johnbones

EVERYONE PLEASE BARE WITH ME ON THIS SUBJECT. IT'S LONG

First off I have been on here with HT with my friends for about 5 years now and have decided to make my own since I have always just used his to browse and read around but never needed to make a thread of my own, WELL it's time to make a thread since I cannot find the info I need and have searched for a few weeks now. I really Hope one of you guys can help me here.

Here goes, I have build a few (6) honda engines making 500hp and they were all b18c's and b16a's and never had a problem with them. Now, my first two ls vtec have been MAJOR fails and have major flaws to it, that's why im here. For the past month I have build a lsv turbo for my daily since it was what I had laying around, well i used a factory ls block that had 190k miles with good compression and put a vtec head on it, also slapped a 57trim turbo on it as well. Went and street tuned it and setup everything like I would normally on my other builds. first test was ok but felt like in 3rd gear up in the 7-8k rpm I felt a major lost in power so I let off, looked at the datalog and everything seems fine with readings of 18degree in wot and full boost which is 12psi 11.1afr. So I figure everything was fine it was just me. So I did another pull without changing anything, went from 2, to 3, to 4th and again felt a lost in power (feels like about 50hp) but I kept my foot in it and a sec later SMOKKKKKKE. Got it back and pulled the head off and I melted two piston, BAD. again I looked at the datalog and it was showing 17-18degree and the boost never went past 12.5psi and afr was 10.9-11.2 all the way.

It's weird because all the hondas Ive did never ever had this problem. So I figure something must of gone wrong like a bad batch of fuel or plugs. I then got another block and did a fresh build, this time new everything, rods, wisco piston, bearings etc. drained the tank and refilled, Well after the setup was all set and done I decided it was time to make wot pulls again. Went back out and did one pull this time started at 18psi. Did one good pull all the way to 4th, pulled perfect, everything was nice and the car felt strong like it should and didn't notice any power loss like before, I then was happy. keep in mind the afr was still the same 10.9-11.2 and timing at 17-18 but boost changed to 18psi. I then did another pull to make sure everything was good, went 2, 3, 4 and on top of 4th about 6k I felt that loss of power again and right after that SMOKE............ got it back and three forged piston were ALL MELTED, one had a HUGE melted hole on the side.

I didn't understand why I kept felting that loss of power and fail afterwards. So I did a few search and found that the way I was hooking up the oil for the vtec and turbo line was wrong, I read and there was people posting about lost of vtec at high rpm when t'ing the turbo and vtec pressure to the oil pressure switch on the engine block next to the oil filter. they stated that up top they would lose vtec but no one said anything about burning there engine, well I put one to one togeter and they said when they lose vtec the cel comes on, in my mind I was thinking that since the cel came on the ecu switches back to low cam timing and tables so they didn't hurt anything, well, on my s300 I have it selected not to look for a vtec oil sensor, so in the s300 it always switched vtec maps on even tho it didn't have oil pressure opening the vtec. in other words, I was running on the vtec map for nonvtec uses.

So Now I have a sandwich plate going to the head and the turbo going to the stock factory oil pressure sensor instead of it both t togeter, NOW im very scared to rerun the car again and I DO NOT want this problem to happen again.
Now I know it's not the afr that are causing my melted piston problem, it's got to be a timing issue.

So I guess what im asking is, can a lsv turbo melt piston running in non vtec mode using the vtec high cam timing and table maps even tho those high valves are way less timing than the low timing valves. how the hell did this happen to me and never happen to me before on any of my other builds, this is my first lsv turbo build and I know it's not in the tune, got to be something with the vtec turning off then causing timing to go all out of wack and cause the motor somehow to get a **** load of timing to melt all three piston that fast.

my setup main parts are,
84mm wisco
stock sleeves
stock rods
e85
1000cc
walbro
s300
4bar map

again ive tuned my past cars and NEVER had this issue but they were all vtec engine and not lsv. Im thinking it's all because I had it T and the power lost was from the vtec shutting off. but still doesn't make since about how the motor melted piston if it was running on non vtec mode with the vtec map. someone please chin in.

JaredKaragen

losses in head side oil pressure wont cause a piston to melt; ever. I believe you'll hear knocking before that happens, and that means crank damage.

If you say VTEC disengaged; and it has different timing and fueling; this could cause it; but you would see a direct correlation in AFR (which you say stays fine) which leads me to think its something else. Honda ECU's are known to shoot random timing blips here and there, but usually thats OEM roms or if the developer hasn't found the code to disable.

I would honestly say personally speaking that too little timing can be just as hurtful as too much timing.

Any chance of any type of o2 contamination to the sensor? How old is the wideband sensor? A point of AFR out of calibration/lazy can spell disaster.

Make sure your not running some sort of VE correction that could be changing things as well. Just an idea. I don't recall if CrapData cut VE out of their ROM.

It would be nice to see a calibration and the datalogs you mention in this post to look for signs of irregularities and made some sort of further diagnosis.

Not tuning it myself; Its hard to give opinions... every engine has its own quirks.

Ive tuned countless B20V/LSV turbo and N/A... each and every one has been completely different in how much timing and how they want to run.... HAvent seen any yet that have done this though. Only one was a guy who kept changing things like cams right after I would tune it and blame me that its "running funny" to try and get free re-tunes.

johnbones

the wb is band new, bought it just for this car, so is all the other little aftermarket parts.

I was affard that there must be a correction somewhere so I zero everything out and still same issue the second time around.

I have the datalog but I don't have a host, can someone host the file for me please?

it still comes down to how did the pistons melt at 16-18degree at wot in non vtec mode using both the vtec ign and fuel tables.

and like I said, this isn't my first tune and builds, ive done these before on full vtec engine where I didn't have the **** up of the turbo and vtec oil pressure t'ing off together causing the vtec to loss oil pressure and cut out. So it's not like Im doing anything different on the tune or the maps and afr and timing. WTF is going on.

SovXietday

Ever occur to you that you were tuning WOT in high cam mapping, but when you dropped out of VTEC you dropped into your untuned, high RPM low cam maps? Also, did you log fuel pressure?

Pics of the pistons would be nice too. Melting pistons is more often a lean condition, too much timing is more of a smashed ringland/spent rod type of deal.

OneBadTurboCRV

I call BS on the "you have built 500hp engines and tuned them". You are blowing engines because you have NO CLUE what you are doing. It is really that simple. Even the first time tuner knows there is more to tuning than "AFRs being perfect". There are plenty of write-ups on other sites that provide methods to go about the madness. There are never one size fits all solutions, and LS/V's are more tricky than your standard Honda engine...

johnbones

ever occur to you that IF you read what I wrote you WOULD HAVE seen that I have my vtec oil pressure disable in the s300 and the computer does not know to switch back to low cam maps if vtec oil pressure was lost or if the vtec was not turned on, all it knows is above this rpm and above this speed and above this throttle percent it will switch to high cam maps. So you please tell me how I was running on the untune low cam maps if my computer never switched back to low cam since it didn't know it was suppose to because the vtec oil pressure was disable and oil pressure was lost due to sharing the oil from the factory oil pressure switch.


call bs all you want, your not helping my problem. So your the one full of ****. Guess you didn't quite read the thread as well.


GUYS, PLEASE how hard is it to simply ask (how did the pistons melt at 16-18degree at wot in non vtec mode using both the vtec ign and fuel tables.)
^^^^ that's all im simply asking.

in case someone else gets smart, all im asking is, can the cams in some way cause timing to increase tuning in vtec high cam maps without the vtec working??

johnbones

ive talked to a few people who builds these engines today and they suggest that if i was to run the vtec engine without vtec being engaged the engine will run wayy to hot and cause a ton of knock since the vtec cams are limited the air flow into the combustion chamber and the intake air is just getting too hot trying to push through the limited valves being open. Well I mean it makes since in a way, if the vtec was not engaged and it was running in non vtec mode, even tho the afr and timing is where it should be the valves are still not opening like they should and doing so would cause crazy amount of knocking and heat which would explain why the piston melted so fast and all at once. I mean, the first time this happen non of the stock piston had crack ringlands, that was what I would expect to fail first if I was running lean, but they melted instead, as if as soon as the vtec shut off the turbo was still pushing the same amount of air into the head but the head could not get it all out fast enough since the valves at non vtec mode only open so little, I dont know the exact percent of valve opening on non vtec mode but I would explain it as 0-100% with one opening at 50% and the other at 75% then when vtec engages it pushes the valves 100% like they should be. WHAT DO YOU GUYS THINK ABOUT THAT? Do you guys think if the vtec engine was to run on non vtec mod in wot with boost at full potential this same reason would happen to the engine?

im just trying to narrow down my problem, since this time will be the time I change the oil flowing to a sandwich plate id like to get other inputs as well. But Im almost sure my problem was because the vtec disengage and I was running wot in non vtec mode creating too much heat.

justYncredible

iTrader: (1)

Someone close this post
If your going to get an attitude with the vets around here then go some where else for help.

If they ask for pics or more information on x,y and z then give them what they need to help, snapping back with a rude comment won't get you anywhere on this forum...it's just that simple.

johnbones

Attitude, WTF, instead of bashing on my thoughts why don't they try to help me, ofcourse there going to bash, because they can't think of a way to understand my view, and OFCOURSE im going to be rude back, if someone punched you in the face your going to say thank you??? or punch back.

and no, im not sorry, im not trying to be rude in anyway, but im not going to **** sit here and be called a fool when those guys can't even seem to give a simple answer let alone just keep bumping this thread saying bs this bs that. grow up internet bully's, if you can't help me don't shine in and be smart, cause im not some punk kid who needs the bs

again, guys, im not trying to be a *** or rude but if you come on that way your not being nice as well. Im just here to get help to solve my issue not to flame on people. make me wonder why in 5 years this is the only post i've ever made on ht. lmao.

cruizinmax

iTrader: (2)

Are you sure your distributor is synced correctly?

Instead of continually blowing engines why not start at a lower psi and get some kind of knock monitoring. Sounds like too much timing to me.

hybrdthry911

So on the first WOT tune pull you hit the motor with 18psi? Smart...

You also don't know for sure if VTEC was disengaging right?

Even if VTEC was disengaging airflow would drop off a lot, but I don't think you would have a complete meltdown. How does less valve lift cause a lot of heat? The only stress I could see happening from this is the VTEC rocker arms/LMA's.

Did you verify the timing with a timing gun and the ECU's timing locked before you began tuning?
Was this all on E85?
Perhaps post up your calibration?

johnbones

YEAP it is. ive got knock on this time, last two times I didn't have a p72 so I didn't have knock support.

no dude, i started out very low, low enough for me to get a very good tune. Not start right out at high boost. I think anyone would know better to do that. I am 100% sure vtec was disengaged, you can feel it and hear it shut off and on before I had this problem, but I though I had fix it with putting a oil restricter on the turbo so the head can get more of the pressure. Before I put a restrictor on the turbo the vtec use to work one run, then not work the next, id have to let of the gas and let the engine come back down to 1k rpm then run it back to vtec and it'd work but half way shut off. then after the restrictor I didn't have that problem anymore so I figure that was it, untill those hard pulls, that's when it shut off again. yes I have good oil pressure and have a guage for that.

both was all e85.
id post up but don't have someone to host them.

pretty much Im sure it was just all because I had both the oil for the turbo and vtec t'd togeter on the very small port for on the stock block, and that was not meant for that purpose. I now have a sandwich plate with -6 instead of what I had before which was -4 to turbo and vtec back side to the head.

i'll post back here when I get it all back togeter and let ya know if that was my problem.

thanks guys for your time