UzY3L

Hello gentlemen,

Where I am from, there is no such thing as a good second-hand RX-8. So the only way to get a good one is to build it yourself. For reference, both cars are left-hand drive.

Bought a non-runner for 1500euros(Car1). Build date is 2003. Hasn't run in over 2 years. Description:
-Needs brake calipers and disks
-Rust (nothing too serious) underneath the chassis
-Needs engine mounts, left and right
-Engine is leaking oil
-Blown radiator
-Blown front airbags (driver and passenger)
-Engine will only start when towed
-Engine compression test reveals Rotor1 at 450kPa and Rotor2 at 0kPa (blown to bits)
-Has only 1 key with no buttons or anything but immobilizer recognizes it or it was bypassed

Other than the above, everything else on the car is fully working. Odometer reads 122,000 Km and it ran for 1.3Km after being towed.


I found another one for 1000euros (Car2). Build date is 2004. Hasn't run since July 2016. Description:

-Dented AEZ 19' rims on the left side (will not be taking those)
-Front-left fender and driver door are dented inwards in a "C" shape. Owner was drifting, skid and hit a pole on his side (explains the dented rims)
-Body and chassis bent in an inward "C" shape around the driver-side door
-Left side airbags deployed. Front airbags have not deployed
-Engine rebuilt in June 2016. Ignition kit replaced with what the owner claims to be an NGK induction kit but from what I found on the web, it's just the original Mazda one. Is this correct?
-Engine starts instantly, whether cold or warm. Even more so, stopping and starting the engine cold or warm, without revving it works also. Can only mean good compression and a healthy. Engine idles at around 800rpm (OBD II info). No jerks or misfires or self-revving issues
-Clutch recently replaced
-Blown radiator (because of the crash)
-Adjustable suspension
-2 sets of keys with remote

Both care are the 171kW / 230 HP models. My question is :

Can I just drop the transmission and engine from Car 2 into Car1 with minor adjustments?

What do I need to move from Car2 to Car1 for it to work, besides:

-Engine
-Transmission
-ECU ?
-Induction kit
-Suspension
-Brake discs and calipers
-Front airbags
-New radiator

What can I do to keep the engine cool with a minimum budget. I thought about removing the thermostat and leaving it circulating all the time and also mounting a fan relay so the fans start at 75degrees Celsius.

Please let me know if I'm on the right track and what else needs doing.

Loki

iTrader: (1)

The ECUs can stay in their cars, the engine and trans swap over easily if they are the same configuration (230 as you say).
I've never heard of an NGK induction kit. Hard to confirm anything without pictures. Do you mean induction like air intake, or induction like ignition coils?

You will want to test each set of ignition coils and pick the best ones, or just replace them with new. Same for spark plugs.

For cooling, removing the thermostat will just make it longer to warm up, which is not desirable. If you plan to race or run in hot climates there are upgrade radiators and water pumps available, but the stock system is enough to get started.

I think that's about it. Invest in an OBD2 reader from ebay so you can properly diagnose any issues once you have it running. Good luck!

dannobre

iTrader: (3)

You can swap all of the mechanical parts over with no issues....

If you swap electrical modules that are CAN reliant you will likely have to program them...but there shouldn't be any reason that they need to be swapped over anyway as long as the systems in the good car all were working

UzY3L

Thank you for your reply.

My mistake, I meant to say "Ignition kit", like the BHR : coils, leads and plugs.

@dannobre : What would I need to do to make Car1, the one with the blown engine, accept the keys from Car2? I'd really like the 2 sets of keys with the remotes to work in Car1

And thank you all for the long read. I tried to structure it as best I could.

And a Merry Christmas to you all!

dannobre

iTrader: (3)

Personally I would get new keys...the remotes can be reprogrammed easily

Swapping over the modules and all the immobilizer stuff is much more difficult that getting keys 😎

UzY3L

Unfortunately for me, I'm going to have to move all of the electrical with the engine from Car2 to Car1.

The reason for this is that the immobilizer from Car1 has been bypassed (anyone with a random key or splicing 2 wires could start it). The other reason is that for 2 keys with remote, I have to pay 660euros which is not cheap at all and is around the cost of the BHR ignition kit which I would much rather have than waste money on the keys.

I know it is against what you have recommended but it is the cheaper option and I'm on a tight budget. I want to consider if it's worth the hassle or if I should save up and not do it.

Anything special to follow or just move every piece of wire from the engine bay of Car2 to Car1?

dannobre

iTrader: (3)

The underhood wiring will be ok....it's the modules under the dash...and the steering column lock assembly that will be your issue ( immobilizer system) and the ECU and dash likely.

The remotes are easy to program to either car

UzY3L

Thanks for the info. It's going to take about a month and a half to build. Gearbox and differential oil will need to be changed also since I'm going this far. I'll keep you updated.

Loki

iTrader: (1)

You can buy keys on ebay for peanuts. If you have one key, you can do all the programming yourself. At worst you get Mazda to do it.

There is a DIY thread in the DIY forum on this exact topic

polatok

well, this sounds familiar!! i am in almost exactly the same boat!! except mine are 04 and 05, 05 being the engine/tranny donor! best of luck mate!

UzY3L

Donor car (Car2) has 2 sets of keys with remotes. Car1 has only 1 key. The DIY thread mentioned I would need 2 keys, which I do not have. Remotes would also be nice, in case I accidentally lock my car.

Mazda are the ones who are charging me 330euros / key, unfortunately.

@polatok : as far as I know, the only difference was that in 2008 they added an additional OMP to the engine but that's about it. Just like me, as long as they both have the same power rating and gearbox, everything will fit. Good luck!


Thank you all for your replies! I got the second car today and they are on their way to the garage for the swap. I'll keep you updated.

polatok

yeah should be a straight swap, about halfway done taking the engine out of both cars. following rotaryresurrections removal thread(which is awesome btw). i am guessing you are getting the garage to do the swap? how much is that costing you, if you dont mind me asking?

mazdaverx7

iTrader: (6)

Would love to see pics of these new 8's!

Loki

iTrader: (1)

If you buy a blank key, any number of blank keys, from ebay, with remotes, then you can go to Mazda and have them cut and programmed for significantly less than buying new keys. I feel like that would save you a lot of time and money swapping over everything from one car to the other. Ask how I know

UzY3L

@polatok : The cars are going to be fixed by my Dad so the costs are going to be pretty low

@mazdaverx7 : I'll post pictures as soon as I can, I'm not near the cars at the moment. Only one of them will live though.

@Loki : Sounds very nice, I'll ask Mazda about it. Getting the keys from eBay is not an option from me unfortunately. But I'll ask them anyway as I am looking to spend as little as possible. My budget, cars and all is about 4000euros, out of which I spent 2500 on the cars already.

UzY3L

UPDATE : Weird thing,due to extreme cold, Car1 (with the blown and leaking engine) started up and was idling at 820-ish RPM after warming up. Lots of smoke even when hot, though.

I know engines with low compression start in low temperatures but this engine has 450kPa in Rotor 1 and 0kPa in Rotor 2 so maybe...stuck seals in Rotor 2?

Either way, since I'm replacing the engine anyway, my Dad thought of something : since this engine basically burns oil and is high-revving, just like a two stroke engine, wouldn't it make sense to use two stroke engine spark plugs?

He took out the NGK plugs and put in new 2T plugs and um...even at warm start-up, the engine seems...fine?

Am I missing something here? What is this witchcraft? Is the engine running fine on only one rotor and with half of the compression?

And is it recommended to use 2T spark plugs for this engine? I mean, it is basically designed to burn oil. I googled but couldn't find anything on this subject, not even here.

Loki

iTrader: (1)

A spark plug is a spark plug, it makes spark and removes heat, it doesn't know anything about oil.

However, you may have noticed that while the leading spark plug holes have a full-size spark plug hole, the trailing spark plug location has a very small hole to the combustion chamber and an undersized electrode, compared to a regular spark plug.

So no, it's not recommended to stick random things in there, if the sizes are wrong, you'll destroy the housings and/or the apex seals on the first revolution. Stick to rotary spark plugs.

As for compression, I guess the test was wrong Did you test with the trailing spark plugs installed or removed?
The other possibility is if you've been adding a lot of oil to the combustion chamber, it's acting a seal between the seals and the housing, bringing up compression until it burns off.

UzY3L

Good tip. My Dad's the mechanic on this one though. He hasn't worked on anything besides normal engine so despite 2 months of complaints, he's now curious about this whole rotary thing also. That being said, I think (and hope ) that he measured the new plugs to fit the old ones before firing it up.

Tests were done by the only Mazda dealer in Romania which has a rotary compression tester. Even if they were wrong, I have nowhere else to turn to since they have the only tester for RX-8s in the country and besides, all RX-8s in Romania have to go to them if they want a compression test. I took the previous cars to them also, before deciding on the build (waste of money but gained valuable info).

I thought the test to be correct, considering the fact that the car wouldn't start, odometer is over 122,000Km (75,000miles) and the engine is full of and leaking oil so the signs of a blown engine are all there.

The fact that it is still smoking even when hot (didn't confirm the color of the smoke though) also indicates that either one Rotor isn't doing anything or that the engine seals are blown and oil and water are jumping all over the place in there.

The engine in Car1 is going to be swapped anyway but until then, I was experimenting and was curious as to the "why" of things.

I attached the pictures with the test. Maybe I'm reading it wrong?

Loki

iTrader: (1)

Hmm. The test looks legitimate and you're reading it right. I'm a bit skeptical that rotor 2 is really all zero across all faces, that implies it's thoroughly destroyed, so when you say it runs smoothly, I have no answers, only questions. Since it's smoking it might just be full of oil and sealing itself that way... but then it would have done the same during the compression test...

It *can* run on a single rotor, but it won't sound happy, at all. By the way, it seems to be very common for rotor 2 to fail before rotor 1 for some reason.

UzY3L

After reading the hell out of anything 13B-MSP related and rotaries in general, seems the issue is that Rotor 1 gets the nice, cold water from the radiator while Rotor 2 is stuck with the not-so-nice, warmer water after it passes through Rotor 1. And the cycle repeats. It gets much worse once the difference between the rotors exceeds 100kPa, since they get thrown out of sync (compression-wise at least).

To my knowledge, the only way to fix the issue would be to have a completely separate cooling system for Rotor 2. Maybe even split the current cooling system into two separate circuits, one for each rotor. Not sure how efficient that would be though.

Granted, this is all information I have read from around the web and have no way of actually proving it but it does seem like a good theory.

CelestialGryphon

iTrader: (1)

...Make it happen. That would be awesome to see.

UzY3L

I also have a list of upgrades since I'm doing this thing :

WS OIL INCREASED PRESSURE KIT RX-8 2003-2008 7.5BAR

AEM RX-8 PERFORMANCE IGNITION COIL KIT

SIX Performance RX-8 Radiator Silicone Hoses - 3PC -

Mishimoto Fan Shroud kit -

MISHIMOTO RX-8 THERMOSTATE LOW TEMP 76°C


Do I really need the silicone hoses or can I just get regular ones? I don't plan on using anything besides the Mazda anti-freeze and the oil (but I will premix).

Anything I should know about the above parts? The thermostat especially, since I've seen RX-8s idle at even 95~100degrees Celsius which is kind of scary and I want to avoid at all costs.

My goal is to have a very long lasting RX-8. Despite much advice to the contrary, it will be a daily-driver, since it will be my only car so I will use it to drive to and from work, at the very least.



edit : I was reading the compression tests wrong. Rotor 1 has 462kPa and Rotor2 has 376kPa. Amazing that the difference between rotors is under 100kPa. Even more amazing is that it starts and also idles at 824RPM, albeit with a lot of smoke.

Loki

iTrader: (1)

You can use regular hoses as long as they're not 12 years old.
I'm not sure about the fan shrowd kit, the stock fans do fine. You may want to invest in a better radiator though.

I would also recommend a Sohn adaptor.

Nothing wrong with daily driving an RX8, it's a car like any other.

You don't NEED the thermostat, it's just a bit of extra buffer if you're expecting to have spikes in heat production, like in racing.

UzY3L

Both cars have blown radiators and fans. The stock radiator is fine for cooling the RX-8, the thermostat is the issue (which even though stated at 86, it actually opens at close to 100), which I will be replacing with the 76 degree one. Cooling solved

So I'll give up on the shroud and go for the stock radiator and stock fans. Thanks for the info, Loki!

The Sohn adapter is not an option, as emissions regulations and registration regulations are very strict. Basically, the car WILL fail the MOT (required before registration) and it WILL fail registration (as it is checked again for ANY modifications to the engine-bay).

MOT to have it road-legal occurs once every 2 years so even if I mount the Sohn after registration, I'd have to take it off once every 2 years. I'll stick with premixing at every fill-up.

That being said, besides is the rest of the list fine? Here's the pressure increase valve (is it a valve?) for the oil :
https://www.wankelshop.com/product_i...-kit-rx-8.html

Loki

iTrader: (1)

Hmm. I have data that suggests otherwise In most days in regular traffic, a healthy RX8 runs around 188F, 86C. If the thermostat was closed, it would run higher. Obviously thermostats can fail, but that's not part of the design.

By contrast, if you're idling in traffic on a very hot day, temperature may begin to climb because the car can't reject sufficient heat. You can't change the air around you or the rate of coolant flow, but you can improve the heat exchanger surface with a bigger rad, or the rate of air flow with a higher flow fan.