I've used this forum a fair bit for research in the past and figured it's time to contribute back! This is a post from the summer of 2022, but hopefully the beta is still useful.
My partner Andrea and I set out to do Phyllis's Engine via the standard route in late September. The plan was to do the approach on day 1 up to Polemonium Ridge and then attempt our climb the following morning with a long hike out on the same day. Despite its inclusion in the Alpine Select, there's actually not a ton of beta (that I could find) on the standard route. Steven Song has a great report from the 5.9 variation and there was also one post on here from 2013 with some good beta as well, but otherwise there's limited details on what to expect. The one other detail that I read on numerous accounts was the cadence of ropes getting stuck on rappels. I had that in the back of my mind for the rest of the trip.
On the 20th, of September we set out from the Helm Creek Trail Head and followed the well paved path all the way to the turn off for Helm Glacier. The glacier was in a very dry condition, so we didn't bother roping up and found it straightforward to navigate. When we reached the top of Gentian Pass we caught eye of the 250m elevation loss below, but the scenery is nice enough to distract from it all. We reached a suitable camp site around an hour before sunset and settled in for the evening.
Andrea on the Helm Glacier
Dropping into Gentian Pass
Sunset at camp
We got going around 9am, when the sun rose and followed the long side hilling traverse around to the Sphinx Glacier entry West of Phyllis's Engine. This glacier looked more complicated to traverse so we made the decision to rope up here. Andrea lead a great line up to the base of the Engine and then we transitioned over to climbing gear. From there we lead 3 pitches to the summit on solid rock, albeit the top of pitch 1 was kitty litter over slab.
Reaching the entrance to the glacier
The Engine off in the distance
Getting closer
Myself above the first part of pitch 1
At the top of pitch 1 looking down at Andrea
The kitty litter slab traverse
Andrea coming up pitch 2
Myself on pitch 2. I ran out of gear just before the top, so Andrea lead the remainder up to the base of pitch 3.
Looking down the exposed and awesome pitch 3
Andrea on the summit
Myself on the summit
On the descent, we found our rope was too short to reach the second rappel station we spotted (on a 60m rope) and so had to build an intermediary rap station and then continue on. I held my breath on each rope pull, but thankfully it never got stuck. We swapped back into our regular gear and then roped up for the glacier again. We didn't reach our camp site until just before sunset. Andrea and I debated crashing for the night, but we had run out of snacks and we figured it's better to slog it out now then be hungry in the morning covering the same distance.
With that, we packed up camp and made our way back towards Helm Glacier. We didn't arrive until well into the night and it was a touch spooky covering the glacier by head lamps only. It was a moonless night, which didn't help.
Helm Glacier at night
After the glacier, it was a long march back to the car, but we finally made it around 4am after 19 hours on the move. I drove us back home where we promptly crashed out for the day.
I have a full recount of the details here if you're interested: https://www.francisbaileyh.com/2022/09/22/phylliss-engine/