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Old 12/14/2006, 07:40 PM   #1 (permalink)
Ripp'd 3.5L
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Location: Alamogordo, NM
Vehicle: Eclipse GT 2005
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HOW TO install a 6G74 engine . . . .

How To. . . Swap a 6G74 in a 3G

For starters, You will need the following:

6G74 engine from a Mitsubishi Diamante (1997-2004)

Upper Alternator Bracket
Upper powersteering Bracket
Vacuum Hose (you will need about 6 feet or so, i believe the size is 8/32)
A/C and Power steering belts
2.5 inch pipe connector
Oil Filter
Can of WD-40 or PB spray. . . . (lubricant spray)
Can of Brake Cleaner
5 Quarts of Motor oil (yes 5 quarts, not 4)
3 Quarts of Transmission fluid

Optional items

Motor Gunk remover (oil aditive)
Coolant flush kit
Spark plugs
Ignition Wires
Distributor cap
Distributor Rotor
Timing Belt
Rear crank oil seal

Recommended but still optional items

Tactrix Reflash Cable
After market Clutch (for those with a 5-speed tranny anything above Stock)
Solid front and rear motor mounts

Things to be modified

Axle bracket
Starter locator plate
Retainment of a EGR system sensor from the 6G72 (will specify later)

Recommended to keep items

Throttle body from 6G72 (unless you would like to modify the "D's" T.B. to fit)
Fuel injectors from 6G72

And finally the Tools you will need:

Wrenches, sockets of sizes from 8mm up to 17mm
Wratchets in sizes of 3/8 in. and 1/2 in.
24mm socket
32mm socket
Ball joint puller
Breaker bar (12+ inch in length)
Car Jack
Jack Stands
Engine Hoist (with load stabilizer preferably)
Wratchet Extensions (for those hard to reach places)
Pipe cutters (also known as Exhaust cutters)
Table grinder
Carbide dremel bit shits (dont know the exact name, but yea. . .just like dremels except made of carbide
Drill and Drill bits
Wood block (or something of equivalent nature)
rubber mallet
Oil pan (4 of these)
Rags (if your messy. . . buy a couple rolls of shop towels)

I would recommend to work on this in a garage, as it will take approx. 3 full days of work (thats if your speedy)

A few notes:
Buy a few ziplock bags to place screws, bolts, nuts etc in to keep from loosing them. Or do as I did, buy a bucket from depot and throw in everything in their . . . Got to admit, it’s a little hard to work with, but least I didn’t lose anything.

Use Color electrical tape and a permanent marker to help you mark all the vacuum tubes and such. The electrical connectors are all different, so no worries their (no need to mark them).

And last but very important note. . . .For spills and stuff, buy a nice big bag of kitty litter, as its just as absorbent, if not even more absorbent then the stuff auto shops use to clean spills. Not to mention it’s a hell of a lot cheaper.

Everything EXCEPT for one sensor clips, bolts back on. The sensors on the 6G74 are located on the side closest to the throttle body, versus what the 6G72 has (on opposite side of throttle body). And i believe the one sensor has to do with the EGR system. Every sensor clip reaches its spot of connectivity without the need of extending any wires. That alone, makes this swap probably one of the easiest ones out their. For that one sensor, all you have to do is switch it out for the one on the 6G72 and NOW everything clips/bolts right back on

Now we Begin. . . . .

Start by placing your 3G on a flat, plain, level, etc surface.

First step is to disconnect the fuel pump by lifting the passenger seats. you should see a metal plate with 4 screws on it. . . remove them and disconnect both plugs that you will see under that metal plate. Once that is done, crank up the engine (yes turn the car on) and let it die out. This will relieve your fuel lines of pressure NOTE: their will still be fuel in those lines so when you come to disconnecting those lines. . . do not forget that their is still fuel in em.

Your going to want to remove the hood, as it will defiantly bug the crap out of you if you pull this engine out from the top. (follow a How to: after market hood install, as it should say how to remove the hood)
Also remove the Strut tower bar.

Now, Engage your emergency brake and start lifting up the front end on 2 jack stands. Follow by removing the wheels. At this point we will be removing the Axles. Start by Removing the 24mm bolts/nuts from the struts (2 on each steering knuckle). once that is done, you will want to remove the tie rod on THE DRIVERS SIDE (use the ball joint puller. . . looks like a giant fork. This will enable you to pull out the axle from rotor. Once that is done, use that same ball joint puller to seperate the axle from the tranny. Meaning put the b.j.p. in between the tranny and the axle and smack it with the hammer to pry the axle out. Now for the Passenger side axle. Locate the axle bracket and unscrew 2 bolts that hold that bracket onto the block (i cant remember if its either 2 or 3 bolts. . . . ) Now pull the axle out from the Rotor (very little room, but it can be done), once you've done that, place a oil pan beneath the Axle end that connects to the tranny, as when you pull this axle out. . . . tranny fluid will follow. Now pull the axle out and that should drain most of the tranny fluid.

Now that we have both axle's out, We will want to remove the manifolds. Start by spraying EVERY SINGLE nut and bolt you find and let em soak for a few minutes. Your going to want to remove the manifolds and downpipe. . . .(refrence How To: install headers for more detail)

Next start by disconnecting the battery and placing it on something other then concrete (it will drain the battery). If you have a cold air intake, remove it. If you got the stock intake. . . remove that mega contraption. Then remove the battery tray.

At this point your going to want to start draining all the fluids. So . . . that’s what we will do. Drain the Tranny (17mm bolt on bottom side of tranny), drain the engine (should be either 14 or 16mm. . . cant remember), and now drain the coolant (plenty of ways to do so, by removing a hose, or doing it the right way. . . drain from the radiator) Once the coolant is drained, disconnect both radiator hoses.

To give yourself plenty of room to work with, Remove the radiator. Two brackets hold the radiator down, each bracket has 2 12mm bolts, remove those bolts, remove the 2 brackets and disconnect the fan electrical plug from the wiring harness and pull the radiator up and out.

Here’s the fun part, start disconnecting every single electrical wire that connects to the ECU wire harness. This should take a good 2 to 3 hours or so. ( reason is, some sensors are in hard to reach areas)

Once that is accomplished, if you have a 5 speed tranny like I do, disconnect the 2 linkage cables from the tranny’s linkage. DO NOT LOSE THOSE PINS AND WASHERS. For those with an auto tranny, disconnect . . . .Remind me later to name this damn thing. . .

Next your going to want to remove the 2 heater hoses (on back side of the engine, connected to the firewall) Keep your coolant bucket handy as, your going to have more coolant come out.

Now as for the powersteering pump. . . . lets do this the smart way and unbolt the pump from the block, instead of disconnecting the whole thing and draining the fluid.

And finally, your last thing to worry about. . . . A/C Freon. Remember these lines are pressurized, follow your local law’s of disposal of Freon, as venting to air is a bad thing for the environment (good for saving your some money lol – I am not saying do this at all)


The only things holding the damn motor and tranny in your engine bay are the 4 motor mounts

Depending on which way you are going to remove the engine and tranny (meaning lifting it out, or dropping it from the bottom), you have to be very careful and not hurt yourself by not doing things the right way. Always have some external source holding the engine and tranny, such as an engine hoist. Your going to want to use a load stabilizer to be able to tilt the engine to be able to remove it since it’s a very tight fit.

For the sake of this HOW TO, I will assume most people will want to “pull it from the top”. . . so. . . here’s how to do this. Unbolt the motor mounts preferably in this order. . . Rear, front, driver side, passenger side. Now since we are pulling this engine out from the top, we need to remove the brackets that hold the mounts in place. Do that, then finish by removing the cross member. Once that is done, assuming you are using a load stabilizer, tilt the engine at about 65-70ish degrees, engine side up. This will allow you to clear the frame and be able to pull the engine and tranny out together.

Depending on what type of tranny you got, the separation of the engine and tranny will be different (for those with 5 speed, you have to disengage the T.O.B. in order to separate the tranny from the engine. . . I don’t know about the auto tranny)

Here's a brief "how to" on seperating the 5 speed tranny from the engine

Do you see this (its the lever that the master clutch cylinder pushes on). By FAR!!! this is the easiest way to access the throw out bearing and not to mention getting it to release is a peace-o-cake!. To start, remove the master clutch cylinder (unscrews by two bolts, no need to disconnect the pressure lines at all). After that. . . Remove the rubber boot like so ( look below)

After removing the boot you should be looking at this. . .
Now to disengage the throw out bearing stick a flat head screw driver between the throw out bearing and the bearing on the pressure plate (dunno if its called a bearing or not lol, lil metal circle shit that hooks onto the the throwout bearing), now keep the screw driver in their and push the release lever to the right (yes. . l. to the right, this pushes the throw out bearing towards the pressure plate. Now twist the screw driver and at the same time start letting the lever off a lil (the screw driver will be pushing the lever. . thus you will begin to feel this on the lever. . . so . . . .release the lever slowly!). Now if done right you will hear a lil "ClIcK" and you now have successfully disengaged the throw out bearing (not to mention another way you'll know if you disengaged it is be looking at the lever . . . it should now be positioned all the way to the left. )

and now. . . for the throw out bearing!

Notice the design of the throw out bearing and the release lever. Only way to get that bearing out is to remove the fork too! :cry: Might i add, its a pain in the ass.
Now. . . ya see this lil circle cap thingy (on the picture below, it has some lil chips on it, from me trying to pound it out lol)

That lil cap needs to be pushed out, in order to do that, you need to push it out from the inside of the bell housing. So. . . . wut i used was a small hex nut and a C-clamp. I positioned one end of the clamp over the the cap (with the hex nut inbetween), and the other end i positioned on the outer shell of the bellhousing. I tightened the clamp up and poooof, the cap pops right out.

Now, refrence the first picture in the above post, unscrew that brass lookin bolt (on the top right in the picture) This bolt holds the lil bar that the lever sits on. After you unscrew that, start pushing the bar towards the cap u just unplugged.

NOTE!!! Remember what position the lil springs are in, or else you'll have to do what i did and that was . . . spend about 20 minutes trying to figure how the damn springs go on . . . :x

Now you should see this

The bar should now be pushed through the lil hole u just made (uncapped hole) and now since you pulled the bar out, the lever should just be chillin ready to be pullout along with the throw out bearing.

Now to re-install. . . .Go backwards lol

Once you have them out and seperated. Start by transferring the alternator over to the 6G74. You cannot use the 6G72 upper Alternator bracket as the 2 bolt holes sit too high for the alternator to reach. Do not put the belt on if you left the power steering pump on the car, as that belt installs behind the alt. belt.

Before transferring the flywheel / torque converter over to the 6G74, mount the tranny onto the block, this will allow us to mark the SLP where it will need to be cut/grinded. I would use some sort of ink/paint to allow you to mark the outline of the tranny’s starter housing onto the SLP when sandwiched together. Once you got the outline, start modifying the starter locator plate to match the tranny’s housing. I DO NOT KNOW if you can use the 6G72 starter locater plate to skip all this process (no one has tried this yet) so tis why we are modifying the 6G74 SLP.

Once that is done. . . .

Transfer the flywheel&clutch / torque converter over to the 6G74. I will advise those with a 5 Speed tranny to. . . .DO NOT USE THE STOCK CLUTCH, as it will slip! (yes. . . I know by experience)

this is what i used for my clutch.

BE WARNED!!! Bolt the flywheel onto the crank right! Or ELSE!

This is what happens if you put the clutch centering plate inbetween the flywheel and crank. It causes the flywheel to stick out an addition 4-5mm closer to the tranny. . . causing the pressure plate to rub against the inside of the bellhousing, inturn putting severe pressure on the crank bolts, eventually. . . . .you'll have wut i got. Oh and ummm be sure to use LOCKTITE. IMO you should use the RED type. Blue will do fine.
Before we start putting everything back in. . . . here are a few more steps to follow

Using a bench grinder, grab the passenger side axle and mill off 1mm of material off of the bracket, this will allow the bracket to sit flat against the back of the 6G74 block.

Decisions. . . decisions. . . If you decide to keep the throttle body off the Diamante, make sure it’s a T.B. made from 1997 to 2000 as the 2001+ models will defiantly not clear the firewall. For those from 1997-2000 you will need to remove the cruise control solenoid in order to just barely clear the damn firewall. For the sake of time, I kept the 6G72 throttle body. It bolts right on.

notice how the throttle body is a bit taller (6G74 on left. . . gold dish lookin thingy), that hight will hit the fire wall

. . . . .since the engine is out of the engine bay, at this time I’d recommend to change the spark plugs, wires, distributor, and rotor.
Also if you do not want to tune . . . I’d stick the 6G72 injectors on at this time. As it is soooooo much more freakin easier to do this at this time.

As for the sensor to be traded for the one on the 6G72

That sensor that you see on the Diamante plenum needs to be taken out and switched with the one that looks almost identical to it on the 6G72.

Now its time to mate the tranny onto the engine. TAKE MY WORD FOR THIS. . . .if it puts up resistance, meaning if they don’t bolt back on to each other easily, then you F%^(#D up something. Always DOUBLE CHECK your work. As you are at the point of no return (been there, done that. . . )

Before you get to the point of "dropping the engine and tranny back in. . . I'd recommend you have the new belts back on, this way you wont have to deal with pulling off the plastic covers in the passengers side fender well. And also a quick note: Re-use the A/C bracket off of the 6G72, reason being the compressor's bolts will not line up with those on the 6G74's Bracket

Now when dropping the engine and tranny back in, your going to need to put them back in at the same angle as you pulled them out, then leveling them out till its even to the point where you can easily remount the motor mounts back on.

Now, start putting everything back together. . . (follow directions backwards)

Once you get to re-installing your down pipe, the flang's will NOT line up to your manifolds, so this means: You will need to cut the half of the downpipe that leads to the front end manifold (manifold closest to front of car) As a temporary solution I would buy piece of pipe from autozone or pepboys, that piece of pipe is about 5 inches in length, and should reconnect your 2 pieces of down pipe together. When you get a chance, have that permenantly welded so you wont have to worry about it falling off or creating rasp.

You will have a SES light for the Knock sensor and Barometric pressure sensor (used evoscan. . . this is what it gave me. Also. . . .If you use the stock 270cc injectors, you will have a SES light for that too.**

And before you thing you are done. . . .DOUBLE, AND TRIPPLE check your work (don’t be a smart one and forget to put in the motor oil, coolant, tranny fluid etc)
Rebuilding at the moment... 6G74 3.8L S/C'd setup in the works

Last edited by Dragon34x; 12/14/2006 at 08:03 PM.
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