Why do 1st Gens run so long? (and 2nd and 3rd gens die?)
 

A couple of years ago I posted a poll on the number of miles on 1st gens. Results are that 55% of those who voted have over 100K on the original engine (28% were over 150K). I find this data amazing!

(original poll: https://www.rx7club.com/showthread.p...2&page=1&pp=15)


Anyhow, I am wondering why do 1st Gens run so long -- especially in comparison to 2nd and 3rd gens, which seem to die early. Virtually every 3rd gen on ebay or AutoTrader has a new engine (unless it is a garage queen). This seems frequent on 2nd gens as well.

Someone told me that the injection system on 1st gens are more robust, and that Mazda cheaped out on the later versions, making them less reliable. True?

most of the places i read rate the 12a engine for 100,000miles.................but on here people have them going strong way past that! I guess we just know how to drive them in just the right way.

Older engines can, in many cases, be stronger and more solid. thats probably why, but who r they rated @ 100,000 then.

plus the 2nd and 3rd hav boost, and most of them pop because of improper modifying.

Edit: in addition, the 1st gens usuallyt have older, and more mature owners.

The complexity of the 2nd and 3rd gen engines got so much more complicated. I was looking at a friends 2nd gen haynes manual and i was overwhelmed with the tons of sensors. The engine has a freaking sensor for just about everything. It makes me think i like my engine much more for the freakin simplicity!

Yeah, it seems the average life is 50K more miles than 2nd gens. What I noticed with 1st gens for sale in my area is they hardly had any rebuilt engines. While there is a greater number of 2nd gens that have had rebuilts.

This is why the SE was released with a 13B fuel injected engine instead of the Jspec 12A Turbo - reliability. Mazda hadn't yet learned how to make a turbo rotary last, and knew it.

my fb had 239k on her befor she blew...:( and now i wait for my "new" motor to get here... and have been over a month... :( my girl has an 81 that has 135k on her and she runs great!

Mine has, let's see, 189 k or so? The carb quit before the engine did @+@

First gens rule! Just got back from a 2600 Km trip over 4 days! never missed a beat! ran flawlessly! 13B 6 port EFI.!

I am quite pleased with my 1st gen. Very glad I got it instead of a z32, or the FC I was looking at.

Only part I hate is I have to check the weather forecast, if its raining my toolbox has to go in the back so I do not spin around on the highway in a turn. Yes it has happened.

If it spins that easily, you may want to look into some better tires. :)


Do the FCs really die that quick? I know the TIIs don't last as long, and obviously the FDs are pretty stressed, but I thought the NA FCs were good for 150k+ miles (which may not be as long as an FB, but long enough that I wouldn't say they die early).

They are new tires. :(

I've noticed that as well. Most FB's still run on the original engine assuming it's taken care of.

I'm suprised you can get yours to spin so easily, I've always thought my 7 was the best in turns out of all the cars I've ever had including a Z28. I have to really be trying to get mine to give loose.

In my car, in wet weather or sand, i cant help but go sideways and do burnouts. Its just too fun:D Dry weather is great though for going fast on the highway on/off ramps(those are like the only good turns around here)

I always heard that it was because the 13B had replaced the 12A in production for the late model year of the second gen rx. Also werent the 12A rotary turbos in Japan pretty reliable when they werent toyed with???

i hate to admit this, but the past 5k i havent been premixing (which i know if really bad and i have been the last 2 fill ups) and i have BEAT THE SHIT out of my car for the last 30k miles (autox, drag, 'spirited driving'), and i rolled over 160k last week.

and people told me not to get an rx7 because they are 'unreliable'.. yea right. my friend had the CLEANEST t2 ive ever seen with 50k on it. he upped the boost with intake/exhaust, but no fuel and literally blew the motor in 20 minutes. i know that was his fault, but still.

i love my first gen man, and i wont blame it when the motor pops, but she hasnt failed me yet (knock on wood)

Yeah people always tell me, don't blow an apex seal going to the store. Fucking jerks, if they only knew the power of the rotary.

yea with my girls fb i have to try pretty hard to get sidways but mine just slides right out... the lsd makes a huge differnce

Our cars are more reliable because most of us don't have boost. Anytime you add that to the equation, your reliability drops down considerably. Plus a lot of people up the boost w/o fuel. 2nd gen NA's are just as reliable as 1st gens. IMO, 1st gens are built a little bit stronger (ie suspension, interior...etc)

I ran mine Til 138 000km
only a Week ago, lost a seal on the express, But my 85 gsl se has had a Cartech Turbo for at least the last 15yrs!!!!!!

If your former statement were true, they wouldn't have put 12A rotaries in every model of Series 3 (1984-1985) RX-7 except the GSL-SE.

For the record, my daily driver only has 171k on the original engine... and still rolling along. I might hold off on the P-port until this engine passes 200k. :D Should get there by roughly November of next year, but I don't know if I can wait that long.

2nd-gen N/As also last a long time. Their 2mm seals are also much easier on the housings, you can take a worn out FC engine and it's rather likely that the rotor housings are still useable.

The Turbo engines, though, burn their candles at both ends (twice as bright but half as long)

Mine just clocked out today at 162k miles. :(

from what a friend of mine told me...mazda went to smaller lighter apex seals on the newer cars...which were susposed to cut down on friction...but lowwerd the life of the engine...which they didn t find out untill it was too late

There seem to be a lot of opinions and theories about this subject, but one fact is indisputable, according to several people I know who make their living working on Mazda rotaries: The 84-85 GSL-SE is the longest life rotary ever built. Some will run 250,000 miles. In my opinion, the explanation is simple - this was the first engine Mazda built with direct oil injection into the chambers, and the last engine they built with the 3 mm apex seals. Previous engines were all carbureted, and the oil was fed into the carb. The 86 and later engines also have the direct oil injection, but they have the 2 mm apex seals, which are just not as durable. Several rebuiders I know will machine out the later rotors for the 3 mm seals if they want to build a bulletproof motor.

As for the 3rd gen cars, the specific output ( as in horsepower per cubic inch) is just too high for long life in a rotary, using current technology.

I was a big fan of the rotaties for 20 years, did rotary engine transplants, built ported engines, etc. But I think the time of the rotary has come and gone. The new technology piston engines with the variable valve timing, and even variable lift, and all the other optimization, combined with turbocharging, has allowed the piston engines IN MASS PRODUCED FORM to outperform the rotary and still get much better fuel mileage. If you don't recognize this you just aren't paying attention to the technology. It is very unlikely the rotary will ever close that gap.