When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would recommend putting in supertech valves springs just for extra safety measure since you already have the engine apart. That way you don't have a O shit moment of dropping a valve on to your new pistons.
Totally agree I didn't see a listing for any J motors ? got a link
Hollow stem intake and high heat resistant Inconel exhaust valves are also available; through another another manufacturer. PM me for details if interested.
- Cylinder 1, 2, and 3 have broken skirts on the non-thrust side of the skirts
- Cylinders 4, 5, and 6 have no damage
- All cylinder walls and ringlands show no signs of damage or wear
Is this correct?
Assuming the above is factual, it would be correct in saying that the skirts more than likely suffered damage during an intake or power stroke. I'd say IF it were one of the two, the power stroke would be more probable here. Also, the fact that it only caused damage to bank 1 (rear) tells me that it could have 'more than likely' been a result of fuel variation by the ECM as the banks are independently controlled in accordance to tuning and/or sensor data being received. That's not to say that other mechanical factors could've been involved such as clearances (unlikely), elevated EGT say from bank 1 exhaust restriction....basically any sort of issue that doesn't involve the ECM or the powertrain electronics.
To me, If it were clearances, the other side would've been affected as well. Same goes for cold revving the engine.
I know you've already said there's no other damage on cylinder walls or ring lands but can you look at all the ring ends and see if they've butted at all? Perhaps they were mildly butting and causing the pistons to rock. And if only bank 1 showed signs of butting, this too would only support that EGTs were elevated and or detonation occurred.
I love engine failure investigations! Sorry it was at your expense.
I realized I may have caused some confusion by something I wrote in my last post about the reason for the pistons to fail. I stated that the clearances between the walls and pistons would have been an unlikely cause for failure. What I meant was in a sense of increased clearances due to wear on the walls or pistons. Obviously, the broken skirts WAS a direct result of piston to wall contact but more than likely not due to wear, but an increased thermal load brought about by say detonation or of the similarity. Mechanical shock could've also been a cause from say preignition that may have abruptly rocked the piston in the cylinder and broke the skirts.
Regardless, it was all isolated to one bank which means I will stick with my initial belief in it being a powertrain electronics or tuning provoked issue.
Robert, could this be due to the design of the stock fuel rail and returnless design? I know some people convert to the parallel feed instead of the stock routing. I can't recall the stock config offhand, but would the rear bank be the side the receives less fuel?
Also, not to dismiss your thoughts, because I agree it is interesting determining the failure cause and discussion is needed, but if it were the ring ends that butted, wouldn't a cracked/broken ring land be the more common result, rather than the broken skirt?
Wouldn't a high EGT, or excessively lean combination typically result in a piston that looks more like Utah's TSX piston where it just melts instead of cracks off? All of the carnage I've seen that have been detonation incurred have been melted pistons or broken ring lands.
You switched to a J35 with the single exhaust port on your turbo setup vs the A2 style heads didn't you? Are you running a stock bottom end or built motor on yours?
robert, could this be due to the design of the stock fuel rail and returnless design? I know some people convert to the parallel feed instead of the stock routing. I can't recall the stock config offhand, but would the rear bank be the side the receives less fuel?
the supply actually tees off with the rear bank first and then the front bank so is don't see that being a tangible concern in this case. However, i wouldn't say impossible until proven so. Aside from this, i've ran 200hp+ dry shots on the stock fuel system of which you probably know uses the injectors as the source of fuel enrichment.
also, not to dismiss your thoughts, because i agree it is interesting determining the failure cause and discussion is needed, but if it were the ring ends that butted, wouldn't a cracked/broken ring land be the more common result, rather than the broken skirt?
Wouldn't a high egt, or excessively lean combination typically result in a piston that looks more like utah's tsx piston where it just melts instead of cracks off? All ofthe carnage i've seen that have been detonation incurred have been melted pistons or broken ring lands.
jesus man, what the hell happened there!? I didn't realize that my whole direction of thoughts shifted from excessive clearances being the cause to way too little clearances. Lmao. Sorry about that and good catch screaminz28. Guess that what happens when you're trying to give attention to a post on here and then become heavily distracted by five little ones. ***shakes head***
please disregard all i wrote on this matter and i'll re-respond (new word) later about this.
you switched to a j35 with the single exhaust port on your turbo setup vs the a2 style heads didn't you? Are you running a stock bottom end or built motor on yours?
to clarify, i only switched from a multi exhaust port cylinder head engine to a single port headed engine because i was simply just doing a swap...not by reason of an advantage in a turbo setup. I am running a stock bottom end on this build but its tweaked for in the right places for boost.
Wouldn't a high EGT, or excessively lean combination typically result in a piston that looks more like Utah's TSX piston where it just melts instead of cracks off? All of the carnage I've seen that have been detonation incurred have been melted pistons or broken ring lands.
Yes it would. I've had customers come to me that got too antsy on a basemap or a part failure (flex pipe that collapses down to the size of a thumb will choke and kill a motor quickly) and roasted their motor in one freeway pull (say 2/3/4/5 pull to 150). It doesn't take much to roast a couple pistons as soon as EGT's skyrocket or the motor suffers a lean condition, even on the most perfect tune. In every situation there have been melted pistons. The plugs and cylinder head(s) (usually exhaust side) will also show if the motor has been seeing lean conditions.
We have bank one breaking/cracking piston skirts while bank two shows no signs of damage at all. Looking at the pistons, I noticed that they ALL (despite having appeared to be cleaned after removal?) have what looks to me like fuel wash. You can see that the upper portion of the crowns, as well as the sides, look identically washed not too mention a central and lower heavy carbon/soot buildup that may have been a bit darker before you cleaned them which supports the possibility of a heavily rich mixture. The carbon buildup seen in the ring lands looks to be patchy to me as well. MAYBE even some signs of something puddling up in the cylinders as seen by a faint line on the bottom of the piston crowns.
Fuel wash is known to cause severe piston rock in a cylinder during compression stroke. This can cause a much more instantaneous or rapid rock of the piston than seen in normal piston rock during a change of direction from stroke. This violent motion could understandably be a reason for skirt breakage...especially if one bank is running richer than the other. Though they are both excessively rich, bank one could've been just enough to cause breakage/cracking to all cylinders on that side.
If the faint puddling lines weren't caused by you from maybe cleaning the cylinders out with the pistons still installed, then I'd also be willing to add the possibility of leaking head gaskets on both banks. This would cause hydraulic-lock during startup if the coolant seeped into the cylinders after the engine was shut off. Did you ever notice the need of having to add coolant or maybe misfiring at startup? Though it's not as possible as fuel wash being the issue, I wouldn't say both head gaskets failing being impossible considering the mileage of the engine and the fact that it's boosted.
We have bank one breaking/cracking piston skirts while bank two shows no signs of damage at all. Looking at the pistons, I noticed that they ALL (despite having appeared to be cleaned after removal?) have what looks to me like fuel wash. You can see that the upper portion of the crowns, as well as the sides, look identically washed nfot too mention a central and lower heavy carbon/soot buildup that may have been a bit darker before you cleaned them which supports the possibility of a heavily rich mixture. The carbon buildup seen in the ring lands looks to be patchy to me as well. MAYBE even some signs of something puddling up in the cylinders as seen by a faint line on the bottom of the piston crowns. the pistons weren't cleaned after removal. Only a quick spray-down to get the coolant off them from when the heads were taken off. And wouldn't fuel wash cause the pistons and cylinder wall to be scuffed up? Mine are nearly perfect with the factory machining marks still in them
Fuel wash is known to cause severe piston rock in a cylinder during compression stroke. This can cause a much more instantaneous or rapid rock of the piston than seen in normal piston rock during a change of direction from stroke. This violent motion could understandably be a reason for skirt breakage...especially if one bank is running richer than the other. Though they are both excessively rich, bank one could've been just enough to cause breakage/cracking to all cylinders on that side.
If the faint puddling lines weren't caused by you from maybe cleaning the cylinders out with the pistons still installed, then I'd also be willing to add the possibility of leaking head gaskets on both banks. This would cause hydraulic-lock during startup if the coolant seeped into the cylinders after the engine was shut off. Did you ever notice the need of having to add coolant or maybe misfiring at startup? Though it's not as possible as fuel wash being the issue, I wouldn't say both head gaskets failing being impossible considering the mileage of the engine and the fact that it's boosted. I haven't had to add coolant at all, and i never had an issue with misfiring at startup. Definitely no head gasket leaks. No lost coolant, the pistons didn't really look like they've been steam cleaned.
^
it depends on how long the rods take to get here. ill be ordering them in the next week or so.
Welcome to my world! One leads to another and to another. The next thing you know, you're broke!
Pauter stocked the J32 rods so it's possible that they'll have them but you'll likely need to supply them with the small end width. If it was like mine and had a 1" opening, they'll mill them down and balance them again.
It is fun getting all these cool parts despite the drain on the wallet.
EDIT:
What piston clearances did you guys settle on? You're in a cold climate like me so I am wondering how much slack you're running and then what startup sounds like on a cold day. Do you see below zero temps and would you be starting this car in those conditions? It was -14F when I left this morning @ 6:30AM.....even colder where I used to live.
We have bank one breaking/cracking piston skirts while bank two shows no signs of damage at all. Looking at the pistons, I noticed that they ALL (despite having appeared to be cleaned after removal?) have what looks to me like fuel wash. You can see that the upper portion of the crowns, as well as the sides, look identically washed not too mention a central and lower heavy carbon/soot buildup that may have been a bit darker before you cleaned them which supports the possibility of a heavily rich mixture. The carbon buildup seen in the ring lands looks to be patchy to me as well. MAYBE even some signs of something puddling up in the cylinders as seen by a faint line on the bottom of the piston crowns.
Fuel wash is known to cause severe piston rock in a cylinder during compression stroke. This can cause a much more instantaneous or rapid rock of the piston than seen in normal piston rock during a change of direction from stroke. This violent motion could understandably be a reason for skirt breakage...especially if one bank is running richer than the other. Though they are both excessively rich, bank one could've been just enough to cause breakage/cracking to all cylinders on that side.
If the faint puddling lines weren't caused by you from maybe cleaning the cylinders out with the pistons still installed, then I'd also be willing to add the possibility of leaking head gaskets on both banks. This would cause hydraulic-lock during startup if the coolant seeped into the cylinders after the engine was shut off. Did you ever notice the need of having to add coolant or maybe misfiring at startup? Though it's not as possible as fuel wash being the issue, I wouldn't say both head gaskets failing being impossible considering the mileage of the engine and the fact that it's boosted.
So I misunderstood your prior post. Instead of too lean, it was potentially too rich on one bank?
If that's the case, wouldn't the more likely scenario be something like a stuck injector rather than the tune or ecu related? It just seems that something mechanical would be more likely.
I don't see the ecu modifying a single bank of pulsewidths independently of the other, unless it was odd fuel trims.
I haven't done enough in Flashpro to know besides the individual cylinder fuel trim, which I assume hasn't been modified. I wouldn't think it was modified unless there was a known 'lean cylinder' on these cars, which I'm not aware of offhand.
Are long and short term fuel trims ignored in open loop? I thought that was only for driveability in closed loop. Are there even separate long and short term fuel trims for the differing banks? For this to occur by tune, I'd think you'd need massive swings on both ends, i.e. +20% on one, and -20% on the other.
Welcome to my world! One leads to another and to another. The next thing you know, you're broke!
Pauter stocked the J32 rods so it's possible that they'll have them but you'll likely need to supply them with the small end width. If it was like mine and had a 1" opening, they'll mill them down and balance them again.
It is fun getting all these cool parts despite the drain on the wallet.
EDIT:
What piston clearances did you guys settle on? You're in a cold climate like me so I am wondering how much slack you're running and then what startup sounds like on a cold day. Do you see below zero temps and would you be starting this car in those conditions? It was -14F when I left this morning @ 6:30AM.....even colder where I used to live.
Im not sure what the clearances are, but I do know they're K-series pistons.
JandE part#309426
At its coldest we usually see about 15-20 degrees, with a very rare single digit temperature around here.
-14 is too cold for me, you got balls for living where you do.
So I misunderstood your prior post. Instead of too lean, it was potentially too rich on one bank?
No, I was the one who went off track on the subject. My last post about running rich (which was the polar opposite of my intended direction in the discussion!) was made to correct the result of my ADD. Again, sorry for the confusion bright to the table on my behalf everyone. I'm getting old here...
If that's the case, wouldn't the more likely scenario be something like a stuck injector rather than the tune or ecu related? It just seems that something mechanical would be more likely.
I was implying that there were a multitude of possible mechanical and electrical issues that could've occurred to create the matter here. A single stuck injector would've damage only ONE cylinder and not the entire bank. I honestly cannot think of one mechanical fault that could've been responsible for breaking all three skirts on one bank...assuming that they all broke on one side wasn't a bizarre coincidence. That's what kept leading my direction of thoughts back to the powertrain electronics and/or tuning.
I don't see the ecu modifying a single bank of pulsewidths independently of the other, unless it was odd fuel trims.
That's basically what closed loop fuel trims are (short and long term) is individual fueling control of each bank for the engine based off of critical data from the bank 1 & 2 sensor 1 air/fuel sensors (aka oxygen sensors). The ECM receives data from each sensor and adjusts that bank in accordance to the programmed ideal mixture (ie: 14.7:1). So if one bank is running slightly lean due to an intake gasket leak, the ECM adds additional fuel through the injectors until the desired AF ratio is reached.
I haven't done enough in Flashpro to know besides the individual cylinder fuel trim, which I assume hasn't been modified. I wouldn't think it was modified unless there was a known 'lean cylinder' on these cars, which I'm not aware of offhand.
Are long and short term fuel trims ignored in open loop? I thought that was only for driveability in closed loop. Are there even separate long and short term fuel trims for the differing banks? For this to occur by tune, I'd think you'd need massive swings on both ends, i.e. +20% on one, and -20% on the other.
Yes, both LTFT and STFT are ignored during open loop but only if that's how the tune was setup. It can be either way depending on many factors but typically fuel trims are ignored for open loop but then the ECM follows fuel map that basically takes the same influential values from the engines data sensors as well as a target AFR of which it maintains until close loop again. I'm leaving a LOT out of that but that's the basic function. So, basically, closed loop can still be in use during all three areas: closed, part and full throttle. It just depends on what the load is, the engine speed, the tune as well as other target ranges that must be seen in certain inputs. And as for the extreme fuel trim swings you talk about, if the fuel wash were just a mild case, it still may not have been seen in time by the ECM to actually set a code or trigger a light when the issue occurred. That's why I initially asked if he had a datalog when the problem happened to see what the ECM was seeing. This could've very well eliminated all the discussion and assumptions we're involved with now. Lol, not that I'm against any of it but you get my drift.
BOLD
I'd also like to add, I've been working with cars nearly all my life. And I don't mean working as a lube center tech for 1/2 of that period either. I mean balls deep in them from day one. In my experience, I've never seen anything more complex or as appealing as tuning and base programming with them. That being said, you begin to understand just how quickly shit can go wrong with forced induction setups, especially on stock motors. Every system (and sub-system) must be at its best and putting fourth 100%. One thing fails or begins lagging, this can create a systematic domino effect of which WILL lead into a catastrophic failure if not quickly seen, identified and fixed. Tracing back the dominoes that have fallen can be nearly impossible. One thing most forget is nearly all of the failures don't happen because internal parts have reached their strength threshold. Failures generally occur because something, somewhere was missed or ignored. Datalogging and critical gauges can help reduce failures in systems or at least see them before they create a much bigger problem. That's why you look beneath the hood of my Accord and see more wiring and electronics than you do engine...I know its laughable. But my car has so much time and money into that I would rather spend more money to ensure its going to last.
Werd.
Last edited by yungone501; 02-16-2015 at 11:14 PM.
I've never seen a motor run "too rich" or "too lean" on one bank without an underlying mechanical issue. Yes, I work on other cars, V8's being one of them. I see a couple percent variance (1-3%) at WOT, if that, in most cases. The larger bank-to-bank variances at lighter loads where air velocity is lower and you start to see the interesting side effects of intake manifolds that aren't quite well balanced, etc. The shop Mustang GT has a 5-8% swing between the two banks at light loads at times, even with the Copperhead ECU running of built in compensations for the expected fueling "misbalance" in those areas. I can show you the bank bias tables in the ecu -- even individual cylinder bias if you like. Once you hit WOT and get some air velocity through that engine it's got a ~1% bias between the banks, big deal... Moot point, as we have zero control over the ECU's bias tables on this platform -- if they even exist.
No Honda ECU (currently) runs the car in closed loop at WOT. The factory lambda sensors are cheap, poor quality, do not hold up, and AFR readings drift dramatically as they age (as much as 1.0 or more off in some cases), and the ECU heater control is very simple (basically useless on F/I cars -- you should see the O2 sensor readings on newer Civics & such after you throw a turbo on it, it'll peg 10.0 when the tail sniffer is at 12.0, lol). Dean's car was at 11.5 off an aftermarket lambda sensor (good quality kit), with the factory lambda sensor reading ~.5 richer (as expected given they are pre turbo). That's neither "rich" nor "lean". So how "rich" is too rich then? Is one bank somehow at 10.5 and the other at 11.5? I've watched customers roll cars in spitting fuel out of the exhaust (literally -- in the high 9 low 10 afr) before getting them properly tuned.
Or maybe, hell, just maybe, the pistons are junk. It's not like we're seeing OEM Honda pistons crack and drop their skirts on 100% stock engines... oh wait, yes we have. On Pilots and Odyssey's. The mechanic I work with in SoCal has pulled OEM pistons out of OEM Honda motors with cracked skirts. It happens, just mom & pop aren't going to go online and talk about it, they just want their minivan running.
Would it surprise you that some Honda engines just are not built for economy and not performance? lol
Vit, while I can agree that the pistons are 'just junk' for a FI use, I disagree about there not being a specific root cause to the failure.
I hope no one is taking offense to this thread and the investigation and questions. I have not heard any accusatory tones or blame being laid which is wonderful, rather as Robert stated previously, it is an attempt to determine the failure to prevent it from occurring again, with much more expensive parts.
I'll concede that Pilots and Odysseys have a notorious tendency to break piston skirts on OEM vehicles since I trust you and your mechanic, though I've not heard or seen one instance of it. I disagree that mom and pop aren't discussing things though. You can merely search the internet for 'MDX broken spark plug' or 'Odyssey broken spark plug' or hell, just 'Honda v6 broken spark plug' and find tons of people in non performance posts that have had that occur.
Is it possible that only people that have broken spark plugs post about them, while broken pistons are a mysterious topic no one discusses? I guess it's possible, but not probable. I'd much rather go from a statistically valid sample (all the reports of broken plugs) vs. the single mechanic in SoCal saying pistons break all the time.
I've seen pistons break in 5.0 Fords fro time to time (the orignal, not Coyote) but I would hardly call it an 'omg issue' as there are thousands of nitrous or FI stock 5.0s in existence without issue. It's also the block that usually goes first. We split a 5.0 right down the middle into 2 pieces while every other component was perfect.
I must ask why there is such confidence in saying the pistons are just junk and there is no specific cause? Is it a lack of care because stronger pistons and rods can tolerate 'whatever happened' without destruction? Or is it a lack of understanding? I don't think it is the latter in anyone's case here, but if it is the former, that's really disheartening to hear.
I sincerely mean no offense as I'm glad you are on the forum and sharing info, but it appears you have simply dismissed the J35 internals as completely weak and terrible, yet the K series stuff is robust? I know Honda can do different things for different reasons, but looking at HP/cylinder it seems odd that Honda would build the J35 so poorly.
You said that K's can handle 400 whp on stock bottom ends without issue. Let's assume that these pistons cracked at 450whp (fair?). That means that the K series pistons can handle 30% more power per piston than the J?
That just seems unlikely from a HP perspective. I could almost think the J35 was more prone to piston cracking because of the worse rod ratio than the J32. The J32 is very high (imo) at 1.88:1, but even the J35 is very good at 1.69:1, which is still better than the K20 or K24. I'd have to do some more calculatons to check the max rod angle, but I'd think that would be a possible reason for the cracked/broken skirts on the J35 vs J32 instead of 'they are junk.'
I remember in the days of B16 and B18 FMU tuning, it was taken as gospel that the B series internals were no good for more than 250whp before you had to sleeve the block, pistons and rods, etc. That was because no one knew any better. Now that we know, that's no longer the assumption. I think we're still in the 'we don't really know' area of the J35, but I'm sure we will find out. Let's just hope it's not at a built block's expense.
The factory lambda sensors are cheap, poor quality, do not hold up, and AFR readings drift dramatically as they age (as much as 1.0 or more off in some cases), and the ECU heater control is very simple (basically useless on F/I cars -- you should see the O2 sensor readings on newer Civics & such after you throw a turbo on it, it'll peg 10.0 when the tail sniffer is at 12.0, lol). Dean's car was at 11.5 off an aftermarket lambda sensor (good quality kit), with the factory lambda sensor reading ~.5 richer (as expected given they are pre turbo). That's neither "rich" nor "lean". So how "rich" is too rich then? Is one bank somehow at 10.5 and the other at 11.5? I've watched customers roll cars in spitting fuel out of the exhaust (literally -- in the high 9 low 10 afr) before getting them properly tuned.
Is there an alternative? I've been trying to understand the purpose of the heaters, are they used constantly or just in the warmup phase or when the temps are simply below a certain threshold?
Does this mean all of us using stock ECU's and Hondata are doomed if pushing things to the edge?
Originally Posted by maddogtheta
Pauter had the J35's in stock last week when SpeedFactory ordered my set.
Welcome to my world! One leads to another and to another. The next thing you know, you're broke!
Pauter stocked the J32 rods so it's possible that they'll have them but you'll likely need to supply them with the small end width. If it was like mine and had a 1" opening, they'll mill them down and balance them again.
Wait help me understand. You need to supply them with the small end width? Why? Shouldn't the width be all the same assuming your using a piston and piston wrist pin size that is the same as stock?
Wait help me understand. You need to supply them with the small end width? Why? Shouldn't the width be all the same assuming your using a piston and piston wrist pin size that is the same as stock?
Don't know. Just passing on my experience. There must be people out there ordering custom pistons and want a larger rod end.....
There are also no direct part numbers from the major players so we're picking and choosing based on specs.
Vit, while I can agree that the pistons are 'just junk' for a FI use, I disagree about there not being a specific root cause to the failure.
I don't disagree -- there is a specific root cause to the failure: weak internals introduced into a scenario where the demand for durability is higher than Honda's design specs. When someone I hold in great regard when it comes to Honda engines tells me this motor was built as a "lightweight economy engine" -- I take that statement as a "your mileage may vary" on the longevity of the motor under higher power applications. A forced induction application (especially turbo) will push EGT's higher than normal, introduces higher cylinder pressures -- these are all "normal" factors the internals have to stand up to once you leave the realm of stock or "bolt on". This in no way states that a certain part "will" have a failure.
Originally Posted by screaminz28
I hope no one is taking offense to this thread and the investigation and questions. I have not heard any accusatory tones or blame being laid which is wonderful, rather as Robert stated previously, it is an attempt to determine the failure to prevent it from occurring again, with much more expensive parts.
None has been taken -- the discussion seems to have made a loop and settling on a couple theories which I do not believe are true as the engine tear down basically showed me a "healthy" running engine, until you look at the cracked skirts. The ring end gap is an interesting one, and I'm not really sure what to make of that one yet.
Originally Posted by screaminz28
I'll concede that Pilots and Odysseys have a notorious tendency to break piston skirts on OEM vehicles since I trust you and your mechanic, though I've not heard or seen one instance of it. I disagree that mom and pop aren't discussing things though. You can merely search the internet for 'MDX broken spark plug' or 'Odyssey broken spark plug' or hell, just 'Honda v6 broken spark plug' and find tons of people in non performance posts that have had that occur.
He used to have pictures on his shop PC -- it's happened. It may not be very common (I hope it isn't), but if we have this issue happening on OEM vehicles with no modifications? The possibility becomes greater on lightweight internals being subjected to F/I...
Originally Posted by screaminz28
Is it possible that only people that have broken spark plugs post about them, while broken pistons are a mysterious topic no one discusses? I guess it's possible, but not probable. I'd much rather go from a statistically valid sample (all the reports of broken plugs) vs. the single mechanic in SoCal saying pistons break all the time.
The mechanic in SoCal is simply one example, I doubt he's the only one who's see it. Honda dealers have probably seen it more than him -- but how many of them are going to talk about it? If it was a common issue, maybe. I've seen forged CP's with cracked/dropped skirts, does that mean they will all drop their skirts? I hope not... I have a set of CP's in my S2000 taking quite a bit of abuse right now...
Originally Posted by screaminz28
I've seen pistons break in 5.0 Fords fro time to time (the orignal, not Coyote) but I would hardly call it an 'omg issue' as there are thousands of nitrous or FI stock 5.0s in existence without issue. It's also the block that usually goes first. We split a 5.0 right down the middle into 2 pieces while every other component was perfect.
We have that older 5.0 engine in a friend/customer's Ford ranger running a turbo, makes amazing power on 8psi (~500whp or so). Haven't split the block yet, lol. Funny you mentioned it though, as I believe I saw talk of the new Coyote engines also splitting, albeit at pretty high power levels (900-1000?).
Originally Posted by screaminz28
I must ask why there is such confidence in saying the pistons are just junk and there is no specific cause? Is it a lack of care because stronger pistons and rods can tolerate 'whatever happened' without destruction? Or is it a lack of understanding? I don't think it is the latter in anyone's case here, but if it is the former, that's really disheartening to hear.
Neither, it's mostly the probability that there will be no actual "resolution" other than some theories as to why until someone in the "know" as to internal design and strength can get the failed parts in their possession and actually run some tests on them (metallurgy, etc). Would be interesting to see how the TL pistons compare to say, the OEM K series pistons.
Originally Posted by screaminz28
I sincerely mean no offense as I'm glad you are on the forum and sharing info, but it appears you have simply dismissed the J35 internals as completely weak and terrible, yet the K series stuff is robust? I know Honda can do different things for different reasons, but looking at HP/cylinder it seems odd that Honda would build the J35 so poorly.
Not dismissed -- but the talk about "too rich" or "too lean", when none of the data supports this is interesting. Is it to say I'm incompetent and after the thousands of cars I've tuned I can't target a proper AFR on a turbo vehicle? Or are Honda engineers incompetent and don't know how to balance fuel delivery to the two banks in the ECU while they have the engine on an engine dyno?
Originally Posted by screaminz28
You said that K's can handle 400 whp on stock bottom ends without issue. Let's assume that these pistons cracked at 450whp (fair?). That means that the K series pistons can handle 30% more power per piston than the J?
The K's can handle much much more than 400, those bottom ends have taken 800whp before they've broken. They are amazing engines. 400-500 on a K is basically the "norm" for a street car that lasts 100k+ miles (yes, I have customers with some pretty high mileage cars at this point lol). The one weak point of the K is revving it too high -- the pistons will start to come apart from sustained high revs (used to be seen on the A2's that were tracked a lot).
Originally Posted by screaminz28
That just seems unlikely from a HP perspective. I could almost think the J35 was more prone to piston cracking because of the worse rod ratio than the J32. The J32 is very high (imo) at 1.88:1, but even the J35 is very good at 1.69:1, which is still better than the K20 or K24. I'd have to do some more calculatons to check the max rod angle, but I'd think that would be a possible reason for the cracked/broken skirts on the J35 vs J32 instead of 'they are junk.'
If my math doesn't fail me, the K20 rod ratio is ~1.62 and K24 is ~1.54.
I wouldn't say so much it's the HP perspective, as HP is simply a function of torque. The torque perspective however... 8psi on a 3.5L is much more torque than 8psi on a 2.0L (or 2.4L).
I'm assuming you're thought pattern is with the rod ratio the piston was possibly being slapped against the bore during the power stroke? I would expect that to leave some very visible clues on the cylinder walls (although maybe not?).
Originally Posted by screaminz28
I remember in the days of B16 and B18 FMU tuning, it was taken as gospel that the B series internals were no good for more than 250whp before you had to sleeve the block, pistons and rods, etc. That was because no one knew any better. Now that we know, that's no longer the assumption. I think we're still in the 'we don't really know' area of the J35, but I'm sure we will find out. Let's just hope it's not at a built block's expense.
Hah, that's a whole other discussion. FMU/piggybacks are garbage. I can't believe I still have people asking me to tune such systems (they get turned down).
Here's some food for thought. I purchased my 01 AP1 with ~64k miles used. Everything looked mint, engine, trans, the works. I boosted the vehicle and ran just under 600whp on the OEM engine for a little while, then one day coolant started dripping down onto the pavement after a hard run through the country (car was on E85 -- no detonation/lean issues/etc). First I thought the head lifted, but no, motor never pushed coolant. I even replaced the head gasket in the search for the source the coolant leak (as it was running down the block on the exhaust side and onto the ground). Nope, not the HG, started the motor up and it just poured coolant out onto the ground. WTH right?
Upon further inspection I found a hairline fracture on the casting of the outside of the block, on a section of the block that actually had reinforcement webbing next to the coolant drain plug. Yes, the block casting itself developed a hairline fracture. Why? Figure that one out... Only thing I can even imagine -- under the additional torque the twisting of the engine against the motor mounts (that bolt up ~6" below the fracture) we exposed a weakness in Honda's block casting. Motor tear down showed a completely healthy engine, FRM sleeves were even mint (and we know how those things love to scuff). Go figure? Good luck finding any more such failures... I think I found references to maybe 2 more similar cases on S2Ki.com.
But hey -- casting failures were common on the 06-11 R18 engines. We even just had a block casting failure on a K20 motor a couple weeks ago... moral of the story, crazy shit happens. I'm sure you know this -- the longer you're around stuff like this, the more things you see that make you go "huh?"
Originally Posted by KN_TL
Is there an alternative? I've been trying to understand the purpose of the heaters, are they used constantly or just in the warmup phase or when the temps are simply below a certain threshold?
Does this mean all of us using stock ECU's and Hondata are doomed if pushing things to the edge?
That's a whole discussion on it's own -- if you want the long version, Google 'wideband heater control'.
Shorty story -- the more heat and pressure you apply to the sensor the more it will skew the reading. The heater control is supposed to compensate and help keep the sensor in it's "normal" operating range. I've yet to see a Honda ECU that is designed to run the O2 sensor accurately beyond an N/A vehicle. I recommend an aftermarket wideband on *EVERY* F/I build (it's actually required on some vehicles -- like the 9th gen Si due to where the OEM sensor must be placed, skews the reading 1.0-1.5 afr).
No I'm not jerking your leg on this -- I put in a *brand new* 2012 civic si wideband into a turbo 2012 Si that I did locally on our dyno -- the *brand new* sensor pegged 10.0 afr the moment I hit 8-9psi with my tail sniffer sitting at 11.6-11.8 afr. I laughed. Yes it was funny, lol.
As screaminz28 stated above, I too don't mean to offend anyone or cast blame on someone/something. And this is simply a discussion on an engine with (what I feel is) a unique failure. I appreciate the maturity and respect shown by everyone here and let's keep things educational. Yes, there's some speculation in the thread but given the circumstances of the matter, there realistically won't be any conclusive diagnosis made here. Theories and ideas, sure. But that's about it.
Moving on, Vit brought up something above that I would like to expand on concerning Honda and their purposeful approach to the design and engineering on the engines they produce. Sure, Honda is definitely not putting performance at the top of their list when designing the engines but one thing they are very good at doing is integrating performance along with the higher priorities. Honda focuses aggressively on weight savings and for the j-series (which is generally used in their heaviest models) this is not a good thing. Anyone ever read their powertrain articles that explain updates and revisions made to engine components? It's always about using a stronger alloy or a design change for reduction of size and that's generally followed up by something about "weight savings". It's done for strength, yes but only so they can make the part using less material and weight.
Bottom line is things aren't going to get any easier for those running stock motors and then adding forced induction without any changes being made to accommodate the nature of boost. Increased compression for decreased emissions and improved efficiency...but in forced induction this means more likely to become damaged quicker and definitely harder to tune for safety/reliability unless boost levels are minimal. Thinner castings (regardless if they're forged) for the pistons and rods means less fatigue resistance and also less forgiving if an issue anywhere occurs. Thinner, low tension rings isn't exactly in "the ideal parts to use" criteria either. I'm extremely surprised that the silicon-aluminum cylinders didn't carry any further than the j37 because of its weight savings advantage and higher thermal transfer rates. That being said, their older engines (j-series) that haven't been twiddled down to twigs is probably better to use than the newer ones for the FI crowd. Perhaps that's why the older j32a2's are known to pull 500hp+ on a good tune and knock resistant fuels such as e85 or better...on stock bottom end! Then we have the j32a3 and j35a8 crowd that seems to be busting shit up around 375hp+ on stock bottom ends. Sure, you have the people that made it much higher but did it last long?
And Vit, I've noticed variation between the factory widebands and my aftermarket Bosch widebands but minimal to say the least. I run a total of four, two on each bank and added bungs a few inches from the exhaust port on the turbo manifolds so they were placed at equal distances on both sides. I think the greatest notable difference between the stock and aftermarket sensors was a .3 variation and I immediately replaced the factory sensor (it was old and used exclusively on a hot ass turbo setup) and never seen that much difference again. I do know that a bank went ape shit once when there was a small exhaust leak at the turbo flange and caused some pretty massive confusion on diagnostics as I was depending too much on datalog and getting confused with the crazy values everywhere. Lol....that was fun. Such a small leak it was too!
And Vit, I've noticed variation between the factory widebands and my aftermarket Bosch widebands but minimal to say the least. I run a total of four, two on each bank and added bungs a few inches from the exhaust port on the turbo manifolds so they were placed at equal distances on both sides. I think the greatest notable difference between the stock and aftermarket sensors was a .3 variation and I immediately replaced the factory sensor (it was old and used exclusively on a hot ass turbo setup) and never seen that much difference again. I do know that a bank went ape shit once when there was a small exhaust leak at the turbo flange and caused some pretty massive confusion on diagnostics as I was depending too much on datalog and getting confused with the crazy values everywhere. Lol....that was fun. Such a small leak it was too!
So all sets of sensors are pre-turbo? Or do you have one post turbo. They can vary.
The Civic example I brought up was on the extreme end -- and it has to do with the design of that engine and O2 sensor placement before the turbo. That same sensor on a supercharger setup is within .2-.3 afr of a wideband or dyno tailpipe sniffer.
Age will definitely be a factor too -- I did an 06 Civic Si the other day at the shop, 155k miles on the car. Solid 1.0 afr off from the dyno wideband, lol.
For the oem wideband discrepancies you mention (I saw your blog post about it as well - very informative!) that's in reference to the 4 wire one that the newer civics use isn't it?
The TL uses a 5 wire Bosch which I believe is an LSU 4.2. Not as good as the newer 4.9 mind you, but the 4.9 wasn't around when the TL came out.
I know the controller will have a bearing on the accuracy as well, but I thought Bosch's 5 wire sensors were some of the best, and accurate from 9:1 all the way to free air.
We are on hold waiting on parts, we have 4 of the pistons and 2 more being made we went with JE 309426 that will give us 10.5-1 compression ratio, the piston to wall clearance is just right for a boosted engine with forged 2618 pistons that like to expand a lot it's .0039 to .0043 not bad for a 100k motor.
bought a Supertech spring and titanium retainer kit (thanks for the great deal VIT )
ordered inconel exhaust and hollow stem intake valves ( thank you Gerzand )
Pauter rods will be ordered in the next day or two (thank you tax return my sons, I owe damit )
The bearings were perfect so I'm ordering standard size ACL race bearings TB Motorworx in San Diego say's they can get them ? if not I can get clevite 77 I think and if not then the stock green size bearings will be ordered
And then a couple days to put it together and we will be ready for more boost 10-12 LBS should do nicely.
As far as the piston failure the only reason I can come up with is, the rear pistons only breaking is the non thrust side on the rear bank has the intake air and the oil jets cooling that side of the piston (that broke), the front bank has the exhaust heat and no piston cooling on the non thrust thrust side, so I think that the heating up and cooling down is causing the piston skirt to fatigue and crack, the plugs and the piston tops show to be even with fuel mixture and timing so that's all I can come up with
Well we got the 2 pistons to match the 4 we had and guess what they wont work the valve reliefs need to be the opposite on the front bank of pistons, the JE pistons are asymmetrical so we cannot flip the piston around so we ordered 3 more pistons custom made for the front bank luckily JE will take these back for a small restocking fee
here is a link describing the asymmetrical pistons
Seems that's common with these builds since there isn't anyone doing this specific platform.
On a side note, CP Carrillo took back my off the self pistons with no restocking fee. But it could be that the dealer I worked though had a good working relationship with them and I was ordering customs as a result.
The bearings were perfect so I'm ordering standard size ACL race bearings TB Motorworx in San Diego say's they can get them ? if not I can get clevite 77 I think and if not then the stock green size bearings will be ordered
Last time I call the guys at TB motorworx they were only able to get OEM bearings wich is what they are running on the J series beast they have, King bearings add the J series to their catalog not too long ago.
Last time I call the guys at TB motorworx they were only able to get OEM bearings wich is what they are running on the J series beast they have, King bearings add the J series to their catalog not too long ago.
Ohhh thanks, I just ordered a set of King bearings they have a great reputation and the stock bearings usually look like they got shipped in a blender
Hey Utah, dismantled a j37a4 this last weekend that had 4 busted skirts and 5 of the 6 cylinders had cracked rings. Guy ran the motor on a large dry shot and the rest is history. Reminded me of your motor...or at least half of it.
Hey Utah, dismantled a j37a4 this last weekend that had 4 busted skirts and 5 of the 6 cylinders had cracked rings. Guy ran the motor on a large dry shot and the rest is history. Reminded me of your motor...or at least half of it.
I remember a video of a MDX on the gas following a TL I think it was wonder if that was the donor,
I remember a video of a MDX on the gas following a TL I think it was wonder if that was the donor,
Lmfao!
No, I'm happy to report NOT. I've been much nicer to her lately since the Accord (Not a TL!) is nearly wrapped up now. And for the record, MDX has the j37a1. The j37a4 belongs to the 4g TL AWD.
No, I'm happy to report NOT. I've been much nicer to her lately since the Accord (Not a TL!) is nearly wrapped up now. And for the record, MDX has the j37a1. The j37a4 belongs to the 4g TL AWD.
Oh good thing looks like you are spending enough money on the accord
02-14-2015, 09:46 AM
