There are lots of resources on the web about what it takes to perform a 2.5 swap in an NC chassis MX-5, and even though I have read as many of them as I could find, I still wasn’t quite sure what I was getting myself into.

It all started with buying a 2006 MX-5 from Copart that I hadn’t seen in person. The photos weren’t too bad and the website said it ran and drove, so I pulled the trigger. The website did not say it had a tire with a screw in it or that it had a worrying top-end clatter. I also had no way of knowing it would develop a misfire within days of getting it back on the road.

It was then I started looking into a 2.5 swap. Engines were cheap and plentiful through the online salvage parts site LKQ. I found a 19,000-mile engine out of a T-boned 2017 Ford Fusion for around $750. A 2.5 engine costs more when you get it out of a Mazda for some reason, even though they both have FoMoCo cast into the side of the block.

Before you can begin to think about pulling the engine, there are a lot of things that have to come out first, including the battery, coolant expansion tank, power steering reservoir and cooler and the airbox. Then, of course, there’s a lot of wiring connections. There isn’t room to detail all of what it takes, but if you’ve pulled engines from other modern cars before, you have what it takes to do it on an NC.

The first thing to consider when pulling an engine out of an NC chassis is that the only way they come out the top is if you separate the engine from the transmission. That sounded like more work, so it was going to have to come out the bottom. If you don’t have a lift, you’ll have to put the car on jack stands on one of their higher settings so you can lower the engine and suspension out the bottom.

That requires removing or disconnecting the front suspension and disconnecting the brake hoses and the starter, steering column shaft and the cooling system and the clutch hydraulics. This car is getting new-to-me shocks and springs and new stainless-steel braided brake hoses, so I removed them rather than just disconnecting them.

That cross bar right in front of the engine is why you can’t pull the engine and transmission as one assembly from the top. It’s got to drop out the bottom.

To disconnect the shocks, it’s similar to an NB. Remove the sway bar link so you can get lots of droop. Then remove the two bolts on the upper control arms so you can pull the shock out from inside it. It’s similar to the long-bolt procedure on previous generation Miatas.

The first things to remove are the hood, front fascia, wiper cowl trim and the steel access panel in the middle of the firewall behind the engine. Those are all simple jobs, but they do take some time. Based on past engine jobs I’ve done on the NB chassis, I thought I’d be able to take the air-conditioning compressor off the block and hang it off the chassis with mechanic’s wire, but that doesn’t work.

A leveler is a great tool to have no matter what kind of engine you’re pulling. It normally attaches to a pair of lifting eyes, but the NC only has one at the left front of the engine.

If you remove an engine from a NC with air conditioning, the better way to go is to have the refrigerant evacuated first so you can remove the hoses from the compressor without getting oily lime-green R134 refrigerant all over everything. That also will allow you to remove the radiator and A/C condenser as one assembly. The way I did it, leaving the condenser in place while removing the radiator also wasn’t the right way. They’re bolted together with lots of brackets and lines so pulling them as one piece is easier.

You’ll want to drain the engine oil and coolant, but a lot of coolant is going to spill during the job anyway. You’ll also want to remove the battery, coolant expansion tank, power steering reservoir and cooler and the factory airbox.

There’s a wiring harness bracket on the right front of the engine that you can remove to attach the other end of the leveler.

Because the transmission is coming out with it, you also have to drain it first, then remove the shifter knob and the center console. When you get the console out, you can remove the shifter along with the upper and lower shift boots, which likely will need to be replaced. After that, duck underneath the car to remove the driveshaft and power plant frame, and disconnect the four blade-terminal connectors. Disconnect the slave cylinder hydraulics from the top left side of the engine. All this transmission work is similar to NA and NB chassis Miatas.

I had never dropped an engine out the bottom in my garage before. I had seen it done many times with the aid of a lift when I worked in a Pontiac dealership many years ago. Doing the job with jack stands, an engine hoist and furniture dollies from Harbor Freight is another matter altogether.

You can support the transmission from underneath with a floor jack. You’ll need at least one buddy to help you with this job. Lowering the engine and transmission simultaneously requires a couple of pairs of hands. Other parts of the job also would be difficult for just one person.

The idea was to set the jack stands as high as I was comfortable with, then lower the front suspension cradle, engine and transmission onto furniture dollies and roll the whole assembly out from under the car. If I needed to lift the car more to get the engine out from under it, I could use the hoist to lift the front of the car.

Turns out I wouldn’t need the hoist. With no engine or suspension in the car, two guys were able to pick up the front the car while another set the jack stands higher. The engine and suspension rolled out from under the car.

Once you have the engine and transmission supported, you can remove the bracket under the bellhousing, which has two subframe support bolts through it. On the right side, the rear subframe guide pin/attachment stud is extra long, so you have to use a box wrench on it to get it loose.

Once you get the engine out, that’s when you can separate it from the transmission and get it up on an engine stand to begin all the steps to swapping necessary parts from the original 2.0-liter to new 2.5-liter. This part of the story focuses on getting everything out and on a stand so you can work on it. For this job, you need two engine stands, one for the old engine and one for the new one.

The next installment in Speed News will be the detailed processes of the 2.5 swap. Then we’ll show you what it takes to set the timing in a 2.5 MZR — it’s not like anything I’ve ever seen — and getting it back in the car and running again.

The front subframe guide pin/attachment stud is much shorter and can be removed with an impact and a deep socket.
The subframe guide pin/attachment studs on the left side are both short and can be removed with an impact and a deep socket.
With all attachment points removed, you can lower the engine on its subframe and the transmission at the same time.
This will give you a good idea how the front subframe is attached and just how long the rear guide pin is on the right side of the car. They keep everything from moving around too much as you lower the whole assembly.
Here’s a look from the left side as the engine and subframe and transmission are lowered on the engine hoist.
Again, it helps a lot if you have another set of hands to lower everything at the same rate. Even though you drained everything, you are still going to have a fair amount of fluid spills. This is a messy job.
We lowered the engine and transmission onto Harbor Freight furniture dollies because they are low profile, which is helpful for getting the engine assembly out from under the car.
Once the assembly is resting fully on the furniture dollies, you can raise the front of the car to a higher position on the jack stands and pull the engine and transmission out from under the car.
The steering column shaft also has to be unbolted from the steering rack before you drop everything out.
Before you can remove the transmission from the engine, you have remove the starter, which has wiring harness brackets on top of each mounting bolt. There are wiring harness mounting brackets all over this car. Even the left engine mount has a harness bracket on it.
The bellhousing has a lot of bolts holding it to the engine, including two bolts that screw in from the front. Make sure you feel around to get all of them before you try yanking on the transmission.
Even with everything out of the car, it was a bit of a struggle to get the transmission off the engine.
Zip off the pressure plate bolts and the disc and pressure plate come right off.
Flying Miata makes a flywheel tooth locking tool you can use to keep the flywheel from turning when you’re removing the flywheel bolts. This tool also will come in handy when timing the new engine.
Once you remove the flywheel, you can get the old engine mounted on an engine stand.
Image courtesy of Eric Green


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