Reading Material for those looking for replacement 3.0L V6
mazda 6 v6 vs fusion v6 are they 100% the same?
V6 Engine Replacement
Requirements for 06 fusion motor into 03 6S
for those who need help setting timing
Any 3.0L Duratec product should work for the bottom end. A simple search will come up with things like Ford Taurus’s and Even Noble’s using the same or almost identical bottom ends (note noble bottom ends are built for turbo applications). Some applications such as Fusion’s and other products with VVT are even more suited to replace our AJ6 power plant because they share the same VVT system that our 6’s know and love. You must maintain the VVT system for our cars due to our ECU’s being tuned to accept this, unless you wish to venture into solutions to eliminate this feature.
There is no direct replacement to my knowledge other than the AJ6 that will be a simple unplug and plug. Even with VVT Equipped power plants like the fusion things like Timing covers and stuff must be exchanged from your old power plant to function properly or modified to fit. Things like Taurus bottom ends however are an entirely larger project as they require you to reuse the Mazda header onto your new bottom end.
Well the engines are out, either route you choose, simply things like spark plugs, oil pan gaskets, plenum seals, vacuum lines, PCVs, front and rear main seals, and other tid bits should be cared for well the motors are easily accessible to avoid head aches. I would also advise checking the timing chains for any slack and tensioners for tension on the chains, as find out after they are in the engine bay is not fun. Replacing motor mounts, CVs, and other suspension components with the engine out of the cradle may also serve you well.
Transmissions on both the MTX and ATX transplants do not matter. Both engines are identical and require no additional modifications for them to mate with your car. It would be advised at the time the engine is out to also service these components well they are visable and accessible. Replace anything that is worn so you do not have to tear it apart again down the road.
There is lots of discussion of IF the CATs are prone to cause “premature” engine failure. It is advised with any route you take that you take your emission laws into consideration and either Gut the cats, cut and splice in test pipes, purchase aftermarket headers or look at factory replacement exhaust manifolds to avoid having another dead engine down the road. There is no great science to diagnosis if the cat has failed other than to see how air/ or light pass through it, but please take it care when looking into.
Also, there have been questions lately about whether the cams must be replaced. The 38 vs 42 teeth cam “issue” is not related to the V6. This has to do with the 2.3L engine swapping and does not relate to our discussion. Rest easy that ford didn’t try and reinvent that wheel.
Lastly, the 3.7Ls in the CX9 and 2G V6 in theory may work. Ford/mazda designed these power plants to be backwards compatible as we are finding with things like the TB’s. You are welcome to give them and the 3.5L out of the Taurus a shot too. No one has yet given it a try so I can not speak if they work, but it has been theorized you could make them work. Going to a Cyclone power plant would be a decent gain in performance, but a tune at a very minimum is going to be required for this to even begin to be discussed.
PS I have been asked several questions on this subject which has resulted in my writing this. I’m sure there is more to add and more I have forgot as it is more like Riding a bike(yeah I can, but god help me if I was asked to write out how to do it) than anything else anymore. Those who have had experience please add more data and info so we can link people to one thread with lots of data, instead of 100 threads with little bits and pieces.