Twin Turbo 408 Bearing Failure Analysis
10-28-2016, 07:05 AM
#22
On The Tree
Ususally detonation shows in the bearings by babbit squeezing out the sides of the upper bearing.
I'd like to see the back side of the #7 top bearing shell before I condemn assembly practices and cleanliness.
I'd like to see the back side of the #7 top bearing shell before I condemn assembly practices and cleanliness.
10-28-2016, 11:04 AM
#23
When the motor came out the first time it has similar damage on the #3 and 4 journal and main bearing and this time its the same thing. I've had gold flakes in the oil in every single filter change but the last one had the most and I heard tapping and that's why I tore it down.
I will get a picture of the #7 top bearing later so we can check it out. All I want to know is what the main cause of this is so it doesn't happen again. For the most part the tune is pretty spot on running 12psi, 16* on 91 with 625ml Meth nozzle and AFRs around 11.0-11.1.
I really appreciate everyone's help and insight to help me figure this out!!
I will get a picture of the #7 top bearing later so we can check it out. All I want to know is what the main cause of this is so it doesn't happen again. For the most part the tune is pretty spot on running 12psi, 16* on 91 with 625ml Meth nozzle and AFRs around 11.0-11.1.
I really appreciate everyone's help and insight to help me figure this out!!
10-28-2016, 10:08 PM
#24
When the motor came out the first time it has similar damage on the #3 and 4 journal and main bearing and this time its the same thing. I've had gold flakes in the oil in every single filter change but the last one had the most and I heard tapping and that's why I tore it down.
I will get a picture of the #7 top bearing later so we can check it out. All I want to know is what the main cause of this is so it doesn't happen again. For the most part the tune is pretty spot on running 12psi, 16* on 91 with 625ml Meth nozzle and AFRs around 11.0-11.1.
I really appreciate everyone's help and insight to help me figure this out!!
I will get a picture of the #7 top bearing later so we can check it out. All I want to know is what the main cause of this is so it doesn't happen again. For the most part the tune is pretty spot on running 12psi, 16* on 91 with 625ml Meth nozzle and AFRs around 11.0-11.1.
I really appreciate everyone's help and insight to help me figure this out!!
You have more than minor detonation the teflon skirt coating looks much worse than a 500 horse dirt track engine after a whole season (roughlt 11-1200 dyno pulls)
10-29-2016, 02:08 AM
#26
10-30-2016, 02:25 AM
#28
Deformed/overheated ring lands
Teflon skirt coating murdered. Not from having a four inch stroke either
Rod bearings that look way shittier than the shell from the rod caps
Uneven bearing wear (copper more so on one side or edge) indicating crankshaft deflection possibly cracked as well
I'll bet the wrist pins rotate tightly inside the pistons also
The rod bushings most likely look galled or crapped up
Teflon skirt coating murdered. Not from having a four inch stroke either
Rod bearings that look way shittier than the shell from the rod caps
Uneven bearing wear (copper more so on one side or edge) indicating crankshaft deflection possibly cracked as well
I'll bet the wrist pins rotate tightly inside the pistons also
The rod bushings most likely look galled or crapped up