63t.

Reusing your 4g61t throttle body is not advise able due to having such a small bore and ISC bore design. Find out from members here if your sensors swap right in for a 92 6 bolt turbo. I think they should as it should be just like the motor I installed.

yes the sensors will swap over from the 1.6, i planned on using the 1.6 throttle body because the motor im buying does not come with one, i will try and find a 90s TB but these parts are hard to find now. Can i use the 1.6 MAF with my dsm ecu or should i look for a 1g maf as well?

1.6 MAF will not run correctly with a DSM ECU.

Find a 1G MAF and if everything else is exactly what it should be for a/to match a 1992, call it a day.

Get into changing MAF sensors and ECU Eproms/ECMLINK later on, and tuning much later on when everything else has been done with maintenance and proof the car is operating correctly.

ok and last question, the oil filter housing. the 1.6 doesnt come with an oil cooler, the 90 has an external oil cooler, the 91+ is cooled with water...do i need to buy a 90 oil filter housing and use that or just use the one on the 92 motor?

I suggest an aftermarket cooler if the 91+ style is not in good shape. Check the large retainer but for proper torque, and better yet, get a new OEM gasket and replace that, and retorque.
Used 90 models are risky business, as they could contain debris or came off questionable motors.
Some of the same ports exist on most of the filter housings, so have a closer look. You can use MightMax oil filter housings too, as they are forward facing.

I am replacing my 91+ style water cooled with a 90 style air cooled because every time I change my oil I have issues getting it all back together or even apart. STM sells the 90 oil filter housing brand new for like 90ish bux and an oil cooler kit.

How complete is the motor?
Doest it come with turbo and manifolds?
Water/stat housing is different on 1990 because of oil cooler.
Sensors easily swap.
Ignition coil and power transistor are different on 91-94. 1990 are like the colt.
Cas might be different too.
Tb can be found, but at a price.
1.6l tb should work, its just smaller. You can get it going first then upgrade later.
Dsm motor also has oil pressure sensor. Guage needs to be added if you want to know oil pressure

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DRCOLT
1989 3g Colt GT turbo w/4g63t
1988 2g Colt sedan turbo w/4g63t +++++

The motor came mostly complete, i needed to get a tb which i found a 90 tb with black isc and i needed a turbo/exhaust manifold, i had a small 16g setup left over in my garage from old dsm days and its in good shape. Im going to be using the 92 intake manifold because its 2.5" compared to the 4g61 2.25" bore.
I bought a 90 ecu with eprom and new caps
PR 1g fmic kit
clutch/flywheel
new front axels

Started the swap a few days ago, Im going to leave the 92 oil filter housing on the block and go with an aftermarket oil gauge which i dont have just yet, i tore out the 4g61 and removed all the vacuum lines and solenoids including the FPR solenoid (not sure if im gonna get a CEL need confirmation if someone knows), removed the ac, ac lines, and ac fuse box. and filled my existing mounts with window weld to stiffen them up. Im gonna start putting the 6bolt together on monday, i need to remove the balance shafts and do the timing belt as well as install some 3g lifters I have.

Not sure what im going to do about the exhaust, Im crossing my fingers that i have enough clearance to bolt up the existing exhaust, im not sure if its the stock exhaust or not, the car did come with a 14b already installed as well.

the stock fuel pump will have to push the black top 450s on low boost until i gather some more funds i might re-install the fpr solenoid until i get the fuel pump and afpr

gonna see if i can use the 1g starter plate or if i have to use my CSM starter plate and ill post that info later since people were unsure.

the only thing im worried about is the guy was trying to remove the existing flywheel before he shipped the motor and said the motor turned a little bit being that he didnt have the timing belt installed im concerned for bent valves but he told me the valves were shut and the cams weren't installed at that time.

When i was cracking off the flywheel bolts myself i rotated the motor quite a bit here and there but i removed the cams before hand so the valves were closed.
My question is when resetting the engine to TDC should i set the crank to TDC first then install the cams at TDC or set the crank to 90 past TDC (so all the pistons are half stroke and install the cams and set them first? Everything ive read says the set the crank to TDC first but has no mention of making sure the valves are closed because they all assume the motor is in time still...thats not the case for me because the crank has been rotated with the timing belt removed

Set it however it makes sense to you. But as long as you assemble everything at or near there respective timing marks (cam dowels facing up) you will be just fine.

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R

My timing belt job was successful now I'm trying to figure out how to mount the 1g punishment racing fmic kit