forcefed7

Just wondering if anyone else has had any problems with either the side seals or apex seals starting to stick at this power level. They seem to free up, but I was just curious people are doing prevent/fix this problem.

HWO

u sure its not rotors connecting with the centre and end plates because they were clearenced properly to start with?

Mr rx-7 tt

iTrader: (5)

I don't think that sticking a seal is your problem.. When you start pushing hp like that clearances become critical..you also start running into issues like cracked end plates, etc..Who built the motor and are you sure you are pushing numbers like that..?

forcefed7

I think it's a side seal or a apex seal starting to bind from the heat causing it to lose compression. Again, I just started running into this problem. It's kind of strange, it happen when I push it past aprox. 620-630. I'm sure someone here has had to run into this problem. Rice? Crisp? Anthony? Any ideas? BTW I built the motor and yes I'm doing those numbers

Thanks

forcefed7

I'm not sure if that's what's happening, At what power level does this become a issue?

Thanks

Anthony Rodrigues

Before you pull the engine down, try boosting your ignition and monitor your water temperatures. It could also be locking an injector. It is very hard to comment without knowledge of your set up and or engine specs. That is good power so we must assume you know the basics about the engine otherwise you wouldnt be making that power. More info?
Regards-Anthony

AJC13B

My setup at the moment is starting to surpass that power level on around 30psi.

I have 3rd gen rotors and I am using the HME 3mm 2 piece seals. My engine builder (Bill Nabhan from Mazsport in Sydney) has asked me not to go past 30psi because the 3rd gen rotor tips will start to close up from the heat and the seals will stick in the grooves in the event of a miss, be it rev limit or ignition break up. So we will peg the boost at 30psi

Comments?

forcefed7

That sounds excatly like what I'm experiencing. What is the fix is for this? Anthony, what did you need to know about my set-up? Single turbo, street port, TEC3, factory apex seals and springs hope that helps.
-thanks

RICE RACING

What clearance did you use for the apex seal grooves???

This is critical, not only this but machining accuarcy, especially on rotors that have been machined to accept 3mm seals is critical. Uniformity of the new goove I.E. in terms of machining tolerances is one of the biggest problems I have seen in engines running 3mm seals I am not saying this is your problem...yet

What size "feeler gauge" did you run down the gap (apex seal to groove) and was it a nice even clearance all the way allong the grooves right to the bottom? I can give you some insight into this if you require the help? Needless to say what tends to happen if this area is in doubt as that as the power (chamber pressure) increases and the time for gas sealing to do its work underneath the seal gets reduced you find that there is not enough gas pressure building up underneath the apex seal, this pressure difference causes the chamber gas to escape over the top of the seal and you hear and feel the effects (almost sounds like detonation) this causes chatter marks and loss of power, can also break seals too. Some people get around it by using double springs (which allso helps due to higher weight of 3mm ferrous seal "different issue") but realy in most cases it is a lack of clearance or enough clearance but inaccurate machining of the groove. Which leads to the time delay between pressure build up under the apex seal compared to the pressure it is holding in the chamber, which causes "binding or sticking !" It is not an inherent problem as Mazda did not design the engines to do what we are asking of them, mainly because increased clearances means increased wear. There is a special mod ification I do the the seals to prevent this without using increased clearances but I have to keep something to my self !

This is a "brief" summary as to what may be happening and infact what I have seen in many engies, but it as Anthony said have the slightest to do with your situation you are experiencing

Keep us posted

good luck

forcefed7

Something similar to gas porting pistons?

AJC13B

Dunno

I just listen to my engine builder. I also think the 30psi limit relates to the higher comp rotors I am using and the fact they may implode at higher boost

fdracer

what's gas porting?

forcefed7

It's when you drill a small hole on the top ring land on a piston engine to let combustion pressure push on the back side of the ring to aid in sealing. Not too many people know about this...

forcefed7

I just wanted to thank you guys for responding. I'm going to pull the motor out after the next two race and inspect it. I have a few things I'm researching and may try on the next engine. I'll keep you guys posted as to what I find and try... Again Thanks (Rice, Anthony,AJC13b,HWO, Mrrx7)

peejay

What happens when you let off the throttle? Or would chamber pressures (near vacuum) be low enough that it doesn't matter?

AJC13B

It just don't matter