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Just bought an rx-8 with a couple problems

Old Mar 11, 2012 | 03:01 AM
  #26  
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From: Caput Mundi
Time for a new engine.
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Old Mar 11, 2012 | 05:05 PM
  #27  
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Hmm... Well that sucks but, on the bright side I get to build a rotary engine. Honestly I'll prob drive it til it gets bad before I do that though.

Maybe the old rotary engines put up different compression numbers but, I read an article by aaroncake that said 75psi is fine but, he was talking about an engine from a cosmo I beleive. And I'm inclined to say he knows what he's talking about because he has videos detailing a full engine build.

Yeah I'll prob get a better starter. That alone should bring up the compression just because the faster spin rate.

By the way guys, this was no mazda compression test. I just took the schrader valve outta my regular comp tester and used that. Also I didn't have the right length to simulate the spark plug threads so that would have brought it down some. I doubt it would be enough to make a difference though. Another thing that may be worth mentioning is the engine was not warm.

And I found the coolant leak. It's a tiny drip from the lower rad hose. I only notice it when it's under pressure. Just thought I'd throw that in.

I haven't done the comp test after the seafoam yet. It's nasty outside again today but, maybe I'll get around to it soon.

Last edited by DustinP; Mar 11, 2012 at 05:45 PM.
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Old Mar 11, 2012 | 07:11 PM
  #28  
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Originally Posted by DustinP
Hmm... Well that sucks but, on the bright side I get to build a rotary engine. Honestly I'll prob drive it til it gets bad before I do that though.

Maybe the old rotary engines put up different compression numbers but, I read an article by aaroncake that said 75psi is fine but, he was talking about an engine from a cosmo I beleive. And I'm inclined to say he knows what he's talking about because he has videos detailing a full engine build.

Yeah I'll prob get a better starter. That alone should bring up the compression just because the faster spin rate.

By the way guys, this was no mazda compression test. I just took the schrader valve outta my regular comp tester and used that. Also I didn't have the right length to simulate the spark plug threads so that would have brought it down some. I doubt it would be enough to make a difference though. Another thing that may be worth mentioning is the engine was not warm.

And I found the coolant leak. It's a tiny drip from the lower rad hose. I only notice it when it's under pressure. Just thought I'd throw that in.

I haven't done the comp test after the seafoam yet. It's nasty outside again today but, maybe I'll get around to it soon.
You cant test a rotary with a piston engine compression tester. Also search google images for the rx8 compression graph and youll see what the correct compression from Mazda are, not some guy on the internet that apparently doesnt know what he is talking about lol. If you continue to drive the engine like this there nay be a chance that it is not rebuildable, and you might have to machine the sideplates and resurface the housings instead of just replace all the seals.
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Old Mar 11, 2012 | 07:30 PM
  #29  
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Originally Posted by Arca_ex
, not some guy on the internet that apparently doesnt know what he is talking about lol. If you continue to drive the engine like this there nay be a chance that it is not rebuildable, and you might have to machine the sideplates and resurface the housings instead of just replace all the seals.

Sounds like you have it all figured out
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Old Mar 11, 2012 | 08:03 PM
  #30  
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Originally Posted by dannobre
Sounds like you have it all figured out
Just saying to go with the numbers from Mazda and let him know what some possible outcomes are from driving a blown motor... unless you have a better suggestion...
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Old Mar 11, 2012 | 08:16 PM
  #31  
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I know Mazda has a special tester but, if you look around the net a little bit you'll see plenty of people using a normal comp tester to get an idea about what kinda condition the engine is in. And they are all giving similar figures for compression... I was just citing that guy cause his article is the first one I read. There are plenty of videos and articles about it on google.

Don't take that as being rude. I'm not trying to say you don't know what you're talking aboutor anything close to that. I just don't wanna spend the money for Mazda to test my compression if I can rule it out by simpler means.

Anyway yeah I thought about the fact that it might ruin the engine parts after I posted that last one.

Last edited by DustinP; Mar 11, 2012 at 08:19 PM.
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Old Mar 12, 2012 | 08:23 AM
  #32  
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I take it that you didn't test compression after seafoam?
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