Hey, me again, as you may have read in my previous post i just bought a 1st gen rx7 from 78....or 79 not completely sure.

A friend of mine who knows more than engines than me just told me that rortary engines are not very durable and that the blok wares down after as little as 100000 km (67000 miles). The only solution would be a conplete revision and likely new block.....

Is this at all true?

 

Do some searches.

What your friend told you is a common myth. Yes, it COULD be toast at that point, but only if it was mistreated.

 

Tell your friend to come give mine a look. 180000 miles and still going. There are several people on this board that have seen over 250000.

If you take care of the engine it WILL go for a very long time.

 

My motor has over 112,000 miles on it. Origional motor. Just went to an auto-x yesterday about 2 hours north of here and got a solid 22MPG and still outran a new Mini Cooper and A Ford Probe.

If the motor is extremely abused they wont last, but if the oil is always checked and routine maintnance than they can last forever.

 

Exactly what i thought! All engines die early when they are mistreated, nomatter whether its a rotary or an inline or whatever.

My friend was just trying to point out that rotarys where weak engines.

Now i do realize this is an acient old myth. Long time ago there was (this is true, not myth) a dutch carmanufacturer SENU who made rotarys engines for their cars aswell. The problem was that these engines were extreemly weak and broke down in no time. After some time this manufacturer started cutting prices for their engine parts (because people were going nuts over the cars breaking) and this ultimitly resulted in the manufacturer going bankrupt.

I know the above story is acurate and true....i know because my granddad drove a SENU. But that was long before 1978 at wich point mazda started using these engines. Now my guess was that by 1978 they had improved the technologie drastically and made it perfectly durable (like any other engine). So it seems that i am right after all....

To tell ya the truth...i was worried...my friend is usually right when it comes to engines. But i did have a hard time believing it and in this case it seems that i am right. Ofcourse, it could be busted like you sayd but this isnt neceraly the truth. It might be mint (after the cleanup) aswell.

anyways, thx, thats all i needed to know. i intent to hold on to this car for as long as i can and intime put it into a garage where it will be nice and dry and turn it into a nice funcar for weekends and such.

Thx guys, you have been more than helpfull

 

Plain and simple, rotary engines last just as long as pistons engines. It all comes down to how it was taken care of.

The legend of rotary engines not lasting long, comes from when they first produced rotary engines. Such a sad way to taint a product if you ask me.

-Error402

 

I would say that a rotary in the na form would have greater reliability than a piston type engine. The piston engine, outside of all the valves and cams to wear out, the pistons recipocating action is not a true up and down. this would put stresses at different parts of the cylinder bore. As the engine matures the blocks cylinder wears in the stressed areas and "deforms" the cylinder walls.

Let's not forget about the trouble with valves and carbon deposits and sealing.

The sipmlisity of the rotary wins assuming the engine was taken care of.

 

SENU? You are from Belgium? Could this be what in America was refered to as "NSU"? This is the company that Mazda bought the rotary patent from. The NSU r80 had design flaws that allowed carbon deposit accumulation to eventually render the engine a useless oil burning smoke machine.
The basic design and internals are the same.

Interesting would be to have an old NSU r80 design, but with zero miles on it; put in the oil of todays technology, and see just how much better than yesteryear the engine would last.

Are there many of these old Wankles to be found where you are?

 

my GS has 160k on it and still starts right up. Its having some carb problems, but teh engine is still strong. Good luck with your car.

 

Are you sure that the car isn't a 79? That was the first year it was available in the U.S.

The myth over here was due to General Motors. They tried to develope a rotary motor, and they couldn't get their design to work. So rather than spend more money on design, they spent money on PR to bash Mazda's rotary motors.

The major change between the NSU and the RX-7 is the treatment that was applied to the rotor housing. By using a different alloy and heat treatment coating, they pretty much eliminated all their longevity problems.

My motor has 142,000 miles on it, approximately 228500 km, and it still has near perfect compression. I can't attest to how it was maintained because I've only owned it for a few months now, but the oil was really clean when I got it.

 

I have 113k on mine pushing 114. Original motor I take it to track days and just run the **** out of it. And it hasn't complained once.

 

193,000 kms on my 13B EGI and still going strong... starts right up in this winter weather (-15 so far), too

 

Some people refer to the real early 79's (ones with one mirror) as 78's. Technically still a 79 though

 

I think your buddy is afraid of what he does not understand. I have a freind that completley hates rotarys because of the "design" but he really just doesnt understand them at all.

 

People like that annoy me. I wish they would just go away.

 

I bought my first GSL-SE in '92 and it had 116,000 plus miles on it. Just a month ago I decided to do an engine exchange before SevenStock. The engine had close to 282,000 miles on it...Thats a decade of mostly hard driving

 

Bah, keep them cool, check the oil now and then, change it now and then, and they will last longer than most piston engines from the same era

 

I cant wait till the new generation Renesis rotary. Now that they have many of the rotary quirks I would love to see how dirable these motors are!!

Would be willing to bet that they will be one of the most reliable sports cars on the Market.

 

Have to agree with indy...keep 'em cool, overheating kills these engines.