1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Has anyone every blown an Apex Seal?

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Old May 3, 2005 | 10:48 AM
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857rotarysteve-0's Avatar
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Has anyone every blown an Apex Seal?

i think i might have blown an apex seal. has anyone ever done this before? how does the car act if it did?
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Old May 3, 2005 | 11:11 AM
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bkm_rx7's Avatar
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lol....nope....never....nobody EVER throws apex seals

But seriously...ive never blown one...but from what i hear...you should have VERY poor power...and probably only running on one rotor...you will for sure have really bad compression...and the car should most likely be near undriveable...

how is yours acting?
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Old May 3, 2005 | 11:16 AM
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the car will drive....poorly...very low on powe and the engine will be slow to rev and it will noticibly shake. you will know, trust me.
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Old May 3, 2005 | 11:19 AM
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Yes. People have blown apex seals here.

From what I've heard, your engine will shake alot, you will have very poor running/power, and of course, your compression will suck.

Of course, you can't test compression on a rotary engine the same way you do on a piston engine. The piston compression tester only measures the highest reading of many compression strokes. That would give you the reading of the compression stroke between the two still-good apex seals and tell you nothing. What you need to do is remove the valve at the end of your compression tester and watch the gauge carefully. You should get three even bounces. If you don't, then you've blown an apex seal.

Now here is where I tell you that you should SEARCH. This has been covered over and over again. Search for "blown apex seal", "compression test", "low compression" and things like that. Limit your search to the first gen section if you want more pertinant results to your car.

Jon
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Old May 3, 2005 | 11:32 AM
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Pull the plugs and listen for the PUFFS.
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Old May 3, 2005 | 11:47 AM
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yes, its bad, ruins rotor housing and rotor. Sometimes the sideplates also. It won't have trademark rotary hum. Very bad, stop driving it and fix it. Yeap...-> lots of $$$
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Old May 3, 2005 | 01:53 PM
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I speak from experience here, and yes thats all true. When my 12A threw an apex seal on the rear rotor, the whole car would shake when the engine was running. VERY rough running and low on power. Drivable, but not at anything above 80 km/h (50 mph). Easiest way to check is to pull the leading spark plugs one at a time and listen for the puffs. you should hear 3 strong puffs, but if you have 1 strong puff then two very weak ones, then you broke an apex seal. Hope this helps.
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Old May 3, 2005 | 06:31 PM
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What are your symptoms?
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Old May 3, 2005 | 06:37 PM
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Old May 5, 2005 | 11:27 AM
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i was just wondering cause my engine is acting up a little, but after listening to your guys input, i no longer think i have an apex seal prob. but i am having problems getting it started and keeping it idleing. i have to spray starting fluid into the carb everytime it sits for a few hours. if you guys can tell me about this, i would really appreciate it.
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Old May 5, 2005 | 01:47 PM
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hmmm...sounds like carburetion issues...fuel related...not sure tho...try to give the car an all around tune up (air filter, fuel filter, oil change, plugs, wires, distributor cap, rotor)

that should give you a good start...if that doesnt help...let us know...

Last edited by bkm_rx7; May 5, 2005 at 01:50 PM.
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Old May 5, 2005 | 11:41 PM
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I blew an apex on my second 12A.It had the leak of death for a while,then without warning at about 3000RPM it popped and ran like absolute sh*t.Barely any idle,very poor power and lots of shaking.It feels like if you pull a sparkplug or 2 on a piston engine.It will do it all the time,regardless of engine speed or throttle position.And youll likely be able to hear it in the sounds of the starter when you try to startup.
The normal,"wah,wah,wah,wah,wah" sound when you turn the key,will switch to,"wah,wah,weeeee,wah,wah,weeeee,wah,wah,weeeee" as the dead chambers come around their cycles.If it still cranks steadily with no change in beat,then your likely OK internally.
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Old May 6, 2005 | 06:36 PM
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When I bought my SE it had a blown apex seal. It barely idled, and it wouldn't idle when it was cold. It could not go any faster than 55 MPH due to a complete lack of power. It also reeked of all the unburned gasoline that it was pouring out into the air. It was difficult to start, and really did not like to start once it had been running. Those are the symptoms of a blown apex seal, in my personal experience.
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Old May 6, 2005 | 07:05 PM
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Pull the spark plugs out of one rotor and then the other. If all are dry and the business ends of them are the same shade of tan or grey your engine is ok. But if the two plugs from one rotor look ok while the two from the other are black and wet with fuel and/or oil you've thrown an apex seal on that rotor.

Last edited by Aviator 902S; May 6, 2005 at 07:07 PM.
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Old May 7, 2005 | 10:35 AM
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I agree it sounds like carb/fuel regulation issues. Pull the plugs and check 'em for spark and burn. While they're out you can crank to make sure you don't have a blown seal.
If they're soaked you've got fuel issues. Replace the fuel filter if that hasn't been done in awhile (Cheap easy fix. It's worth a shot.) Then start checking stuff in the carb. Make sure everything is doing what it should, opening to the right place when it should etc. Floats are a good place to start when it's a fuel issue.
If the plugs are dry and they have spark, listen for your fuel pump to come on. I had a bad connection in my relay once that gave me hell. Work one minute. Die the next. That was a pain to figure out.
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Old May 7, 2005 | 02:26 PM
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I've never blown an apex. I end up rebuilding before it can happen.
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