There is one piece of advice that you will rarely see on this or any forum. I have had a few discussions with the local rotory guru (testament - he's owns over 30 of these cars and has been working on them for over 30 years, kind of like a 30/30 guy).

In his opinion, the number one reason the engines go on these cars is "overheating" and also in his opinion, the number one reason they over heat is vac leaks. This is especially true on FI set ups - as we all know, a lean condition can cause over heating and vac leaks are a major cause of this condition (a vac leaks are common on these old cars). I don't know how many threads I have read about poor or high idle that may have be a result of this - but i do know that a lot of these people continue to drive their cars regardless.

I know this is not a "how to", but it is something we all should be aware of and take very seriously -

 

thanks....

 

yep no-1 reason for any car's failure is poor maintenence........rotary or not.

 

very interesting, and makes sence. with all the vacum lines and just about any-one of them can leak at any time.pinning down the leak(s) is the diffacult part and many get fed-up and give up trying to find the reason the engine runs funny and just drive it the way it is. the number one reason a rotory engine fails is,,, neglect. and or common sense.

 

well i guess its a good thing my holley runs rich as a **** then :P

 

Incorrect.

The #1 reason a rotary dies, is too fat of a chick in the passenger seat.

 

so thats why there are so many broken down 7's around here

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And just how DO those fat chicks get in YOU'RE car Cody? Just playing around. Thanks for the thread, When I first got mine it had a bizillionleaks so I gutted the rats nest.My rule of thumb is to richen up the fuel mix so I guess it really payed off in a rotor.

 

I would say that no.1 reson rotaries die is because people try to sqweese too much HP out of a little engine.

Ooops there goes another apex seal...

 

I'm not referring to motors that are exploding, I'm referring to the fact that a lot of these cars smoke to some extent and some are at the point where they require a rebuild. In most cases, this is due to an overheating problem at some point. A few are due to rad problems or other cooling problems - but most (and this is opinion), are due to running these cars in a lean conditon (due to vac leaks) and slowly cooking the seals/o-rings

 

I think the main reason they break is due to normal rotary failures. Typically from apex seals worn down too thin under spec's and eventually break. Overheating should only happen if a coolant hose bursts or the water pump bearing goes out and coolant spues out. Ofcourse, you should be watching the temp gauge, so if you see it wonder past half, you should shut it off and see why its not in the normal temp range.

I haven't heard of a normal asperated lean running rotary that broke before you could tell it was running lean enough to cause problems. If its running so lean, it would run rough enough to cause it to hesitate enough to barely start and really be down on power in part throttle conditions.

Now a lean running turbo rotary with lots of boost is not a good thing, I'd rather choke it up running 9:1a/f then have it run lean at 15psi boost.

Now I have seen that the 12a's fitted with the water-oil cooler tend to have hardened 0-rings were ever it touches the oil and start to leak sooner then the front mount oil cooler'd 12a's. I definitely believe the '79-82 engines probably last longer then the '83-85 12a's if they were driven the same way.

 

I've owned a couple of these cars and both the temp gauges never came near the half way mark. If they do, you are most likely running the car hot - Even at the half way mark. And I think that is why people don't realize they are even running with high temps - the gauge is not accurate or is at least misleading.
I agree that apex seals are a killer but that is not what i am referring to. Total engine failure is one thing - burning oil (which progressively gets worse) is another.
I don't agree that over heating will only occur with coolent problems - a lean condition will also cause over heating - it won't be as noticeable or extreme, but it will be there. And I know for a fact that people will drive their cars with poor or lumpy idle and not realize why they have it or what kind of damage it may be causing. If the leak is so bad that they can't start or drive the car (or major power loss), then I would also assume that the owner would do something about it. Again, I am not referring to the extreme case of leaning out. Think of it this way - you temp gauge is at the half way mark (and you think thats normal), you have a higher than normal idle but you put up with it (or you can't find the problem), so you continue to drive. As the months/years of driving continue, your car runs a little worse and you gradually seem to be puffing a little more oil. Eventually, you need a rebuild.
Note - I'm note referring to a lot of the people on this forum who know the symptoms. I'm taking about the new guy who doesn't fully understand this car and will assume things are OK.
That is the reason why I thought this would be a good post for the FAQ section (newbies) - it was not intended to be posted on it's own under the title it was given - the post was moved by an administrator which is fine, however, it is may be causing some confusion.

 

hmm. i dont know about that... IMO the number 1 reason for failure is the fact that most of these cars have between 150K to 300K miles.. Its just normal! You push any engine to 200K miles and your looking at a rebuild no matter what type of engine rotary or not.

And then theres the fact that these cars are 20 years old.. Doesn't matter what you do to take care of it 20 years will take its toll on every piece of rubber and any piece that moves and comes in contact with any liquid...

 

I read once, in Grassroots Motorsports Mag, that a reason the 3rd Gens died early was because they ran lean. And the reason they ran lean was because the fuel filter was so hard to get to that nobody replaced them.

 

I also agree on this point. And I also think the high milage / age is another reason that the vac linies are brittle / cracked or splitting.

I didn't really want to debate this although it's great to hear all the different veiws. So.. In an effort to get to the real purpose of this post, let's say the #1 reason is not "lean conditions" - I'll go with that (it was only an opinion). I only want to bring forward that vac's leaks are engine killers and many may not be aware of this. They are not only an inconvience by way of poor idle or rough running conditions, they can also do a lot of damage and should be fixed immediately - can we agree on that

 

my #1 recommendation ot maintenace is to add 2 cycle oil to the gas whether the OMP works or not, I had a rotary make it 386k and the other at 250k so I dont wanna hear that it dont work

 

I definitely agree with Mike on the pre-mixing thing. If you have a working OMP, definitely add a few onces of 2cycle oil if you intend to drive it really hard, like at a road course. I think if you are only going down the highway at 70mph, its up to you. But no omp, and running 2cycle is cleaner then engine oil burning with deposits on the rotors and near the rotor tips, and will reduce apex seal aging to some extent.

 

"Vacuum leaks as the leading cause of oil seal deterioation" is a very general statement.
It depends on where you leak. The FD has a complex vacuum route system due to the twin sequential control. An unfortunate leak there could cause overboosting issues or something to that effect.

For small leaks (I mean small), the ECU can compensate and trim the fuel a bit, but it's limited.

It's really maintenance and fixing stuff instead of driving until a problem occurs.

From my experience of troubleshooting (and rebuilding) rotaries, a lot of owners neglect coolant maintenance which could lead to warping of the housings and could leak either coolant or oil into the combustion chamber; thus smoking when running.

I agree with pre-mix as well. Engines burn a whole lot cleaner with pre-mix, but there is maintenance that comes with it (not much IMHO).

J

 

I'd say #1 reason is not changing your oil often enough. The average driver sees 'clean' oil and thinks good enough - not realizing that while wankel engines don't build up the sludge that piston engines do, they still require regular oil changes to maintain adequate lubrication and flow.

 

I'd say that the #1 cause of failure in these engines is overheating, plain and simple. Not from "running lean" or any BS like that, but from oil-rotted heater hoses that blow while people are driving.

 

id say #1 is from overheating, and #2 it running lean in the rear rotor, pop

carl.

 

I'm a newbie, and all I read from a lot of posts is that overheating is bad...very bad. Is a badly overheated engine rebuildable, or is there just too much damage? What would be the weak spots: housings? rotors? etc? Thanks guys

 

A badly overheated engine core is useless. The alum housings warp and won't seal properly. And they're really expensive to boot.