2011 Compression Test Results at 45K Miles - Failure Is an Option
 

My engine warranty is up next month, so I took my 8 to the stealership to have it officially compression tested well in advance. It seems to have passed. Not beautiful, but passing. Very marginal, just like its owner. Congratulate me?

Props for the tech's grasp of grammar, capitalization, and punctuation.

https://cimg4.ibsrv.net/gimg/www.rx8...c46824e745.jpg

https://cimg6.ibsrv.net/gimg/www.rx8...f33aafa9ee.png

7.3 @ 300 is 6.7 normalized, so failing? Sounds like the tech isn't quite grasping some other stuff :/

If it's a Mazda Compression tester, those numbers are normalized to 250rpms. Those numbers look pretty normal for a 45k miles engine.

You bring up the discussion I had with the service manager. It would be ~500 feet, but yeah. He said Mazda has 2 testers in use. One normalizes and the other does not. He says his rig does normalize, and these are the normalized numbers with the starter RPM included for my information, because I specifically asked for it. Obviously, a second opinion from another stealership is needed to be sure.

I'm hoping it is passing. I do not relish the idea of having to decide what to do with the car. It is long paid off and decently track prepared, which means passing compression equals easy decision to keep. If failing, I can get what probably amounts to a lousy job of replacing the engine for "free" or trade it on the 2019 MX-5 and be done with it, but with a car payment attached. And, there is always the risk I will miss the dumb grin it puts on my face.

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Pretty sure the car payments would add up to more than a new non-crappy engine installed by non-crappy people? :)
The car only has 45k, it's practically new!

Well, that is certainly true. I do have the capability to install a reman myself in my horribly insufficient, terribly well air-conditioned, far too small four car garagemajal, however that brings up another key question. Which is better: an original S2 engine that barely fails compression testing and is pretty consistent on every rotor face, or a "new" reman from a reputable builder? I think I lean toward the known quantity of the original engine, which would severely limit resale opportunities in the future. I dunno. It's not an easy decision. Of course, in the best case, the car is worth at most $10K as it sits.

Also, have you driven the 2019 MX-5 Club? Damn, that car is fast compared to an 8! Handling is arguably better, too. So light and nimble...

Mazda remans, even the S2s, are nearly all brand new blocks coming from Japan with little to no reused parts. Usually just components like the oil pan, front cover, and some other minor components. Assembled by a technician that does it for a living, and they arent getting cranked out like crazy the way that they used to be. Id say a mazda reman might be a real good bet.

Good to see the numbers.

Assuming it starts from hot ok, and you're not feeling like it is overly down on power at the track, I would just keep on driving :-D

Especially if its free, which from the OP's comments it sounds like it still has some warranty left.

True. It could conceivably be "free" from the dealership, but then I have to trust the dealership monkeys to work on my car, which is asking a hell of a lot. How many dealership engine replacements end up being trouble-free I wonder? Also, I would have to find a way to make it fail its compression test and convince the dealer and potentially Mazda USA it actually failed.

Is it worth more now with a passing compression test result, or would it be worth more right after a warranty engine replacement? Thoughts on that question?

BTW, it shows no signs of low compression. Power feels about right. Never has any starting problems. Idles perfectly.

Maybe I should test the coolant for combustion gases and explore that avenue too...

I'm sure it's worth more with a fresh engine.

It sounds like the fear of dealer mechanics is playing into your rationale. Unless there are specific horror stories about that dealer (in which case find another?), they are still responsible for not having mix ups and get more training on the car than most other mechanics. They should know that the client can escalate to MNAO if it goes south.

There are obviously monkeys, but feel like the odds are on your side.

I'm kinda skeptical that their tester displays rpm but then also converts the numbers to Not that rpm. That sounds like really bad design, or user error.

Have you seen how awful my compression numbers are? For a very long time my 8 started up perfectly and showed zero signs of failing compression.. that is until my numbers dropped into the high 40's in psi when normalized.

It helped a lot that my starter cranks the engine at like 315-330rpm and i have a very healthy ignition and fuel system. They went a long way in getting all the life out of this engine and masking the symptoms as long as possible

I'm on my second engine. First engine failed at 65K, replaced under warranty in 2010. Car now has 140K - so something like 75K miles on the current engine. Had a compression test done a year ago and the scores were all in the high sevens and low 8's when normalized, so a solid engine. Haven't had any issues engine wise since the second motor was installed by my local dealer, and it was all free. Additionally, I would definitely think the car is worth more to a potential buyer knowing that the engine has recently been replaced.

Two most pressing questions needing answers: 1. Is it actually failing? 2. Can I make it fail before the end of next month?

The plan is to take it to the track for 8 hours of drive time the first weekend in May. I may do it without premix. Then, I'll take it to another Mazda dealer across town to see what their results are--without premix this time.

And yes, I absolutely hate having someone else work on my car. I have done 95% of all work on this car myself so far. I trust no one.

Dealer-installed remans come with a warranty, though, so I don't see why you should worry. It's short, but if something is really messed up during the installation, then it wouldn't take long for the issue to surface anyway.

And I know Miata is the answer and all, but... maybe try something else out? If you don't want to be strapped by car payment then go explore the used market.

If youre set on a miata:

Get a reman installed in the 8, keep all the paperwork and documentation
Drive a couple of thousand miles to break in the engine.
Sell private party to a buyer that you provide all proof of a fresh reman to in order to put your 8 at the top of the market

Use profit as a larger down on a Miata


End result: you get a miata and someone gets a 8 with a fresh motor with properly documented history

I don’t understand what the problem is. Lol. If you like the car and want to enjoy it at the track, go for it.

Seems like a healthy engine to me with those numbers. It’s only got 45k for crying out loud.

Now if you’re feeling like it’s time for something new in your life (plus car payment) then that’s a different story.

That engine passed the test. For all you know, that engine can still be enjoyed for another 50,000 miles easy before NEEDING a rebuild.

Yeah, this is likely the best way forward, assuming I can get it to fail a compression test to Mazda USA's satisfaction. As it sits, with a barely passing engine, it is worth probably $10-12K, which is just-keep-it money, and it is depreciating more every day.

I won't know if the engine is truly healthy until I have a second opinion. The plan is still to take it to the track for at least 6 more hours and have it re-tested at a different dealership--one that I know for a fact has done many engine replacements.

New set of results, still with no clear outcome. Different dealership after a 3 day Italian tune-up and a fresh tank of gas without premix.

Normalized to sea level and 250 RPM:

R1
6.8, 7.1, 7.2

R2
6.9, 6.6, 6.6

The service manager insisted the failure point for warranty replacement according to Mazda is 6.3. I seem to remember it being 6.8 and need to verify it with Mazda NA.

If it is failing, I will go ahead with the reman under warranty. If passing, it is barely passing, which rather sucks for all options but trade-in, although who knows how long it will continue to seemingly run fine? I could get several more years of enjoyment out of it and weigh my options again when it finally gives up.

The minimum is 6.9 kgf/cm² normalized, your SA should double check the service manual.

https://cimg4.ibsrv.net/gimg/www.rx8...3c72708a3e.png

Minimum by Mazda is 6.9, your motor failed. If the dealer is giving you trouble with the warranty, give MNAO a call and typically that helps. You can also tell them you are unhappy with the service the dealership is providing (assuming you feel like that is the case) and request that the repair is done at the Mazda Dealer/Service Center of your choosing once approved for a warranty claim for remanufactured engine, they may honor that request.

Edit: Also, There is a maximum allowance of 1.5 between the highest and lowest number of the 3 values on a rotor, and a maximum allowance of 1.0 between the highest and lowest respective numbers between the front and rear rotor.

You’re at a cross road...

if you like the car, keep it. Engine is perfectly fine to me. I’ve had a daily RX-8 below 5.0 bar and ran fine, although down on power and didn’t wanna hot start.

Had another @ 6.0 bar that ran perfectly without any issues.

I think yours is still enjoyable for many years to come.

Yeah, I found that in my FSM yesterday evening. The engine is failing on 2 of the 3 metrics. It is definitely on its way out, according to the specs.

Being that I just lost my job, a warranty reman is my only option short of continuing to drive it as-is, which makes no economic sense. Now to find a dealer I can more or less trust in the DFW area and start the battle...

For posterity, here is how the engine was used and maintained:

USAGE
Occasional daily driver and weekend tourer
Track toy once per month for ~4 years

MAINTENANCE
Regular JASO FD premix since 5K miles at 1/2 Oz per gallon street, 1 Oz per gallon track
Oil changes every 3K miles, weight varied from 20 to 40, conventional and synthetic
No cat or high flow race cat since 10K miles
BHR coils since 10K miles
Spark plugs changed every 10K miles


I wonder where it would be without the track hours? Better or worse or the same? Hmmm...

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I think it could have had more wear with tracking, but IDK, really.

My car had 43k miles when I bought it, and it had higher numbers(or I wouldn't have bought it). It was first owned by a neurologist, so I assume that the car isn't driven too hard. The second owner said he drove it in the summer as a spirited driver, but I don't he has done any tracking. I am the third owner.

Too many factors to consider here.

Of course there is no way to know what effect track hours might have on this engine with the information we have, but it certainly would be cool if we COULD know. Probably less carbon, but accelerated wear or something along those lines. In any case, it was a hell of a lot of fun wearing it out.

A 5 minute phone call to Mazda NA sorted out that dealership. They called yesterday afternoon, apologized, blamed the tech (poor bloke), and offered to make an appointment for engine replacement. Not sure I'm going to use them. I have until June 29th to take it in.

Well is THAT case... I vote you beat the living snot out off it daily. Rev it while cold, bounce off the fuel cutoff and pour in 0w16 oil for good measure.

Then, right before you take it in for engine replacement, have them run a compression test again to see where it’s at.

LOL.

Anyone know if the release bearing included in the Exedy OEM replacement clutch kit is good now? We used to recommend using an SKF or Koyo part instead, but I have it in my head Exedy recently sourced the Koyo part for inclusion in the kit. I just ordered the clutch kit and need to know if I should source a different bearing.

Anyone want to bet the stealership will try to charge me full labor for installing a new "aftermarket" clutch with the engine? They already tried to charge me 2 hours labor for a 45 minute compression test...

Also, now is a good time for people to chime in with engine replacement experiences in the DFW area. So far, I have been less than impressed with Hiley Mazda and El Dorado Mazda, although El Dorado has a couple of rotary enthusiast master mechanics working there, and they have done many RX-8 engines.

Can’t help you there. Only ever took my RX8 to the stealer one time back in 2005, lol.

Sorry to hear about your employment situation though. You can count on me to truly and sincerely help you in any way possible, but all I can do until that day is to make the offer one brother to another ... :)

Steve,

Sorry to hear about both your engine and your employment situation. There is never a good time to be unemployed, but there have been worse times than now to be there. It is my prayer that the job market will be able to meet all your requirements and even exceed them.


One question about your car: Did you observe and record (or remember) what your general oil consumption was? Both for track use and street? I know there are some S2 anecdotal consumption quotes floating around, and even some graphs, and I am interested if you have an idea of what your particular oil system was delivering.

Thank you, and all the best to you.

Guys,

Thanks for the well-wishing on the employment situation. Such is the life of an IT consultant. The company I was contracting with had a bad quarter and let all consultants go. It happens, and I save money for exactly this. I have 5 months to find a new gig before dipping into regular savings. I'm fine. I just don't think it prudent to be spending much on cars or adding a car payment to the monthly burn until employed again.

I would call oil consumption normal. It burned 1/2 quart per 2 track hours. On the street, I would need to add a little at each third or fourth tank of gas, depending on how I drove it. I also premixed starting when I acquired the car at 10K miles. The previous owner premixed beginning at 5K miles. So, it had regular premix from 5K to 45K miles.

So, no thoughts on the release bearing included with the OE Exedy clutch kit from anyone?

Thanks for this. No, I haven't had to order a clutch, wish I had an answer for you.

To be clear, it doesn't NEED a clutch, but it is always a good idea to replace the wearable parts when broken apart for other reasons.

Truthfully, if youre able to i would just buy the koyo release bearing. If when it arrives and you compare the two and find they are identical (markings and all) then just sell the release bearing and recoup your funds. Even if exedy sources the bearing from koyo now, theres no garuntee that you wont get a box from old stock that does not have the koyo or updated bearing.

I haven't had much luck with "oem replacements" of clutch components on this car. This might in part be due to s1 vs s2 differences. As a result, for all the clutch components, I would only use parts that match manufacturer and model with the oem ones you take off the car.

I used an exedy "oem" MZK1002 replacement kit in an s2 when I swapped my engine in 2015, although there was nothing wrong with my stock clutch at the time (~50k miles and a bunch of track days).
After this, the clutch pedal was stiffer than stock, and the release bearing died a little over a year later and trashed the pressure plate. If I recall correctly, the clutch was not identical in appearance to the original and neither was the pressure plate. It took me a while to bleed and adjust after replacing and it is possible that I drove around for a while with the bearing touching, so contributing to premature failure and maybe not entirely to blame on the bearing (although I think some of my adjustment issues may have been due to the differences in the other parts).

I replaced the bearing with ACT RB110 and went back to my original oem pressure plate and clutch (since they still looked good and I didn't want to buy another new pair at that time). I took good care to bleed and adjust properly at the start this time. The release bearing died after a year of street and track time. One of the clutch springs was broken when I took it apart and the pressure plate had been worn by the failing bearing. This one was down to the part for sure.

Replaced with new clutch, pressure plate and release bearing sourced from mazdaspeed motorsports. All feel good after 2 years of track time, but almost no street miles.

Mazda sourced clutch is made by exedy. It has N318 7H21A written on it.
Mazda sourced release bearing has Koyo Lic.SKF CBU 543 625 J printed on it. (that last number might be a 9, but I'm fairly sure it's a 5)
The pressure plate didn't have anything I could identify it by.

After 45k your pressure plate and clutch might still be in good condition. In that case I would just replace the release bearing with one matching the original.

I now see Exedy list MZK1014 for the s2, which is different to the one I started with, so it could be that is fine now.
If you have a mazda motorsports account, I would check the cost of the components there. It wasn't that much different to the exedy kit when I got mine.

I'm sorry to hear about your job situation and your RX-8 engine. Best of luck - from what I gather none of us know if all of the TLC will result in achieving 50K, 120K, or 200K on an S2 engine. I just rolled over only 51K on my 2010 GT and my warranty runs out in a few days since it was purchased by the PO in May 2011. I have so much fun driving it on weekends and to work that a reman is already in my budgeting plan. Keep us in the loop on your plans.

I’ve always used the TB with the Exedy clutch kit, but while I was extremely abusive with continuous 8k+ clutch drops for Pro Solo drag starts etc, but I’d swap it all out every several years just to be safe. I didn’t find it to be any better or worse than OE except some of the early S1 PPs were know to fall apart early, mostly 2004 models I think. Worst case you can order the TB that Mazdatrix sells separate instead. Unless the stealer charges you to swap the existing used one over too it’s kind if BS to get charged extra for installing a new one. They never miss a chance to ding a wallet though. That’s why I only took mine there one time, lol.

Can someone explain the normalization factor? Is that dependent on atmospheric pressure?

Thanks for the info. It turns out, the dealer wants to run "4 or 5 tests" to see if the engine can be approved for replacement. The only two I could get out of the service advisor are exhaust gas test and a second compression test. I assume there might be some Zoom Zoom cleaner in there somewhere. Maybe a cat efficiency test? Anyone able to chime on on what it is they do exactly?

Miraculously, the very same person who told me a compression test takes all of 2 hours told me these 4 or 5 tests can be done in 2 hours. Hmmm...

I digress. The actual drop-off of the car for the engine replacement may not be for a couple months, so I have plenty of time to figure out the release bearing.

Just to be sort of safe, I changed the oil with Castrol GTX 5W20 and ran all the premix out of the gas tank. I also removed my brake ducts and installed the factory cat. The only thing I haven't done is swap out the BHR coils for stock, because I don't want to waste that money. Hopefully they won't give me too much trouble. In any case, I'm a stubborn SOB, and I'll get around any potential roadblocks.

hopefully it all works out, employment and engine replacement.

if you want to make sure if fails the test just stick the piece of cardboard on the radiator/oil coolers and drive the crap out of it.

4 or 5 tests for what? It failed the compression test. Exhaust gasses are irrelevant and not a criteria that Mazda looks for. It already failed the compression test by a large margin, and the reason why they would try to find passing numbers is to try and charge you to get the motor replaced at a larger invoice that what MNAO will pay the dealer to replace the motor (MNAO will pay the dealer exactly only X amount because MNAO sets the labor hours approved for the R&R of the motor. MNAO will supply the motor and whatever parts. The dealer cant sell those things to you for any profit of any kind and they cant overcharge for labor either. Some dealers hate this and will try and keep things out of warranty so that they can charge the customer more money than they would make otherwise. Bad business, but its reality and it happens all over the world.

Give MNAO a call again, tell them whats up, and tell them you do not trust the dealer any longer and want to take the car somewhere else. MNAO wants to keep customer happiness as high as possible to keep people coming back to buy cars from them or share their positive experience, so they wont take this service teams B.S lightly.

Speaking from experience working at a dealer before and working with dealerships as well when working at independent shops.

I'm just playing the game. I have been in contact with Mazda NA a couple of times and will use them as leverage as needed.

The engine failed the block test, too. Exhaust gas in the coolant. That surprised me a little bit, because I have checked for bubbles in the bottle fairly frequently and have never seen any. Anyway, it has now failed on at least two fronts.

It also failed another compression test with similar numbers as before. I still have no idea what else they may have "tested," but the process today took 1.5 hours, so it could not have been much of anything.

The service manager tried to jerk me around a little bit about track use, but I pointed out the MX-5 juxtaposed against candy stripes on mazda.com and reminded him that the decision does not lie with him. Mazda NA approved the engine replacement anyway, so it's set.

This may or may not actually be true, but the Mazda NA rep told me they have no S2 remans in stock, and I will be receiving a new engine. We shall see. The dealer should receive it within about a week they said.

Finally, I asked about having the new clutch installed at no charge, due to there being no extra labor involved. The service manager bristled, but the tech verified my assertion, and the SM grudgingly agreed. I can do it myself in about 4 hours, but I'd rather not have to crack it open again.

BTW, the release bearing included with the Exedy kit looks like generic junk, so I ordered an SKF bearing for comparison. The Exedy bearing has no markings anywhere and is smaller and lighter than the Koyo bearing I put in my Miata last summer. Hopefully, the SKF bearing is more robust.

And you never overheated, yes?

Surprised to see a potential coolant seal rupture in your engine.

this is a great read,
sorry to hear about the engine and job ,

was the engine ever comp tested previously,
as a way of measuring wear over time?

If you paid less than $120 for it then it’s just the usual hyped up junk, the average joe is too cheap to pay for a quality TO bearing. That’s why I recommended the race clutch version from Mazdatrix.

Nope. Never overheated. It did spend quite a bit of time at 215 to 218F on the track, but that should have been OK. If I keep the car, I will work on bringing the peak temp down, before taking it back to the track.

UOA was always great. Coolant was never detected in the oil.

It was not compression tested previously, although I really wish it had been, just to fill in some gaps.

Now you tell me! It is the $55 SKF that Charles once recommended. In any case, I doubt this car will see much more track time. Maybe twice a year, when I instruct for BMW CCA. But I might just buy a friend's bimmer and be done with it. Otherwise, the Miata will get the nod.

I never got the cat test procedure that the Mazda dealer did to determine that my glowing cat is still OK - they approved it for continued use. I have the document in case the car catches fire or fries items during normal use.

Glowing at idle? Or glowing after a hard drive?

Glowing after a hard drive is normal as long as it's not excessive. My OEM cat had the ring around the rear O2 glow after a hard drive and when I took it off, it's in perfect condition.

You can also read an inferred cat temperature with a live data OBD2 reader. It shouldn't be over 1290 F/700 C at a steady hot idle.

Lest people believe this engine died prematurely, it probably did not.

Racers expect about 100 track hours out of a well-maintained factory-built piston engine. If you get more, you are doing really well.

I started tracking this car in November of 2012 and more or less stopped in September of 2016. That amounts to ~46 track days. Since then, it has seen ~8 track days, for a total of 54 track days. Each track day amounts to ~2 hours of drive time. That multiplies out to 108 max track hours.

Some of those days were wet, which features loads much closer to street driving, and I did not drive all 2 hours on some other days, so the real number is probably closer to 90 track hours plus whatever street driving I did during those years. And, I drove it hard. Very hard.

That being the case, this engine is probably right about where it should be in terms of compression, assuming Wankel engines follow roughly the same wear schedules as Otto engines. I wore it out honestly, and it performed as it should have.

The rest has always been part of the plan. Drive it hard until right before the warranty expires, take it in to see if it requires replacement, then decide what to do with it. That's where I am now.

FYI, the SKF N4081 release bearing has almost exactly twice the mass as the little one included in the Exedy kit. Mass does not necessarily matter, but it does appear to be a better constructed unit. I'm going with it.