: This thread is intended to spark a discussion and could possibly evolve to an actual swap being attempted. Please avoid turning it into an insult-fest or pissing contest. People I'm hoping will join the thread have been through the common swap and have a lot of insight.
Background: I normally find the idea of engine swaps on vehicles built after 1995 to be a waste of resources (time, money, materials) because these later vehicles rely on computerized ignition systems, diagnostic, and emissions systems. I'm also turned off at the plain-Jane, ridiculous engine swaps most car guys do, which is to shoe horn a V8 (typically Chevy) into anything and everything, (IMHO) the dumbest of which is done to air-cooled Volkswagens. That being said, there are some swaps I can appreciate, one of which is the most common in the air-cooled VW world where the current common/popular swap is an older Subaru EJ series engine. One of the more clever I've seen is some series of Fiat engine that works well in an older Beetle. One of the rare V8 swaps that tend to work well is the First Gen Chevrolet Blazers. And then there is the popular 2.5L swap into the Mazda 2.0/2.3L that requires a minimum of parts to be changed.
The idea: I've been keeping a 2.5L swap in the back of my mind after reading several threads and communicating with those who've accomplished it. The process looks involved but isn't that scary (for myself). My vehicle's 2.3L has 164K miles on it and still runs well with minimal oil consumption, which I believe is due to my vigilance in maintenance. One item which I believe is overlooked is the valve cover gasket was redesigned to prevent excessive oil consumption. I caught that just in time during a routine spark plug replacement service when I observed oil soaked threads on #4
and minor soaked threads on #3
. Another indication of a problem was when I proceeded to remove the valve cover to replace the gasket -- several of the fasteners on the driver's side of the engine were loose. Since my vehicle is not in a rust belt state, I don't have the worries of corrosion that would normally preclude spending the money on a proposed swap.
Meanwhile, my mind will occasionally fiddle with the idea of engine candidates and what will be required for the swap. A few days ago, during my evening commute, I glanced over and noticed a Ford Escape in the adjacent lane. I remembered the Escape's engine is one of the more suitable candidates because, for whatever reason, they're cheaper to acquire. I noticed this particular vehicle had a V6 badge at which point my brain started wondering what it would take to put a V6 in my MZ3.
- Will it fit in the Mazda's engine bay
- PCM/ECU Requirements
- Modifying the existing harness to work with the donor PCM/ECU
- Transmission swap required?
- Radiator upgrade needed?
- Front suspension modifications required (extra weight of the engine)?
- Front brake upgrades required? Again, extra weight of the engine)
If the engine won't fit in the Mazda's engine bay, then this idea is dead.
The donor vehicle's PCM/ECU will have to accompany the engine since the stock PCM is programmed for the stock 4-cylinder. That being said, will it be possible to modify the stock harness to work with the upgraded PCM? I'm thinking the donor's harness accompanies the engine as well as other connectors which feed the various dashboard gauges. That's where splicing and modifying harnesses will come into play and will entail referencing wiring diagrams for both vehicles.
Will the V6 engine bolt to the stock transmission, or will the donor transmission have to be adapted? If so, will the drive axles line up with the donor? That could be the show stopper unless everything is measured before the project is even attempted. Assuming the stock transmission will bolt to the V6, will it need to be strengthened to handle the extra torque? I don't know if the escape came with a manual transmission option, but my vehicle is an automatic. We can discuss both options.
The V6 requires more cooling capacity and may need a larger radiator if the donor's radiator will not fit the MZ3's bay. If the V6 radiator and I4 are similar, then that's money and time saved.
A large engine is going to carry a a few hundred pounds of extra weight, which is one aspect of a large engine most people don't take into consideration. That weight means the front suspension and brakes have to compensate for the heavier load.
Did I miss anything?
I'm just spit balling here since I've not seen any mention of this having been attempted. I'd love to be directed to any links if it has. I'm thinking a MZ3 with the V6 would be a major screamer as well as sleeper. Please daydream about this and throw out ideas.