Yep,That's a complete head. first stage piston, rings, second stage piston/seals, the whole top end. Simply remove the end of the stainless lines that connect to the compressor and the two bolts that attach the first stage head, slip the whole head off. It does help if the crank shaft is at the top of its stroke when removing the lower connecting rod end.The new head, even included the paper gasket.I changed the head on mine because I was worried about oil blow by on the first stage piston rings. I had about 10 hours of run on it. its wasn't really bad, just bad enough to worry me. The complete, new head went on without issue. I seated the rings for about 10 minutes at zero load. changed the oil. I have about 3 hours on the new head, very little, what I would consider a normal amount of oil blow by still.I took a set of first stage piston rings and second stage seals, rebuilt my original head and have it boxed up ready to go when needed.BTW, the yong heng uses a one piece, second stage seal with an O ring under it. Luckily, I had installed similar seals before. install the 3 O rings on the piston. Then, put the seals in HOT water, let them get a little soft and pliable. Used a small set of needle nose pliers to stretch them just a tiny bit, enough that they would slip on the piston without any damage. If you're not careful, you'll ruin a seal before you get it on the piston. Go slow, don't force them on the piston.Once the seals are on the piston, it does not want to go into the bore. I again heated the seals(and piston) in HOT water. Worked them a bit with my fingers to conform them to the piston. Then shocked them in ice water, letting them completely cool. Now, they JUST slipped into the head. Again, go slow, a little wiggling/working of the piston will get the seals in without damage. The first stage rings are easy. just be careful you don't snap a ring as they are hard and brittle. I did break the used middle ring removing it from the piston...
Does anyone have a guess as to what part would be needed to repair the mophorn compressor with a crankcase cover that exploded?
just looke more closely are your (frightening) photo. I'm guessing a casting defect? The screws did not fail since they are still there holding what's left of the crankcase. And the breather did not blow out either. Yowza.