Duratec / Mazda L-Series MZR I4 2.0 / 2.3 / 2.5 Swap

[DPDISXR4Ti]

There are several vendors making various needed bits for Duratec swaps. I've mentioned some already and should probably put them all in one post for easy reference. That'll be for another day. For now, here's one I hadn't heard of until a couple days ago:

https://xl1racesupply.com/collections/ford-duratec

For the old skool type, they have an adapter so that you can use a Pinto intake manifold designed for a carb setup.

<11/1/25 Edit.... I have made the second post in this thread a "Duratec Vendors" post>
https://forum.merkurclub.net/forum/view ... 84#p366784

[DPDISXR4Ti]

Some tidbits from Brian Axup at Esslinger on building a junkyard 2.5...
...if you're going to go Junkyard Dog on it, start with a 2.5L and swap out the front timing cover for an early VCT 2.3L from a 2006-09 Fusion, then put the necessary crank and cam sensors on for your ECU as well as the right coolant necks, alternator, 2.3L Ecoboost waterpump, and the intake manifold & throttlebody that best suit your swap.

...the early 2.3L VCT timing cover has external access to the detent for the tensioner. If you ever need to remove the cam gears with the engine in the car, having this access point to the tensioner is priceless.


Bringing this topic back up as I noticed on my last junkyard trip that there are lots of 2006-09 2.3 Fusions in the junkyard these days - 14 actually, as I check their on-line inventory) Thought it might be fun to pull a front cover from one some day, so I did a little research. A 21mm socket is needed for the crank bolt, which will likely be the tough part - a battery powered impact may not be enough. Given that, plan on pulling a spark plug (16mm spark plug socket), and stuff some rope down the hole to "soft-seize" the engine when you rotate it. The crank pulley should come off easily once the bolt is out as it's not an interference fit to the crankshaft.

Related note... The latest 2.5 uses a 24mm socket for it's crank bolt along with a diamond-encrusted lock washer.

[DPDISXR4Ti]

I guy by the name of Trevor Smith ([email protected]) sells this alternator kit for the Duratec. He sells it mostly to MG guys, but we might also find it useful...

DuratecAltKit.jpg

[my8950]

I guy by the name of Trevor Smith ([email protected]) sells this alternator kit for the Duratec. He sells it mostly to MG guys, but we might also find it useful...

Bracket looks good, pretty beefy, but good...
Having options is good!

[andyofcolumbusmerkur]

Belt friction at the alternator seems optimized and I approve of over built braket.

[DPDISXR4Ti]

I've invited Don Haulsee to share some of the details on his two 2.5 Duratec builds. In the mean time here's one of the details he shared with me. I should preface this by saying I've pretty much given up on using a factory PCM and am leaning towards using a Speeduino from SpeedyEFI.com. Assuming a 2.5 donor from a Ford Fusion, you'd want the additional items from a Mazda donor...

2006 - 2012 Mazda w/ VCT Coils, Valve cover, & crank sensor. They are smart coils and the sensor is Hall effect. The coil boots are different on VCT vs non-VCT heads, not actually related to engine displacement as all 3 displacements are available with VCT and only the 2.0L and 2.3L are available without VCT. The Mazda crank sensor works fine with the Ford 36-1 trigger wheel.

Most common Mazda donor would likely be a Mazda3.

[DRHaulsee]

Hi all. It's been at least 5 years since I posted here. I've owned 7 XR's beginning in 1998 although I currently don't have one. My claim to fame is that I'm one of the early adopters/developers of the Folvo conversion (Volvo 16 valve head on a 2.3 block). I built two such engines that went into Euro Capri's, MGB's, and FC RX7's. All of those car are also gone.

Beginning around 2016 I began to swap 2.5 Fusion Duratecs into RX7's and RX8's. In this post I'm going to go over some of my experiences doing so. Let me say I currently have a 2008 RX8 with a turbo 2.5 Duratec, a 2006 Mazdaspeed6 (with a 2.5 bottom end), and a 2009 Mazdaspeed3. The Speed engines aren't really suitable for swapping due to them having early version of Direct Injection.

Why did I move from Folvo's to the Duratec? Quite simply it was cost, availability, and effort required. A Folvo is custom EVERYTHING while a Duratec is dirt cheap, available everywhere, requires essentially zero machine work, and is a modern DOHC, 16 valve, VVT, all aluminum block. Speaking from personal experience, blow one today and pick up another at almost any junkyard tomorrow for a pittance.

Previous posts have discussed many of the design aspects and parts availability for the Duratec. I'm going to go over what I'm running and pitfalls I encountered.

I prefer the 2012-2016 2.5 Fusion Duratecs. The timing chain system on these are rock solid unlike the earlier 2006-2010 2.3's. The 2.3 versions (particularly the Mazda ones) suffer from timing chain wear and failed VVT's on the intake cam. A failed VVT can easily bend a bunch of valves. The Fusion engines are cheap while the 2009 - 2012 Mazda6/CX7 engines tend to be substantially more expensive and I don't think the timing chain is as rugged as the Ford unit.

For my 2.5's I use the 2.3 Fusion 36-1 harmonic balancer as it is the 6 rib single belt style. This is shorter and fits my RX8 better. Bear in mind that changing that pulley isn't a simple job. There are no keyways and proper timing tools are required. Also, diamond coated friction washers are used and the harmonic balancer bolt is torque to yield. Don't skimp, buy a new bolt and do proper timing. The consequences are severe.

The Ford coils are dumb coils. An aftermarket (MegaSquirt or Speeduino) can't fire these coils directly. An ignitor is required. At first I used a Bosch ignitor with Ford coils but found that knock off Bosch hardware was less than reliable. Beginning in 2006 all Mazda versions used smart 3 wire coils. The coil bolt pattern is different from the Ford coil so a Mazda valve cover must be used. The Ford crank sensor is a 2 wire VR design and must use shielded wire while the Mazda version version is a 3 wire Hall effect. The Hall effect sensor is much easier to deal with.

Intake manifold options are limited as most Duratecs are for front wheel drive applications. The Ranger unit is a no-go in a car application. It's too tall. A NC Miata intake can be used but there are a few things to watch out for. The NC intake is a variable length runner two piece design. The inner part is aluminum while the outer is plastic. The plastic part holds boost pressure with no problem. I've used one in the past and simply locked the runners in the short path. The ports on the inner side of the aluminum piece are shorter than the ports in the 2.5 head. I have ported these to match in the past. There isn't much surface above once they are port matched. Check sealing carefully here. The other issue is that the plastic outer intake will hit the PCV block on the side of the engine and prevent the bottom of intake from sealing to the head. That intake leak is very difficult to find unless you know this is an issue. The other items with the Miata intake are it is a drive by wire throttle body and the throttle body points awkwardly out the side. Piping to this can get difficult. It is very hard to find a cable throttle body that will bolt directly to the Miata outer intake. Ecoboost and Mazdaspeed intakes can't be used as they have eight intake ports rather than four.

For the RX8 I used a Miata inner and then made an aluminum weldment to bolt to the inner. (I need to figure out how to post pictures here). This allowed me to use my throttle body (1989 Supercoupe) with no adapter.

There are some aftermarket intakes but they are pricey.

Transmission options are confusing. There are several possibilities:
T9 with a bell housing from the UK. (Not my cup of tea)
Ecoboost MT-82 (I don't know much about this)
Ranger (Shifter under the dash although it has been done in a Fox body)
NC Miata N7 5 speed (nice transmission but not the strongest, twisted about 10 degrees, mount is a unique Power Plant (PP design) that ties trans to diff)
NC Miata 6 speed (Nice transmission, stronger than the 5 speed, also twisted about 10 degrees, PP mount end to be expensive as MIata owners are looking for them)
RX8 with an adapter plate (Series 1 are weaker that Series 2. PP mount, Series 1 are cheap, Series 2 not so much and are essentially identical to the NC 6 speed internally, adapter plates are available reasonably priced from RX8 Gearbox adapters in the UK, CAUTION - this adapter is only about 6 mm thick)
Esslinger adapter for a T5 (I built one of these for a friend. I don't consider it a fully developed option for street use, all the required parts get expensive)
There are other possibilities with adapter plates. Having said that I have experience with using the Miata 5 speed, the RX8 adapter, and the Miata 6 speed. I'm currently running the Miata 6 speed.

More later.

Don Haulsee

[DPDISXR4Ti]

Thanks for posting Don. Did you consider using the MX-5 2.0 intake manifold? Since the runners are a seperate AL piece, it looks like it's easy enough to modify. https://youtu.be/_e9CnYe_2qI?si=n-e1281d3d6Z7Ku3

But even used, they tend to be expensive and there's risk for errors given that the AT version is different from the MT version (no flaps). It might be easier to just get the Brazillion intake that's made for the 2.5 out-of-the-box.

[DRHaulsee]

Brad,
I discussed using the NC Miata intake in my post. I used a full NC Miata intake on my first install in an RX7. At the time I didn't recognize that the plastic part of the intake interfered with the PCV housing. The intake didn't seal along the bottom edge resulting in a vacuum leak.

RX7_7_11_21_2.jpg

For my RX8 I used the inner aluminum piece ported to match the 2.5 port. There isn't much material on the top of the intake ports once that's done.The picture below shows that as well as the mockup of making a bolt on outer intake.

INtake Mockup.jpg

Here's the intake mounted on the RX8 engine.

RX8_INtake.jpg

[DRHaulsee]

And here is the completed install with the RX8 covers in place. This got it through inspection as it was visual only. The inspector even told me how much he liked a turbo install on a rotary engine. He'd never seen one before.

Covers_Mounted.jpg

[DPDISXR4Ti]

Brad,
I discussed using the NC Miata intake in my post. I used a full NC Miata intake on my first install in an RX7.

Good grief, I really should try reading!

That really is an odd angle/location that the TB comes out. It looks like your TB cable makes quite a bend. It's too bad DBW isn't a viable option.

The forward-facing plenum you made (?) looks a little more conventional.

[DRHaulsee]

Brad wrote:
"That really is an odd angle/location that the TB comes out. It looks like your TB cable makes quite a bend. It's too bad DBW isn't a viable option."

But DBW is if you want to run a Haltec. Tuned By Shawn can set that up for you on an NC harness. Mind you, it's not cheap.

What do you want to discuss next next? Clutch/flywheel woes? Or perhaps oil pan, turbo lubrication, and turbo drain? Or, turbo manifolds/turbo? Or, coolant return from the back of the head?

[DPDISXR4Ti]

What do you want to discuss next next? Clutch/flywheel woes? Or perhaps oil pan, turbo lubrication, and turbo drain? Or, turbo manifolds/turbo? Or, coolant return from the back of the head?

We haven't really covered clutch/flywheels, so that's probably a worthwhile topic.

[DRHaulsee]

Brad and I had a conversation off forum about cam trigger pattern. Here's that bit:

I said:
"The Speedy (https://speedyefi.com/product/fishdog-u ... duino-ecu/) supports VVT but the Duratec cam wheel sensor isn't supported. It has 6 lobes and no one has written a decoder for that. While you have the valve cover off cut all but 1 flag off the intake cam wheel at the back of the cam"

Brad replied:
Does this ^^ make it look like a Mazda cam, and thus you can use the VVT decoder written for Mazda? Would you then need the Mazda VVT solenoid/sensor in place of the Ford?

Let me clarify. The early Mazda (2004-2005) used a 5 tooth trigger pattern as did the Ford Zetec. The Ford ST170 in Europe used that same pattern. In 2006 both Ford and Mazda began using a 6 tooth pattern on 2.3's and 2.5's. Speeduino has a decoder for the 5 tooth pattern but not the 6 tooth. I think Megasquirt has a decoder for the 6 tooth pattern but it seems to be hidden and requires some effort to get to it. Both Speeduino and Megasquirt will support sequential and VVT with a single tooth cam wheel.

The Ford and Mazda (excluding Mazdaspeed engines) use the same Hall effect cam sensor. In the case of Speeduino make sure the signal back to the ecu is between 3.3 and 5 volts. I'm not sure if MS has that restriction.

Here's a photo of the 5 tooth pattern. Not my photo. I got it from the Speeduino manual.

Cam Pattern_5.jpg

Here"s the 6 tooth pattern. I got this from the web someplace,

Cam Pattern_6.jpg

[DPDISXR4Ti]

Thanks Don, but still a little confused. You suggested I cut off 5 of the 6 teeth. If so, which one stays? Or doesn't it matter?

Can it really do the job correctly with just one tooth? Would it somehow do it "better" with a 5-tooth trigger?

Similar question, asked differently... What does the factory PCM do with the input from a 5 or 6-tooth trigger?

In the Speeduino manual, I do find this...

For standard VVT operation (including open-loop and single VVT control), the primary requirement for VVT functionality is a stable and accurate cam signal, which a single tooth cam trigger used in conjunction with a multi-tooth crank trigger provides.