2004 RX-8 Compression Test Results
03-26-2014, 02:41 PM
#1
New Member
Thread Starter
Join Date: Mar 2014
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
2004 RX-8 Compression Test Results
Just had a compression test done on my stock 2004 Mazda RX-8.
-ROTOR 1 @ 250 RPM: 660, 670, 690
-ROTOR 2 @ 249 RPM: 700, 690, 670
I know Mazda says the minimum is 680kpa. Judging from my numbers, only a couple of faces seem to fall below this. However, this is with the stock starter that is known to be weak and could thus bias the results. The ignition components have less than 3K miles on them. The only thing I have noticed is a slow start (2-3 seconds) occasionally.
I know it's hard to really judge since it is the old starter, but do these numbers seem healthy enough? I'm definitely going to put a 2kW starter on it soon.
Sorry if this is the wrong place to post this - it isn't letting me post anywhere else.
-ROTOR 1 @ 250 RPM: 660, 670, 690
-ROTOR 2 @ 249 RPM: 700, 690, 670
I know Mazda says the minimum is 680kpa. Judging from my numbers, only a couple of faces seem to fall below this. However, this is with the stock starter that is known to be weak and could thus bias the results. The ignition components have less than 3K miles on them. The only thing I have noticed is a slow start (2-3 seconds) occasionally.
I know it's hard to really judge since it is the old starter, but do these numbers seem healthy enough? I'm definitely going to put a 2kW starter on it soon.
Sorry if this is the wrong place to post this - it isn't letting me post anywhere else.
03-26-2014, 02:59 PM
#3
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 240 Likes
on
110 Posts
..or just read the new member thread, specifically this section that explains the results of compression tests: https://www.rx8club.com/new-member-f...4/#post4533734 (link jumps to it).
The starter only biases the result if it is above or below 250rpm. It appears that your starter is already on that line, so it won't be contributing any bias. You have 1 face that is clearly failing, 2 more faces that are just about failing.
This would indeed cause the slower starts.
The starter only biases the result if it is above or below 250rpm. It appears that your starter is already on that line, so it won't be contributing any bias. You have 1 face that is clearly failing, 2 more faces that are just about failing.
This would indeed cause the slower starts.
03-26-2014, 04:43 PM
#5
Zoom-Zooom
I worked as a mazda tech for a few yrs and those numbers aren't hateful, but is showing signs of possible failure do you have the Mode6 print out and the compression print out as well or did they just write that down for you. Cause i've caught a tech lowering the numbers trying to get a engine job out of mazda warranty/customer before.
Last edited by RJayX-8; 03-26-2014 at 04:50 PM.
03-26-2014, 04:46 PM
#6
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 240 Likes
on
110 Posts
Numbers that are failing are NOT "pretty good".
THESE numbers are "pretty good": https://www.rx8club.com/new-member-f...-today-248964/ (which are ~150kpa higher with 10rpms less cranking speed)
Last edited by RIWWP; 03-26-2014 at 04:50 PM.
03-26-2014, 04:59 PM
#7
Zoom-Zooom
Uh, no offense intended, but that is the kind of response I'd expect out of a dealer tech ... wrong.
Numbers that are failing are NOT "pretty good".
THESE numbers are "pretty good": https://www.rx8club.com/new-member-f...-today-248964/ (which are ~150kpa higher with 10rpms less cranking speed)
Numbers that are failing are NOT "pretty good".
THESE numbers are "pretty good": https://www.rx8club.com/new-member-f...-today-248964/ (which are ~150kpa higher with 10rpms less cranking speed)
03-26-2014, 05:15 PM
#8
Zoom-Zooom
Uh, no offense intended, but that is the kind of response I'd expect out of a dealer tech ... wrong.
Numbers that are failing are NOT "pretty good".
THESE numbers are "pretty good": https://www.rx8club.com/new-member-f...-today-248964/ (which are ~150kpa higher with 10rpms less cranking speed)
Numbers that are failing are NOT "pretty good".
THESE numbers are "pretty good": https://www.rx8club.com/new-member-f...-today-248964/ (which are ~150kpa higher with 10rpms less cranking speed)
The differences in his chambers are questionable to me. the things i would like know
did the tech do the test more than once as cold start and a hot start (meaning let the car set and cool then do test and record his numbers, then start it let it warm up and do the test again). when ever i had a questionable compression test I looked at things like the engine temp, battery voltage, got my Mode6 data to see what the cat was reading and also visually inspect the cat.
03-26-2014, 05:16 PM
#9
Dark Moderator
iTrader: (18)
even at 650 his front rotor's first number is 660. Showing obvious signs of wear and eventual failure. You realize this is the exact reason people hate dealers? O yea 660 good numbers two weeks later the motor blows. Mazda as a stealership BLOWS. This forum has a collective knowledge that would rival any of mazda''s finest. Mazda might wanna pull their heads outa each others asses and realize the things they teach and the things they practice are WRONG and the only things it's doing is pissing customers and rotary heads off.
03-26-2014, 05:26 PM
#10
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 240 Likes
on
110 Posts
650 Kilopascal (kPa)
=
6.62816 Kilogram-force/Square Centimeter (kg/cm²)
Mazda's manual and official documentation is that 6.9 kg/cm2 is the MINIMUM allowable compression. Not 6.7, which is what his 660kpa is.
His numbers ARE failing. Period. 3 faces! Trying to claim that it takes X under the minimum to fail is playing fast and loose with Mazda's specs. The minimum is the minimum. Period.
Point to where it says that 660 kpa is acceptable? If your dealership refused to replace engines under warranty because they were between 651kpa and 679kpa, it just means that you were another stealership lying to the customer to get out of a warranty claim. I feel for whomever you screwed over from that.
Sure, plenty of engines are down there, but that just means that they are all doing pretty poorly. That doesn't mean that the standard of good compression is lower.
=
6.62816 Kilogram-force/Square Centimeter (kg/cm²)
Mazda's manual and official documentation is that 6.9 kg/cm2 is the MINIMUM allowable compression. Not 6.7, which is what his 660kpa is.
His numbers ARE failing. Period. 3 faces! Trying to claim that it takes X under the minimum to fail is playing fast and loose with Mazda's specs. The minimum is the minimum. Period.
Read the compression and engine speed.
Compression pressure
Standard: 830 kPa {8.5 kgf·cm 2, 120 psi} [250 rpm]
Minimum: 680 kPa {6.9 kgf·cm 2, 98.6 psi} [250 rpm]
Standard difference in chambers: Within 150 kPa {1.5 kgf·cm 2, 21.8psi}
Standard difference in rotors: Within 100 kPa {1.0 kgf·cm 2, 14.5 psi}
Compression pressure
Standard: 830 kPa {8.5 kgf·cm 2, 120 psi} [250 rpm]
Minimum: 680 kPa {6.9 kgf·cm 2, 98.6 psi} [250 rpm]
Standard difference in chambers: Within 150 kPa {1.5 kgf·cm 2, 21.8psi}
Standard difference in rotors: Within 100 kPa {1.0 kgf·cm 2, 14.5 psi}
Sure, plenty of engines are down there, but that just means that they are all doing pretty poorly. That doesn't mean that the standard of good compression is lower.
Last edited by RIWWP; 03-26-2014 at 05:30 PM.
03-26-2014, 05:33 PM
#11
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 240 Likes
on
110 Posts
BTW, that info is from the RX-8 shop manual, pulled straight from the Mazda dealer service site, and not through the foxed.ca collection or any of the other public collections.
03-26-2014, 05:37 PM
#12
Zoom-Zooom
even at 650 his front rotor's first number is 660. Showing obvious signs of wear and eventual failure. You realize this is the exact reason people hate dealers? O yea 660 good numbers two weeks later the motor blows. Mazda as a stealership BLOWS. This forum has a collective knowledge that would rival any of mazda''s finest. Mazda might wanna pull their heads outa each others asses and realize the things they teach and the things they practice are WRONG and the only things it's doing is pissing customers and rotary heads off.
03-26-2014, 05:42 PM
#13
Zoom-Zooom
650 Kilopascal (kPa)
=
6.62816 Kilogram-force/Square Centimeter (kg/cm²)
Mazda's manual and official documentation is that 6.9 kg/cm2 is the MINIMUM allowable compression. Not 6.7, which is what his 660kpa is.
His numbers ARE failing. Period. 3 faces! Trying to claim that it takes X under the minimum to fail is playing fast and loose with Mazda's specs. The minimum is the minimum. Period.
Point to where it says that 660 kpa is acceptable? If your dealership refused to replace engines under warranty because they were between 651kpa and 679kpa, it just means that you were another stealership lying to the customer to get out of a warranty claim. I feel for whomever you screwed over from that.
Sure, plenty of engines are down there, but that just means that they are all doing pretty poorly. That doesn't mean that the standard of good compression is lower.
=
6.62816 Kilogram-force/Square Centimeter (kg/cm²)
Mazda's manual and official documentation is that 6.9 kg/cm2 is the MINIMUM allowable compression. Not 6.7, which is what his 660kpa is.
His numbers ARE failing. Period. 3 faces! Trying to claim that it takes X under the minimum to fail is playing fast and loose with Mazda's specs. The minimum is the minimum. Period.
Point to where it says that 660 kpa is acceptable? If your dealership refused to replace engines under warranty because they were between 651kpa and 679kpa, it just means that you were another stealership lying to the customer to get out of a warranty claim. I feel for whomever you screwed over from that.
Sure, plenty of engines are down there, but that just means that they are all doing pretty poorly. That doesn't mean that the standard of good compression is lower.
Last edited by RJayX-8; 03-26-2014 at 05:46 PM.
03-26-2014, 05:47 PM
#15
03-26-2014, 06:00 PM
#17
Zoom-Zooom
Look man i'm not trying to fight bout this, and 90% of these dealers out here you can't trust. but from my side of it I just putting out there what Mazda tells us to go by and I'm being honest they don't go by the shop manual period..... if any rx8 comes in the shop with a possible blown motor or hard start, first thing we are told to do call the 1-800 number get case # for it they will instruct us to do a simple compression test record finding and record the Mode6 data if the compression is above 650 and the cat fails only replace the cat, if the motor fails and the cat fails depending on mileage, and customer records they will pay for the motor but customer has to pay for the cat.
03-26-2014, 06:07 PM
#18
Zoom-Zooom
[/QUOTE] Point to where it says that 660 kpa is acceptable? If your dealership refused to replace engines under warranty because they were between 651kpa and 679kpa, it just means that you were another stealership lying to the customer to get out of a warranty claim. I feel for whomever you screwed over from that.
[/QUOTE]
Dude i feel sorry the ones i couldn't get approved to but what can I Do, Do it anyway and lose my job.......NO!! I do what i can to for those and try to keep them running and hope that when and if they come back through that door that if the motor is blown that I can reference back to the previous RO and get Mazda to Goodwill it or meet the customer halfway and thats it.
[/QUOTE]
Dude i feel sorry the ones i couldn't get approved to but what can I Do, Do it anyway and lose my job.......NO!! I do what i can to for those and try to keep them running and hope that when and if they come back through that door that if the motor is blown that I can reference back to the previous RO and get Mazda to Goodwill it or meet the customer halfway and thats it.
03-27-2014, 10:00 AM
#19
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 240 Likes
on
110 Posts
Mazda giving you a hard time on warranty replacements doesn't change the definition of a failed engine. My problem is not that you had trouble getting Mazda to agree to replacements, my problem is first a claim that it was good numbers, then a backpedal claim to "showing signs of possible failure" when half of the faces are clearly below spec and the other half are on the line.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
Last edited by RIWWP; 03-27-2014 at 10:15 AM.
03-27-2014, 04:41 PM
#20
Zoom-Zooom
Mazda giving you a hard time on warranty replacements doesn't change the definition of a failed engine. My problem is not that you had trouble getting Mazda to agree to replacements, my problem is first a claim that it was good numbers, then a backpedal claim to "showing signs of possible failure" when half of the faces are clearly below spec and the other half are on the line.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
03-27-2014, 04:47 PM
#21
Zoom-Zooom
Mazda giving you a hard time on warranty replacements doesn't change the definition of a failed engine. My problem is not that you had trouble getting Mazda to agree to replacements, my problem is first a claim that it was good numbers, then a backpedal claim to "showing signs of possible failure" when half of the faces are clearly below spec and the other half are on the line.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
Whether or not Mazda would grant warranty coverage has nothing at all to do with the fact that the scores still fail.
Telling a customer: "Your engine has failed, but Mazda isn't granting warranty coverage" sucks for both sides, but it's the truth.
Telling a customer: "Your engine is acceptable, so Mazda isn't granting warranty coverage" is at best deliberately misleading. It's the kind of crap that we see dealers giving customers all the time, and it's what gets us all pissed off.
03-27-2014, 04:55 PM
#23
Dark Moderator
iTrader: (18)
Rjayx you arent going to win this. Your original statement concluded that you believed everything was fine. That it only showed signs of possible failure. RIWWP has proved to you that the numbers are failing.. Now your just back peddling...trying to make it seem as if you were trying to say something other than what you actually said.
03-27-2014, 05:51 PM
#25
Zoom-Zooom
Rjayx you arent going to win this. Your original statement concluded that you believed everything was fine. That it only showed signs of possible failure. RIWWP has proved to you that the numbers are failing.. Now your just back peddling...trying to make it seem as if you were trying to say something other than what you actually said.