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Both back driver side pistons were broken. I did a full valvetrain job that only lasted 1400 miles before this happening. I went with:
Ws6 store got cam
melling hv oil pump
243 port & polish heads
fast 92 intake and tb
one piece push rods
trunion kit
dual valve springs
double roller timing chain
Ssra
Fast Fuel Rail
Slp Lid elbow
ls7 rollers
I kept the stock fuel pump and I used some used 32-35 injectors from a Saab my friend convinced me to use. A week before this happened the fuel gauge was not working properly.
I called my tuner and he said he left the fuel trims at -/+ 5(But I did not get a print out becuse his printer broke) and told me my fuel system had failed if that happened. I had just put a stock fuel pump bc mine had gone out a year before these upgrades. Spark plugs were not melted or damaged just cover with a think later of oil. This piston had the rings welded to it.
The second pic down the piston is burned away. Didn't you hear detonation or anything? Did it overheat? Does it have nitrous or other power adder?
This has nothing to do with a valve job.
Looks to be a lean condition or too much timing advance. The part about the tuner mentioning fuel trims makes me think he tuned it with the narrowband O2’s instead of a wideband.
Looks to be a lean condition or too much timing advance. The part about the tuner mentioning fuel trims makes me think he tuned it with the narrowband O2’s instead of a wideband.
Agree. Definitely should not be tuning on the stock O2s.
Even with worn out valve seals, in my experience if oil gets into the chambers you'll hear pinging. My TA would ping and leave oil on the plugs when the valve seals were worn out. Burned one quart of oil every 500 miles. Didn't burn pistons etc.
Melted usually means lean.
Lean will also cause detonation.
Tuning part Throttle with fuel trims is fine.
Wide open throttle must be tuned with a wideband.
You can not use fuel trims to tune WOT...WOT fueling is based on commended PE ratio, VE, and MAF(unless SD). IF you don't hit commanded PE then your VE and/or MAF tables are off. You can not tune accurately off of Narrow bands, but you can still get the fueling into a conservative range. Usually if the Narrow band readings are consistently in the 880-920mv range @ WOT you won't be lean enough to do any damage but that doesn't mean the fueling is ideal either. Wide band is of course the ideal method to tune WOT.
All that being said, your tune would have to be Way OFF in order to cause that kind of damage. My guess is the injector data is wrong in the tune or the fuel system has a issue. I would never use injectors without good supplied data. There are GM options out there that will work fine. L67 3800 OEM injectors for example would be perfect for your setup.
The second pic down the piston is burned away. Didn't you hear detonation or anything? Did it overheat? Does it have nitrous or other power adder?
This has nothing to do with a valve job.
No, this is my first performance build and I did not know what to listen or look for. No over heating, always at 210. No nitrous or power adder, the only thing added 3 days before this was the free ram air mod with the ws6 store plate that covers where the Hood hooks.
Looks to be a lean condition or too much timing advance. The part about the tuner mentioning fuel trims makes me think he tuned it with the narrowband O2’s instead of a wideband.
I did not mess with the timing at all one but, the only thing was install the double roller timing chain at 0. I have no knowledge about the difference in O2's. So look into getting widebands?
Even with worn out valve seals, in my experience if oil gets into the chambers you'll hear pinging. My TA would ping and leave oil on the plugs when the valve seals were worn out. Burned one quart of oil every 500 miles. Didn't burn pistons etc.
How much spark advance?
When I opened everything up, everything related to the valves seemed to be fine, there was a pool of fuel on 2 cylinders tho that turned bad. Which made me believe it might've been those stupid injectors I let myself get talked into using. I got Brand new 36lb FAST to replce those so I'm hoping it helps..
Melted usually means lean.
Lean will also cause detonation.
Tuning part Throttle with fuel trims is fine.
Wide open throttle must be tuned with a wideband.
yes I was flooring it like there was no tomorrow the day it came out the shop in stock 02's...sounds like a combination of O2s and used injectors might have done this??
You can not use fuel trims to tune WOT...WOT fueling is based on commended PE ratio, VE, and MAF(unless SD). IF you don't hit commanded PE then your VE and/or MAF tables are off. You can not tune accurately off of Narrow bands, but you can still get the fueling into a conservative range. Usually if the Narrow band readings are consistently in the 880-920mv range @ WOT you won't be lean enough to do any damage but that doesn't mean the fueling is ideal either. Wide band is of course the ideal method to tune WOT.
All that being said, your tune would have to be Way OFF in order to cause that kind of damage. My guess is the injector data is wrong in the tune or the fuel system has a issue. I would never use injectors without good supplied data. There are GM options out there that will work fine. L67 3800 OEM injectors for example would be perfect for your setup.
Ok I see, so the O2s I need are called wideband o2s?
Ok so the next set up will go like this(added):
-228 cam by comp cams
-255 lph fuel pump from ws6 store
-fast 36lb injectors
-k&n fuel filter
-steel barbell
-blue spring in the hv oil pump
-clutch masters fx350 (has fx250 rn)
- wiseco 3.903 forged pistons with the rings it comes with
-ls6 valley cover with catch can
-strange 12 bolt
But from what I'm reading I need wideband O2s as well right?
The type of O2 sensor used by the Tuner doing the tuning needs to be a Wide Band O2 sensor. Quality tuners have their own wide band O2 sensor or access to a wide band O2 sensor to use while tuning.
The data from car's stock narrow band O2 sensors isn't suitable for doing WOT (wide open throttle tuning) correctly. The car's stock O2 sensors are fine after the car is correctly tuned.
Going to the Fast 36# injectors that the injector data is available for should help get the tuner.
Might want to add a block check to that list first. Heat enough to melt a piston may have damaged the bore.
What are you reading 210 degrees operating temp on? The factory f body gauge?
I have 2 ls1 camaros and they run right below 210 on the gauge which is around 190 on a scanner. But if they hit 210 on the gauge it's actually higher on a scanner, like 230. That gauge is the equivalent of a dummy light.
The type of O2 sensor used by the Tuner doing the tuning needs to be a Wide Band O2 sensor. Quality tuners have their own wide band O2 sensor or access to a wide band O2 sensor to use while tuning.
The data from car's stock narrow band O2 sensors isn't suitable for doing WOT (wide open throttle tuning) correctly. The car's stock O2 sensors are fine after the car is correctly tuned.
Going to the Fast 36# injectors that the injector data is available for should help get the tuner.
Ok, well the guy is suppose to be somw of the best in thw business right now.
What does that wideband o2 look like?
Might want to add a block check to that list first. Heat enough to melt a piston may have damaged the bore.
What are you reading 210 degrees operating temp on? The factory f body gauge?
I have 2 ls1 camaros and they run right below 210 on the gauge which is around 190 on a scanner. But if they hit 210 on the gauge it's actually higher on a scanner, like 230. That gauge is the equivalent of a dummy light.
yea everything is at the machine shop right now, the guy said the heads had a little damage due to the pieces of the piston going everywhere but it was fixable and he did suggest a new bore which will bedone for the forged pistons anyway..
I want to get it right this time, but will have a conversation with my tuner as well.
03-05-2020, 09:42 PM
Broken Pistons 
