Series II Compression Test Results & Discussion
 

Hi all. I thought I'd start this thread to compile compression test data on Series II RX-8s and also to get your advice on my situation. Just had a compression test done today.

Basic info:
2009 R3
97,000 miles

Compression test results:
Rotor 1 - Test 1
RPM: 332
740 kPa (107 psi)
760 kPa (110 psi)
760 kPa (110 psi)

Rotor 1 - Test 2
RPM: 332
740 kPa (107 psi)
770 kPa (112 psi)
750 kPa (109 psi)

Rotor 2 - Test 1
RPM: 330
830 kPa (120 psi)
820 kPa (119 psi)
830 kPa (120 psi)

Rotor 2 - Test 2
RPM: 330
830 kPa (120 psi)
830 kPa (120 psi)
820 kPa (119 psi)

History:
Owned since new (DEC 2009) Average oil changes every 4.5k. Up to 75k miles use was 60% highway, thereafter I would say 90% highway. Cat replaced @ 6k miles, most likely plugged up while car had been sitting on dealer lot. Spark plugs replaced @ 36k, 66k, and recently just now at 97k (more on that later). Coils replaced at 77k. While many of you will criticize me for going that long (and in hindsight I'll probably agree), this is consistent with the schedule recommended in the owner's manual. I take it to 7500+ rpm on a near daily basis, on an empty stretch of road on my way to work (2nd, 3rd and 4th gear). Only started premixing recently (3 tanks so far). So my car can be a data point on what you might expect to happen to an SII if you keep to Mazda's maintenance schedule.

Potentially related symptoms:
Occasionally will take an extra second or so of cranking to fire up (usually fires up in < 2s) when warm. Only happens after a little bit of cooling time (7k redline on startup). This has been going on for some time.

The last few months there has been an occasional stumble at idle when the engine is warm. Could be due to crudded up spark plugs. Recently, there seems to be a slight loss of top-end power. I noticed this because on an uphill stretch of road where I can go WOT, the car tops out at a lower speed than before.

Potentially related problem:
Asked dealer to swap in new plugs while they were doing the compression test. Tech reported that Rotor 1 leading spark plug had been loose. On closer examination I see that the crush washer was not at all compressed, so it was never torqued down properly, and there is carbon crud at base of spark plug threads. Plugs were last changed by this same dealership, so it was like this for 30k miles:mad: Could this have caused carbon buildup & lower compression on Rotor 1?

Now I would be OK with those compression #s if they were at 250 rpm, but they are at 330. (At least my starter is doing really well :rolleyes:). Service advisor insisted that the compression #s were passing even though I asked about normalizing the values to 250 psi. He suggested a de-carb w/ seafoam. When I got home, I checked the Series II workshop manual, and I see that the minimum is about 760 kPa even at 300 rpm, so 740 kPa @ 330 rpm would seem like it's clearly failing.

This has been a frustrating day, because it seems like Rotor 1 is on it's way out, but being propped up by Rotor 2, so no major driveability issues yet. Apparently there is enough ambiguity in the test results for the dealer to claim the compression is still good? I welcome your suggestions for best course of action. I hope other people post their SII compression results and outcomes as well.

Thanks!

Rotor 1 is definitely below spec, they need to replace the engine. Sucks about the loose plug. And yeah the 09-11 starter is powerful, I have one in my 04'.


https://cimg8.ibsrv.net/gimg/www.rx8...caa9066956.png

Zoom zoom power clean it. If pressed that's what the dealer would do and your numbers would likely be above the line afterwards.

If you are still under warranty, I would press hard on the dealer for an engine replacement. 97K miles is cutting it close. If your dealer won't work with you, find one that will.

Even if it was 99,999 miles it should still be covered. 100,001 and they wouldn,t think twice to deny, so stick to your guns. Sounds like you've been a loyal customer getting your service work done there. Get your paperwork together, get a meeting with the service manager, use your prior service history noting the sparkplug issue, and be firm but professional/calm/polite about making it clear you know that R1 is out of spec ...

^ yep. I got a reman installed under warranty at 96,000 miles.

If you don't mind me asking... If I was to be completing all of these services myself and have receipts of every time I purchased the maintenance items, documented mileage at time of service, would Mazda have an issue with replacing the engine IF it where needed. I'm still under the 8yr/100k core warranty on my 09 R3 w/ 47k mi. If that paper trail isn't good enough, then am i screwed for the day I need an engine? If it still falls in the warranty window @ the time that is.

You just have to show maintenance records. I put all mine in MazdaUSA owners section (I did all the maintenance on from ~20k to 113k), and it was good enough for my replacement at 96,990 miles. Didn't even question it.

Cool. Thank you.

what he said, they owe you a new/reman engine replacement!

btw where are you originally from?

Is it reasonable for the dealer to want to do a de-carb first? From what I've read here it can help the seals seat better, or it can do absolutely nothing... Can this be counter-productive?

Nadrealista, originally I'm from Russia.

A proper decarb can indeed improve compression.

However, there are a lot of "IFs" around that. It has to be done right, AND carbon buildup can be the only reason for compression loss. If you have had a lot of carbon buildup that unseated the seats and they wore badly, decarbing could hurt compression. It's a big unknown to do so really.

I feel like this is going to be a long process... :banghead:
Dealer rep claimed that their computer didn't show my vehicle being under any kind of warranty. Called MNAO to confirm warranty coverage (of course I'm still covered), and told dealer rep to call MNAO to verify on his end.

Step 0/10

There was a dealer in RI that got an 8 in for "trouble starting", they did a compression test and found the engine to be badly failing. The handed the owner a repair estimate. $10,000 for the engine, $6,000 for the labor to install it.

If that wasn't bad enough, only when he pitched a fit over it did they "remember" that his car was under the 5yr 60k powertrain warranty still and replaced it free of charge.

:uhh:


Dealers can be such assholes.

Hmmm... Did not know this even existed. I learn something from you every day. Now perhaps I can just buy OEM filters online and stop paying the dealer for nothing. :D

Good news everyone! :wiggle:
Dealer rep was able to verify warranty coverage, and I should be getting a new motor! I think the problem was that so few SII's have needed it, that they were not familiar with the particular engine core warranty for the SII. It does not come up when they look up the VIN #.

I just signed up to the MazdaUSA MyMazda owners section. I am curious as to what you put down as your service facility? I plan on doing some work myself on my car (oil changes, brakes; ignition coils, wires, and plugs etc.) I currently have 3 years and 60,000ish miles left on my engine warranty (2010 GT w/40,000+ miles) and would like to keep myself covered if something were to happen to it.

Car is currently at the dealer, should be getting a reman next week. Keeping my fingers crossed that everything goes well...

I'll repost my results after doing proper homework. Sry for my stupidity.

RIWWP can you direct Jastreb to your warnings about too much sealant used in remans and what to watch for and change with his cooling system once he has his reman in. Your warnings were very important, so he doesn't have a reman premature failure due to a clogged cooling system.

Mobile only till monday. Unsure how many times you make a request to me without letting me know. :)

New owner's thread i think, if not my site rx8help.com, if not, just search reman excessive sealant, you will find info

Mystery compression improvement
 

Dealer just called me and informed me that they did 2 more compression tests on the original engine.

The results from the last test:
Rotor 1
RPM: 310
850 kPa (123 psi)
830 kPa (120 psi)
850 kPa (123 psi)

Rotor 2
RPM: 314 psi
920 kPa (133 psi)
940 kPa (136 psi)
930 kPa (135 psi)

Service rep says this is the strongest Renny they've seen in a very long time and there's absolutely nothing wrong with it. Since the previous (see original post) compression test, I had driven it for a week and a half. The only things that I had been doing differently was pre-mixing with Royal Purple TCW-III and new spark plugs. And somehow I magically gained 10+ psi of compression across the board :dunno: ?

Also was told misfire count for last drive cycle was 13, which doesn't actually mean too much without knowing what that drive cycle was.

I asked specifically about testing at proper engine temps, and was assured the correct procedure was followed. Picking the car up tomorrow after having wasted a week and $100 on a rental car :mad:. I may go get another test done at another dealership just to be sure...

The only way I would believe that magically improved compression numbers is if I was standing right next to the tech during the compression test, so I strongly recommend you do just that. And don't premix before the compression test!

The last tank of gas that I put in the car didn't have premix. I'm taking it somewhere else, I'm done with these people - they wasted my time for an entire week.

To make things worse, on my way back from work last night I hit a random-ass box in the middle of the freeway which f*cked up the bumper on the rental car. :rant:I guess the silver lining is that had been in the 8, it would have probably taken out the oil cooler also.

What ever happened to this?

Big update & more dealer ridiculousness
 

Ok guys, long time since I updated and there's a lot to talk about. I did not believe the mystery improvement on the 2nd compression test, so I took it to an independent shop (Lucky7 Racing in Duarte) for a 3rd compression test. The 3rd test basically confirmed the results of the 1st - compression below spec on Rotor 1, Rotor 2 ok but not stellar. I then took it for a 4th compression test at a different dealer who re-confirmed the compression results and got a replacement engine approved from Mazda.

The final (4th) compression test results (normalized to 250 rpm):
Rotor 1
Min: 96 psi (6.75 kgf/cm^2)
Max: 98.6 psi (6.93 kgf/cm^2)

Rotor 2
Min: 105 psi (7.38 kgf/cm^2)
Max: 106 psi (7.45 kgf/cm^2)

Rotor 1 had suffered from a loose leading spark plug for a while, which may have contributed to extra carbon buildup. Otherwise maintenance history is described in 1st post.

By 5/29 the 1st reman engine was in my car, but started experiencing problems almost immediately while dealer was road testing it (after 1.5 miles). I was told it had low compression, tech also mentioned knocking. Subsequent conversation with service advisor indicated overheating as well. Mazda sent another reman engine (which took almost 3 weeks to arrive). The dealer had given me a 2014 Mazda3 loaner, so I was ok with the wait. My advice to anyone needs their engine replaced at a dealer and does not have a second car - count on lengthy unexpected delays, make sure a loaner is provided.

The 2nd engine is now in my car. Now for the fun parts:
We had agreed last week that the car would be ready on Wed, 6/24. My internet was out and I did not have their phone # handy, so I assumed that since they had not contacted me, everything was on schedule. When I got there, it turned out everything was put back together, but they hadn't finished road testing and said they couldn't release the car. They then asked if the service manager could road test it that night so that they could have it ready by Friday (my next opportunity to pick it up), since they were so busy in the shop. I was miffed at them having wasted an 1hr+ of my time, but I said OK, whatever it takes to get it done.

This morning they call me and said that during the "test drive" there was a rattling noise and it threw a P2070. The suggested solution to a stuck open SSV, according to them, is to replace the entire intake manifold to the tune of $3k for the parts alone. :icon_bs: And that this would not be covered under warranty. After a little bit of research I know you can get a brand new SSV for $250, and that most of the time they just need a good cleaning.

EDIT #2: When pressed as to why replace the intake manifold instead of just the SSV, the reply was "so much carbon in the intake manifold, no guarantee that this would work".

Of course, they had also tried to sell me a $1k clutch job earlier, even though the engine was out of the car anyway. I agreed that a new clutch at 99k miles was a good idea, but bought all the OEM parts online and they agreed to bolt them on for no extra charge.

They also said there is rust in the coolant and that they recommend a coolant flush. Rust from where?? There should be new coolant in there! The old engine block? The new engine block? Can't be the radiator, that thing is aluminum!
If there's really rusty gunk in the coolant, can I just keep an eye on the coolant temps and flush it like I was going to in 1-1.5k miles, so that I also get any excess sealant? Or should I do a flush immediately?

Going to talk to them tomorrow morning, and possibly go get her back.

Got her back
 

Picked her up this afternoon. Drove to work about 50 miles. No CEL and no codes so far (did Dealer clear them? OBD monitor shows codes cleared right around the time I picked her up).

Can definitely hear a rattle while under load. I've been keeping the rpms low, but rattle goes away at 4,500 rpm or so, and butt dyno senses an increase in torque at that point. Seemed a little more gutless than usual at low rpm, though it could be confirmation bias. Also idle oscillates between 750 and 1250 rpm, with corresponding oscillations in STFT between -2% & +2%. Is all that consistent with gunked up SSV? I really which they would have told me intake manifold was gunked up before putting it all back together, I would have paid extra to clean the valves while it was out of the car.

rust is common on remans because mazda uses water to test the cooling system and depending on how long they sit.

Marginal compression on re-man and detonation
 

So, sad news for me. Finally got around to taking it to Lucky7 to figure out my "intake valve rattles". Turns out it was detonation all along. On top of that, they did a compression test and the results are low 100s to high 90s psi, after compensation. I'll should be able to get the actual printouts tomorrow. I feel sick :puke:Damn the dealership and their false diagnosis... I suppose this might also explain why it's been running hot, in spite of thoroughly flushing the cooling system.


We talked about how the injectors may be clogged. I guess it makes sense - if the injectors are clogged on one of the rotors, the ECU would compensate with fuel trim but that is based on O2 sensor data that averages both rotors. I have been running 10-15% LTFT across the board (idle and cruise) trying to figure out if I have a vacuum leak. But the result is probably that one rotor is still running lean, while the other one is pig rich. It looks like the injectors will be sent out for cleaning middle of next week. They also said it is a good idea to replace the fuel pump (original with 105k miles), which I tend to agree with.


In the meantime I'm gonna need my car to get to work in the next few days. If I add some octane booster (California only has 91) and keep the load low and the revs high to minimize detonation, would you say it's safe to drive around?

On one hand, no, it isn't safe to drive around, you could damage the engine.

On the other hand, the engine is already damaged.


So your choice really.

I decided to keep it at the shop at least until the injectors are cleaned and the fuel filter replaced, to avoid hurting it further. Compression numbers are compensated to 250rpm. I don't have the raw #s yet.

front rotor
692 kPa (7.06 kgf/cm2)
683 kPa (6.96 kgf/cm2)
688 kPA (7.02 kgf/cm2)

Rear rotor
697 kPa (7.11 kgf/cm2)
692 kPa (7.06 kgf/cm2)
670 kPa (6.83 kgf/cm2)

Based on results from my last engine, Lucky7s compensated numbers seem to be about 10% lower than the dealership's. I suspect the engine will still pass a dealership compression test. Also, the lowest number from this engine is still better than the compression on my "good" rotor on my original engine using the same tester.

how often did you use fuel injector cleaner and which brand? Also if you didn't drive hard enough often enough to give fuel injectors workout.

I like to use redline and techron FI cleaners. and in your case maintenance dose could be a good idea going forward.

have them test the injectors before they clean them...and make sure they flush the fuel lines before re-installation of the cleaned injectors.

Had my 2010 R3 tested before I decided to replace OEM with full aftermarket exhaust system.
Dealer charged me 1.5 hours labor (which I argued over but they insisted it takes well over an hour..)

Cost: 210.18
Mileage: 64 000KM


https://cimg1.ibsrv.net/gimg/www.rx8...28f50bf159.jpg


https://cimg2.ibsrv.net/gimg/www.rx8...73510b4fc8.jpg

From the compression chart the engine seems fine..
Not sure why they didn't normalize or bother typing out the readings.

Yeah, that is not the proper way to do it at the dealer but if those numbers are from the dealer equipment then they should be normalized already and even if they were not, that is a solid engine.

We have an RX-8 owner in our local group who is a Mazda tech and I have watched him do it many times, they hook it up the the WDS and it runs the numbers from the tester and then they print it out. They did not do it as outlined in the SII FSM.

I'll add my compression tests here:

2009 R3

1st Compression Test @ 25k miles:
(Results are expressed in kg/cm^2 and the values have NOT been normalized)
Rotor 1: = 8.2/8.4/8.5 @ 281 rpms
Rotor 2: 8.3/8.1/8.4 @ 282 rpms
(Original thread can be found here: https://www.rx8club.com/series-ii-te...2-rpms-241988/ )

2nd Compression Test @ 56k miles:
(Results are expressed in kg/cm^2 and the values have NOT been normalized)
Rotor 1: 7.3/7.4/7.2 @ 308 rpms
Rotor 2: 7.2/7.4/7.3 @ 309 rpms
When normalized, all values (all 3 faces on both front and rear rotors) are all below the FAILING spec of 6.9.

I did everything I could to prolong the engine's life - premixed, changed the oil every 2k miles (did the double change to get 8 quarts out), replaced the spark plugs every spring and then again mid-summer, replaced ignition coils. Kept a notebook in the car recording gas mileage at each fill up and oil consumption vs. miles driver at every fill up. Monitored the coolant temps and oil temps religiously, and never allowed the engine to overheat (max ever was 215 F for less than 1 minute), removed the cat to prevent any clogging problems, and never had any misfires register as a flashing CEL (dealer reported that over the last 10 drive cycles the ECU logged only 1 misfire, which they told me was well below the threshold to trigger a flashing CEL).

I'm a bit of a dinosaur, so my maintenance records are all hand written. I'm thinking I should put them into an online/electronic format to facilitate the dealer being able to review them and avoid any potential problems (the dealer is clearly reluctant to honor the 8 year/100,000 mile engine core warranty and replace the engine under warranty).


Overall, I'm in my winter car (BMW 128i) several weeks before I was planning on transitioning over to it. Which, could be worse.

That sucks, I am sure they will get you a reman installed. What was your oil consumption like?

maybe it was Friday afternoon engine, maybe you babied her to much...but in the end you will get new engine so you are covered...

Bummer. These posts really have me wondering where my compression sits at 34K very hard miles.

I would be curious. We have a local member and tech who works at the largest volume dealer in Texas and they have only replaced engines in a couple of S2's, but hundreds and hundreds of S1's. But shit happens, these engines are built by hand.

Oil consumption was 0.5-0.75 quarts every 1,000 miles driven (decreasing when I did longer highway trips), while some spirited driving on backroads on the weekends would generally consume 0.5 qt. Which to my understanding is normal.

Considering that the car has a completely failed engine but still drives "normally" (starts immediately, goes, no stalling or other obvious issues, it just doesn't have the power it use to have), I would guess that there are plenty more S2's out there with bag engines. The upgraded starter for the S2 seems like a band aid "fix" to keep the car going even if the compression is below spec.


I find it interesting that the compression is bad across the board. On closer inspection it looks like possibly 1 apex seal is bad, and that 4-6 or more side seals are potentially bad.

That is good consumption. The S2 starter will mask a hot start issue for sure.

I am surprised it dropped like that in just 30k miles. I wonder what what is really going on here. Carbon buildup?

Poacher, are you still under the powertrain warranty? If you're not, the dealer will initially claim ignorance of the engine core warranty for Series II, but the proof is right there in the warranty booklet that came with the car. It doesn't show up when they look it up in their normal way (not part of SP77), but it is a subset of the powertrain warranty and they will be able to dig it up when pressed.

I'm a few months outside the power train warranty. I showed them the warranty booklet indicating the 8 year engine core warranty but they didn't "believe me" (..."it's not on our computer system and this information is directly from Mazda..."). Quick phone call to Mazda North America and 10 minutes later they called me back to inform me that they had given the dealer the secret handshake or whatever is needed to get the computer system to "remember" the rotary engine core warranty and that I'm cleared for service (was very refreshing to receive such prompt and effective service over the phone).

Unfortunately, but not unexpected, the timing of this whole deal was not great as I've been working 14+ hour days dealing with FDA and DEA inspections at work so I have not had a chance to get the car in to the dealer yet (the car is waiting patiently in the garage). Shooting for Tuesday when things go back to the normal level of hectic.

Poacher sorry to hear. Good luck, and I hope your dealer treats you well.

Jastreb, what happened with your 8? You on a reman now?

Little update on my reman, she's running great. Been through a number of AutoXs now. Probably 10 000KMs on it now.

Poacher, good luck with your re-man. I hope it turns out better than mine. While the engine is out of the car, you may want to consider getting your fuel injectors cleaned, especially if you often run the tank to empty.

Shumster, yes I am on a re-man. It has been a headache from the very first day. You can read here if interested:
https://www.rx8club.com/series-ii-te...nation-260675/

I am glad it's been running well for you though!

[RANT] :rant:
I honestly regret getting the warranty engine replacement. The original engine had compression that was getting low, and below spec on one rotor, but at least it could go up a hill at 70mph in 5th gear without detonation. I wanted a strong engine as a starting point for performance mods - instead I have basically ruined my ownership experience for the last 6 months. Should have left well enough alone, and saved money for a proper custom re-build (time & money I have spent trying to troubleshoot the re-man). Now I am down to my last option - take it back to the dealer and hope they can either find and fix the cause, or get me another re-man (which would be the 3rd re-man to go into the car).
[/RANT]

In my opinion, far too many threads come up when you search the RX8club forums in which the original issue/question is never answered. I therefore feel it is only right to provide an "update" to my situation with my failed S2 engine.

Within a few days of the scheduled appointment to drop the car off at the dealer to get a reman engine, I got to talking cars with a rather wealthy friend of mine who was considering building an RX8 to race in addition to the RX7 that he currently runs in IT-7R. He made me an offer for the car with its current blown engine in it, and I said I would get back to him. Less than 24 hours later I received word that the 2016 Miata I had ordered in August was finally in. After considering available garage space, my wife's repeated pleas for a Range Rover, and our current fleet of vehicles we rarely drive, I decided to sell the RX8 to my friend, knowing that it would be where it belongs - out swapping paint on the race track every weekend.

TL;DR: I decided to avoid the potential complications of a reman engine and sold my RX8.

I am in no way shape or form upset with how things turned out. Mentally, I was prepared for engine failure from day 1. I loved the RX8 and consider myself lucky to have had the chance to drive a rotary (and I have extended this opportunity to everyone I know who can operate 3 pedals). As a hand-built engine that has its roots in racing, I cannot state clearly enough that I hold ABSOLUTELY no "grudge" at all against Mazda, the RX8 or the rotary engine. I had an opportunity to pass the car on to someone who would use it for its intended purpose - racing - and as an added bonus it made sense financially as well.

Poacher, glad your RX-8 found a new home. You do have quite a collection of cars! Hopefully your friend gets it a proper re-build and not something silly like an LS-2 swap.

All these horror stories about failed remans are concerning. Although, the engines are rebuilt in the US, maybe that's the problem ;)

If I lived in the states and I needed a new engine, I'd much rather get my engine rebuilt by a reputable rotary engine builder. Although if it's under warranty I guess you don't really have a choice do you.

Well my original engine built in Japan failed at 22,000 miles and my first reman lasted 74,000 miles. And in the beginning, before the Cat contracted builds and the reman plant in VA was built, the engines were coming from Japan and they still had failures. But the remans sucking is nothing new, the FD remans are not considered to be greatly reliable either. There are many factors.


That said, the rate of premature failures in Series II engines is way lower. We have a local guy who is a dealer tech and his dealer has done hundreds of S1 engine replacements and only a handful of S2 engine replacements.