fastguy46

Hi, I'm new to the RX8 Club, however not new to RX8s. I'm the second owner of a 2004 RX8 - 4 port automatic. I've owned and loved the car since 2006. My RX8 has been well maintained and cared for;

• New plugs every year
• Oil changes every 3000 miles
• New coils & wires every 2 years
• With a new upstream O2 sensor it sails through California smog
• The only problem it's had is a failed evap purge solenoid, so I've been under the intake manifold.

So here is the question;

• My RX8 now has 95,000 miles on the odometer. While it starts fine and runs great, a compression check show 73-75-73 on both sides. So we're coming due and I want to plan what to do next.

Current thinking;

1. Swap the current motor for a Mazda remanufactured motor.
2. Rebuild the current motor and change everything - rotors, housings, belts, hoses, injectors, motor mounts, etc.

Pretty sure someone else here has been where I am and can offer a few pointers. Really appreciate the help.

Jedi54

iTrader: (7)

fastguy: usually swapping in a Reman engine is the easier option as it's pretty straightforward for a shop or you if you're up to doing the job.
You could rebuild the current motor but the car will be down for a longer period of time while you assess the components of the current motor and compile a list of what can be reused, what needs to be replaced, and then order the appropriate parts.
Plus, if you're waiting on an engine builder that can add time and definitely cost.

If it's still running strong my advice is keep enjoying it and just start planning out next steps but no sense swapping the motor now if it'll still perform well.

fastguy46

Thanks for the help Jedi.

Right now my RX8 looks great, runs great, it's fun to drive and hands down has been the most reliable car I've owned. I'm thinking it's a keeper.

My son has a 2000 square foot shop on his ranch. We've rebuilt countless dirt bike engines, a few Porsches and we have a GTM kit car project underway. I'd say we're 'pretty good' at building engines, however every time we crack a new motor for the first time, we make a few mistakes. I expect the rotary will be no exception.

I love the idea of 'doing nothing' but drive the car for now. I'm moderately concerned that Mazda remanufactured engines, and housings will become un-obtanium. Maybe pick up a remanufactured motor, rotors, housings and few other things and sit them on the shelf. That will guarantee that the existing motor is still running strong at 200k.

Thanks again for the advice. Y'all are great.

Jedi54

iTrader: (7)

It is tough to say how long Mazda will continue providing reman engines but I do expect them to be around for a little while longer.
never hurts to have a spare Reni lying around but don't feel as though you have to do that now.

I noticed you were in CA, what part if you don't mind me asking.

if you guys are up for cracking open a Renesis motor, check out Atkins Rotary they usually have a good supply of parts and their Manuals & Videos (yes, still available in VHS ) are a good source of information.


The RX-8 contrary to popular belief can be a reliable car if you've got a good one and it's well maintained. My 2005 ran incredibly well even up to the day the motor was swapped for a Reman and the only reason I did that is because the compression was getting a little low but driving it or seeing the dyno results you would have never known the motor was letting up. It was still under the Mazda extended warranty so I couldn't pass up a free engine.
Enjoy driving the car and looking forward to hearing about you and your son rebuilding the engine if you ever decide to crack it open.

fartblaster69

You know the history of the motor and have space to do the work. I'd be inclined to do the work myself. I was in the same position last year- knew the car's history, passed CA smog, no hot start issues, but compression was similar and i had a barn to work in. I did it myself. Replacing basically everything that might be an issue on a 10 year old 100k car cost me ~2500$ (i kept the injectors, so maybe you're even more extreme than me), and the actual rebuild was easier than pulling/replacing the motor. I've done a couple engine rebuilds in the past and this one was much more straightforward than i planned. It's not that difficult. I budgeted to replace the rotor housings, but mine were in great shape; i plugged them back in.

I don't expect to rebuild the motor again cuz it's a dedicated fun car and doesn't see many miles any more. If i do it will be a passion project and hunting down parts will be fun-work. Factor that in to your plans if it's similar.

thew

I to say. rebuild it.. Be sure to checkout Racing Beat for Parts. OR Atkins. Keep the Zoom Zoom Going.
My 2004 has about 24,000 miles on it today. . I wish i got to drive it more.. But its still show room fresh!.

Jedi54

iTrader: (7)

Thew, long time no see.

​​​​​​Happy to hear you've still got the car

thew

Oh yea.. I love it. But never get to drive it. .. How ya been man ? Long time no see.

fastguy46

Hi All,

So first up thanks so much for the help. Here is what I plan to do.

1. Buy a Mazda Factory rebuilt motor. I can swap the existing motor out in a few days - maybe a week if I take my time.
2. Then rebuild the current motor at my leisure. That will take time, care and focus.

So here is the question;

• Seems like I can take the motor out and leave the automatic transmission in the car. The obvious advantage is the driveshaft stays, and there will be less drama than taking the motor and transmission out together. Is this a good idea?

I have found postings of guys doing the above with a manual transmission, but not an automatic. Some possibility it's more trouble than it's worth and I should just drop the automatic. No clutch, no linkage.

Thanks for the help.

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