Yep, not even 3000mi after a complete rebuild with mazda seals. I bought the car last April with only 5000mi on a rotorsports rebuild, tuned powerfc, 1300cc RC injectors, and a supra fuel pump. That broke an apex tip in july. I then rebuilt it myself adding a large FMIC, new fuel filter, ignition amp, new plugs and wires, and a LC-1 wideband. Tuned to 10.5 afr @ 15psi on stock turbos. Quality 93 octane, mobile1 15-40, and pre-mixing all the way since.
It doesn't make sense--I've been running it hard all summer in 95 degree weather and now it cracks an apex on the way to a friend's house on a 60 degree night with a tank full of gas? On the way I raced it through third gear and that's what did it in.
15psi of boost.
35 IAT.
89 Coolant Temp.
I didn't see what the wideband was reading but it's always around 10-11 at WOT.
Vacuum and Idle are low so I know a small piece has broken off.
That makes three rebuilds in 8000 miles!
As a professional mechanic I have done everything I could think of to protect this engine. I guess the mazda seals are just too brittle. I will plan on using RA seals next time.
Or maybe it's LS1 time...

 

Did it boost creep or spike?

 

Couldn't have gone over 17psi which I believe is the limit of the Map sensor.
I just did a lot of reading on the RA seals. No good news there.

 

Thats shitty luck or something, reading stuff like this makes me double think doing my rotary rebuild and just selling off what i have and going the LS1 route.

 

2PSI is a large boost spike for these cars...And the turbos can push more boost(14.5 or 15PSI is the limit of the stock 2 bar map sensor) than the map sensor can read, it just means that it will be unmetered air.

What tuning and engine building experience do you have? Where did you learn how to tune?

 

If the temperature-correction curve wasn't tuned well, the car could have run lean in the cooler weather.

 

I know people hate to hear it but sometimes that is the better route.

Do it once, do it right.

 

Yea i did the math,, it will cost me 3100 to get my current rotary setup to where i want it or about 5000 to get an ls1 with it where i want it,, the 1900 for some increased reliability is looking better at each one of these threads.

 

Nah it will cost alot more than 5k for the complete LS1 conversion, even if you do all the work yourself.

I thought about doing that to mine but im not a big fan of v8. Well i like it, i like all engines but i cant see myself driving a japanese car sounding like a v8. It will be cool knowing my FD is finally reliable but then after like a month or 2, ill get bored.

Which is why you see alot of LSx FD's for sale faster than people selling blown FD's.

 

Yea i hear you, what i meant was after i sell the current pile of rotary stuff i have (singe turbo kit, large intercooler etc etc) the difference will only be 1900 between getting each setup to where i would like it.

 

i dont like the idea of using 15-40 in turbo cars. i think you should 20w-50w in your car. are you sure you didnt get 87 octane by mistake?

 

Oo, i didnt know you had a hefty amount of mods.

If i was the OP, i would def go LS1 route if i wanted to really keep the FD. But for the people who blow engines like once every couple of years only because of hard abuse, then i dont see the point.

I say do it if it constantly gives you problems (rotary related) but if not, keep the rotary alive since theres only like 10% of FD's on the road with actual rotaries LOLOL

 

It's been 3 months and I'm still not bored with mine. I just love the reliability of the LS1. It's my daily driver and I beat on it daily and it's still running strong

 

You didn't read good enough then. Contact Jason at Rx7 Store about his use of the RA seals. All the bad press about these seals have to do with the early batches nearly 3 yrs ago. Also their original apex seals springs weren't heat treated and was the main cause of compression loss. I have them and have 15k on my 91 vert. The key to make them work is to use Mazda's apex seals springs and not the RA versions.

 

Im not saying all people who did the conversion got bored and sell right away. Im just saying a large majority of people who did convert ended up selling before a years time.

Moreso than people who blew their rotary or people who had their rotary FD for a long time.

 

I am 100% sure that the fuel was good 94 octane. I fill up at the same texico gas station every time and I know the owners.
My life is automotive. I work 60hrs a week in a state-of-the-art independent repair shop specializing in complex diagnostics. You know, the stuff other shops turn away. I've seen it all and wired entire cars from scratch. I am very meticulous and obsessive when it comes to my cars and the vehicles of my customers which is why this fustrates me so much.
It is possible that the boost crept up to 17psi as I went all the way through third gear and this would be beyond the stock map sensors range. Also, the car was tuned at rotorsports before I bought it. The inj map looks smooth and I have not had to make any adjustments. Cruises at 14.5, tapers to 10.5 under boost.

If a seal is broken on the same rotor I will suspect and injector fault or inbalance.
NRS 1pc seals look like a good way to go. That sharp point on 2pc seals is a major weak point and I know that is the piece that broke off.

However, If I ever go the V8 route, it will not be in a rx7.

 

I had four cars this week, all imports, with injector issues. Gets me thinking....

 

If you rebuild your 7 again(after such a short time, I doubt anyone would blame you if you get rid of it), I'd suggest a few things...Clean and flow test the injectors(should be part of any rebuild, really), port the wastegate(should have been done when the car was first being built for high boost levels, but sometimes this gets left undone), maybe attend a Chuck Westbrook PFC Seminar(not saying you don't know your ****, I'm just saying we can all stand to learn).

 

Thank God

 

You know, this is going to add fuel to the fire, but I don't care.

A lot of you guys like Rynberg etc. go around on this forum spouting off that "you get what you pay for" and how some builders are gods while others build from scrap parts laying on the floor.

As some of you may know, I work more on the budget end of things while still maintaining great quality and reliability, based on the customers budget and the goals for the setup. I help a lot of people this way, but I take a lot of **** talking from some of the rich guys on here who actually think anything less than 4g's for an engine block is a steaming pile of crap.

I have been able to have success doing things the way I do, reusing what some others would want to replace as a matter of course. I have as good a reputation from the standpoint of failures as any other builder I'm aware of, though of course I would not claim to be better than, or know more than, any particular other builder, especially those with lots more experience in building and racing.

My stance has always been that the SETUP is more important than how the engine block itself is put together. Sure, the engine has to be done meticulously to hold up. But, you can take a bone stock engine in good health and make 600rwhp out of it if the SETUP is perfect, and by the same token you can take a 6 thousand dollar fully modded engine and screw it up at stock power levels if the SETUP is imperfect. Turbo rotaries are very finicky with regard to the setup and tuning, so it doesnt take much for damage to occur. Or, in other words, it's more likely that you'll tear one up than not.

So, if you stand back and think about it, it makes less sense to put a ton of money into an intricate engine build and hope it lasts forever, than to put less money into a standard build and be prepared to go back through it in 2-3 years. IF you break it due to a mistake, then you won't feel so bad, and you won't be out so much money. You can still build 2 more and be ahead of where you would have been if you had built that one really bad *** one earlier. Odds are, if you did something to damage the standard engine, the high dollar one would have broken too.

Now, ask yourself...would it have been better for him to pay 1500 bucks for a budget engine? Let's say the budget engine is not 100% perfect. Let's say it "only" makes 110psi compression. Big deal! It'll run for 3 or 4 good years unless it breaks from too much timing or too much boost. Let's say that whatever happened to this big time engine of his, happened to the budget engine? Well, he wouldn't feel nearly so bad, and in fact he could ride on it until it actually broke and wouldn't run well enough to drive anymore. Then he could build 1 or 2 more and still be ahead of where he is now.

Instead, we're about to lose a rotary brother to an engine swap, or possibly he might sell the car altogether because of the high cost of this engine "built the right way" that failed just as soon as a 1000 dollar engine might have.

Rynberg and all you other high dollar, new rotorhousing engine sackriders, before you go spouting off the next time on the forum about "doing it right" and "getting what you pay for" come and talk to this guy.

To the OP, good luck with your saga. If you decide to go the rotary route once more, I'd love to help you out if possible, or you might also check with mr rx7 tt who is in va. beach area and really knows his **** too.

 

i love it when people blame their mishaps on the apex seals. especially when they're running 15psi on a stock map sensor with a known-to-creep intake/exhaust/IC setup.

do you know what happens when you go over 15psi?

 

You may want to consider posting your PFC maps in the PFC forum to get some feedback on the tune you have. There's a fellow that not too long ago blew his motor up and many believe the timing (among other factors) was to blame. Check it out.

https://www.rx7club.com/power-fc-forum-47/please-checkout-my-maps-688161/

Do you have a datalogit?

 

You never know what you're getting as far as pump gas goes. Air/fuel ratios aren't the end all to tuning. Knock, EGT, and fuel pressure are just as important.

Just because the map sensor only functions to approx. 17 psi doesn't mean the turbos can't produce more than 17 psi boost. If you haven't disconnected power to your Power FC, you should be able to check the peak boost in memory. You could also see peak knock reading.

I see mention of the first blown motor and adding new mods but no mention of the failure analysis for each engine. You're gonna keep going in circles chasing your tail if you never find the root cause, which is not it being a rotary engine.

Replacement of injectors, wiring harness, and engine sensor is a must if the car is high milage.

Good luck, please stay rotary or sell it to someone who will.

Jack

 

This is why I NEVER plan to take my engine over 12 psi and have as many safeguards and reliability mods in place so I don't ... it's like having unprotected sex, sure it feels better, but when you get the clap or hep or herpes symplex 10 .. it ****** sucks!

 

hahahahaha