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-   -   Low compression (https://www.rx8club.com/rx-8-discussion-3/low-compression-233780/)

Okawa May 27, 2012 05:32 PM

Low compression
 
I was cleaning my spark plugs today and decided to check the compression. Its 75 rear rotor and 77 on the front rotor.

Just wondering should I take this down to the dealer ship and see if I can get the engine warrantied or does it need to be lower then that?

Also how much would they bitch if I wanted them to put in a new clutch I bought while they are putting in a new engine?

64000 miles 2005.

Surtur May 27, 2012 06:22 PM

From what I understand, you need a special tool to measure compression on a rotary engine. Also, a proper compression measurement for a rotary would have 3 numbers per rotor plus a the rpm at which the measurement was taken.

I would search the board for compression threads to learn more.

Okawa May 27, 2012 06:51 PM

I under stand if I wanted to check each number indavidually I need a special tool. But it should still give me the maximum PSI from all 3 (which is 75PSI and 77PSI).

Am I wrong?

Surtur May 27, 2012 06:56 PM

From what I understand from the compression threads I've read, yes that is wrong.

You need the 6 measurements (one for each face on the two rotors, 2 x 3 = 6) and the rpm at which the measurement was taken to tell if the engine will qualify for replacement.

Okawa May 27, 2012 08:33 PM

Ok I barrowed a buddys that he used on his RX7, I am getting roughly 75-80 on all 6. Nothing dropping so I am assuming the apex seals are ok.

But I thought spec was 98-120 75-80 seems very low.

Surtur May 27, 2012 09:15 PM

This thread has some of the information I'm talking about:

https://www.rx8club.com/series-i-tech-garage-22/do-we-have-diy-compression-test-138892/

nycgps May 27, 2012 09:27 PM

1 Attachment(s)
You need something like this to TEST YOUR ENGINE PROPERLY :)

https://www.rx8club.com/attachment.p...1&d=1338172001


I mean a piston compression tool works too, but sometimes you really gonna have a hard tell to "tell" which face has less compression.

Okawa May 28, 2012 03:17 AM

I think the compression is "good" on each face, but the overall compression is around 75 is this normal?

I have seen videos of this engine running at 100+ PSI and the rating from Mazda says 98-120 PSI.

I am sure all the faces are pretty good I am more concerned about the 75PSI right now.

monchie May 28, 2012 11:35 PM

How and where did you get that Mazda compression tester nycgps? Can you buy that outside besides the Mazda dealerships? Just curious.


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