Rx8 build project
07-13-2022, 12:59 PM
#1
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Rx8 build project
How’s it going y’all! I’ve got a new project I’m starting up soon and I’m looking for as much info as I can absorb. So here’s my plan on paper:
-Buy a blown rotary and rebuild it myself over the next few months
-Buy all the bits and pieces I need to rebuild the engine, my budget is endless, but I’d prefer to keep the build as low cost as it reliably can be.
-Once engine is done and making compression, buy a shell (or a complete car with blown motor)
-Put the car together in my garage with misery and tears
So a little background, I’m an apprentice level mechanic, I’ve worked in the auto industry for 4 yrs and worked under a mentor for 6 months. I am by no means an expert, but I’m confident in my ability to figure out just about anything with time, a computer, money, and internet. That being said, I’ve never done an engine swap, nor have I ever worked on a rotary, but that’s part of the fun to me. I want a puzzle, I want a challenge, that I can toss money at. I’ve spent quite a while researching rotary’s as I’ve wanted an rx8 for years, I could careless about the issues if I can learn to fix it myself.
And what better way to do that than build it myself?
So I guess to summarize, where are the best places to get info on rebuilding a rotary, OR would it be better for me to purchase a blown motor for 200 bucks, send It in to be rebuilt, and put it in the car myself? I’m weighing my options, but I know I don’t want to buy a running working one. That’s no fun. I want to tinker.
-Buy a blown rotary and rebuild it myself over the next few months
-Buy all the bits and pieces I need to rebuild the engine, my budget is endless, but I’d prefer to keep the build as low cost as it reliably can be.
-Once engine is done and making compression, buy a shell (or a complete car with blown motor)
-Put the car together in my garage with misery and tears
So a little background, I’m an apprentice level mechanic, I’ve worked in the auto industry for 4 yrs and worked under a mentor for 6 months. I am by no means an expert, but I’m confident in my ability to figure out just about anything with time, a computer, money, and internet. That being said, I’ve never done an engine swap, nor have I ever worked on a rotary, but that’s part of the fun to me. I want a puzzle, I want a challenge, that I can toss money at. I’ve spent quite a while researching rotary’s as I’ve wanted an rx8 for years, I could careless about the issues if I can learn to fix it myself.
And what better way to do that than build it myself?
So I guess to summarize, where are the best places to get info on rebuilding a rotary, OR would it be better for me to purchase a blown motor for 200 bucks, send It in to be rebuilt, and put it in the car myself? I’m weighing my options, but I know I don’t want to buy a running working one. That’s no fun. I want to tinker.
Last edited by zXShadow; 07-13-2022 at 01:02 PM.
07-13-2022, 01:14 PM
#2
Don't rebuild your engine or one you buy, by the time you replace all the out of spec bits and pieces, you may as well buy an engine built by Mazda or a professional rebuilder. If your goal is to tinker, you can still tinker with the engine you take out while having a driveable car, and if your goal is to have a driveable car for a long time, rebuilding whatever engine is in there now is not the best way to that.
As far as best practices: measure everything, make sure it's in spec. Do it right or do it twice. These rebuilds aren't like a piston engine that you can hone, throw new seals in and go. There's no point in putting new seals into housings that are flaking/chatter marked or irons that have been scoured by previous seals. And very few places can replate or hone housings.
But other than that this is a good plan. Having a good body/blown engine cheap purchase that you then put a known good engine is probably the best recipe for many miles of smiles these days.
As far as best practices: measure everything, make sure it's in spec. Do it right or do it twice. These rebuilds aren't like a piston engine that you can hone, throw new seals in and go. There's no point in putting new seals into housings that are flaking/chatter marked or irons that have been scoured by previous seals. And very few places can replate or hone housings.
But other than that this is a good plan. Having a good body/blown engine cheap purchase that you then put a known good engine is probably the best recipe for many miles of smiles these days.
Last edited by Loki; 07-13-2022 at 01:17 PM.
07-13-2022, 01:51 PM
#3
Registered
Thread Starter
Don't rebuild your engine or one you buy, by the time you replace all the out of spec bits and pieces, you may as well buy an engine built by Mazda or a professional rebuilder. If your goal is to tinker, you can still tinker with the engine you take out while having a driveable car, and if your goal is to have a driveable car for a long time, rebuilding whatever engine is in there now is not the best way to that.
As far as best practices: measure everything, make sure it's in spec. Do it right or do it twice. These rebuilds aren't like a piston engine that you can hone, throw new seals in and go. There's no point in putting new seals into housings that are flaking/chatter marked or irons that have been scoured by previous seals. And very few places can replate or hone housings.
But other than that this is a good plan. Having a good body/blown engine cheap purchase that you then put a known good engine is probably the best recipe for many miles of smiles these days.
As far as best practices: measure everything, make sure it's in spec. Do it right or do it twice. These rebuilds aren't like a piston engine that you can hone, throw new seals in and go. There's no point in putting new seals into housings that are flaking/chatter marked or irons that have been scoured by previous seals. And very few places can replate or hone housings.
But other than that this is a good plan. Having a good body/blown engine cheap purchase that you then put a known good engine is probably the best recipe for many miles of smiles these days.
What engine rebuild company’s do you recommend/where’s the best place to buy one? You said not to rebuild the engine currently in the car, would it be cheaper in the long run for me to just buy an already rebuilt motor, or could I send in a non-running motor as a core? I’ve seen that most places will use the old core, but I agree that’s hit or miss.
07-13-2022, 02:16 PM
#4
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Thread Starter
What engine rebuild companies would you recommend? Would it be worth it for me to pay a little extra to get a somewhat built one with better than OEM seals and maybe a street port? I’ve looked into rotary resurrection as I’ve seen it mentioned a lot on here. That info was exactly what I needed to hear though so thank you!
07-13-2022, 03:08 PM
#5
Registered
Loki hit it on the nose. Blown motors or really any used motor should be treated as a pile of scrap. Generally these engines wear out exponentially so rebuilding a bad/lazy motor won't turn out well either. Compression values should follow this trend as well. Which is why everyone always says to compression test first for 90% of engine issues since it shows the health of the engine.
In your search for an Rx8 I would be wary of anyone selling a recently rebuilt engine as they could have had parts that been run into the ground. So buying a shell car and going with a mazda reman or a trusted shop's new engine is the way to go. If you can find a high mileage running car with compression issues for a low price that would be ideal so you could see the health of the car. Besides this way you'd be able to take out the bad motor and know how to hook everything back up.
For the renesis there really isn't a reason to move away from the mazda seals as they were designed with strength and longevity in mind. Harder or 'unbreakable' aftermarket seals will just wear your housing wall faster. For porting, cleaning up the stock ports and opening up the exhaust ports is really all you should do. Without tuning you will only lose power if you go to an aggressive port, even with tuning street or bridge porting will have power loses in low/mid RPM with slight gains up top.
For the car in general on any Rx8 first upgrades for reliability
-2.7kw starter upgrade.............(the faster the rotors spin the more compression they make >> starts better)
-new battery..............................(higher CCA the better)
-new coils +plugs +leads..........(the coils usually fail around 30k to 50k miles, many people upgrade to one of the LS coil kits for the Rx8)
-new cat or decat......................(usually the cat clogs due to bad coils^^ which causes excessive heat and wear on the exhaust side of the engine)
In your search for an Rx8 I would be wary of anyone selling a recently rebuilt engine as they could have had parts that been run into the ground. So buying a shell car and going with a mazda reman or a trusted shop's new engine is the way to go. If you can find a high mileage running car with compression issues for a low price that would be ideal so you could see the health of the car. Besides this way you'd be able to take out the bad motor and know how to hook everything back up.
For the renesis there really isn't a reason to move away from the mazda seals as they were designed with strength and longevity in mind. Harder or 'unbreakable' aftermarket seals will just wear your housing wall faster. For porting, cleaning up the stock ports and opening up the exhaust ports is really all you should do. Without tuning you will only lose power if you go to an aggressive port, even with tuning street or bridge porting will have power loses in low/mid RPM with slight gains up top.
For the car in general on any Rx8 first upgrades for reliability
-2.7kw starter upgrade.............(the faster the rotors spin the more compression they make >> starts better)
-new battery..............................(higher CCA the better)
-new coils +plugs +leads..........(the coils usually fail around 30k to 50k miles, many people upgrade to one of the LS coil kits for the Rx8)
-new cat or decat......................(usually the cat clogs due to bad coils^^ which causes excessive heat and wear on the exhaust side of the engine)
07-13-2022, 09:17 PM
#6
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How’s it going y’all! I’ve got a new project I’m starting up soon and I’m looking for as much info as I can absorb. So here’s my plan on paper:
-Buy a blown rotary and rebuild it myself over the next few months
-Buy all the bits and pieces I need to rebuild the engine, my budget is endless, but I’d prefer to keep the build as low cost as it reliably can be.
-Once engine is done and making compression, buy a shell (or a complete car with blown motor)
-Put the car together in my garage with misery and tears
So a little background, I’m an apprentice level mechanic, I’ve worked in the auto industry for 4 yrs and worked under a mentor for 6 months. I am by no means an expert, but I’m confident in my ability to figure out just about anything with time, a computer, money, and internet. That being said, I’ve never done an engine swap, nor have I ever worked on a rotary, but that’s part of the fun to me. I want a puzzle, I want a challenge, that I can toss money at. I’ve spent quite a while researching rotary’s as I’ve wanted an rx8 for years, I could careless about the issues if I can learn to fix it myself.
And what better way to do that than build it myself?
So I guess to summarize, where are the best places to get info on rebuilding a rotary, OR would it be better for me to purchase a blown motor for 200 bucks, send It in to be rebuilt, and put it in the car myself? I’m weighing my options, but I know I don’t want to buy a running working one. That’s no fun. I want to tinker.
-Buy a blown rotary and rebuild it myself over the next few months
-Buy all the bits and pieces I need to rebuild the engine, my budget is endless, but I’d prefer to keep the build as low cost as it reliably can be.
-Once engine is done and making compression, buy a shell (or a complete car with blown motor)
-Put the car together in my garage with misery and tears
So a little background, I’m an apprentice level mechanic, I’ve worked in the auto industry for 4 yrs and worked under a mentor for 6 months. I am by no means an expert, but I’m confident in my ability to figure out just about anything with time, a computer, money, and internet. That being said, I’ve never done an engine swap, nor have I ever worked on a rotary, but that’s part of the fun to me. I want a puzzle, I want a challenge, that I can toss money at. I’ve spent quite a while researching rotary’s as I’ve wanted an rx8 for years, I could careless about the issues if I can learn to fix it myself.
And what better way to do that than build it myself?
So I guess to summarize, where are the best places to get info on rebuilding a rotary, OR would it be better for me to purchase a blown motor for 200 bucks, send It in to be rebuilt, and put it in the car myself? I’m weighing my options, but I know I don’t want to buy a running working one. That’s no fun. I want to tinker.
does anyone know where this goes
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