Known Engine Problems (by engine model)

[bernie-rx7]

You could have dont that. The auxillary ports were found on non-Turbo 13B's (At leased in Canada anyways), they were designed to open up around 3800 rpm to allow better airflow into the engine creating a superchaged effect. They work from the pressure in the exhaust in the 86-88 modles and the 89-91 modles work from the airpump. Usually the brass bushings that the actuator rods sit in seize up and usually you can just take a pair of pliers and turn them loose.

I don't understand what you mean when you say supercharged effect? I was under the understanding that the airpump worked more as an idle compensator at low rpm and disengaged under load (you'll find this is the case). The secondary ports will open up under loading to allow more air/fuel into the chamber however are not activated by any "supercharger" effect. By using such a term you can confuse people on this forum into believing that the air pump on an NA 6 port pressurises the inlet manifold under load, which is incorrect. With that said you are correct in stating that carbon builds ups can prevent secondary ports from opening, and that once in a while they need a good ol flogging to prevent the actuators from getting blocked.

I don't want to be a smart arse or chop you down. But, just be very careful when giving advise on this forum if you don't know how to choose your words carefully. There are alot of very knowledgable readers who will jump at the chance to put you in your place if you pretend to be an expert.

[C-Murder]

I didn't quite understand either when I was told that, I guess its more of an effect than an actual pressurisation. I only know what I know, I guess I just saw people didn't already post this so I added it. If they want to be constructive and add thats great.

[fdrx7]

This post has been bothering me for a while and I'm bored at work.....

This engine is a very fargile engine.

Bullshit. Gross generalizations like this do nothing and help nobody.

First, if you do not red line this engine enough (aka the red line is not touched once at leased every month), the carbon build ups will seize the auxillary ports designed to open at 3500rpm to let in more air.

Most 13b's don't even have auxiliary ports let alone exhaust actuated ones. How about restricting your comments to NA 86-88 motors?

Second, these engines show little signs before they blow up, for a short while they will blow lots of blue smoke and may be hard to start.

Brilliant insights. The motor itself will only blow smoke if an oil control ring is worn. They die a very slow death and only at high mileage unless you've destroyed it. Hard to start is just a sign of low compression. Again, this is a sign of an old engine unless the compression seals have been damaged. They don't just blow up, there's always a very good reason and those always come with pretty obvious warnings.

If you have any more questions about this engine, just ask.

I have one. Have you ever actually seen a 13b? Your post is of no help to anyone (ok maybe NA S4 owners) and only serves to perpetuate the same old bullshit.

BTW the 'supercharging' effect (DITS) is just marketing crap. It's just resonance tuning of the manifold, something piston motors had about 50 years earlier.

[bernie-rx7]

I guess its more of an effect than an actual pressurisation.

What do you mean by "an effect"?? A phenomenon? Something that kind of happens but not really???

C-Murder "NEWSFLASH!" The "EFFECT" of supercharging IS inlet pressurisation!!!!

The air pump only works to help the damn things idle smoothly and isn't there for any other reason.

[WAR-20B]

Mazda 20B triple rotor

Built in batch runs of 1000. The first batch where notorious for premature failure.
The cause was shaft flex causing a little centre rotor wobble & the rest is history.

Usually occurred around 2000rpm - 3000rpm when "snap-torque" would load the shaft from 10% torque to 95% torque in around 1-second.

These engines can be identified by 000-999 on each rotor housing & side plate.

Mazda modified the shafts for the 2nd batch run & all those after it.

2nd Batch run can be identified by A000 to A999. Last batch was D000 to D999. Black paint on rotor housings with no batch numbers stamping are "warranty" engines