H2AD teardown
I purchased a H2AD T-mod first run core with 2048TTSN, new in 1984, removed for time and 180hp upgrade. With all logs back to installation, shipped, it cost me $3500. I tore it down within a month of it's last flight. Lifters were fine, good faces, oil filter had no metal, nothing odd/suspicious in the oil analysis. Upon disassembly, cam looked good, cleanup showed some hairline cracks in two lobe tips, and scratching at one of them removed 0.25"x0.03" x 0.015" deep sliver from the face of the lobe, making the cam scrap.
Case is good, YT by Crankcase Services in OK, crank, rods, gears, all ok, crank at standard and good per SB505 (YT on OH) by Aircraft Specialties.
Having done the research, I was replacing the cam a lifters anyway, and figured in the expense. There are plenty of non-H2 cam/lifter failures out there too . . . the H2 is the only engine you can check without teardown, and people DO check due to the history and AD's.
I also am replacing cyls, since the OH odds (cracking heads) don't look good to me. Complete, I expect to spend $16K and have a 'certifiable' clean OH good for another 2000 hours.
Just my $0.02
Rick 90432