Holy balls that looks like fun.

So, I know rotaries are known for having issues, especially with apex seals. How long does it take the average rotary-head to replace an apex seal? Does the engines light weight make it easier than say, replacing rings? And what about cost?

Like this?


It's a NB Rotary build in Poland I have been following on Facebook.

Depends on experience swapping them out. If you've done it before it can be done in two to three hours from start to finish if only replacing Apex seals / springs and gaskets. Side seals take the longest to install due to they have to be clearanced to the corner seals.

The engine is actually "layered" (plate / housing w rotor / plate / housing w rotor/ plate). Basically have to disassemble it to the bottom housing to get to the rear rotor in order to swap out the seals. Weight wont have much to do with it.

Apex seals are expensive, factory Mazda's are around 275 a set, aftermarket are around the same price. High end ceramic performance seals are about 1500.

And how long do they last? THe 30k everybody says or better?

Aren't the best apex seals some unobtainium titanium shit? That are like +2000.
I've heard of some using specifically cheerio cereal boxes as seals.

Edit:
Per video - Yes! but much more brap.brap.firball.brapness :P

The rotary hate is the result of misinformation.
Take a factory turbo car that is extremely sensitive to detonation, add years of backyard modifiers who know nothing about tuning EMS and you get a lot of blown up engines. Just swaping exhaust without tuning can make one of these things lean out enough to detonate and a little, and that's all it takes.

This is like back in the 80s when people were spraying dry nitrous into their carburetors and then crying "dang ol' NOS blew up mah 350, that shit is dangerous I tell you what."

Ah FTB, you and your rants. I suppose next you'll suggest this is also a better swap than the K24? :giggle:

Seriously though. Its a very cool motor but.. Poor fuel economy and expensive maintenance. How is that not deserving of a bad rap?

OP can probably offer more insight than I can.
Im not saying theyre perfect DD status or anything, but its all blown way out of proportion. Ive seen people on this board basically say that they are garbage.

They definitely can be reliable. There is no way they could be used in aircraft if they couldnt be super reliable.

I think they make great race engines. Just look at Formula Mazda. They make plenty of power and with a conservative rev limiter and the tuning dialed-in they are very reliable.

My '89 RX7 went 156k miles before needing a rebuild. Then I drove it another 30k before selling it to a guy who still had it last time I checked. Car required no more maintenance than any other. I replaced the clutch and the shifter bushings. That's about it.

I think the same fart can kids that do stupid things to Hondas gave rotaries a bad name. Hondas are just a bit more tolerant of stupidity.

One thing that's bittersweet about this site is the classifieds and vendor section. Since starting this thread I am now also going to be upgrading my primary injectors from 850cc to 1000cc as well as upgrading my 550 cfm intercooler to the 725 cfm stage 2 (in black!) that fab9tuning offers.

Has anyone ever done research about the effect of painted intercoolers?

Depending on the paint but yes most over the counter paints decrease the efficiency. Theres some speciality paints that are extremely thin that dont drop it much but no idea which they are.

Yeah, I doubt that wrinkle black spray would be good for heat exchange.

Sorry I just love this quote

I find it kinda funny that most of the people talking up rotaries don't have one currently, or haven't had one for a very long time, or have never had one.

Also I find it kinda odd that most of those people consider having to mix oil into their gas, WOT the car at least once when driving it, have no torque til like 5k rpm, and even when short shifting and taking it easy still get no more than about 15-17mpg, totally REGULAR maintenance and TOTALLY normal and reliable and great.

Now, I don't own one and never have, but have had friends and relatives with FD's and RX8's so I did get my fair share of feedback on them as well as helped wrench on them. And all were really low mileage very expensive cars that were never hacked or backyard "fixed". All sold them and would never consider a rotary again.

Now, please don't take this as hatred, its not. I really appreciate what these engines/setups do and I admire some of these builds (even if secretly :giggle: ) so keep on keepin on.

:)

Meh. I originally bought the Miata and got rid of the rx7 because the switches and some plastic interior parts were ageing and the Miata was purported to weigh 500 lbs less. Nobody told me the Miata handled like shit out of the box. Miata was seven years newer and had many less miles so I bought it. It's great now but it was a real let down after the '89 rx7 stock to stock.

I think most of the guys premix the oil in as an insurance policy in case the built - in system fails. I'm not sure on the specifics of all that. I'm in the category of people that have never owned a wankel.
I have known quite a few Formula Mazda owners and car builders who were ecstatic about the engine. While I was rebuilding my POS reciprocating engines every couple or races they were running 3-4 seasons on their sealed 13Bs. IIRC they contributed a lot of this reliability to the rules limiting revs.

I won't talk "up" a rotary and I own one. They just aren't for everyone plain and simple. I personally wouldn't daily drive one for my 45 mile commute to work.

However, when going for high hp and low weight ... that's where the rotary shines. The rotary definitely has it's "quirks" and those do include either oil injection or pre-mixing (for those not familiar with rotaries imagine what piston rings would do if there was no oil to cool them).

Torque on the rotary is going to be based on porting and turbo sizing. I have seen rotary builds pulling 400 ft lbs by 4k rpm:
400rwtq @ 4100rpms - RX7Club.com
350 ft lbs by 3800rpm:
Autox FD Dyno - RX7Club.com

WOT driving is what these engines are all about, that's why I have one in my Miata. Horrible gas mileage doesn't bother me personally in a weekend warrior, again it's not my daily driver.

Rotard haters are dumb.

This shit is fucking rad.