Hey kids! New acquisition.

Head gasket failed between cyl one and two?

Other areas on the verge of failure.

And the clogging of the intake manifold EGR passages: progressively more clogged towards cyl one end?

Kinda nuts, but I'm envious, looks like fun.

 

Send head to machine shop? If you have valve seals in the gasket kit the shop could install them in their process. @The Critic went that route; maybe he will comment.

Addendum: @The Critic's thread:

2011 Prius Head Gasket Failure | PriusChat

 

Even if the head is still flat/straight, you need to replace the valve guide seals!
NOW is the easiest time to do it, while the head is off.

 

That's good! You got to it before he head warped. That's always good.

 

I went down this very road about a year ago.
Looking at that head gasket I say it was leaking coolant into 3 of 4 cylinders. I replaced my head gasket at 175k and only had one part of the gasket where the black sealant was worn away.
A neat trick for the rough running on startup is to carefully vent the pressure off of the coolant overflow tank every time you shut the engine off. A good head gasket will only pressurize the coolant tank a little. A blown one will sound like you are opening a hot 2 liter of soda every time. releasing the pressure this way will keep coolant from being pushed into the cylinder while the car sits, and minimize the rough starts. Some old school mechanics would intentionally leave the radiator or overflow cap loose to prevent pressure from building up specifically to solve this problem so a car could limp along for a little while longer if needed. Couldnt tell from the pictures, did you rotate the engine and make sure all pistons came up to the same level to rule out bent connecting rods?
Mine had almost no visible wear at 175k. I replaced the water pump too. There is some discussion that the head gasket sealing material was not really compatible with the kind of coolant Toyota uses, and they seem to fail pretty reliably in the range that both you and I experienced. I have yet to hear of a single re-do needed after a head gasket change, I think the newer or aftermarket gaskets must use a more robust material.

The whole rest of my car that has 192k on it now is so tight I cannot believe it. I think it will go until the insulation falls off the wires or some plastic parts get too brittle and start falling apart wholesale.

Change the transmission fluid if you have not. It doesnt cost much and if you want a few more hundred thousand miles, it would be a good idea.

 

Watch closely for the timing chain to jump when you go to release the tensioner, I had to try three times, the first two times it jumped a tooth. I don't think you could double check yourself too much on this particular step before you button everything back up. Everything else was very straight forward. If you got it apart you will get it back together. I took a weekend to get mine apart, got the head work done through the week, and put it back together the following week. That was about 17,000 miles ago and all is still well.

 

@Ianmeister i'm curious if you locked the cams when removing? Not sure how crucial it is, but I believe it makes reassemble easier. There's a trick of putting a tri-fold strips of shop towel in one cam shaft journal, then gently retightening, so they hold positions.