E

Epsound

Well Known Member
Just wondering is anyone is using one of these. I am interested in your experiences. Will this work on 9A? Are there mods that need to be made in the cowling for a forward mounting full pump? Does it use a conical or dynofocal mount......and so on.


Thanks in advance for your input.

E.
 
I seem to recall the H2AD are the variety to stay away from. I dont recall what the problem was/is with them. Someone here can answer your question. I think its been discussed here too. You may try the search function.
 
H2AD Lycomings were used in 1978-1980? C-172s. The problem was bad camshaft or bad camshaft/lifter combinations. I have a $7,802 lamp on my desk... made from the camshaft with the first lobe almost wiped round and the second lobe about half worn through. The cost of the rebuild to fac new specs was .. well you know that already, $7802. Makes a cool lamp... Was using the A/C in a flight school setting, flying about 105 hours per month. We were adding some oil additive.. Linkite? that obviously didn't help. We rebuilt with a cam from a different mfr (Air Support, maybe... this was 1991 or so, so my memory isn't perfect)... That camshaft ran 6000 hours I think. We sold the A/C in 1993... it went to another flight school and they took it from 5000 hrs to about 11000 hours. Then it sold to a private party who brought it back and now its in a T-hangar across from mine... probably has 12000 hours on it now.

I think the fleet of engines likely all have replacement camshafts by now. Sure haven't heard of any problems lately...
 
I have heard about this additive...

and was told that this is how it got the bad rep. However, I was also told that the additive that lycoming recomended is now pretty much standard in most aviation oils we buy. Don't know this other than because it's what I was told. That being said, I hear it is a beefy engine and have had a couple A&P's that say the bad rep makes it a cheap buy but the engine is still reliable for the most part.


E.
 
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H2AD

We have one in our RV6. It appears low usage is a significant contributor to the Lifter/Can Lob issue.
They need to be ran regularly. They are equipped with a single drive dual Magneto. A modified mount is available from
Vans or you can modify the top rear area adjacent to the accessory case.
They use a stamped rocker arm. Another plus is the oil pump is accessible from the outside.
If you use a mechanical fuel pump the cowl will need a small bump.i know of three that went well beyond the TBO mark.
The cylinders are pricey as compared to other O320. We have been very happy with ours.
If you need more information contact me via my email
 
H2AD

I was very happy with the one I had in my 6A. It was a strong dependable engine. Make sure you have a provision for a fuel pump. The dual mag was no problem. I raised the entire front sides of my cowl profile rather than do bumps. 1 " foam covered with glass clothe was sufficient.

It's a little trouble but you can get 160 HP for $2-3,000 typically. But, if resell is in your near future, it will make it harder to sell because some folks fear them. Fixed pitch only is also a limitation.
 
I've just bought an H2AD for use in my -9A.

They use a modified Dynafocal-1 mount with a deeper top cross tube to clear the rear of the crankcase. If you specify it at the time of ordering your finish kit Vans will sent you the mount you need. I'm told the H2AD mount will suit other Dynafocal-1 engines but not the other way around - so if you're not sure what way you're going to go, perhaps order the H2AD mount anyway?

If you have a standard mount, as has been said, you can modify it locally. I'm doing just that, but taking it a step further. Through Vans, I was put in contact with the company that actually makes the -9A engine mounts and they're more than happy to pre-bend a new cross-tube for you to weld straight in. Cost is $65USD + shipping.

There's a lot of bad press about the H2AD, mainly carried over from the early days when they did do (quite) a bit of chewing through camshafts, but this has all but disappeared now Lycoming specifies a special additive in the oil - that is in many aviation oils now anyway.:rolleyes: This stigma means you can often get a reasonably low-time H2AD much cheaper than other -320's.

Apparently, you can get roller lifters for this engine based on Ford 351C engines as well, there's a couple of threads here on that particular mod.

You will need a cowling bump if you use the engine-driven fuel pump, otherwise run a pair of Facets. The dual-mag arrangement can be off-putting for many people, but LSE will install trigger magnets in your flywheel for $75 if you want to use their EI system.

Finally, if you ever plan to run a constant-speed prop, this engine is not for you. It has a solid crankshaft. You can use MT props or a couple of other electric ones out there, but that is significantly more expensive than using a traditional CS prop.
 
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High time engine

I know of the engine Evan is looking at purchasing.
It is a high time engine that has not been running
for some years. It will need to be rebuilt and has already been factory
rebuilt at least once. Does anyone have
any input or experience with rebuilding an H2AD?
 
I used G & N near Chicago. Like I said, the replacement cam went about 6000 hours. Three rebuilds that made TBO. I think the original problem was the original Lycoming cam. I doubt the oil additive made any difference.

The rumored story is that when Air Support took their cam in to show the FAA for approval, the FAA said "oh that looks terrible; we would never approve this," whereupon the submitting engineer relied "OK, that's great, that's the Lycoming cam, here's ours"...

Regarding the comments about consistency of use... we were flying over 100 hours per MONTH, with 100 hour inspections and the original cam went bad at 1500 hours since new. At that time, we rented 172s at $54 per hour, so 500 hours early was very bad news, i.e. about $27k revenue short of where we expected to be when we overhauled an engine.
 
H2AD Overhaul

The overhaul is straight forward.
Divco did the case.
We used Aircraft Specialties for the internals, carb and mag overhaul.
The crank polished in spec
Replaced the cam and lifters, did the "T" Modification.
Chrome cylinders.
 
Are they...

still manufacturing the cams? Or, would you be subject to whats available on the market (used)?

E.
 
You can still get them - current part number for the assembly with pin, etc. is LW-16511. Aero lists it for $960, Air Power shows it for $919, etc. There might be places to purchase them for a bit less but that will be the ballpark number for new.

Bob
 
H2AD

I am running one in my RV-4, and have no problems whatsoever. I am an A&P/IA, and re-built mine myself. I have a mere 6K in my "firewall forward". I overhauled the cylinders, and had all the rotating steel sent out and inspected/yellow tagged. I am using an MA4SPA carb, and Bendix 3500 dual magneto which I also overhauled. Because the H2AD has an odd location for the fuel pump(frontof case), I eliminated it (the RV-4 cowl is tight) and I run 2 electric Fawcet pumps. One pump is continuous on, and the other is boost for take-offs/landings/emergency. I use Aeroshell 100PLUS which has the additive in it already. The VANS H2AD engine mount has a curved upper cross tube which allows the case clearance. The baffles had to be hand crafted, as the case shape is not the same as other series of engines...anyone interested in knowing more, I can send pics via private E-mail easily.
 
Thanks all

This has all been very helpful. Thanks for the input everyone.

I hope to connect later with those of you who offered offline guidance and info.


Best,


E.
 
KRviator said:
They use a modified Dynafocal-1 mount with a deeper top cross tube to clear the rear of the crankcase. If you specify it at the time of ordering your finish kit Vans will sent you the mount you need. I'm told the H2AD mount will suit other Dynafocal-1 engines but not the other way around - so if you're not sure what way you're going to go, perhaps order the H2AD mount anyway?
Click to expand...

Way back in 1998 or so Van's sent the engine mount for my O-360-A1A. I had it painted and then found out it was for an H2AD engine. It worked perfectly except I had to turn the vacuum pump 90 degrees to clear the inlet pipe. Vacuum pump is gone now so it's no longer a factor. If you're not sure but need a mount, the H2AD mount might be the way to go.
 
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