For those that have been following my rookie season in the SCCA T1 class, you know that I seized my motor on July 4th at Roebling Road.
With the significant help of my brother-in-law, we swapped the motor out with a new LS6 crate motor and I got back out on the track in St Louis July 27th for 2 of 3 in class and 2 of 24 overall.
While the car was at my brother-in-laws shop, he took apart the old motor. I thought many of you might be interested in the cause and like to see some pictures.
As I previously posted, I thought my lower than normal oil pressures might have contributed to the death of my motor. My hot idle oil pressure was 25 psi. Turns out I was probably wrong.
We strongly believe the cause of the engine failure was insufficient clearance between the crankshaft and the rod bearings on pistons 3 and 4, a factory defect. This belief is based on the destruction of rod 3 and significant heat markings on the crankshaft where this rod was. Since there are four rods downstream in the oil flow path of rod 4 and they were fine, I do not believe the low oil pressure contributed to this failure. I could be wrong as I'm certainly not an expert on this. But my brother-in-law has built and seen the inside of many engines and he is confident the gap was too small. However, he also felt this motor probably would've stood up to a 100,000 miles of normal usage. Unfortunately, my usage wasn't normal.
We also noted something else that may be a factory installation problem, but we're not sure. We found the lifters, which have a small square oil port on one side of them, were installed inconsistently. The oil flow path on the block is on one side of the lifters, but some lifters oil ports were 180 out from this path. However, the heads, valves, pushrods all look fine, so this may not be a problem. We need to do a little more research to see if these are supposed to face one direction or the other or if it just doesn't matter.
Prior to installing my new motor, my brother-in-law took it apart, checked the gaps between the crankshaft and the rods, checked the torques of all bolts, and verified the lifters were all in with the oil ports facing the path on the block. Everything checked out fine on my new motor. I'd like to get this one on a dyno as it feels noticeably stronger than my old one.
The oil drain plug - a magnetic one I had installed shortly after buying the car. This didn't bode well for the inside of the engine.
The oil pan with many parts of rods 3 and 4 and pistons 3 and 4.
The spot on the crankshaft where rod 3 should be. Note the blueing of the crankshaft where the rod was.
The majority of rod 3.
The top of piston 3 showing a crack where it impacted the head (spark plug?), and marks from the valves.
Looking down the shaft of rod 4 into the bottom of piston 4. Note you can see half the pin that holds the piston to the rod. There should be piston covering this pin. This rod had all but pulled the pin out of this piston as well.
Four of the lifters. You can see the small square oil port on the left three. The fourth one is 180 out from the other three and you can't see the same little small square oil port.
Six more lifters showing one oil port down, two up, one down, two up.
Picture of a head for those that haven't seen one. The heads actually survived this with only the loss of a few valves. The heads themselves are somehow unscratched.
With the significant help of my brother-in-law, we swapped the motor out with a new LS6 crate motor and I got back out on the track in St Louis July 27th for 2 of 3 in class and 2 of 24 overall.
While the car was at my brother-in-laws shop, he took apart the old motor. I thought many of you might be interested in the cause and like to see some pictures.
As I previously posted, I thought my lower than normal oil pressures might have contributed to the death of my motor. My hot idle oil pressure was 25 psi. Turns out I was probably wrong.
We strongly believe the cause of the engine failure was insufficient clearance between the crankshaft and the rod bearings on pistons 3 and 4, a factory defect. This belief is based on the destruction of rod 3 and significant heat markings on the crankshaft where this rod was. Since there are four rods downstream in the oil flow path of rod 4 and they were fine, I do not believe the low oil pressure contributed to this failure. I could be wrong as I'm certainly not an expert on this. But my brother-in-law has built and seen the inside of many engines and he is confident the gap was too small. However, he also felt this motor probably would've stood up to a 100,000 miles of normal usage. Unfortunately, my usage wasn't normal.
We also noted something else that may be a factory installation problem, but we're not sure. We found the lifters, which have a small square oil port on one side of them, were installed inconsistently. The oil flow path on the block is on one side of the lifters, but some lifters oil ports were 180 out from this path. However, the heads, valves, pushrods all look fine, so this may not be a problem. We need to do a little more research to see if these are supposed to face one direction or the other or if it just doesn't matter.
Prior to installing my new motor, my brother-in-law took it apart, checked the gaps between the crankshaft and the rods, checked the torques of all bolts, and verified the lifters were all in with the oil ports facing the path on the block. Everything checked out fine on my new motor. I'd like to get this one on a dyno as it feels noticeably stronger than my old one.
The oil drain plug - a magnetic one I had installed shortly after buying the car. This didn't bode well for the inside of the engine.
The oil pan with many parts of rods 3 and 4 and pistons 3 and 4.
The spot on the crankshaft where rod 3 should be. Note the blueing of the crankshaft where the rod was.
The majority of rod 3.
The top of piston 3 showing a crack where it impacted the head (spark plug?), and marks from the valves.
Looking down the shaft of rod 4 into the bottom of piston 4. Note you can see half the pin that holds the piston to the rod. There should be piston covering this pin. This rod had all but pulled the pin out of this piston as well.
Four of the lifters. You can see the small square oil port on the left three. The fourth one is 180 out from the other three and you can't see the same little small square oil port.
Six more lifters showing one oil port down, two up, one down, two up.
Picture of a head for those that haven't seen one. The heads actually survived this with only the loss of a few valves. The heads themselves are somehow unscratched.