Installing JDM engine in USDM vehicle

Hello, everyone. I am new to this forum and Mazdaspeed3 ownership. My son and I bought a 2008 Mazdaspeed3 with a great body but bad engine. The previous owner disassembled the motor down to the block to check out the cylinder heads after a misfire on cylinder 1 and white smoke coming from the exhaust. He suspected a blown head gasket and perhaps some other damage. Having not even seen the engine operating, I was leaning towards an engine swap since I got it so cheap. I was looking at some of the JDM engines, but I have been getting mixed information on whether or not this is a good idea. I know I will have to swap out some of the parts from my us engine but this should not be a problem as many parts like the turbo and others were already replaced by the previous owner. I just wanted to see if anyone had experience with a JDM swap to see if this is reasonable. Some have told me just to treat it like a long block and swap out most of the parts, but I would love any advice anyone could offer.

 

Welcome to mso, there should be a few threads on this exact topic.... Yes swap all your accessories over, including turbo, do that compression and leak down test asap once running in case you need to claim warranty.

Generally they're from a cx7 which is the gen1 engine

 

Which the only major differences are the piston design, revised vvt if it hasn't already been changed and valve cover you are going to want to use the gen 2 one

 

Thanks for the feedback so far. If there are other threads, I will check those out. I think I must be using the wrong search criteria because I didn't find them initially. But, I will try to see if I can find them. I would hate for people to repeat what has already been said.

Thanks Awafrican for your thoughts. So, I think your are suggesting to only keep the block and change over all accessories, correct? That would be the turbo, starter, wiring harness, etc. Is there anything that can be kept?

 

If you have a set of injectors ready to pull I'd be sending those for cleaning and putting them in the new block, as Easter bunny said if you have a gen2 valve cover I'd even be putting that on (it's the superior VC). All depends how far you want to go, if you have the time to rebuild your hpfp and clean it I'd even be swapping that on. Below is a search to all the other threads about this.

Search on the site is iffy at best, I reccomend the good old Google with your search query and limiting the search to the forms; "jdm engine site:Mazdaspeed.org"
https://www.google.com/search?q=jdm...telus-ca-revc&sourceid=chrome-mobile&ie=UTF-8