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Compression test results (Mazda tester)

Old Dec 21, 2014 | 07:01 PM
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Compression test results (Mazda tester)

These are the results from my compression test today. Front rotor has no compression and the rear is decent. I feel pretty confident the engine is done, but I just wanted to confirm with you guys. I've never seen no compression before. Any info would be good.
Attached Thumbnails Compression test results (Mazda tester)-image.jpg  
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Old Dec 21, 2014 | 07:04 PM
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Here's the results to the rear rotor.
Attached Thumbnails Compression test results (Mazda tester)-image.jpg  
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Old Dec 21, 2014 | 10:53 PM
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yep.
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Old Dec 22, 2014 | 12:25 AM
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Last time an apex seal went out, I got some type of reading. Just wanted to see if anyone has experienced this before.
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Old Dec 22, 2014 | 11:06 AM
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If your getting a zero reading your engine needs a rebuild.
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Old Dec 22, 2014 | 11:34 AM
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Originally Posted by JP's 93 fd
Last time an apex seal went out, I got some type of reading. Just wanted to see if anyone has experienced this before.
it depends how violently it blew.

you can crank the engine with that bad rotor's spark plugs out (and with the EGI fuse out of course) and listen for any pulses. chances are it just has zero compression.
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Old Dec 22, 2014 | 12:38 PM
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The mazda tester won't read below a certain threshhold. I forgot the exact number offhand. Just to make sure try it a few more times. Make sure the sender is snug. I like to tighten it gently with a wrench. Make sure the connector is securely clipped onto the sender. Also make sure you are cranking with the egi fuse removed and the throttle wide open.
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Old Dec 22, 2014 | 12:57 PM
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Thanks for the feedback guys. The sender was snug and there were no puffs coming out the spark plug hole. I made sure my Mazda Tester was working by testing the rear rotor and I got a reading. Now it's confirmed. Next step is deciding which way to go, reman or rebuilding it.
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Old Dec 22, 2014 | 02:32 PM
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I'd break it down and assess the damage before going with a reman. If you do go with the reman I'd break that down and inspect/clean/rebuild that before installing it as well. Just to be safe...
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Old Dec 22, 2014 | 02:57 PM
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We have the newest version of the Mazda Tester. Compression below 295 kpa in any of the combustion chambers reads all zeros. Also engine speed 100rpm or lower will read all zeros.
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Old Dec 22, 2014 | 04:11 PM
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Thanks for the input fendamonky. I unfortunately don't have the experience or time to break down the engine. I can take the engine out of the car and put it back in no problem. I emailed Ray Crowe regarding the reman and he told me it's $2,800 with a core plus $320 for shipping both ways. I also read this thread https://www.rx7club.com/3rd-generati...inues-1035361/ and this kind of scared me in buying a reman. Also, it's coincidence that Banzai-Racing posted in my thread because it's either getting a reman from Ray Crowe or getting the Level 5 engine rebuild through Banzai-Racing.
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Old Dec 22, 2014 | 05:06 PM
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Will the car run normally? If it will, you must have "some " compression.
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Old Dec 22, 2014 | 05:22 PM
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Originally Posted by adam c
Will the car run normally? If it will, you must have "some " compression.
It has a very lumpy idle and it lacks power. The car struggled when I drove it back into my driveway after it was towed. Also, just for info, my engine went out while I was driving on the freeway. I immediately noticed the lack of power when it gave out.
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Old Dec 22, 2014 | 05:57 PM
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My FC went out on the highway also...it was noticeable but it got me home..45 miles..on one rotor!
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Old Dec 28, 2014 | 06:58 PM
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I'm curious where you think you're going to get a reman from?

I thought Mazda stopped producing remans. I know you can all the parts you need but, from what I understood, remans are a thing of the past.

I remember a thread about Ray selling his last reman.
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Old Dec 29, 2014 | 08:50 AM
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Originally Posted by tt7hvn
I'm curious where you think you're going to get a reman from?

I thought Mazda stopped producing remans. I know you can all the parts you need but, from what I understood, remans are a thing of the past.

I remember a thread about Ray selling his last reman.
I believe there was a stop to remans many many years ago. However Mazda is making remans again as of a few years ago. They are being made at a plant in Richmond, Va. Mazda no longer makes NEW engines (I picked up the very last one in the country in 2012, Ray had it in stock but it wasn't listed for sale as the rear iron was damaged.) but the remans ARE available.

I suggested breaking it down and checking everything based off of what people/shops have seen when they crack them open. Hell, even my NEW engine had a bunch of buildup in the water passages that I would never have known about otherwise..
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Old Dec 29, 2014 | 09:36 AM
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Less than 100rpm wont get you an accurate test.

using some normalizing calculations, 42psi (which banzai stated will get you all 0's) and 100psi (which banzai stated will get you a zero rpm), you could still have almost 80psi at 250rpm.

now, 80psi is still not good, but it would explain why the car runs with a lumpy idle (and not ridiculously difficult to keep running like it would be on one rotor)
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Old Dec 29, 2014 | 10:08 AM
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About 3-4 years ago Mazda briefly closed the reman program. At the time they were selling brand new motors for around $4000, which was a pretty good deal in my opinion. Remans have been available for some time now.
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