Well, I knew it wouldnt last forever. At the end of backstraight at Mosport about 9300rpm just before I lifted for turn 8, BOOM or should i say POP the engine expired. The rear apex seal let go and ended my test day. It is an unmistakable noise when a seal goes away. So now the engine is already out of the car (only took about 2 hours to get it out) and you can see the damage when you look into the rear ports, 2 broken apex seals. So I will go and see Danny Manning tomorrow and set about a plan to make it better stronger and faster than before!
I really cant complain about how long the engine went. It endured be run extremely lean, extremely rich, 280 degrees of water temp, racing at 300 degrees oil temp ( and finishing 2nd starting at the back!) and all the other trials of a race car being developed. So I will keep everybody posted if your interested on what damage we find when it comes apart,and what we are doing for the next engine.

 

hehe pics please? although it hurts to see something like that, it helps to deter me from abusing my engine when I start to drive.

 

Rotary

 

your just mad ( to twinturbo FC )

 

From reading the tread title I thought this was gonna be about you losing your virginity.

Sorry to hear about the engine though.

 

Its hard to keep track of everyones car on the forum here, escpecially with my memory!! But if I remember correctly, this was the car at MOM???

If it is then I most definatly want to see some pics of the porting!!!

Also, when you rebuild the motor, have you considered using re-coated rotor housings from JHB?

 

9300rpm! Ouch.

Anyhow I was there at the alms on saturday and cheers and I drove to your car after your race. Car does not seem loud at all compared to the other cars.

Wished I got to finally meet you.

good luck on the rebuild.



Now after typing that stuff out I realized you were not 23racer. Dam aluminum dust.........

Sorry to hear this. When were you at mosport Al.

 

you were using stock Mazda seals? if so i think this is a testament to their durability.

oh well, i'm sure you guys will be up and running stronger than ever in short time

 

My car was not at the ALMS weekend, that was 23Racer. The seals appear to be steel apex seals btu we wont know until we pull it apart. I will try and take some pics when Danny tears it down. As far as the rebuild goes I trust Danny Manning and will do whatever he says to do. He has been building rotary engine since the 70's or something like that, and his last engine went 4 years of racing! So I cant really mess with success!

 

hehehe, I blew mine up too... the apex doesn't appear to have let go totally though, the idle is a bit uneven but other than that the engine seems to be fine, it's weird!
40-40-40 front and 0-40-0 rear compression numbers though, I'm AMAZED at how well the car runs despite practically no compression!

It'll still spin the tires through 2nd gear...

 

Dan Manning pulled apart the engine tonight and we found what we had. It was a J-port and did have carbon apex seals. It was an apex seal that failed! Who ever said carbon seals dont wreck everything when let go was definately wrong. The rotor is all banged up, the housing is scored etc! The long and the short of it is we are building a complete new engine! This one will be a bridgeport with all the good pieces, except we are going to use steel RX-8 apex seals. The stock RX-8 engine turns 9500 rpm at the factory rev limiter, so we should have no problems there. We need that rpm because of the 4.88 rear gears the car has. At Shannonville i dont need that rpm but i do at Mosport! Should be an interesting build over the next little while. After a 5 hour engine break-in we are going back to the dyno to see how it runs! Maybe I will see some of you at a late lapping day at the end of the year of possibly the last race weekend in October!

 

Dam you blow alot of engines.

 

Really. So much for spending all that extra money on the seals.

So is the stock RX8 seals single piece?

Whats your prices on new housings

I might try and build my own engine for kicks this winter. Porting and all.

Take lots of pics

 

yeah I know I blow a lot of motors! stock ems + more boost than stock = stupid idea!
not a mistake I'll be repeating (again).

and it's been nearly a year since I blew a motor... that's gotta count for something?

this engine actually isn't "blown" since all the seals seem to be intact and it works perfect at high RPM, it still has like 95% of the horsepower it had before...

just no compression down low.... and a lopey idle.. clears up above 3000 though..

 

can you explain the reasoning behind using the RX-8 apex seals? the only benefit i see is lower rotational mass. however a few issues to consider:

the seals are THINNER than the old 13b 2mm seals. not only does this pose clearance issues, but with a peripheral exhaust port it has been shown that excessive arcing (bending) of the seal occurs when passing over the port.
also the stock renesis seal is a 2-piece design, further leading to less durability in a race application.
the corner seals on the renesis rotor is also different than the standard 13b.

the ULTIMATE seal to use in your application, IMO, is a one-piece ceramic seal. i know they are made in 3mm, not too sure about 2mm though...

 

I've ripped apart 6-7 engines. All engines had excessive corner seal wear and all of them chipped at the corner on the seal on the thin part.

For me I'm going single piece seals. (But I'm no expert)

Maybe you can squeeze out info from manning

Need to get some reliable motors going! Seems to me we are going to loose a few rotax brothers!

 

I am definately not a rotary expert! However a stock RX-8 will rev at 9500RPM all day long, Speed Source uses the stock seals so I am told, and if its good enough for them, its good enough for me! I only run for 20-30 minutes at a time, they run for 3 hours! Danny told me that it is a 2piece seal instead of a 3 piece seal, thats why it will work better! Danny's last engine ran for 4 seasons and the engine in the car was basically his old engine that the previous owner had modified to a J port.

 

I prefer the single piece seals too, after seeing all the housing damage that Ian was mentioning.

Aaron, I'm pretty sure that not too many people would bother using ceramic apex seals in an NA application. Overkill and $$$$$.

 

yes, a stock RX-8 will rev at 9.5k all day long, however the seals do not have any intake OR exhaust ports to cross, this is why they can make those seals thinner. the problem comes when using these seals in a peripheral intake and/or exhaust port application. the RX-8 seals will tend to flex excessively when crossing the ports.

 

We are not building a p/port engine. We are building a bridgeport. I spoke to Mazda Motorsport Development today, and they said the stock steels seals will work for my application as well, as many of the racers in the usa are not allowed to modifiy seals and they rev to 10,000rpm! They are very interesting people to chat with and have a lot of rotary knowledge. I did order a new baffle plate from them , as the one in my engine was hand made judging by it s appearance. Like I said before I am not an engine builder, and MMD said I can use RX-8 rotors or RX-7 rotors either will suit my purpose.