| ozzmodan |
Now that I'm going into my engine I've been doing quite a bit of looking around at different apex seals & the two that come up as the frontrunners seem to be the Mazda apex seals & the Real World Solutions (Rotary Aviation) seals.
From what I've heard the Rotary Aviation seals seem to handle detonation & high boost better than the stock apex seals but at the cost of wearing the housings down more than the stock seals. Some argue that the housings by the time you do another rebuild should really be relapped/replaced anyway so the extra wear isn't that big of a deal. I'd also be running premix so in theory some of the additional wear would be offset.
I've heard other people say that stock seals will handle extra boost just fine & unless it's a serious detonation the apex seals will survive despite the reputation that any detonation will definately kill the engine.
The question is this:
For a street ported 4 port, running 12 psi boost & premix, what apex seals would you choose? |
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| KKMCanada |
From personal experience, the stock seals handle high boost better than the Ra seals, also the Ra springs are not comparable to the mazda springs
Only one seal has been tested for resonance against the housing and that is the mazda seal, the aftermarket has no way to test whether or not the material is compatible with the housing itself. Excessive chatter is often the result along with failing of the chrome surface prematurely.
The parts of the motor are engineered so one part is always the most consumable, and that part is the one sized and priced to be replaced. In the case of the rotary, the apex seal is the consumable. With aftermarket seals the role is flipped with the rotor, the rotor slots tends to wear faster, once the clearance is opened up, combustion gases load the seal against the housing, the more pressure underneath the seal the more the seal burns down and wears out the chrome.
The last pitfall is that just addressing apex seal strength does nothing for the side seals and the corner seals, if the motor does not break from apex seal failure due to "unrbeakable" apex seals it will die a short time later from other causes related to broke side seals and corner seals.
The best cure is good tuning, one cannot protect against parts failing like stuck injectors , broken wires and hoses though either. If detonation happens to part failure , it just will happen, the only safe guard available against that is a ecu with knock sensing, such as power fc or FCon, but still it can only do so much, lose an injector at 1.0 kg/cm3 or spike to 2 kg/cm3 and something is likely still to break.
The use of Japanese market only Mazda race internal seals which are the same material as mazda oem parts but have been hardened for much higher body strength is another good choice, the kit includes apex seals, corner seals, side seals, coupled with 8.5:1 rotors, that combination is the toughest motor you can build, you will break spark plugs and crack the teeth off the stationary gear before the motor's seals fails from detonation.
The kit is not the cheapest but when you look at it, not that much more expensive than the production seals. Retail on production parts for all the seals is about 550, retail for the mazda race seal kits is about 950.00 ish... I know the aftermarket seals are cheap, but that also tells you exactly how much resources have been poured into testing as well.
kkm |
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| bigmack000 |
| nice post!:thumbup: |
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| ozzmodan |
Where would you get Mazda race kit?? If they are hardened more, wouldn't they have the same result as some aftermarket seals with rotor slots wearing quicker?
Kyle |
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| KKMCanada |
Good question, from looking at them, I would have to say the surface hardening has just been increased deeper through the seal, from the visual difference, it looks like the seal flanks are untouched, just the face and core is stronger. Then again there is more to seals than just hardness, if it resonates, and vibrates excessively, thats what will wear the seal slot faster, along with the fact that some materials will retain lube better than others.
The seal kits are availabe via special order from select shops in Japan. I am bringing in a few kits in the near future, and plan to run a set in my own car, I have seen them in action and they do survive abuse, they have also been around long enough that I have had the chance to tear down an engine with some pretty hard kilometers on it, and the wear internally was no different than a what a stock sealed motor would look like.
I myself have been through the ringer twice now with aftermarket seals and never again... I wont run any internals that dont come in a mazda bag.. |
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| ozzmodan |
I'll look more into what apex seals I want to run in the next few months, but give me a shout if your going to be ordering some of the racing Mazda kits anyways, I might be interested in getting some at the same time. BTW how extensive is the rebuild kit & are any of the other components in it any different from stock?
Kyle |
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| KKMCanada |
| I checked into the kit level, and there are 2 kits, one with springs and one without, the one with springs isnt recommended till you start breaking 600 rwhp. The standard springs with the uprated seals is what 95% of the people there are buying. |
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| ae86dorikin |
| how much do they go for? |
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