H2AD experience?

[rocketbob]

The 172 in our flying club with an H2AD went 3800 hrs. before overhaul. It was flogged daily in hot and cold weather by student pilots and never missed a beat. Never got preheated either, other than a blanket and a light bulb.

[airtractor8]

I have a H2AD fitted to my RV6 and have had no problems other than needing to fit a bigger oil cooler and shift it to the rear right engine baffle to get oil temps down. Turns out this model engine runs a larger cooler than other o320 models when fitted to the 172 as well. It starts easy and runs great and does about 165TAS at 2500rpm on the f/p metal prop. These engines are also sometimes available at bargain prices due to all the well documented, negative hype that continues to surround them. I paid 2 grand for mine...yes you read it right 2k and it came complete and with full log book history AND 1000hrs to run and didn't come from a wreck. So if your on a budget, ask around, your sure to find one just like I did under a hanger bench somewere that nobody wants!
cheers Graham

[airtractor8]

Hi Alex

Originally Posted by Alex Caldwell

You've got me thinking, now that the plane is all set up for the H2AD, maybe I should just look for another one with some time left on it to keep as a spare when the time comes, instead of thinking $16,000 overhaul on this one. Would probably be back flying a lot quicker than the overhaul route as well.

Thats exactly what I did believe it or not!. I got another one for a spare with 700hrs to run almost complete and with logs for $2500....not as good a deal as the first one but ok compaired to what you would pay for a "normal" 0320!.Look around for a private owner or a shop thats done the Pen Yan 180hp engine conversion to an "N" model 172 and you may find the engine they removed available at a bargain price. The Pen yan company is also a source for used H2AD parts from engines removed for their 180hp conversions. I got a spin on oil filter housing from them(its differant from all other 0320's)in great condition and they're good people to deal with as well.
Regards Graham

[osxuser]

From a mechanics standpoint, I'd fly behind an H2AD without a second thought. I think twice before I fly behind a Sube...

I've worked on a ton of them with NO evidence that they are any worse in their current form than an conventional lyc.

[rjcthree]

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

[339A]

I have an H2AD on my 9A and so far have had no trouble. This engine made it out to Grand Turk Island in the Caribbean and back to Colorado. I purchased it for $5,000. It was built with the T mod and already had the spin on oil filter. When I got it had 780 hours on a factory overhaul. I have put 330 hours on it in two years and it continues to do very well. Burns a quart every 10 hours. Compression checks out in the 76/80 range. Fuel burn is ~ 7.5 Gals/hr at 8000 ft.
I did use the mechanical fuel pump and had to add a bump to the cowl. It starts better than any engine I've seen. I had already ordered the Dyna Focal mount from Vans so I just modified mine. The upper crossover tube had to be removed and "bent" more to clear the accessory case. That is the only difference in the mount. As for the exhaust contact Larry Vetterman directly and tell him you have an H2AD and he will get you what you need. It was not a problem. Bolted right up.
Only problem I had was with the carburetor when the "lead slug" that covers the bolt holes in the bowl came loose and stuck the float during a zero G maneuver.
I inspect the lifters/cam every 50 hours and have not had any issues so far. These engines can be a good deal if you can find one that has been treated well. If mine continues to keep running like it has I think a 2000 hour TBO should not be a problem. Many of these engines were used on 172N models, which most of us have flown behind, before we knew anything "bad" about them.