Over 25 sprint races and numerous time trial, qualifying sessions and practices on the new s2 motor now. Best motor I've had so far (my fifth motor sadly). Best power, runs smooth, no problems at all. This is the first season I've started and finished every race. Hopefully this great motor will continue to hold up so well.

Well... sadly the motor blew last weekend. I was hoping to get more out of this new motor - it seemed so strong. A coolant seal blew big time which blasted the coolant out and coolant now leaks into the combustion chambers as well. So this had nothing to do with the apex seals or lubrication from pre mixing. Nevertheless, I never overheated this motor and it was running super strong until suddenly it started blowing out all its coolant during Sunday's qualifying. Disappointing these motors don't hold up better. I suppose almost two years isn't so bad for a hard worked race motor... but still... maybe time to switch to a Miata?


The motor should be easy to rebuild I think.

Zoom Zoom Boom. No chance the heat from extreme internal friction due to the lack of an OMP caused any issue? Please post tear down pics.

That seems like a stretch . Souns like he got a good run from the engine to me.

Re the coolant seal fail : ... i wonder if extra dowelling would solve this . In my FI engines that weren't dowelled i see evidence of housing flex ...this could be the issue ...........................

An engine per season is too rich for my blood :)

I think racing is just tough on these motors in general. My motor failures since I started racing the car in 2008:


Motor 1 (original) - coolant seal failure
Motor 2 - failed on start up due to incorrect assembly by builder, oops
Motor 3 (used) - some kind of bearing failure
Motor 4 (rebuilt by pineapple racing) - corner seal failure
Motor 5 (rebuilt by local guy) - oil seal failure
Motor 6 (brand new series 2 motor) - coolant seal failure


So as you can see I've seen it all!


I could give a long list of 13B turbo motor failures from my previous rx7 race car and other piston motors too... racing is a tough life!

Magnus - you seem the type to be detailed in your endeavors... any chance you have the hours logged on each of motors 4-6? I imagine (1) had more street miles, (2) obviously doesn't matter and (3) was used and in unknown internal condition...

It would just be fuel for speculation, but I would find it interesting...

Eh... I'm not as detailed as I should be. Motors seem to last me at most two years. I do a lot of racing... probably 60-70 hours of track time each year. I figure the latest motor - a brand new series 2 motor - lasted about 80 hours of track time. I suppose that's not bad in the world of racing. Motors 5 and 6 have lasted me the longest. Maybe I'm just getting better at not abusing the car! Motor 1 I used to get it too hot all the time because I had the stock radiator so I was not surprised to have a coolant seal failure. Motor 6 I kept conservatively tuned and engine temps were good at all times so I was hoping it would last longer.

80 hours doesn't sound terribly bad when always being driven at the limits - if it's rebuildable and the internals are reusable, that would be a plus as well!

Pretty interesting data.

Hmm, I had 23 track days which is about 50-60hrs on my original s2 engine, along with 51k miles when it failed. Although not great, looks like that is not terrible either.

After 1 year I have 23hrs on my pineapple rebuild, along with 14k street miles.

Hey Magnus,
sorry to bring up this old thread, but recently I ran my car overheating(So Disappointed, My Fault Though) and I was planning in swapping over the s2 engine in my s1. I was just wondering would you recommend the swap as a daily and does all your electronics work? I know everybody going to say, just put the correct engine Blah, blah, blah... I love my car and the renesis, but I want it to be more reliable, and you also pulled some impressive numbers on the dyno.

Honestly, I think you would be better off having your s1 engine rebuilt...

Any reliability benefit of the s2 core engine is really down to the oil injectors. Since you can't use those in an s1, you won't get this benefit.

There's no difference in power between s1 and s2.

AND, I doubt you want to have to premix every tank driving on the street.

The reason to do this when this thread started was that you could buy a brand new crate s2 motor. Those are no longer available.

So, if you want more reliability, get your s1 engine rebuild by someone reputable, consider having it balanced if you are going to drive it hard. Maybe add a Sohn OMP adapter, and stay on top of maintenance (coils, plugs, oil changes).

I agree with above. Premix on a street car is too much of a pain. Not really any significant reliability improvements.


S2 crate motors are still available from Mazda Comp, but officially they hold them for the Star Mazda racers.

Yeah, thank you very much for the reply. Yeah, I decided on rebuilding mines with OJImports and premixing whenever I can to make that baby last. Definitely getting that sohn, thank you so much. I hope I get to pull the same numbers as Magnus on the dyno though. Wish Me Luck!

Magnus, what did you use for premix? Looks like I may be giving this a try...

EDIT: Also, 1oz premix / gallon gives a ratio of 128:1 fuel to oil. That seems ok if it is a supplement to a working oil injection system, but is it really enough by itself?
50:1 seems more typical for a 2 cycle engine. I understand that uses the oil to lube more than just the piston rings though, so maybe 100:1 is a good ratio to shoot for in a rotary?

EDIT2: Did some searching... I'm thinking a good 2 stroke oil at a 100:1 ratio and then monitor the condition of the plugs. Less seems to work for folks as well (i.e. 128:1 seems ok with no OMP, 256:1 with the OMP). Still interested in what you used Magnus :-)

Yeah he premixed and removed the OMP. But it is a hassle to premix all the time if it is a street car. Better off with a Sohn adapter IMO

Yeah except you can't run a SOHN adapter on a Series II Renesis.

Sorry I wasn't specific enough, better off running a s1 engine w a sohn. Unless, its a track only car

I would have to agree that a Sohn is a good idea on a S1 engine.


Most racers seem to agree on 1 ounce per gallon premix if the oil injection is removed. Honestly I don't really know if more is better but I can tell you that my motor failure (coolant seal) was entirely unrelated to anything that has to do with the premix or oil injection... so 1 ounce per gallon seems to work.


I think any good quality two stroke oil is good. I get a good deal on TORCO and their product is of excellent quality so I only used TORCO synthetic pre mix.

Thanks Magnus, very good to know.

And yes, I understand about the downsides. The reason for me going down this path is that I just happen to have a good s1 chassis and a good s2 core that I would like to turn into a track car.

I run Idemitsu premix when on track in an S2 as a precaution to supplement, haven't had any issues yet.

Idemitsu is not terribly expensive either - something like $70-75 per case or so from Mazdatrix (plus shipping). at $6 or so per quart, that's an additional 19c per gallon of fuel if you're running 1oz per gallon...

So, I got my transplant running and tested it for 2 days on track. Worked flawlessly. Thank You Magnus for posting such a clear guide.

Couple of notes:

1. I made a small bracket out of a strip of aluminum to bolt down the OMP in the location magnus shows. Mine ended up pretty closest to the clutch bleed valve, so be careful of that.

2. Since I had the oil line from the s2 oil injection feed, I decided to cut and plug that, rather than crimping & welding the tube on the housing. My first attempt failed, so make sure whatever you do here can withstand some heat and pressure.

3. I used the s2 gasket between engine and transmission, since it was already on my s2 engine. In retrospect, I think it would be better to match this gasket to the transmission. Since I left the s1 transmission in the car, I should have used the smaller piece that goes on the back of the s1 motor. As it is, I think it is fine, but I did struggle a bit to get the transmission bolts correctly torqued up.

One additional note

4. The s2 motor has a different oil pan which does not appear to be as thick as the s1, and the chassis has a metal undertray to protect it. Without drilling and tapping holes the undertray won't fit on the s1. I'm not sure if this is a cause for any concern or not, but I'll be trying to avoid any off road excursions just in case :-D

Just saw this:
https://www.rx8club.com/series-i-eng...3/#post4786763

If it works, then we can leave the OMP out of the engine bay. Will try it when I get a chance...


Edit: Tried this and I was able to remove the CEL, but the engine stayed in limp mod until I plugged the OMP back in.

I remember looking this thread over before beginning my S2 swap (full power/drivetrain swap including all electronics) into my 2004 S1. I wasn't sold on the idea of blocking off the OMP and running premix only which is why I chose the route I did, but now that I have a daily RX-7 that only runs premix with no OMP, now I think this route might've been the better option. I do 1 Oz. per gallon in the SA and it's really not as unbearable as some may think for a daily driven car (like those that buy 1 quart of 2 stroke at a time rather than ordering a case of 12 from mazdatrix like I do). But I think that the route I chose was a good learning experience, I just wanted the car to run as a stock series 2 would is all and the entire swap is pretty much direct bolt on and drop in (meaning no modification to anything on the car to fit the parts, they all just bolt right up).

But anyway, thanks for posting this thread, it played a large role in deciding to pulled the trigger on my build. And yes the electronics swap is the biggest pain in the ass ever, if you want a series 2, just sell your S1 and buy a damn S2, they're more than cheap enough to where the benefits of the swap don't justify the work and effort that goes into it vs. the cost of a running S2

Link to my build thread: https://www.rx8club.com/rotary-swaps...-my-s1-261187/

https://cimg2.ibsrv.net/gimg/www.rx8...c601a81ea2.png

Glad the info was of use!

I dont mean to play devil's advocate but....in my experience there is a huge difference between the racing reliability of the renisis and the early peripheral exhaust port 13Bs. We have raced on one stock port S5 engine in my FC racecar for 6 years now. Min 5 weekends per year usually more like 8-10. Car still makes 180 to the rear wheels, same as it did after break in 6 years ago. Never a hint of issues. I did blow up a motor prior to that due to massive over heating but a STARK contrast to trying to make a reni reliable for racing...which the teams i've worked with always struggled with...

Road racing a Renesis catless, I wouldn't run less than 2 oz. and probably closer to 3 oz. In an earlier post I had said Star Mazda was running spec pre-mixed fuel @ 1 oz, but I don't know why I said that unless I was thinking of something else. I never knew what the Star spec oil ratio was. People run 1/2 oz plus the MOP with a cat on the street RX8, so 1 oz per gal and no MOP can't be much more than that.

The problem with an OE build is you have no way of knowing what you're getting as compared to the detail of a quality hand-built motor, which depending on who built it you might not be so sure anyway. I don't think the top Star racers would run an unopened OE motor unless they had no other choice. Most of them are using hand built engines.



.

I just did the same swap on my s1 except I got an automatic s2 engine for a good deal and placed it in s1 manual car. I used s1 lower intake and injectors with s2 upper intake. S2 e shaft sensor is the same, s2 upper intake sensors and throttle body plug into s1 electronics. I left the omp stuff on the engine and placed the s1 omp beside my washer spray nozzle. No need in deleting the omp system and capping of the feed scource.

I guess that works too.

Dumb question; You are still premixing right? (since I assume that S2 omp is not going to be working without the ECU driving it).

Yeah I'm premixing, got 500 miles on the car now. Also the omp system fails open. Pressured oil was going into the intake right at the vacuum point below the oil filler. I ended up blocking the oil feed on the front of the engine

So now up to 27 days, 20k miles and approx 74 track hours on my pineapple rebuild.
14 days, 5k miles and approx 51 hours with no OMP and premixed fuel only.

Still starts good every time.
Does seem like I am down on power now though. Suffering from a misfire code that only happens occasionally on track. Have suspected that as the reason I'm down on power, but after going through all the normal reasons for a misfire I'm now wondering if it might be caused by low compression on one rotor face :dunno:

Thanks for the Series 2 , post. Question, based on this information is it possible to use just the series 2 core in a Series 1 build.

Thus removing everything Series 2 related including the OMP system & replace everything from the series 1?

Here in Australia, Series 2 motors seem to out number series 1 motors in wrecking yards & are offered at lower prices !!!!

As far as I know, and recall, you can use all the accessories from the series 1, apart from the OMP pump, since it doesn't have the mechanical attachment to drive it (series 2 is electric).
So, you just need the core from a series 2. But, you will have to premix all your gas with it, which is a pain for a street driven car. I'm also not sure how well it will hold up to street use with no oil injection. Honestly, for street use, I would rebuild the s1 core... That way you know it will be good for some time and avoid the whole premix mess. Even an s2 core, if it is used, might already be down on compression.

My track build is still working well (aside from the unexplainable misfire code which I am now simply ignoring), but in my case I started with a known good s2 core.

Hi Magnus, what were the symptoms of your oil seal failure?
I suspect that I have that issue now...

He hasn’t posted in this thread for over 2.5 years and hasn’t been on the forum for over a year.

Just answering some questions regarding 100% premix and street driven use on a series 2 (I guess it applies to series 1s too), but I had decided to ditch my 100% series 2 swap into series 1 build (entire car - mechanical and electronics) in favor of just buying a working series 2 car (2010 R3 with 131k miles on numbers matching engine - carfax seems to line up with mileage). I’ve noticed oil usage degrade to virtually zero over the last 14,000 miles I’ve driven since August 2018 which I’m sure either the lines are clogged or 1 or both OMPs failed and, as a counter measure, I upped my premix ratio to 1.0 Oz per gallon from the 0.5 Oz per gallon I’ve used since buying. I know it’s not much to go off of, but so far the car still starts on a dime hot and cold and runs like a champ with zero issues. I’m thinking of keeping this engine in to see how far it can go as is as it’s my primary daily and I have an 18,887K mile engine ready to go if/when this one decides to poop itself.

*Also something to mention is that running 100% premix isn’t bad at all for a street driven car. I actually prefer it which is why I removed the OMP from my SA22C which was perfectly good, but line was clogged and the block off plate was cheaper than a new line. I think I just like knowing my engine is getting all of the lubrication it needs vs depending on OMP(s) that may or may not be working 100%

The oil usage probably dropped off due to the amount of premix you use. I've found that heavy premixing with no OMP on a street car results in the oil level actually rising over time.

fuel and oil systems are 100% separate and never mix. If that were the case the last 3 simultaneous oil analysis I’ve had done would’ve shown fuel mixed with it. Premixing will never cause your oil level to rise

Still kinda here lurking... have been taking a break from the racing the past few years. Anyone want to buy an RX8 race car with a bad motor??? ;)

Are far as the oil seal failure it will be very apparent with white exhaust smoke and fouled plugs... can still run through. I did Nationals at Laguna Seca with a bad seal.

Except ....when it does ! Hard to get your head around ...I wouldn't have believed it unless I saw it with my own eyes either.
Any fuel will evaporate off unless the engine never gets hot for any length of time. The premix oil however , will stay there.

You are not the first person to report low omp oil usage when using premix ;)

Well my point was that if someone hasn’t been around in a while then sending an email or pm might be more advantageous than bumping an old thread noob-style :)

EDIT: Apologies for the long and mostly OT post. I guess I could have started a new thread on my mis-fire issue. The relevant part for this thread is that I have run for ~67 hours on track with no OMP and pre-mix only, and compression still seems good :-)

=====
Thanks for the replies :-)

My engine seems to smoke a little bit continually, and then produces James Bond style smoke screens while misfiring 2-3 times per lap once I get on it. Keeping revs down seems to help with avoiding the smoke screens, but it will still hesitate and miss. Had to cut my last weekend at Laguna Seca short as I was making no power while it did this and getting a meatball flag to come in. Was basically un-driveable on track, although it drives fine at low rpm

Coinciding with the bad misfires (creating smoke) I also seem to get evap leak codes (P0442 and P0455). I'm not sure if that is co-incidental or not. Maybe the same vacuum that is sucking oil in is causing the evap leak codes? Last time out I also got an Intake runner stuck open code (P2004). Never seen that one before.

Thinking about the behavior, I have a suspicion that it sucks oil in at high rpm when the throttle is closed (i.e. under strong vacuum), but I'll need to drive it more to be sure of that. The reason I say this is that it seems to rev out in 2nd gear fine. But after shifting to 3rd, or after braking from high rpm and then getting back on the gas, it misfires and smokes. The oil level also drops noticeably after it does this (0.5-1qt after 15 min of trying to drive on track).

I also get smoke on start up after letting it sit for a while, or after driving hard. (driving at low rpm and not letting it sit doesn't produce smoke that is noticeable from the drivers seat).

I'm going to try a de-carb to see if that frees anything up, but otherwise looks like it may be engine out time.

~4 years, 90 track hours and 23k miles on this rebuild. OMP system was deleted at 23 hours and 14k miles and run with 100:1 premix as a dedicated track car since then.
Very occasional misfire (only on track) started at 33 hours and 17k miles. Did all the normal stuff to try and resolve that and then just lived with it. Progressed to the current state over the last 2 track days (~3hrs), although it had occasionally missed and blown smoke in the past, most of the misfires were not noticeable beyond the flashing CEL.

Compression still seems good in that it starts up with no issues. Very occasionally I'll get a long crank after turning it off for ~5 min (typically while filling up with gas). It has an s2 starter and I have not measured the compression though.

Is your pvc line from the oil fill/sump connected directly to the intake like OE or into a catch can? Any oil coming out there?

It's currently connected to the intake. I did remove and check while the car was standing still and did not get excess pressure or oil when revving it, but I will run this into a catch can and drive it under load to see what happens...

You should be able to tell if any oil is coming out. There will be residue inside the bellows/preTB area if anything is blowing up from the oil sump. A good engine will be bone dry there. If you need a catch can then it’s only because you need a new engine.

Well there is oil coming out. Lots of it... I installed a catch can, and although it was vented a little, it wasn't vented enough to stop my dipstick from blowing out.

Tried a water de-carb, but I'm not sure it was very successful. I sucked about a gallon through in total, but it went in slowly and I didn't get any steam out of the tailpipes (although it was enough to make it miss and pop quite dramatically).

After that, took a ~15 min drive in which I revved it up in 3rd and let it coast down 3-4 times. This was enough to collect a quart of oil, blow out the dipstick and deposit at least half a quart in my engine bay.

Basically at high rpm it is blowing oil out at quite a rate. Keep the revs low, with not much vacuum, and it doesn't seem to have any problem.

It seems after a little over 90 track hours this engine is toast :-(

Why did they engine blow? No ONP? Or did the carbon build up in exhaust cause it?