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-   -   Can you have a blown apex seal AND still have good compression? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/can-you-have-blown-apex-seal-still-have-good-compression-369047/)

blownapexseal7 11-17-04 01:33 AM

Can you have a blown apex seal AND still have good compression?
 
Is it possible? Good being 95psi or around there

7-sins 11-17-04 01:41 AM

What are your symptoms? you could have a sticking seal... maybe a fractured seal.... Does the car idle rough but still has great power? Has it started to run a little more rich or have you noticed more gas consumption? What about when you crank it, does the sound from the motor sound like its skipping a beat? Also are the 3 faces on front and rear rotors close to 95 psi or do you have a noticeable difference?

DamonB 11-17-04 07:19 AM

No. A blown seal will never have good compression. If it did it wouldn't be blown.

Conv.WS6 11-17-04 08:29 AM

Depends on how you are taking a compression test. If you are doing the standard max compression at each cylinder/spark plug you are doing the wrong kind of compression test. Easy way to do this is just to hold the release valve of the tester, and see if the reading fluctuates in 3 even pulses. With one blown apex seal you will get a strong pulse, followed by 2 weak pulses. If you have 2 strong pulses followed by a weak pulse it's more than likely a side seal. A vac/boost guage at idle will show a shaky vac instead of the level 15-18 mmhg if the seal is bad as well. Of course the only TRUE way is to do a compression test, but on a normally running car, the vac/boost guage gives a good precursor. LOL..... Oh lord, this just reminds me that I've blown up way too many rotaries. good luck.

DaleClark 11-17-04 08:30 AM

There are, however, varying degrees of "blown". I've seen blown engines that had one broken apex seal and 100,000+ miles on the motor that could barely start or idle. I've also seen blown engines with only 5,000 or so miles on it that generally started and ran fine, and made good power. I drove that motor hard until I finally killed it by breaking a dowel pin seat :).

The biggest thing to look for are 3 bounces when you do the compression test. If all 3 chambers are making good compression, you're cool.

Dale


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