I made a to-do list on cardboard to both keep organized and enjoy the satisfaction of crossing things off the list. I had several things started and almost complete, so I wanted to focus on finishing some items.
One of the items I’d started and not finished was the exhaust, so I decided to get that knocked out. I’d need the O2 sensors for the engine to run properly anyway. I like to build my exhaust to be serviceable and adaptable over time if I choose to swap mufflers and my old design put the catalytic converter behind the crossmember, which would ultimately limit the length my muffler could be. I decided to move the cat in front of the crossmember to allow future changes to the muffler. Here’s an exhaust fab tip – keep your old O2 sensors around for welding in the new bungs. This will help ensure the threads aren’t distorted during welding.
Here was the final result:
The muffler is attached with a band clamp on either side. Since my exhaust is 2.5”, I found a Dynomax tailpipe (PN# 54287
) that bolted in to the stock locations. And here is a terrible quality picture of the whole system installed in the TJ:
I promise to get some better pictures when I can get this on a rack or at least jack stands.
The ECU was swapped out, radiator full of coolant and I was ready to hear the Jeep run – or so I thought. When I went to crank the engine, the starter struggled to spin it over like it was hydro locked. Weird. I pulled the spark plugs and was greeted with coolant pouring out of multiple cylinders.
Yep, curse words were spoken.
Now is when I started to connect the dots from things I noticed during the disassembly of the donor – no thermostat and little to no coolant (can’t remember if it was dry or low). I’m having serious doubts about this motor as a whole at this point.
In a bit of, well, desperation, I pulled the intake and changed gaskets hoping I might have messed up when installing the Hughes plenum kit. Nope. No change. It still leaked live a sieve. I pulled out my inspection camera (which if you don’t have one in your toolbox, I highly recommend it.) to try to verify where the leak was coming from. Here is what I found:
Coming from the top of the cylinder either means I have a head gasket that failed spectacularly or a severely cracked head, which these Magnums are known for. Due to other obligations and a pending family vacation to Las Vegas, the TJ was put on hold for a few weeks while I figured out a path forward.