Six and a half hours, three men, and a lot of swearing later, and my engine has a new headgasket. This was the most difficult task I have faced on that car, and I've come out with a better appreciation for engines, and a newfound confidence that there really isn't anything this car can throw at me that I can't handle (although that doesn't mean I can afford it). Here's hoping that I don't have any further major repairs to do.
I do also need to extend sincere thanks to two of my coworkers - Joe Krzeszewski and Doug Mildram - for using the better part of their Saturday helping me. I would have been in much deeper poo had I not had help, and I probably wouldn't have gotten it done in one day.
Swapping the headgasket --- for those of you not aware --- means removing the head of the engine, the intake manifold, the exhaust manifold, and several other little bits and pieces. We started the day by attempting to remove the nuts that hold the exhaust manifold in place, as we were fairly confident those would be the most difficult to remove. Thankfully, most of them were quite easy to remove, but there were two issues: we snapped one head stud, and we had to torch another. The head stud that snapped broke at the nut, so there was plenty of material to grab onto after the head was out, and there was no issue backing it out with a pair of channellocks. The remaining nuts all backed their studs out from the block; not a single nut came off a stud. That's the power of rust.
Once we had the exhaust manifold loose, it was then time to remove the intake manifold. I had already removed all of the intake hoses and ducting when we pulled out the torch, because oxy-acetylene is scary stuff and I didn't need to risk anything getting melted. The intake was physically easier to remove than the exhaust, but it was significantly more complicated, due to little things like the fuel system, the throttle, and about a dozen vacuum hoses. Once again, pretty much everything went according to plan, and the intake manifold was soon sitting on the ground.
At this point, it was time to remove the timing belt cover and the cam pulley, as those were the last components that attached the head to the block (aside from those pesky little head bolts). I think you're probably supposed to replace the timing belt when you loosen it, but given that I'm running a $60 Gates Racing belt with under 5k miles on it, I really didn't want to replace it. Worst case, I snap the timing belt and then install a new one (non-interference engines FTW).
Now it was time for the big deal; we were removing the head. We had previously removed the valve cover, so we began loosening all the bolts in pattern from the head. Everything came out fine and the bolts were in good shape. One of the nice things about having a small engine is the fact that you can lift the head by yourself. The head lifted off without issue, and there it was... the heart of the Volvo.
This photo was taken after the old gasket was removed and the coolant was drained from the cylinders
Overall, the engine appears to be in fantastic shape. A bit of built up carbon, but that's to be expected. Crosshatching is still visible on the cylinder walls, which I've been told is a good sign.
Cylinder bore looks good to me
At this point, it was time to start putting things back together. We scraped down the mating surfaces on the head and the block, checked both to ensure they were flat, and then installed new exhaust studs on the head. After that, we started putting gaskets on. The head gasket went on, then the exhaust gaskets went on the studs, and then we put the head in place. Finally, it was time for what was easily the most physically difficult part: installing the new torque-to-yield head bolts.
Torque-to-yield bolts are designed to actually stretch slightly when installed properly, ensuring the best seal possible. They're installed in stages: first, all bolts are torqued to a low torque spec (14ft/lbs in my case, or 10 Nrp), then the bolts are torqued in sequence to a higher torque (in my case, 43ft/lbs or 31Nrp), and finally the bolts are turned another 90 degrees from that higher torque number, thus stretching the bolt slightly. That final 90 degrees is obscenely difficult to turn, especially when you're leaning over the engine trying to get leverage on the wrench.
Eventually, we got the head bolted down and began reassembling the rest of the engine. There's not a lot to say about the reassembly, it was basically everything in the disassembly, but in reverse. A couple hours later, and we were ready to fire it up. She ran beautifully.
We came to the conclusion that I'd been running with an exhaust leak for quite a while, and replacing the exhaust gaskets seems to have resolved that. The power delivery is better, it sounds better, everything is so much smoother. It was a worthwhile endeavor and something that needed to be done, regardless of my idiocy with regards to boost.