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Quick question on rotary design, see what you guys think.

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Quick question on rotary design, see what you guys think.

Old 09-22-2015, 05:51 PM
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Quick question on rotary design, see what you guys think.

okay, i have a question and wanted to see your guy's opinion. talking to two different so called expert of the rotary, I have heard two different sides of the story. i understand the apex seals are drawn to the rotor housing by centrifugal force. one guy tells me that high or mid ranged rpm driving can wear out the seals faster do to the force pressing the seal close or onto the housing causing premature failure. on the other hand the other is telling me that low and mid rmp driving will cause the apex seals to float or in other words not completely seal a chamber causing unburnt fuel etc. entering the next chamber. Iv own my baby for 2 years and kept the rpms up between 4 and 5, and never had a problem just wanted to see what you guys thought about this.
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Old 09-22-2015, 08:11 PM
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Your understanding is incorrect. The apex seals are pressed against the rotor housing by the apex seal springs.

We need to keep the RPMs up in order to avoid carbon buildup which is harmful to the engine. That's also the reason we need to redline the motor on occasion, to burn out any built up carbon deposits.

One of the surest ways to a sick and failing motor is to baby it allatime. "Drive it like you stole it."
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Old 09-23-2015, 12:10 AM
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Do not talk to these experts any more. Centrifugal force is nothing but inertia, and a 10 gram seal doesn't have a lot of that. If you want the straight dope, there is a great book by Japanese gentleman whose name escapes me, about the development of the rotary.. I want to say it came out in the 70s and lays out the practical basics of the rotary design.

Long story short, the apex seal slides on an oil film ( from the oil injection ports) and both the seal itself and the coating on the housing are designed to not wear into each other. They're good for longer than the life of the car if all goes well.

It doesn't go well when the engine is not in top shape and the oil film is either absent, washed with fuel or the seal and spring are carboned up and not flat against the housing, or something is creating more heat than expected, like a clogged cat. In those cases the seal can develop hotspots that wear faster, which allows blow by, which erodes the seal more still, etc. Actually the real challenge is keeping the seal and housing perfectly flat. Any imperfection creates a hot spot. Example, spark plug holes sit in hot zones that can bulge out microscopically when heated and wear faster.

So basically, stay on top of your engine health and premix, and you can drive at whatever regime you want

Last edited by Loki; 09-23-2015 at 12:18 AM.
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Old 09-23-2015, 10:23 AM
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The missing point in both cases is that there is an apex seal spring providing all of the pressure needed to push the seal against the housing.
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Old 09-23-2015, 10:48 AM
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In my many years as a car enthusiast, I have found that anyone who is referred to as, or refers to themselves as an expert, is generally the opposite of an expert.
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Old 09-23-2015, 04:46 PM
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Sorry I meant to say not by centrifugal force lol. Also I know my way around the rotary, I just didnt want to take the time typing in all what I do know to prove these guys are bith wrong. I just wanted to see what you guys thought about these comments iv heard, I know their both idiotic. I appreciate all the comments.
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