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What are apex seals?

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Old Feb 7, 2010 | 11:45 PM
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Seamoan's Avatar
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From: CADIZ SPAIN
What are apex seals?

and why does everyone keep bringing them up when i tell them about my car? they ask how are the apex seals or they laugh at my apex seals and just walk away. they hold the rotor in place?
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Old Feb 8, 2010 | 09:27 AM
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Apex seals are the seals at the tips of the rotors, roughly equivalent to the compression ring on a piston. Back in the day, the major reliability problems with the rotary stemmed from poor apex seal design. They were too soft, too hard, and the proper material had not yet been discovered. Consequently, they would fail which would result in a lack of compression. These days we don't have apex seal issues. Rotary engines generally blow from overboosting, inadequate fuel supply or because they are simply worn out.
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Old Feb 8, 2010 | 01:16 PM
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the internet is ur friend. ask it anything and u'll get links to the answer.
http://auto.howstuffworks.com/rotary-engine2.htm
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Old Feb 8, 2010 | 02:55 PM
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thanks for helping me out to! i also didnt know what apex seals where.
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Old Feb 8, 2010 | 11:08 PM
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From: CADIZ SPAIN
Originally Posted by rxtasy3
the internet is ur friend. ask it anything and u'll get links to the answer.
http://auto.howstuffworks.com/rotary-engine2.htm
good link

edit : i jus read it, great link! this url should be stickied somewhere haha

Last edited by Seamoan; Feb 8, 2010 at 11:25 PM.
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Old Feb 9, 2010 | 01:07 AM
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I don't mean to be rude but if u own a rotary engine how could you not know what an apex seal is??
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Old Feb 9, 2010 | 01:14 AM
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From: CADIZ SPAIN
im not even going to answer that
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Old Feb 9, 2010 | 09:40 AM
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Originally Posted by w.sen
I don't mean to be rude but if u own a rotary engine how could you not know what an apex seal is??
Quick, without Googling, tell me how many teeth there are on the stationary gears.

See my point?

Everyone has to start somewhere.
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Old Feb 9, 2010 | 11:04 AM
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Originally Posted by Aaron Cake
Quick, without Googling, tell me how many teeth there are on the stationary gears.

See my point?

Everyone has to start somewhere.
damn! i've been in rotaries since mid 80s and even i don't know the answer to that.
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Old Feb 10, 2010 | 10:31 AM
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From: Stamford, CT
CT

Originally Posted by Aaron Cake
Apex seals are the seals at the tips of the rotors, roughly equivalent to the compression ring on a piston. Back in the day, the major reliability problems with the rotary stemmed from poor apex seal design. They were too soft, too hard, and the proper material had not yet been discovered. Consequently, they would fail which would result in a lack of compression. These days we don't have apex seal issues. Rotary engines generally blow from overboosting, inadequate fuel supply or because they are simply worn out.
I agree up through the end of the JDM FD; but Mazda went with a computer controlled MOP starting in 2003. The changes in the engine (in case anyone is thinking of an engine swap) caused Mazda to also move the oil injection ports outward to better lubricate the corner seals (at the outboard edges of the apex seals). Unfortunate, this caused the center of the apex seals to be inadequately lubricated. Additionally, the North American 2004 and 2005 engines had the computer controlled oil injection dialed back so badly that it is typical for these engines to suffer low compression by 50K miles. Oil injection levels were increased for 2006 and a reflash of the computer was made available to correct the values in the North American 2004 and 2005 engines; but not before the damage was done in those engines. The 2009+ engines have dual computer controlled MOPs and three oil injection points per rotor; but require a swap of the PCM along with the engine.

Last edited by longpath; Feb 10, 2010 at 10:33 AM. Reason: forgot to mention that the 2004-2005 MOP problem was only North America
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