Hey All,
I have been a card-carrying member of the rx7club for over ten years now. Love my rotaries. I am an ASE master-certified tech, so I have a good understanding of vehicles and components in general. I worked with Dave and Kim at KDR Performance in PA (now speed1) for a few years. That being said...

I recently blew the engine in my '04 RX8. Oddly enough, it broke in a manner I've never seen before. It now rattles when reving, almost like the rotor bearing is spun and the rotor is laterally walking and hitting the side housings. Low compression as well.

Now, I want to replace my motor. Looking around online, I was surprised at the cost of a remanufactured motor, so I was thinking I would use one of those 'JDM' companies and purchase a motor through them. I've done my fair share of JDM swaps in the RX7s, but never on an 8. Does anyone have any pointers or knowledge of differences between the two, or is it a simple swap (provided I am using the JDM ECU and harness)? Depending on the responses here, I will decide whether or not to go factory and spend the 5K, or a used JDM for 2.5K.

As always, thanks for you assistance on this and I look forward to your input.

 

The Japanese engines are identical to ours. If all you're swapping is the block, go for it. Don't need to change the ECU, it'll cause you more headaches than anything. Just make sure it's the high-power 6-port variant, not the 4-port. In NA all manual cars came with the high-power motor, but Japan and Europe had all kinds of engine /transmission mixes.

 

Thank you for your prompt response Loki.

I do have the 6 port already. So, I can purchase the block, swap manifolds and electric components, and not have to worry about interoperability?

If I kept JDM parts on the long block, would I be required to change ecus and harnesses?

Thanks again!

 

Longblock parts are the same...so you shouldn't have any issues at all

 

If you decide to stay with the Renesis I have a contact in central NJ that can find you one for a good price. 908-583-7032 ask for Dorthy

 

I am actually considering this route myself. So I would be able to keep mu USDM ECU and harness and just plug it into the JDM motor/trans?

Does anyone have any recommendations for importers with some sort of warranty on the motor? I keep finding ones that dont even offer a startup warranty. I think I used JDM Engine Zone in clifton a few years ago for a 3sgte.

 

Yes, you can. Just be sure that you get the correct variant for your ECU. 6 port / High power and 4 port / low power.

I apologize, I cannot make any solid recommendations about a JDM importer. All the ones I dealt with for my 5 speed manual trans were a huge pain.

 

Thanks! I figured that would be the case but just double checking beforehand.

 

 

Check the pump switch. They tend to be fragile and get broken easily. If it gets banged it may have moved out of alignment S well. AFAIK the wiring is the same....but I would just use your USDM harness that is already in the car.

 

If my motor ever goes, I would buy a built motor from one of the reputable folks out there. Some start with a Mazda Reman and then build from there with better assembly processes and a few tweaks. You will pay more for it, but likely will get something that lasts a lot longer. It depends on who is close to you with a good reputation. I have a recommendations for Florida, South West, CA and the old South, someone would have to give you one for PA.

 

Can you buy a JDM 13B 6 port motor and use your US factory engine harness and transmission? Basically buy the JDM 13B 6 port engine with the 5 speed transmission attached, pull the 5 speed transmission off and bolt on your 6 speed transmission?

 

don't buy a "jdm" engine ever. just get a rebuild from a reputable rebuilder or mazda . also the 6ports or high power came with 6speeds the 5speed was for the 4port or low power

 

You can get a Mazda reman for ~$3000, if you shop around. If you buy a JDM engine, you are literally rolling the dice on its condition. There is at least a 50% chance any given JDM engine will be no good.

 

Just to add, I am not aware of any mechanical differences between JDM and USDM RX-8 engines. These cars and engines are built in the same factory.

 

I have done the swap. It's all the same stuff as the US car accept you will find that the brake booster vacuum is twisted over to the wrong side but if you flip it over you're good to go since the car was RHD