So soon after figuring out that cylinder #5 wasn't firing, I took it out for some test runs, regularly hitting the rev limiter and overboosting as I was sorting out the transmission shifting programming. Multiple trips to 6,000rpm and 17-20psi of boost until eventually the head gasket let loose on #5. It actually blew out the side of the engine so was a massive cylinder leak to atmosphere, no water!
https://www.youtube.com/shorts/g9lXrICAzOc
https://www.youtube.com/shorts/BWsrUxhPmJc
Cleaned it up and put it back together.
Soon after it started developing a bad vibration. It seemed to only be in 3rd and 4th so I pulled the 4L60e apart, found nothing, changed u-joints, nada, and came to the conclusion the always whinny 4.56 gears must have an issue. I put fresh races, bearings and new set of 3.42 gears in the rear end and the vibration was cured. I found some chatter marks on some of the races and figure the carrier was moving around some causing issues. At some point during the rear gear fixing process my son dumped a quart of gear oil on me while I was under the car and after fighting this vibration for so long, that was a straw that made me walk away from the car for a few months.
In the process it got a new transmission cross member as well.
I always chuckle at the absurdly large exhaust system on this car. I didn't want any post turbo restrictions, lol. 4" from the turbo to rear axle, then 3" over the real axle.
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"How I learned to stop worrying and love the OHC Pontiac L6"
The Silver Buick- '77 Skylark coupe w/455, SPX, MegaSquirt 3 & TKO-600 (Drag Week 2011, 2012 & 2015!)
1969 Firebird with a turbo'd Pontiac L6 controlled by a MegaSquirt 3 and backed with a microsquirt controlled 4L60e and 4.56 gears! (Drag Week 2018!)