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Engine Swap Compatibility 2.3 to 2.5

26K views 26 replies 9 participants last post by  VWandDodge 
#1 ·
I am replacing the engine on my 06 2.3 due to excessive oil consumption. 2-3 quarts every 300 miles.

I am looking at getting a 2.5 off ebay and am also considering replacing the manual transmission. Does anyone know is the later transmissions will bolt into the 06 3? I believe the are six speeds? (2010 -2012). If I replace the TCM will it work? Mainly I am concerned about bolting it on, the linkage, etc.

Also, will the later Mazda 2014-15 work as a core? Is it possible to get these engines to work with the older 04-09s?
 
#2 ·
I do not believe the SkyActiv engines are easily transferable to a Gen 1 Mazda3; that includes all of the Gen 3 engines as well as the later Gen 2 engines. You might be far better off using a Ford Duratec 2.5 liter motor as it is virtually the same motor as your 2.3.
 
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#3 ·
There is info about the 6 speed swap on here. It's doable, but it's not a drop in by any means. You've also got to swap the axles, spindles, and linkage.

Skyactiv will not work because of massive ECU differences.
 
#5 ·
I just purchased a 2010 Mazda 6 2.5 with 69k engine shipped to my house for $380. Hopefully I can it to work. It was so cheap I just took the chance. They have a few of these low mileage 2.5 for clearance sale right now. Check ebay. The place is from Philly.

The engine comes with the exhaust manifold so I am thinking I may be able to just drop it in and have an exhaust pipe welded rather than swapping the front cover, oil pan, etc. I will need to purchase an alternator but everything else is there.

Any thoughts?
 
#6 ·
The reason you'll need to swap the timing cover and oil pan is because your car runs a double stack crank pulley, and has the a/c mounted below the motor. Do you have a link to the engine you bought so we can see pics of the engine and exhaust manifold? You may be better off with your original exhaust manifold. It'll bolt on, it's not really worth dicking around trying to make pipe extensions when you already have a drop in solution.

$380 shipped is a GREAT price, and even better is the nice low mileage. Great find!

If you're interested, message me for a throttle body adapter kit. I should have this next batch ready by next weekend.
 
#7 ·
Thanks for the info.

The photo shows the same timing cover that I have. You are right about the pulley. If I want AC I will have to swap the oil pan. I already have the timing tools since I just did the chain on the 2.3.

So far, here is the plan:

Swap Crank Pulley, Valve cover, Flywheel, and Oil Pan.

Use the existing exhaust manifold and hope the cat has some life left in it after all the oil burning.


Uncertainty:

Will a 2010 M6 TB work on a 2006 M3? I understand the Ford has issues but has anyone tried the Mazda version? If not it comes down to purchasing a TB kit or using RV sealant on the intake manifold.
 
#12 · (Edited)
In the cylinder head exhaust ports. It did not come with the manifold like the picture showed.

Unfortunately, I am using my 2.3 intake manifold, though the 2.5 looks like it could work, it has a bad vacuum actuator on it and I can't find one anywhere except the dealer... the attachment for it is located on the top instead of the bottom, as is on the 2.3. Same attachement though. There may be issues with the connector reaching up. Other than that, all the sensors are exactly the same on both engines. Same numbers on them. The egr valve may be different (there were some cars made in 2010 with a different EGR valve), so I swapped that. They look identical though.

Also, the front cover is the same. There is a slightly different angle for the motor mount, which is probably there to solve the mount issues people were having. It looks like a more level angle which seems to put less stress on the mount. I could be wrong, but that is the only change on the front cover and I do not think they did it for no reason.

The engine oil in the engine I received was black. It was starting to sludge in side. I knew there was a reason it was cheap and this was it. It seems the owner followed the 15k oil change rule that the dealers are telling them. Soooo many cars out there now with this issue and failing sticking actuators. I replaced the solenoid and tried to swap the actuator with the one I bought for the 2.3 and the sprocket is different. The 2.5 chain is bigger and beefier. I put the old actuator in and will hopefully be able to clean it out with some engine flushing. If not I will replace it. Lesson learned, money saved could have been put towards an engine that was in better shape. I just jumped on this buy early in the morning after drinking a few beers. Figured $380 I could part it out... I decided to use it since the plugs look good and the compression is great. We will see. Most likely I will be pulling it apart again to replace the actuator.
 
#13 · (Edited)
Also, I should add that a vcst delete does not seem possible with this intake since they put the sensor at the top on the shaft itself. It also looks like a digital sensor where the 2.3 has an analogue looking sensor. You would have to put the shaft back in. So to use the mazda 2.5 manifold you would have to attach the old one and leave it hanging somewhere while rigging up the shaft some how. The two are different sizes so you cant swap them. All this just did not seem worth it to me. The gap on the 2.3. intake is nearly non existent and rtv saelant is quick and easy.

This could be well known here, but just letting people know the actuator valve on the mazda intake could be main issue, making it no better than the ford intake. The TB however looks identical and has the same size servo motor on it. As opposed to the Ford TB which is a completely different looking unit.
 
#14 ·
You can use the Fusion 2.5 intake and leave the flapper components hooked up without actually doing anything. It's ugly, but it works perfectly.

Right now I'm running the Fusion 2.5 intake manifold, a Speed3 throttle body, and version 2 of my evap port adapter. Car runs phenomenal. I have no check codes.

As you can see below, the passenger side solenoid is plugged in, but not plumbed. Drivers side is plugged in, plumbed to the flapper sensor. The flapper sensor is just tucked into the harness, and is NOT attached to the manifold (Fusion doesn't have the flappers anyway).
As far as the ECU is concerned, the system is 100% functional. All system readings on DashCommand show well within parameters. I've had the system setup this way for almost 10k miles now. Just installed the Speed3 tb last week. If you're interested, I can sell you the side port adapter instead of a full kit. Let me know. I like seeing these swaps get on the road the best way possible. I also sell the oil dipstick handles shown.


 
#15 ·
I just started it and it runs great! Miraculously no codes. Only issue I had was the coolant hose from the res hit the serpentine belt and I had to get a universal hose for it.

I am using the original intake with sealant at the top. If I decide to use the Mazda 2.5 intake I will let you know if I need any adapter for it.

On a different note, you are a machinist? I have a cafe racer motorcycle project...
 
#18 ·
I bought a 2012 ford fusion 2.5. I have already pulled my motor and swapped all the parts from the 2.5. I just dropped the motor in the Mazda yesterday. I ran into a bit of a problem. The serpentine belt that came off the Mazda in the first place seems to be to long now. The diagram below is the rout i am going with it and it is too long. I haven't seen any one talk about needing to get a different size belt. Anyone heard of this before. I don't see how i could screw up placements of the pulleys but i suppose if any one could it would be me.
 
#19 ·
As long as you install the accessories in the same orientation as they are on the original engine you're fine. You need to make sure to use the Mazda belt tensioner as well, the Ford tensioner is a different size. I think I installed the mazda tensioner pulley on the Ford tensioner since it was basically brand new. Also, it's easy to get the belt routing wrong and end up with too much slack.
 
#20 ·
I had both tensioner pulleys on at first until i was installing the engine and the ford on on the bottom wouldn't fit cause of my AC lines. So now i have the Mazda one on the top. I looked up the routing to make sure i had it right. Ill triple check again but its weird.
 
#21 ·
Did I read your post correctly, you used a Mazda 6 2.5L Throttle body and it worked with the electronics? A few people were saying in the original thread on this swap that they were not compatible like the Ford ones. If it does thats awesome and good info to note.
 
#22 ·
Who's post? You can use the Speed3/Speed6/CX7 throttle body, which are a direct bolt on to the 2.5 manifold and work with the 2.3 electronics, and it looks like a few people have been able to use 2010-ish 2.5 Mazda3 throttle body as well.

However you still need an adapter for the evap line and a vacuum source for retaining the flapper controls. I sell that kit.
 
#24 ·
2010-ish Mazda3 2.5 throttle body, any year Speed3/6/CX7 throttle body, or your original 2.3 throttle body.

What I was saying in those posts is that the 2.5 throttle body (not including 2010 Mazda3) does NOT work, because the pinout and voltages are different. And I actually need to change that a little. It's not the pinout, it's just the voltages that are different, the ECU cannot match the voltage.
 
#25 ·
I am replacing the engine on my 06 2.3 due to excessive oil consumption. 2-3 quarts every 300 miles.

I am looking at getting a 2.5 off ebay and am also considering replacing the manual transmission. Does anyone know is the later transmissions will bolt into the 06 3? I believe the are six speeds? (2010 -2012). If I replace the TCM will it work? Mainly I am concerned about bolting it on, the linkage, etc.

Also, will the later Mazda 2014-15 work as a core? Is it possible to get these engines to work with the older 04-09s?
I just purchased a 2010 Mazda 6 2.5 with 69k engine shipped to my house for $380. Hopefully I can it to work. It was so cheap I just took the chance. They have a few of these low mileage 2.5 for clearance sale right now. Check ebay. The place is from Philly.

The engine comes with the exhaust manifold so I am thinking I may be able to just drop it in and have an exhaust pipe welded rather than swapping the front cover, oil pan, etc. I will need to purchase an alternator but everything else is there.

Any thoughts?
Hi..could you help me to find an engine like the one you got..i'm not seeing any for that price..i'm garyyoung94@yahoo.com..
 
#27 ·
Someone correct me here, but the only major difference should be the flywheel setup if the donor vehicle is an automatic and the bell housing and flywheel are still attached. There are other swap threads here which discusses this, so take what I've posted with a grain of salt. I didn't want you to be ignored but also don't want to misinform you.
 
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