Blew Piston rebuilt forged engine
#62
Safety Car
It sounds like you are hard on an engine. I wouldn't be against a cast iron block in your case. They are usually good for 1500 HP.
The LS aluminum block has its advantages but if you are doing strong straight line pulls I would go cast iron just for consistency.
I thought you would have drive line issues before you found weaknesses in the LS1 block honestly.
The LS aluminum block has its advantages but if you are doing strong straight line pulls I would go cast iron just for consistency.
I thought you would have drive line issues before you found weaknesses in the LS1 block honestly.
Last edited by Rob 02; 09-26-2017 at 01:43 AM.
#63
Advanced
I will never run TRE injectors again. I had a set of 80# injectors and had one stick wide open in the first half hour of run time. I sent the whole set back to them for them to test. They sent them back with one new injector an said the rest were good. Put them in an went for a test drive and about 20 miles laters another one stuck open.
#64
Why not just get a TSP sleeved 5.3 bored out to the size you need and not have to worry about this problem again?
A sleeved Aluminium LS is just fine at 1200-1500 HP, no need to go to iron at that level.
Your lean AFR's on the dyno suggest that it was leaning out and detonation got that piston despite the tuner calling for plenty of fuel.
That doesn't mean the injectors were actually responding to the demand, thats possibly what cracked the sleeve too, a machinist would have (should have) caught such an obvious crack.
A sleeved Aluminium LS is just fine at 1200-1500 HP, no need to go to iron at that level.
Your lean AFR's on the dyno suggest that it was leaning out and detonation got that piston despite the tuner calling for plenty of fuel.
That doesn't mean the injectors were actually responding to the demand, thats possibly what cracked the sleeve too, a machinist would have (should have) caught such an obvious crack.
#66
Racer
Thread Starter
So I took the engine apart last weekend and I found 2 more pistons busted in the same spot as the first one I noticed.
Today I just got an email back from the guy who I sent the TRE Injectors to to test. This is what he wrote to me:
"Your set of eight TRE Performance Chinese cheapo aftermarket injectors flow tested bad right out of the box (after an initial exterior cleaning / de-greasing), and flow tested at close to a 43 % flow balance.
The engine would not have run well with these injectors.
Wow, they were worse than we thought. You had two injectors that were way too low, and could have caused a blown engine.
An Injector Flow Balance of under 5 % is considered necessary for proper engine performance. When I sell refurbished sets, I try to get them flow matched at one to three percent flow balance.
The closer the flow rates of the injectors are to each other, the better the engine will run, and the engine will run smoother and get better miles per gallon.
There were no visible deposits / residue inside the injectors. The discharge tips were clean for a used set of injectors.
Attached are pictures of one of the flow tests I ran on your set of injectors.
Picture # 0757 is of the initial pre test ( before ultrasonic cleaning ).
These injectors are not worth spending the time or effort to clean !!!!!"
So hopefully with a new set of ID injectors and new pistons and block Ill be back on the road.
Today I just got an email back from the guy who I sent the TRE Injectors to to test. This is what he wrote to me:
"Your set of eight TRE Performance Chinese cheapo aftermarket injectors flow tested bad right out of the box (after an initial exterior cleaning / de-greasing), and flow tested at close to a 43 % flow balance.
The engine would not have run well with these injectors.
Wow, they were worse than we thought. You had two injectors that were way too low, and could have caused a blown engine.
An Injector Flow Balance of under 5 % is considered necessary for proper engine performance. When I sell refurbished sets, I try to get them flow matched at one to three percent flow balance.
The closer the flow rates of the injectors are to each other, the better the engine will run, and the engine will run smoother and get better miles per gallon.
There were no visible deposits / residue inside the injectors. The discharge tips were clean for a used set of injectors.
Attached are pictures of one of the flow tests I ran on your set of injectors.
Picture # 0757 is of the initial pre test ( before ultrasonic cleaning ).
These injectors are not worth spending the time or effort to clean !!!!!"
So hopefully with a new set of ID injectors and new pistons and block Ill be back on the road.
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blackmachdown (11-06-2017)
#68
Race Director
Member Since: Dec 2010
Location: Atlanta, GA
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2020 Corvette of the Year Finalist (performance mods)
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that sucks... fuel injector connection has some nice bosch injectors, just another option to look into... I have been running their 127's for about 3 years and they have worked great
#71
Drifting
I found this very interesting. My stock LS6 failed in the exact same manner, on the road course.
#7 piston cracked in identical way and location. Cylinder wall was cracked, oil got a little milky, etc. My car actually ran OK coming off the track, I had no idea anything was up until I parked the car and there was a light tapping noise at idle. I towed it home from there.
That spark plug was bent up and the cylinder looked steam cleaned. Block was trashed so I did a full forged rebuild. 5.3 alum block bored to 5.7L.
#7 piston cracked in identical way and location. Cylinder wall was cracked, oil got a little milky, etc. My car actually ran OK coming off the track, I had no idea anything was up until I parked the car and there was a light tapping noise at idle. I towed it home from there.
That spark plug was bent up and the cylinder looked steam cleaned. Block was trashed so I did a full forged rebuild. 5.3 alum block bored to 5.7L.
#72
Drifting
I'll also add I had no knock either. but things were certainly getting hot. I flow tested the injectors after the failure and they were fine.