apex seals
12-14-08, 10:59 AM
#1
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apex seals
is there a diffrence in the standard apex seals for a 93. is there a company that makes a higher quality seal than the oem. is the master kit from atkins any good?
12-14-08, 08:24 PM
#2
The challenge with apex seals is making them well-sealing, durable, tough, and not destructive to the housing surfaces that they ride on.
Mazda has used a variety of cast iron 2mm seal designs. In general they are an excellent balance of the above mentioned properties.
There are some expensive 3mm seals made of ceramic (Ianetti for one) that cost a lot, are brittle, don't seal as well, but are tougher against detonation damage. Tougher, but definitely not indestructible. Plus, going to a 3mm seal requires some fairly precise machining of the rotors and sometimes that becomes an issue.
The Atkins seals are well regarded also and have a reputation for being friendly to rotor housing surfaces. The softer material (cast iron also I believe) seals very well but isn't as tough against detonation damage.
There are still other options. But that's a rundown of the major ones.
Mazda has used a variety of cast iron 2mm seal designs. In general they are an excellent balance of the above mentioned properties.
There are some expensive 3mm seals made of ceramic (Ianetti for one) that cost a lot, are brittle, don't seal as well, but are tougher against detonation damage. Tougher, but definitely not indestructible. Plus, going to a 3mm seal requires some fairly precise machining of the rotors and sometimes that becomes an issue.
The Atkins seals are well regarded also and have a reputation for being friendly to rotor housing surfaces. The softer material (cast iron also I believe) seals very well but isn't as tough against detonation damage.
There are still other options. But that's a rundown of the major ones.
12-15-08, 11:14 AM
#4
Yes. Any form of detonation, preignition, etc will cause an explosion (normal combustion is actually a controlled burn that creates a steady increase in chamber pressure and does not shock the engine internals). On a piston engine it's hard on things but usually doesn't damage the motor badly.
On a rotary the shape of the combustion chamber focuses that shock wave onto the apex seal, putting an immense shear force across it. As a result apex seals tend to break almost immediately once you get detonation. Like I said, ceramic 3mm seals only help some - detonation can definitely still break them.
IMHO, unless you've built several motors with OEM seals and they just don't hold up even with extensive attention to tuning, the expense of 3mm seals and rotor machining is better spent on something like auxiliary injection. AI really helps prevent the detonation and preignition and has numerous other benefits.
Dave
On a rotary the shape of the combustion chamber focuses that shock wave onto the apex seal, putting an immense shear force across it. As a result apex seals tend to break almost immediately once you get detonation. Like I said, ceramic 3mm seals only help some - detonation can definitely still break them.
IMHO, unless you've built several motors with OEM seals and they just don't hold up even with extensive attention to tuning, the expense of 3mm seals and rotor machining is better spent on something like auxiliary injection. AI really helps prevent the detonation and preignition and has numerous other benefits.
Dave
Last edited by dgeesaman; 12-15-08 at 11:16 AM.
12-15-08, 12:00 PM
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what is the auxillary injection i have the bigger fuel pump done fuel regulator and i believe 550 pri and 1200 secondary
thank you for all your help sofar
thank you for all your help sofar
12-15-08, 12:27 PM
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how much power are you planning on making? mazda two piece seals and atkins are great seals. the key is a good tune, excuse me, and EXCELLENT tune. but based on your injector sizes, you arent shooting for much. if you want a good high hp, relatively cheap seal, go with ALS. but id say anythng below 550whp stick with atkins or oem. i dont know about oem, but i have seen atkins standard 2mm make over 600, but i personally wouldnt push them that far. just my opinion though
12-15-08, 04:40 PM
#7
AI = methanol (alcohol) or water injection.
The key is that new AI systems are able to be programmed to inject based on another parameter such as boost pressure.
Whether it's water or some kind of alcohol, AI really cools down the combustion chamber, making life much easier for your apex seals. Knock levels go down, you don't need race gas to push big HP, and your combustion temps stay cooler. And other good things.
There is new info about AI in the 3rd gen FAQ and a pretty interesting thread by Howard Coleman about the details. If you're interested get started with those and then dig into the AI section of this forum.
Dave
The key is that new AI systems are able to be programmed to inject based on another parameter such as boost pressure.
Whether it's water or some kind of alcohol, AI really cools down the combustion chamber, making life much easier for your apex seals. Knock levels go down, you don't need race gas to push big HP, and your combustion temps stay cooler. And other good things.
There is new info about AI in the 3rd gen FAQ and a pretty interesting thread by Howard Coleman about the details. If you're interested get started with those and then dig into the AI section of this forum.
Dave
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12-15-08, 09:55 PM
#9
But the ceramic apex seals are the best ****, too bad it cost so much, not affordable unless you are a race car driver or a rich M/F.
Last edited by -CON-; 12-15-08 at 10:08 PM.
