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Big Mike's 3s 2.5 Swap

25K views 85 replies 11 participants last post by  bigboi407 
#1 · (Edited)
Hello everyone, my name is mike, I picked up a 2004 Mazda 3s for a good price, 3rd gear is blown, and the engine rattles to hell at around 3.5k RPMs, but in all, the interior is very clean, the car all around doesnt look bad at all, 173k on the clock, and it came with Quite a few goodies, and looked like a good opportunity to 1up my neighbor on his mediocre mechanic abilities (Has a shop, a lift, tons of tools, Cant fix anything right, thinks hes Mr. know it all)

17" Advan Racing RG2 Wheels
MSDS 4-1 Headers
EXEDY ZF501 Chromoly Racing Flywheel
K&N Intake

Swap Purchase List:
2012 Ford Fusion 2.5 Engine $425 + $30 gas to pick it up

2004 Mazda 3 5 speed transmission 66k miles $422 Shipped from Canada

Crankshaft bolt ~$15
Mazda stock code- LF0111406

Flywheel bolts ~$6 x6
Mazda stock code- LF0111511

Axle bolts for 04-05 ~$12 x2
Mazda stock code- 9YA021083F

Crankshaft friction washer ~$13 x2
Mazda stock code- L3H511407
Ford code- 1S7Z-6378-AA

Camshaft friction washer (only required if you remove cam sprockets) $13 x2
Mazda stock code- L3K912429

Mazda PCV Valve $15

EXEDY MZK1003 Clutch Kit $ 154.79
MOOG RK620040 Control Arm $ 58.89
MOOG RK620041 Control Arm $ 59.79
MOOG K80235 Stabilizer Bar Link $ 23.79 X2 = $ 47.58
Shipping Ground $ 16.98


it has some shifter mod, im not sure of what, but the gears are VERY close together, I like it, i dont think the missus will like it tho, LOL, there are probably other mods, And after looking at the power output of the 2.5 with everything ill be putting into it, it looks like it would be fun when its done












Aaaaaand How about this one?? Haha..... im shocked it held





And much much more to come, i just ordered my 2.5 with 45k Miles and it is about 100 mile drive away

Im debating on what to do about the transmission, because i can find one from canada with 66k miles for $420 delivered to my shop, or pull one locally and hope it works for about $150, IF i can find one, either way i need one because the one i have is from a junkyard and looks much much dirtier than the engine (not taken care of)

I need to get this going sooner than later because my DD is Cursed and it broke down for the last time and im currently using my work truck, which ALSO needs another transmission
 
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#2 ·
wtf on that bolt though.....

My vote is go with the transmission with likely a return/warranty option and is ready to go, vs having to pull from a junker.

The transmission may have a short shifter plate on it like the JBR or Corksport one.
Don't put it on the new one. They're common to binding the selector, and yeah... means you miss shifts all the time.
A shorter shifter like the TWM is all the car needs. Along with solid shifter base bushings.
 
#3 · (Edited)


Razo shift knob, And im assuming this is an after market shifter of some sort?





ive only skimmed through the FSM a few times, Is there a section with all the engine bay wiring? i looked briefly and didnt see exactly what i was looking for, I ask because there are a bunch of little random grounds all over the place which look Added , EDIT: Just realized the shifter has TWM cut out in it.
 
#5 ·
The shifter linkage lines connect to the plate that shifts on the transmission, if that looks OEM, it may just be so worn out that you had issues regardless of the shifter.

Either way, solid bushings on the shifter base will give a huge improvement after a [working] transmission.

But since you have the TWM already, that should also help.
It's just the fact everything is made of plastic, and it all wears out over time, but the TWM's ball at the bottom is slightly larger than the OEM plastic ball and helps fill the gap a bit more... and doesn't flex.

But the TWM isn't really regarded as being 'awfully short' of a throw.
When attached to a short shifter plate... then yeah, it's stupid short.
 
#6 · (Edited)
Where would i find the Engine/o2/sensors wiring harness Diagram? Ive been searching all day and cannot find the layout of the engine harness (Probably MY Error, Lol)

EDIT: I just ordered a Factory 2004 Mazda 3 wiring diagram Book $18.95 shipped..........

EDIT #2: Just ordered Timing tools, Balance shaft delete & a 5spd transmission with 66k from Canada for $420 shipped to my office =)
 
#14 ·
from what i read in the swap thread and what everyone else said was to use the 2.3 IM and Milans adapter plate
That was before we knew the stock SPeed3/6 throttle body bolts right up to the 2.5 intake manifold, and plugs into the 2.3 electronics. As this way you wont be having to worry about mis matched ports at all, and can actually use the 2.5 intake manifold. :)
 
#11 ·
Ah! Must be a ceiling lamp or something then lol! It looks almost like a screwdriver punched a hole into the thing!

I've heard you have to as well, but I honestly haven't seen a reason why.

But I do know for a fact the 2.5 intake ports are much larger! And certainly don't match up with the 2.3's IM ports.
 
#17 · (Edited)
Heres how the engine sits until the washers and bolts arrive (i did clean up the water block after i took the pic, didnt stand out until i took this pic, then i realized, damn thats caked up





I need to buy a pigtail connector for the solenoid, mine was cut so short to the connection i cant use it, Part # WPT-1251
 
#21 · (Edited)
im not TOO happy about the outer case condition, but it is from canada, inside the bellhousing looks spotless, Aside from the rust, they look identical, is it possible to change out AT LEAST the rear cover of the transmission?id change over Everything thats rusted out if i could

 
#30 ·
Bigboi407, Milan's adapter plate works, but it's not ideal. His plate isn't port matched to the head, so you end up with a section of port that is permanently covered. This doesn't help flow characteristics at all. By default, the 2.5 tb cannot be used, because while the connector is the same, electrically it is very different (different voltages, etc). The 2.3 tb is maybe 1.5mm smaller in diameter (bore size) compared to the 2.5 intake manifold, but does not bolt on.

I'm producing adapter kits, available next week, that will allow you to use your 2.3 tb on a 2.5 manifold, to do things the right way. If you are interested, send me a PM
 
#31 ·
The intake plate was the 1st fix people found to make the swap work. But since then much better options have come about. Using the 2.3 intake manifold on the 2.5 is really a last ditch effort to make it work, and is in no way optimum because of the mis matched port sizing.

Going with the Speed/cx7 Throttle body like mentions is a vastly better option that wont involve any adapter, or spacers of any kind.
 
#32 ·
Yes agreed i ran the adapter plate for 2 or 3 months no cels it ran but was a bit wacky on power i switched to stock 2.5 i/m and cx7 tb with 2.5 injectors and fuel rail and it was a whole new machine. Like night and day my experience switching the i/m was kind of a pia but well worth it. Imo its the way to go and i have no cels still

Sent from my SM-G925V using Tapatalk
 
#34 · (Edited)
So what do i have to do to get this 2.5 swap to work? the How-To's are all misinforming and vague, now all a sudden the adapter plate method went from #1 option to completely thrown out the window, on top of a $100 adapter plate that is now useless i have to buy a CX7 throttle body to put onto the 2.5 IM, is what you guys are saying? how is that done with the vacuum and other differences, this wasnt specified anywhere

i hope there arent anymore surprises (no pun intended), ill just be really pissed off if i threw all this $$ down for nothing
 
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