When the initial talks of a IM being made by MSF'ers, a lot of designs were thrown around and discussed. Fluid-dynamic expert I'm not, but I did remember discussion on how certain designs, mostly OEM and due to packaging, does not allow balanced flow to all cylinders, esp under boost. The MR2 was one car that was notorious for doing this...this is from knowledge gleaned 20yrs ago, when my friend upped his boost without additional fueling and not first hand. In the MR2's case, it was the farthest cyl from the TB, and it makes sense from a NA/PI point of view. The interesting thing for us, is cyl 3 & 4 being closest to the TB...as such, I'd subscribe to the theory of imbalance flow, where cyl 3 & 4 are running consistently leaner than cyl 1 & 2...so who's gonna tap each EM runner with $1500 worth of gauges to check? =)

Regarding the tuning side of things and track work: I always run a detuned map for track...for example, on the GT3071, when I was running 22psi on the street, I'd run 20psi on the track...whereas I might pull fuel up top for the street, I richen up to 10.9AFR @ 7000 [linear taper from 11.8] for a track map. At the track, it's not that last 10whp that will win...it's finishing.

http://sphotos-b.ak.fbcdn.net/hphoto...60926703_o.jpg

The methanol related ring land failures are probably related to over advanced timing rather than anything else thermal expansion related.

This whole pooling on valves complaint stuff needs to be put to bed. Any port injector motor running more than a 30% duty cycle is going to spray and pool on a closed valve. If it caused any issues at all related to reliability there would be failures all over the place.

Zigatapatalka

Couldnt agree more about the fuel pooling behind the valves. With close to 100% idc that injector is a constant spray of fuel.

Now lex mentioned a good point about the cracked ringlands being on the exhaust side. Could this be related to poor piston top design and fuel washing the exhaust side of the cylinder wall.

Sent from your couch

:07: I just am hesitant to install it and run meth in the runners right now because I know 1 person in particular who is sketched by it.. and I trust his judgement.

I want to stop there because this is a ringland thread and I don't want to derail or bring in drama from another thread.

I guess it's worth pointing out that this issue being discussed is very likely related to the other thread made by Dano regarding heat management...specifically, break down of oil that many of us used, such as Pennzoil Platinum, which is more than fine for the street, but likely not sufficient for extended track work...a 20min stint is like 15+ laps of oil sloshing from side to side...being heated, without much chance to release that heat. Once that oil breaks down, even your "safe" tune will be too hot.

I'm inclined to think that even T6 may not be enough...we have shops here in Toronto, telling us to run a "proper track oil"...

When I would track my bike I would run 20w-50 oil then use 10w-40 for the street. Maybe we should consider something like that for track use.

I defintely feel heat is the major factor here. Curious to see the results of these next couple of motor tear downs.

Sent from your couch

it'll be interesting to see how my stock motor is if/when it is ever taken apart. I ran T6 during the track season in 2011 and 2012, including those 2 hot days in 2011 at Mosport big track (30+ C) where I was able to cook the power steering pump on day 1 and completely seize the power steering pump on day 2.

i haven't run a compression test yet (ignorance is bliss) but it still reads -12 psi vacuum when letting off at WOT, and reads -10 psi at idle.

on the built motor though, Motul 300v is what i'll run at the track.

FWIW, I'm pulling the same amount of vacuum and my compression numbers were 190 - 165 - 150 - 175. I haven't noticed any oil consumption, up until my most recent fill up and I had lost about a 1/4 of a quart. My idle is somewhat rough, but I've always attributed that to VVT/timing chain stretch problems.

I'm assuming that if I have a cracked ringland, it was probably caused by one of the previous owners running low octane fuel and detonating like a motherfucker. Detonation will fuck your ringlands, even with forged pistons.

To he honest. I don't even remember. I haven't handled a stock piston/rod combo in such a long time that I can't even infer the orientation of the one in my picture.

When I re ringed my forged motor not too long ago, I did notice that the exhaust side of the piston skirt coating was noticeably more worn than the intake side. This can be an indicator of where the majority of the stress lies in combustion given our motor layout.

If the oil was too thin for track use you will get spun bearings.

There are several possibilities here.

1. Heat in single event or over time deteriorating the piston or butting rings. Heat is the enemy of every turbo motor.

2. Detonation between the two rings due to heat and fuel washing down the cylinder wall. Might not take much and might happen outside the timing Window the ecu is listening for.

3. Luck of the draw. Some will fail and some won't. Especially if the car was assembled on a Friday, driven hard, put away wet and had slightly tighter ring gaps.

In the end tracked cars have failed as well as street ones. Heat management should extend the life of any engine and component so it's a good place to start.

This is an example of an engine that was run very hard for a long time. Iirc, it did suffer from somewhat high ECT's part of the time. This was a local guy's car that was tuned prior to him moving into the area.

Model/Year: 2007 MS3
Mileage: ~80k
Compression Results: Unk
Cylinders /w Cracked Ringlands: 2/3/4 shattered
Suspected Event Causing Failure and Other Info: Long term, WOT detonation with GT3076 and pump 93 (too aggressive of tune)
Pictures:

Pieces of piston 4 exploded into the intake manifold, and were sucked back into the other cylinders where they bounced around (you can still see the deto marks pretty well, though). The engine let go in the high revs, and had been experiencing boost spike issues with the GT3076/MBC/improperly adjusted preload on the IWG.

Cylinder1 - Cyl1 Photos by phate1985 | Photobucket

No cracked lands in cylinder 1
http://i64.photobucket.com/albums/h1...ps8deae3e7.jpg
http://i64.photobucket.com/albums/h1...ps71044397.jpg

Cylinder2 - Cyl2 Photos by phate1985 | Photobucket

http://i64.photobucket.com/albums/h1...ps14746efc.jpg
http://i64.photobucket.com/albums/h1...psd90834dc.jpg

http://i64.photobucket.com/albums/h1...psdedc4895.jpg
http://i64.photobucket.com/albums/h1...ps8de5c4fd.jpg
http://i64.photobucket.com/albums/h1...ps9eaac6dd.jpg

Cylinder3 - Cyl3 Photos by phate1985 | Photobucket

http://i64.photobucket.com/albums/h1...ps07eb2700.jpg
http://i64.photobucket.com/albums/h1...ps00dcc042.jpg

http://i64.photobucket.com/albums/h1...ps1fc2005c.jpg
http://i64.photobucket.com/albums/h1...psdd5b4223.jpg
http://i64.photobucket.com/albums/h1...ps4202e5b1.jpg


Cylinder4 (lol) - Cyl4 Photos by phate1985 | Photobucket

http://i64.photobucket.com/albums/h1...ps4b254ff6.jpg
http://i64.photobucket.com/albums/h1...ps3bdd340a.jpg

Each cylinder's albums are linked. I am not 100% confident the rings didn't get shifted a bit between pulling them and taking pics.






I will finally be getting my 4 EGT probes and logger hooked up after this weekend. Hopefully we can glean some info from it.

The fact that these failures are coming out 8 years after the car was released shows that it can also be age related and heat cycle related.

Holy crap @phate;! It's like silence of the lambs in there!

One of our Celestial Blue Pu's is under suspicion of a cracked ringland in cylinder 4 /w 35K KMs or so.

EDIT: I think we should also take into account that people have parted out their cars and ditched the platform when discovering less then ideal compression numbers as well as the genesis of most builds have been due to venting a rod. Not many people have gone the route of discovering low compression then building.

Ring orientation has nothing to do with cracked ringlands. The rings are always rotating as the piston moves up and down, so even if it was an orientation problem, there is nothing we can do.

Do our stock pistons have "anti-detonation grooves" in them? I know those are more theory than proven, but I'm just curious.

@phate; that's a lot of detonation on those crowns.
@BlueStreak; maybe so but not all low compression results necessarily mean a cracked ringland.

Absolutely, I agree. Has there been evidence of low compression due to rings?

After some debate with myself I've decided to take one for the team.

I will be running my car this year at Time Attack with no extra cooling aside from an intercooler. I will have the following gauges installed: EGT at the exhaust manifold turbo inlet, Oil temp in the pan, Oil pressure stock location, and water temp in the upper rad house. I will record the values I get from my abuse at the circuit this year. Before/after each event I will perform a compression and leakdown test to see if indeed I can cause a broken ring land. This will at least give us some data as to how much "heat", "load" and "time" it takes to crack a ringland. That is if I haven't cracked one already LOL. I have a spare forged motor ready to go, so why not take one for the team and see what we can find.

Temperatures, Loads, Time on track, and tune details will be put forth and reviewed by everyone here to see what we can find.

My car is fully bolted as they say so if anyone wants a complete list of modifications regarding the engine I will post it up. The most abuse this motor has currently seen is 85,000km of street driving and the worst I have put it though was 6 or 7 back to back logs to test of the track-ability of a tune. So it should be fairly healthy based on my current abuse.

If anyone wants to add anything or help me put together a way to organize the data please post up. Let's get stop talking about it and get it figured out. We worked around vented rods, we will work around cracked pistons.

Gdam

Out w wife at charity event and it looks
Like lots of fun
Going on in here. Must read when I get back

Lex do you not think cracked lands is less age related than the fact that we now blow fewer motors due to rod failure ?

I suppose one begets the other when u think about it.

BTW. I still love this place. Phate. U r Insane my brother!!

Can't wait to see pics on a PC.


Tappin

A ton of deto. I wasn't the one who tuned the car, and after getting to know the owner a bit, I suspect he turned up the boost controller some after the tune was done. By the time I ever saw the car, it had been running like that for thousands of miles :/ No bueno, I'm sure it just ate away at it, little by little.

You may be on to something hear Justin. Check out the failure posted most are gen1 piston design!!!!!!!!!!!! I would think If the coolant temps are high the cylinders with flow differences would be the first to go as det would likely happen hear first. And this brings a maintenance idem in the mix for the person that may track there car. Possible thermastat swap would be in order!!???

I don't think there's a smoking gun just yet with this. We'll track the failures and see if anything emerges. There can be a number of reasons for the failure. In any case, I am a strong believer in heat management and how it extends the life of mechanical components as a whole. These cars run hot so it's a good place to start.

I cant believe you managed to respond to that post. The only thing I read was HAY GUYZ, IM DRUNK!

Anyone have a contact @ i-MOTO? They abuse this engine more than anyone else, 24 hour races and 2.5 hour "sprints" in traffic. I would be interested in what they have setup for cooling and if that are using the stock internals(I think they have to), and if so what they are setting their ring gap to. Those cars are down on power, but certainly not on heat.

@Todd98SE;

Sorry Lex, different group (MotoIQ is not i-Moto racing team) but I will see what I can do.

http://i-moto-racing.myshopify.com/p...car-chassis-32

At a quick glance i-Moto is using a custom radiator. No details about oil and transmission cooling.

I think I just bought their race seat from last yr's car...when I get it in hand, maybe I can send them an email or something and get them to come on here to chat.

I think that @skeurton; has contacted them and received return e-mails from them.

I met them @ the Grand Am event in NJ and they are very easy going and easy to talk to.

I think if someone where to contact them, they'd have no problem responding.

Talking with out engine builder they told me this is nothing more than a heat issue. They said even if I upgrade the cooling it will still be a bandaid. The ring gap needs to be opened up as a start. If we are still getting cracked ringlands then we are running to much heat for the pistons. Although they believe just the ring gap will fix the issue.

Either way I'd like to see how much heat this motor can take.

Does anyone have any comparable data regarding EGT's? I know sensor placement as well as timing will affect the readings. Is there anything I can test for that will allow us to estimate cylinder combustion temperatures? If boost is fixed and I run 5* timing at RL, then up it in 2* increments to see theml temp change does that change in temp refer to the energy being added into the chamber, or is it more complicat d then that? Most things I have been reading suggest to keep EGT's at a most of 1650F when measured at 3" from the head.

@kritz; and I met Gareth Nixon up at an OCC meet last year, he was looking to sell this car which does lists both oil and tranny cooling as well as a 3 core radiator: Grand AM Continental Tires Mazda Speed 3 For Sale

He handed out business cards but I don't have it anymore. Steve do you still have his contact info? Just gives us another option to contact. iMOTO isn't the only ones racing these, they are just the only ones winning :P

EGTs and piston temperatures are not directly related. As you advance timing the EGTs will go down and piston temps will go up. Adding boost and/or leaning the afr will cause both EGTs and piston temps to go up.

The lower the ignition timing, the higher the EGT's will be until you get beyond MBT. Then they go through the roof. I would assume that 5* at redline would result in EGT's that are ridiculously high to start, then as you add the timing EGT's will gradually come down, and it moves the heat into the combustion chamber rather than the exhaust

EDIT: Ziggo beat me to it.

I would've thought the same exact thing ^^^(and I'm pretty sure this must be a common misconception because I've read that idea many times).

I ganked these (the below quotes) from a debate about egt behavior in another thread per djuosnteisn.

He also credits the author of a book that contains the info and the link is posted below.





quote from this post in another thread:
http://www.mazdaspeedforums.org/foru...ml#post1915217

Lets hammer out a testing proceedure then.

Boost and AFR will remain constant in this instance.
Lets say at 5* I see ~2000 egt as I advance timing it will go down. At what point do I know I have reached MBT? Also does advancing beyond MBT provide any gains?

I doubt anyone has really done this before. Most guys street tune and we just tune to the knock sensor. A few pulls on the street is not +20mins on track.

Yes, I fact I emailed him recently. I will shoot you over his info. I was looking to see if he wanted to part with a LSD.

You won't know you've hit mbt without a dyno.

This. It's the only reliable way to find mbt, and it's worth every penny.

They have a lot of used parts for sale on their site (for cheap).

How do I use the dyno to find MBT? What should I be looking for?

I don't mind renting a dyno for a few hours. I just don't want to go in it blind. Would this data then be used for my motor only? Or would it be engine dependant? Say at X AFR @ Y psi = Z timing. Does it work that way?

@Fobio; will know what to look for.
He's worth every penny.

It is engine and load specific, along with weather specific. As you walk up timing, gains decrease per 1* of timing. Then power plateaus, then power drops. That last point where you gained power is MBT. Back off a couple/few degrees to play it safe.

You have to be sure to keep things as consistent as possible between the runs. ect's and bat's are especially important to watch