mazda cx-7 motor into gen 2 mazdaspeed3

Hi y’all, i have a gen 2 mazdaspeed3 that is getting a it’s motor replaced, i purchased a cx7 motor online, i know they are basically the same engine gotta swap harness over because of auto transmission from cx7 and all that, but anything else that will need to be swapped over? i will be swapping the mazdaspeed3 ecu to the new cx7 motor it’s tuned with cobb ap and all that will that affect anything? i just want to know exactly how to get it running well and don’t want to have to run into issues after the motor is in the car, thank you.

 

Turbos are different so if the CX7 engine is coming with the turbo they won't be the same. Not sure if you're going to reuse your old one.

While the motor is out it would be a good idea to do VVT/timing chain replacement and to reseal the oil pan/rear main seal.

Might as well change the PCV valve, the PCV Plate with an upgraded one and check the valves for excess carbon build up.

 

You'll need to slap a pilot bearing in the crank. Since the cx7 has an auto trans, it doesn't have one in there.

 

do i really gotta do that? what happens if i don’t, like i mate the manual trans to the cx7 motor?

 

The input shaft of the manual transmission REQUIRES a pilot bearing. This cannot be avoided. An automatic transmission doesn't have one because of the way the torque converter bolts to the flex plate VS how the input shaft of the manual transmission fits into a flywheel.

Without a pilot bearing there is nothing supporting the input shaft. Over time the shaft is going to flex and spin causing excessive wear on the input shaft bearing as well as the clutch.

Luckily your CX7 motor shouldn't have one in the crankshaft as of now so you'll only need to just install the new one. Should be straightforward. Take a socket that's a little smaller than the outside of the bearing and tap it in till it's seated

 

Exactly this

 

thank you so much for this information, i would’ve never known, also one more question, can the pilot bearing be oem? i have an upgraded clutch and flywheel, is it possible it will speed up wearing out the pilot bearing, thanks for the info once again.

 

A factory or OE equivalent should be fine. I've never heard of or seen an upgraded pilot bearing.

 

Hi there

New here how did your swap go?? Im thinking of doing the same but with a gen1 mazda axela mps 2006 hit a rock and smashd my sump an motor prices are hugely different with the Mazda axela turbo and the cx7 turbo $2000 different so am looking at this option