FIRSTHAND experience with Franklins

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moparrob66

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Moparrob
Hello- choosing a powerplant for my Zenith 801 and leaning towards a 220 Franklin. I gather from forums that parts can be hard to find, but has anyone here had difficulties getting parts and being grounded because of it?

I'm also considering an O-360.

I like that the cylinders on the franklin are cast one-piece aluminum with replaceable steel liners. I dont like that there are 6 of them to futz with and replace.

I like that it makes 220 horsepower, but I dont like being obliged to use 100ll. Could one decrease compression by stacking cylinder base gaskets and use mogas at 200 horsepower?

I like the price for the ones I've been able to find vs the O-360, which seems to be in higher demand. Maybe because so many certified aircraft use/need them?

I like the cam down below the crank and the inspection cover on top. I like the carb at the rear of the engine rather than breathing through a hot oil pan.

Any other pros or cons vs. the O-360? Since its experimental, repairs might have some flexibility as far as making parts I cant find. (No, I wont try sand casting my own jugs. Not this month anyway).
 
Yes! Thanks! I sent an email but havent heard back yet. As i get closer I'll call and see what they have.
 
I had a Franklin 6V335A in a helicopter I once owned. The initial engine cratered when an improperly ground crankshaft let go. The replacement engine went 400+ hours before I sold the aircraft, and it was pretty bullet-proof. The joke about Franklins (at least in a helicopter) is: How do you know when a Franklin is out of oil? It stops leaking! Silicone gaskets helped a lot. Mine ran better on fine-wire plugs.

Susan Prall in Texas is the go-to person for parts. Christopher Collum at Air Worx is reputed to do excellent overhaul work.

HTH. Have fun!
 
bnt83 said:

AirWorx – Engine overhaul

airworxaviation.com airworxaviation.com

They seem to do a lot of Franklin engines.

Helpful Videos – AirWorx

airworxaviation.com airworxaviation.com
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They do, but there has been controversy with them and they have created controversy with others. I wouldn’t be opposed to using them but id proceed with caution if I sent them a Franklin, and there are other overhaulers I would probably favor.

Some Parts have been hard to come by for Franklins, which has led to difficulties by all the active Franklin participants, which has led to some of the controversy, and suspect parts being used over the years.

I’ve got a helicopter I fly and maintain with the 6v-350 on it. It’s a great power plant but I would be a bit concerned with parts availability if I was trying to make money with it. Parts haven’t been a problem for us, but we haven’t needed much either.
 
They typically run smoother than even other 6 cylinders. And definitely smoother than any 4 cylinder HO engine.
 
Perhaps not an issue, or you've already considered it, but resale of this great airplane with a Franklin in it is going to take a hit. Its going to be an extremely small resale market - or the purchaser will value it as an engine replacement project.

If resale is not a consideration then obviously a non-issue.
 
Ooh. Good point. I knew auto conversions were hard on resale value. Would s lycoming be that much better for resale?
 
Mikey52 said:
They typically run smoother than even other 6 cylinders. And definitely smoother than any 4 cylinder HO engine.
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My only FIRSTHAND experience with one was 4.7 hours logged in N2502U back in the early 1990's, a C172D, with I a 180HP Franklin. The guy on the field that owned it at the time used to go on an on about how smooth it was. He was nice enough to let me fly it some. He sure did baby that thing, was strict about smooth application of power using the vernier only...no jam it to the firewall or pull it to idle, etc....
Honestly, I guess it was smoother than the flight school's 172N that I was used to renting, but it sure didn't seem special to me at the time....
 
Excellent thanks! I suppose so far the biggest thing against it might be resale value, but I'm not especially building it to sell. Smoother engines should last longer, no?
 
moparrob66 said:
Excellent thanks! I suppose so far the biggest thing against it might be resale value, but I'm not especially building it to sell. Smoother engines should last longer, no?
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Not necessarily. Lycoming 360s have a reputation for often going well over 2000 hours (plenty of them even beyond 3000) and they are not exactly considered to be smooth.
 
moparrob66 said:
Smoother engines should last longer, no?
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Depends. Some engine models inherently operate smoother. However, run it with a prop out of balance and the smoothest engine won't last longer. Most of my Franklin experience is with helicopters and it is a fine engine. But as mentioned, the support side is getting a bit tight. So you may want to take that into consideration since you are starting at the ground level with your project.
 
Good points all. I understand that my auto experience doesnt all carry over to aviation, but couldnt an EAB franklin 220 owner lower the compression a smidge and run mogas at, say, 190-200 hp? What would be the downside?
 
moparrob66 said:
Good points all. I understand that my auto experience doesnt all carry over to aviation, but couldnt an EAB franklin 220 owner lower the compression a smidge and run mogas at, say, 190-200 hp? What would be the downside?
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Without a dyno and instrumentation, the hard part would be figuring out how big a smidge you need to get.
Trial and error with billet connecting rods wouldn't be cheap either.
 
Im thinking spacers under the jugs, maybe longer pushrods. If i had the bore x stroke and combustion chamber volume, its pretty easy to calculate how thick a shim would drop the compression to mogas levels.
 
Base gasket, shim stock, dykem, scribe, plasma cutter. Cant be that difficult. If it works I'll start production!
 
Are you getting a scorching great deal on this motor? Otherwise, I can't fathom why'd you pick an engine that's going to be harder to support than a Lycoming which can already burn MOGAS, has parts readily available, and anyone can work on it especially in an AOG scenario.
 
I wouldnt say scorching. Definitely cheaper than the lycomings out there, though.
 
I looked but i dont think i should go under 180 horses with my intended use....hauling 4 butts in and out of my backyard strip to the back country.
 
Edit....didnt see this on their website. Checking it out now!
 
Add up the costs. That's where the reality hits you. For instance, you can probably buy the engine mount to fit the Lycoming to the 801, but you sure won't find a ready-made mount for the Franklin to 801. So that has to be designed and welded up. Money, there. The exhaust system becomes another hassle. With the Franklin's carb at the back of the engine rather than beneath it, is there enough fuel head pressure to feed it in a steep climb? Or does the Frank have a mechanical fuel pump? If it does, now you need an electrical backup boost pump, too. Besides, the "carb on the hot oil pan" helps to reduce the chances of carb ice. The difference that way in the two systems is starkly apparent between most Continentals and the Lycomings.

Does the Franklin need an oddball propeller?

Cylinder base seals are typically an O-ring sort of thing that fits into a chamfer in the bore in the case, so that the cylinders seat directly metal-to-metal on the case. Proper nut torques ensure that the cylinder does not move at all. If it does, the studs break. Very bad. If you shim the cylinders, now you have a sealing problem, and you must not use gaskets. They allow movement and the life of that engine would be vey short. Besides that, are pushrods that much longer available?

I designed and did the installation of a Subaru into a Glastar for an owner. In the end, for the same money, he could have had the Lycoming in a month instead of the Soob in over a year, and the resale value would have been twice what he got for it eventually. The reliability of the Lyc would have been far greater, as the Soob had to have two electric fuel pumps (no mechanical pump mount) and electronic ignition, all of it reliant on the aircraft's electrical system. Knowing how often electrics fail in airplanes, I was never comfortable flying it.

We homebuilders are famous for saving money no matter how much it costs.
 
ateamer said:
Not necessarily. Lycoming 360s have a reputation for often going well over 2000 hours (plenty of them even beyond 3000) and they are not exactly considered to be smooth.
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A good -360 with a balanced prop is a very smooth set up. Also -320s.
 
moparrob66 said:
Ooh. Good point. I knew auto conversions were hard on resale value. Would s lycoming be that much better for resale?
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The go-to engines for Zenith Aircraft right now is Viking Aicrafts Honda conversion. Ignore any comments on this board by people not involved in the experimental world, or have way-out-of-date opinions on Jan and his unsuccessful Subaru conversions.

Check out the engines on Vikings website and on the various Viking and Zenith Aircraft Facebook pages.

If I had the physical ability and patience I would gladly swap out my Lycoming O-235 for a Viking engine in my Zenith 601XL. So much better in every way - and a lot less expensive.

The Viking engine will add to the resale value, not detract from it.
 
When i contacted Franklin (Colorado), they say everything for the 801 fwf is available now with the exception of the exhaust. They were unsure of that at the moment.
 
Hondas are great. Everyone who has one seems to like vikings. I cant help but imagine flying one for any distance would be like going down the freeway in 3rd gear. Thats gotta be hard on the longevity...
 
Lndwarrior said:
The Viking engine will add to the resale value, not detract from it.
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Separate markets. The guys that want an auto-engined airplane will pay for it. The guys that are skeptical of them won't. In my experience, I would say that the Lycoming would have the broader appeal.
 
“Auto-engine” includes Franks.As in Tucker.
 
I suppose so. It was an aircraft engine first, though. I think. The UL is $50k
 
Dan Thomas said:
Separate markets. The guys that want an auto-engined airplane will pay for it. The guys that are skeptical of them won't. In my experience, I would say that the Lycoming would have the broader appeal.
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Not in the Zenith crowd. What many people don't understand when it comes to experimental builds is just how many separate components you have to source, figure out to install, figure out fuel systems, install separate starters, alternators, figure out how to wire the lyco or continental in a safe manner and decide where to install components, and on and on. You buy a Viking system and 90% of it is prebuilt and installed, and the rest Viking has detailed design and wiring harness' ready to go. Yes the old engines, in themselves, are very reliable, but what homebuilders quickly realize is how many separate components from different manufacturers have to be assembled in one-off configurations (because every homebuilt except Van's are one-off firewall forward). And you quickly begin to realize just how many points of failure you have built and wired in to your one-off homebuilt. Compare that to a Viking where the entire engine system and wiring harness is a proven Honda factory system. The idea that your one-off old engine system is more reliable than a Honda factory system suddenly does not seem so logical. Installing your one-off old engine in a homebuilt is not as reliable as the same engine installed in a certificated aircraft. THIS is the true reality of homebuilt aircraft.
 
Many years ago I took my 6 worn out Franklin cylinders to an engine shop located on the field in Wetumpka AL. No idea if they are still in business but they were super knowledgeable and did a fabulous job repairing my cylinders. Had them resleeved along with new valve guides. Thanks to a Trade-A-Plane ad, I located a decent set of used exhaust valves that came out of a Franklin airboat engine. New valves were not available back then. The old engine ran like a top afterwards! Good times:)
 
^^^seeing another completed 801 is encouraging! Thanks!
 
There’s a 801 that just came into our airport from out west.It has a Franklin (180 hp I think) and it sits on a weird motor mount,like the mount is underneath the engine instead of behind it.This is probably common for them as I’ve never seen another one but it puts a lot of strain on the 2 top tubes and welds.This one actually broke will trailering back and upon inspection the one break was an old one so the po was flying with a partially broken engine mount.Doesn’t really factor in but just an interesting observation
 
Wow! Scary failure! Thats a good one to keep an eye on.
 
Lndwarrior said:
The idea that your one-off old engine system is more reliable than a Honda factory system suddenly does not seem so logical. Installing your one-off old engine in a homebuilt is not as reliable as the same engine installed in a certificated aircraft. THIS is the true reality of homebuilt aircraft.
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So now. tell us what makes the Viking as reliable as a Lycoming. Does it have dual ignition? Does it have electronic ignition and fuel injection with a backup module and a backup alternator and battery and bus? If not, what happens when the inevitable eventual electrical system glitch damages the power supply? Remember that 90% of engine problems are electrical, not mechanical, and always have been. Even a huge percentage of airframe issues are electrical.

Lycoming has had its iE2 engines on offer for about 15 years now. Electronic dual ignition, and electronic fuel injection. A separate alternator on the back of the engine powers it all in the event of airframe electrical failure. They had to do that to get certification. The reason we still use two magnetos on legacy engines, and only one carb or mechanical fuel injection, is that electrical stuff tends to fail. Magnetos are self-contained and do not rely on the airframe electrical power. They work well if they are properly maintained, but so many aren't. Your Viking might work well too, if it's properly maintained, but the usual myth that owners keep believing, "If it ain't broke, don't fix it" results in so many failures.

I have had a magneto fail in flight. To be sure, it was a 60-year-old Case magneto, certified by the FAA in the 1930s. But it had lasted all that time. When the fancy ECU in your car fails, and it will fail long before 60 years are up, it tends to junk the car because it costs too much to replace. Does that Viking have two ECUs?


Like I said, I was not comfortable flying that Glastar's Subaru with two electrical fuel pumps (it had a carb) and single electronic ignition. It would NEVER get certification that way. In RAF's gyrocopters with that same conversion they used two ignition sources driving one set of plugs, at least. But the spark transfer device I saw in one would make an awful lot of radio noise.

Been a homebuilder and around homebuilding since I started flying in 1973. Seen too many people die due to poorly thought-out "experimental" stuff. I've had two engine failures, too, both of them really old certified engines that were not properly maintained. That tends to make one really conservative.

What's your experience?
 
Call these guys and see if they have "NEW" camshafts, crankshafts, cases and cylinders. Those are the parts that are hard to find for most unsupported engines.

Franklin Aerospace - Engine Parts

We provide Franklin Engine Parts for customers all over the world. It is our goal to be sure all franklin engine parts are compatable and safe.
www.franklinaerospace.us www.franklinaerospace.us

March 2017 interview.
 
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