Lycoming O 320H2A(D)

I know I have seen some comments on this engine but can't find the thread!
General feeling I get is that they are not popular due to cam problems and fitment difficulties.
Has anyone got any positive comments or good points to report?
They are certainly cheap enough but may not be inexpensive. Thanks.

Search h2ad

Here is a couple. You might want to google different forms of H2AD like: h2ad, O-320-H2AD, 320H2AD. In general you know the engine has a somewhat checkered past, but most of that has been addressed. Never the less that is why they are cheaper. Van supports the engine with an engine mount, however there is a list of workarounds to adapt for its unique features, but there is nothing earth shaking in adapting it. Good Luck.



http://www.vansairforce.com/community/showthread.php?t=1554&highlight=h2ad
http://www.vansairforce.com/community/showthread.php?t=8184&highlight=h2ad
http://www.vansairforce.com/community/showthread.php?t=7048&highlight=h2ad
http://www.vansairforce.com/community/showthread.php?t=1824&highlight=h2ad

No

Allan,
The engine has a SINGLE mag drive shaft that turns both mags. I saw the wreckage of a Piper that broke that shaft one night, losing the engine and the resultant FIVE fatalities.

For me, two mags driven by TWO separate shafts,

good point

pierre smith said:

For me, two mags driven by TWO separate shafts,

Click to expand...

pierre excellent point and I never figured out why they did that, however two points: One it has happened but the chance is rare; two, you can convert to a single mag and put in a flywheel triggered electronic ignition. Just a thought, but I am with you I don't like the twin pak mags.

H2AD engine

I've got one in my 6A and am having excellent performance with it. It is the easiest starting engine I've ever flown behind in my 9,000 hours.

As for mags: many engines in various aircraft have single drive mags, including some larger six cylinder ones. Had the accident noted had two conventional mags, a shaft failure on one of the mags could have caused the same result.

Cessna sure produced a ton of 172's with this engine. Many are still giving good service. There are postings about users going 3000-4000 hours between overhauls.

Do a search for my past postings and you will see pix of the minor cowl mod required due to the mechanical fuel pump being on the front left of the engine. The engine mount has a greater bow in the top rear in order to clear the 'killer' mag. The baffles are trimmed slightly different in places and the throttle/mixture attach base plate has to be bent slightly.

Certainly someone with a fat wallet would buy a more popular engine, but for those of us with limitations on our airplane budgets, the H engine gets you in the air just fine! If that is your situation, do not be afraid of the H2AD engine. Just educate yourself about its features and go fly! Upgrade when your $ ship comes in!

O320-H2AD in a -4

I have installed an H2AD in my -4, however I havent flown in yet...soon though I hope! I got mine for a "song", and did the rebuild myself...have about 6K in the whole thing.I am also an AP/IA,and have many hours behind an H2AD in a C172. The simple facts are, ALL engines have a single drive to the mags, however, most split the drive in the accessory case whereas the H2, and several others, split the drive inside the mag...just a mental block to the average person.There have been internal case failures that caused both mags to fail on other engines with seperate mags. The H2 had some teething issues which have been cleaned up over the years.All Lycomings are sensitive to cam lubrication,the H2 is just a "hair" more so.Always practice warm up,and be easy on the throttle on start up, and you will help any engine to last. There are some fitment issues with th H2 in an RV, particularly the fuel pump. I chose to eliminate the mechanical pump, and have 2 electrics, and a small backup battery.Most all cars built in the last 15 years have nothing but electric fuel pumps, and the reliability is outstanding.If anyone is puting an H2 in a -4, I may be able to answer any fit problems....there are a couple pics in this forum under -4 projects
Bill Englert,RV-4 beyond finishing.

Go for it!

As already mentioned there is nothing wrong with the H2AD motor. Yes it had some cam issues when it first came out that led to a bad public opinion of this engine. As we all know, this has hapened in the past to many products that turned out in the long run to be real gems. Heck, there are a gazillion of them out there on 172s giving trouble free service WAY past TBO. I personally know of one that was on a traffic spotting plane here in town that had 2800 hours on it before it was overhauled. There are simple mods that can be done to solve any of the cam issues these engines had in the past (if it hasn't already been done). As GMC said if your worried about the dual mag you can always put in a single mag with an electroninc ignition.
Keep in mind this IS a CERTIFIED engine. I personally would rather fly behind a certified engine over a conversion any day. I'm sure your insurance company would feel the same way! I feel the H2AD makes an oustanding engine for a builder on a budget. But hey thats just my opinion. I'm sure someone will disagree.

Once again, thanks guys; the diverse answers and opinions are what makes aviating the challenge it is. Given that I have yet to fix a rivet to the beast I have plenty of time (and a motivated apprentice engineer son) to get the engine on offer and have it modified and o'hauled. Given that we fly with one fuel line, one throttle linkage, one oil pump, one elevator pushrod, etc. it's all a matter of personal acceptance. Cheers.

One Mag, One EI...

There is a fix for the single mag drive, put a crankcase sensor with a lightspeed Plasma II EI. I flew a friends RV6 with that setup on an H2AD for 5 years and 1000 safe hours. Redundancy with a modern igntion...Cool part is you can leave the extra set of unused plug wires tied off in case one mag fails someplace, you can hook up the other wires to the mag sparkplugs...
Remember, the IO-360A1B6 has the same setup with a single mag drive, the crankcase sensor with EI is the same fix for it as well....

Rob Ray