I bought a 370z back in January of 2021. The previous owner had an AAM Twin Turbo kit installed by AAM in Maryland about 1-2k miles ago and it ran like a beast.
In mid-April I was driving the car normally under 40 mph, heard a weird pop/thud noise and then all of a sudden the engine started making some terrible noises. I pulled over and shut it off and had it towed home. After some investigation it appears the car is squirting oil out of the passenger side of the block/lower girdle.
So I decided to do some more investigating... I drained the oil, didn't see anything bad until I took the oil pan off and found some treasures… From what I can tell there is a chunk of block, some oil squirter parts and a check ball from the oil squirter as well.
At this point I knew I had to pull the engine and would most likely need a whole new long block…
With the AAM Twin Turbo kit the whole engine has to be removed from the bottom by dropping the whole cradle. Thankfully my Dad has a lift which made the job a lot easier. It was honestly a VERY simple process. Disconnect the exhaust, driveshaft, suspension, water and electrical, intercooler/intake piping and the engine basically fell out of the bottom.
After I got the engine out I took it apart to assess the damage and what I found was pretty interesting.
It appears that the rod for cylinder 6 broke in half and wrapped itself around the crank leaving the piston buried into the head. Weirdest thing is the car still started/idled fine, I guess it was essentially a 5 cylinder engine at that point.
Last weekend I got the engine back into the Z. It was a tight fit with the AAM TT kit, had to be REALLY careful putting it back in. The clearance on the driver side turbo is VERY close to the body of the car. The only way to pull the engine or put the engine back in is from the bottom using a lift.
The whole process took about 1 month working only nights and weekends. A lot of the time was spent researching the AAM TT kit and associated parts. Overall it was pretty easy, just time consuming.
I found A LOT of broken vacuum lines running to the boost control solenoid and wastegate actuators which I believe caused the over boost situation I had. The broken lines were most likely preventing the wastegate actuators from getting enough pressure to compress the spring and open the wastegate. Also I believe the fuel pressure regulator was never seeing boost which was causing lean conditions. Now that I have it all together the Ecutek tune maps are working as expected and adjusts the boost on the fly. Wish I could have seen the broken lines before I blew my engine but there is ZERO room in that engine bay with the twin turbos in there.
I did add some performance upgrades while I was in there. New HKS spark plugs, upgraded vacuum lines, different wastegate actuators, a 34 row setrab oil cooler, z1 engine mounts, z1 transmission mounts, z1 subframe collars and the bell raceworks diff brace.
I obviously would have rather NOT blown up my engine but it gave me the opportunity to really learn this engine/layout. Still hope I don’t have to do it again! Hah
Just thought I'd share my journey of bringing my car back to life. It runs like a beast again. Hopefully I'll get a few more years out of this engine.