LQ9 bent rods at 16psi/12*/11.5AFR
10-23-2014, 11:19 AM
#61
The stock rods and pistons are always gonna be a concern when making 600+..
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
10-23-2014, 11:41 AM
#63
Restricted User
If anything, it had to do with hitting the limiter too hard or faulty water injection nozzle. These rods weren't bent from too much power or detonation. There would be some sign of detonation, and at you're power level, you're a few hundred HP below where others usually end up bending these rods.
10-23-2014, 11:49 AM
#64
Can somebody explain exactly what the rev limiter is doing to bend the rods? If its screwing-up the combustion timing I could see that being an issue with any engine.
I think I felt some spark-blow out too at one point...its something I've been dealing with even with the small plug gap, usually from a little too much water/meth. I've been trimming it back little by little. Could be having the same effect I guess.
I think I felt some spark-blow out too at one point...its something I've been dealing with even with the small plug gap, usually from a little too much water/meth. I've been trimming it back little by little. Could be having the same effect I guess.
10-23-2014, 11:52 AM
#65
Sux Vince,..
At this point, why not buy a set of $300 aftermarket rods and throw in it and not worry about it?
The stock rods and pistons are always gonna be a concern when making 600+..
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
At this point, why not buy a set of $300 aftermarket rods and throw in it and not worry about it?
The stock rods and pistons are always gonna be a concern when making 600+..
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
Its amazing how the pistons are blemish-free - its a testament to their strength. If I get rods, it will probably require a rebalance of the assembly. I might jump to a forged rotator at that point. Hate to bend that up too if I dont figure this out.
10-23-2014, 12:09 PM
#66
Can somebody explain exactly what the rev limiter is doing to bend the rods? If its screwing-up the combustion timing I could see that being an issue with any engine.
I think I felt some spark-blow out too at one point...its something I've been dealing with even with the small plug gap, usually from a little too much water/meth. I've been trimming it back little by little. Could be having the same effect I guess.
I think I felt some spark-blow out too at one point...its something I've been dealing with even with the small plug gap, usually from a little too much water/meth. I've been trimming it back little by little. Could be having the same effect I guess.
I was probably making around 1000rwhp when i bent mine. I was on more timing and 3psi more then I dynoed 888 with.
As said before and like db I am near certain I heard it happen as I was banging the limiter. I wanted an 8.9 so bad haha i knew better though.
10-23-2014, 01:02 PM
#67
TECH Enthusiast
I'll take the bent rods over that rear axle issues of your c5 anyday!!!
Its amazing how the pistons are blemish-free - its a testament to their strength. If I get rods, it will probably require a rebalance of the assembly. I might jump to a forged rotator at that point. Hate to bend that up too if I dont figure this out.
Its amazing how the pistons are blemish-free - its a testament to their strength. If I get rods, it will probably require a rebalance of the assembly. I might jump to a forged rotator at that point. Hate to bend that up too if I dont figure this out.
I also don't think it had anything to do with detonation.. If it was, head gaskets and Pistons would have gave up way before the rods bent.
It's not from meth or hydraulic-ing the motor, if that was the case, they would either all be bent or some on both sides...I agree with your theory of all the rods bending on one side being the "first throw" of the crank after TDC.
Getting on and off the rev limiter "could" be the issues, due to the stresses of extreme load to no load to extreme load again...not sure I think this is the actual cause but...possible yes..
Usually when you get on the rev limiter hard under boost it will yack a head gasket, both from misfiring/leaning it out (hard fuel cut) and a splash of detonation mixed in. Any time you get into the rev limiter, it's not a good thing, very hard on boosted/spray motors.
As for "hitting the crank" with too much torque too soon in the rpm range, I'm not buying that either. Turbos do make a ton of torque but not like hitting it with a 200hp shot of dope at 3k RPMs like we all have been doing on Ls1s for 15 years.
I think if you get a set of cheap aftermarket rods and pistons,you won't have this issue again. You can get scat or eagle rods for $315 shipped, another $400 for rings/pistons and you'll be solid. I know this goes against the whole junkyard/do it for pennies theory everyone is so crazy about here but...how much is your time/labor worth to you to be swapping popped motors every year?
Dingle ball hone it, set your ring gaps and measure your rod bearing clearances and throw it together.. I wouldn't even balance it. The rods/piston weighs are usually pretty close.. Throw em in and go. Now you can make 900-1000hp
10-23-2014, 01:10 PM
#68
Speaking of pistons and sorry for the sidebar but what are people using in the stock bore without going to a 4.005 piston? I know they are supposed to be 4.000 but I thought people had issue with the stock bore being slightly larger?
10-23-2014, 01:23 PM
#69
It's not from meth or hydraulic-ing the motor, if that was the case, they would either all be bent or some on both sides...I agree with your theory of all the rods bending on one side being the "first throw" of the crank after TDC.
Getting on and off the rev limiter "could" be the issues, due to the stresses of extreme load to no load to extreme load again...not sure I think this is the actual cause but...possible yes..
Usually when you get on the rev limiter hard under boost it will yack a head gasket, both from misfiring/leaning it out (hard fuel cut) and a splash of detonation mixed in. Any time you get into the rev limiter, it's not a good thing, very hard on boosted/spray motors.
As for "hitting the crank" with too much torque too soon in the rpm range, I'm not buying that either. Turbos do make a ton of torque but not like hitting it with a 200hp shot of dope at 3k RPMs like we all have been doing on Ls1s for 15 years.
I think if you get a set of cheap aftermarket rods and pistons,you won't have this issue again. You can get scat or eagle rods for $315 shipped, another $400 for rings/pistons and you'll be solid. I know this goes against the whole junkyard/do it for pennies theory everyone is so crazy about here but...how much is your time/labor worth to you to be swapping popped motors every year?
Dingle ball hone it, set your ring gaps and measure your rod bearing clearances and throw it together.. I wouldn't even balance it. The rods/piston weighs are usually pretty close.. Throw em in and go. Now you can make 900-1000hp
Getting on and off the rev limiter "could" be the issues, due to the stresses of extreme load to no load to extreme load again...not sure I think this is the actual cause but...possible yes..
Usually when you get on the rev limiter hard under boost it will yack a head gasket, both from misfiring/leaning it out (hard fuel cut) and a splash of detonation mixed in. Any time you get into the rev limiter, it's not a good thing, very hard on boosted/spray motors.
As for "hitting the crank" with too much torque too soon in the rpm range, I'm not buying that either. Turbos do make a ton of torque but not like hitting it with a 200hp shot of dope at 3k RPMs like we all have been doing on Ls1s for 15 years.
I think if you get a set of cheap aftermarket rods and pistons,you won't have this issue again. You can get scat or eagle rods for $315 shipped, another $400 for rings/pistons and you'll be solid. I know this goes against the whole junkyard/do it for pennies theory everyone is so crazy about here but...how much is your time/labor worth to you to be swapping popped motors every year?
Dingle ball hone it, set your ring gaps and measure your rod bearing clearances and throw it together.. I wouldn't even balance it. The rods/piston weighs are usually pretty close.. Throw em in and go. Now you can make 900-1000hp
Something is going on to bend one bank only.
I found a loose ground wire for the coils on that cylinder head........
10-23-2014, 02:00 PM
#70
what is the chances of all the meth staying heavy to one bank and causing some hydrolicing. or what about a little valve float that feels like spark blowout ? if the intake valve on one cylinder is floating and causing some reversion in that port could it blow the meth out of that port over to the other bank. ??? im just thinking but this does'nt make sence without somthing being off.
10-23-2014, 03:08 PM
#71
what is the chances of all the meth staying heavy to one bank and causing some hydrolicing. or what about a little valve float that feels like spark blowout ? if the intake valve on one cylinder is floating and causing some reversion in that port could it blow the meth out of that port over to the other bank. ??? im just thinking but this does'nt make sence without somthing being off.
I'm really upset with myself with the coil grounding thing...I mistakenly left that bolt loose that grounds the head and coils - this is huge and its like having an uncontrolled rev limiter on that bank....
Its all making sense now.
10-24-2014, 07:59 AM
#73
The Holley efi harness has a separate grd wire for each coil pack, one of which was not connected/loose. I also ran separate grd wires to each head for a better grd. This a mustang so the wiring is different than stock.
Last edited by 69-chvl; 10-24-2014 at 09:35 AM.
10-24-2014, 12:30 PM
#74
SCAT puts blame that my pistons were out of the hole 0.005", even though I have no signs of impact and ran a stock 0.051 MLS gasket.
10-24-2014, 12:46 PM
#75
You said it's a Holley EFI, what coil packs are you running and what dwell times is it set for?
10-24-2014, 01:05 PM
#76
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on a non logic level input coil the ground is switched to fire the coil. it may be possible that a bad coil ground could be triggering the coils causing erratic and inconsistent timing on the affected coils. all it takes is a few degrees.
10-24-2014, 01:46 PM
#78
Looking back I did have break-up - thought it was the spark-blow out from too much meth...but evidently it wasnt. I did some research about rev limiters and possible damage to engines and there is alot of info on this and what I had was worse than a rev limiter - erract/incomplete spark and the fuel and meth were continuing to inject at full-tilt. Lucky to not have damaged my ecu as the coils were being driven hard and there is a chance of fly-back voltage and who knows what quirky things could happen at that point. I did this a total of 3 times.
Again - only the rods on this bank are bent.
Anything is possible at this point.
10-24-2014, 02:30 PM
#79
Both times i bent number one was on the limiter. I think the cycle starts over and it doesnt fire the coil for number 1 but injector 1 dumps fuel and it hydo locked that cylinder and bent the rod. Other times were under high gear pulls. Now the limiter is 7999 and back on at 3000rpm to prevent any damage from that again. I thing yours was hyro locked on that side of the motor.
10-24-2014, 02:54 PM
#80
Both times i bent number one was on the limiter. I think the cycle starts over and it doesnt fire the coil for number 1 but injector 1 dumps fuel and it hydo locked that cylinder and bent the rod. Other times were under high gear pulls. Now the limiter is 7999 and back on at 3000rpm to prevent any damage from that again. I thing yours was hyro locked on that side of the motor.