At least part of the point of doing tech stories in Speed News is to make mistakes for readers, and document them, honestly, so readers don’t have to make them when they attempt to do the work. The 2.5 swap into the 2006 Mazda MX-5 I’m currently undertaking is a perfect example.
One of the modifications necessary for the swap is cutting away the motor mount boss on the timing cover. The 2.5 came out of a front-drive car, but the mounting boss used to secure the engine under the hood of the Ford Fusion it came out of gets in the way of the serpentine belt when adapted to the MX-5. Because the Fusion uses two drive belts, there’s no way to route the belt on the MX-5 using the Fusion tensioner and idler. You have to remove the three studs, then cut it so you can route the belt as it is on a stock 2.0 liter.
As I mentioned in previous columns, the information on the internet for doing a 2.5 swap is a bit like the “pirates code,” more like guidelines, really. Helpful, not great, and certainly not something that would prevent me, the reader from making mistakes.
Some of the information online is on YouTube in video form, and some is stashed on various websites. As an erstwhile magazine editor, I’m still convinced the best way to do tech stories is words and pictures. Video has its place, but most of the self-filmed stuff on YouTube just doesn’t contain the level of detail needed to help the reader to avoid mistakes.
Almost expectedly, the timing covers shown in the 2.5 swaps online are not like mine, so I cut it as best I could, in a way that mirrored what I saw online. As you might imagine, when I bolted it on and routed the belt, it was still in the way. So I cut it more, and ended up cutting a small hole through the cover into the timing chain cavity.
So I had to take it back apart, scrape off all the gray RTV, and then figure out what to do about the hole. That was a mistake worth warning you about. Test fit the cover and the belt before you seal it with RTV, and it’s not necessary to cut off as much as I did.
It reminded me of all the kids’ toys, Legos and build-it-yourself furniture I’ve put together over the years. Inevitably, there comes a moment where you have to disassemble some portion of what you’ve just put together so you can include a critical piece you forgot. Call it the “IKEA moment.”
I used to get frustrated by it, but only recently — after decades of messing with cars and engines — have I come to realize that it happens so often, I should expect it, and not be aggravated by it. Embrace it, even. That happened just last night in the garage, and it spawned the idea for this column, which I’m writing the following morning. Funny how that works. One activity is source material for another.
The hole in the aluminum timing cover was small, so rather than taking it to a welder and stalling the job even further, I put some electrical tape over the hole on the outside of the cover, mixed up some JB Weld and set the cover in a vise so that the epoxy would “puddle” over the hole. The tape supported the JB Weld and the next morning it had cured and covered the hole as I hoped it would.
I think it should do the trick, and I made sure to take pictures of everything in the event you decide to do this swap and end up with the same timing cover I had. You will know what to expect and you can avoid at least one IKEA moment in your life.