1996 Civic with a non-VTEC 1.6.  Over 300,000 miles, one owner. A few years ago, my brother-in-law blew a head gasket. He tried changing it twice and it never lasted. I got a rebuilt head from headsonly.com and it had been great. A couple years later, the crank snout broke so I replaced the crank, main and rod bearings and rings and honed the cylinders. Amazingly, they were still in spec at 75mm so a simple hone was all it needed. Ran great a couple more years. He went to start it one morning and just as it was catching, it suddenly sounded like the compression was gone like when plugs are removed. Timing belt is tight and in time, cam and crank turn, and valve train moves. Cylinders 1-3 are at 30 pounds and 4 is at 55. I can’t figure out why all cylinders lost compression. I have yet to pull the head off, hoping it’s something I can fix. My sister said it’s lasted plenty long but I’m dying to know what happened. If I have to, I’ll do a leak down test but figured I’d ask you first.