STC # for the Lycoming 340 A1A

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STC # for the Lycoming 340 A1A

Postby Guardian Aerospace » Tue Jun 01, 2010 10:42 pm

I am rebuilding a C170B with a Lycoming 340 AIA 170HP STC. I do not have a copy of this STC in the aircraft documentation and was wondering if anyone knew the exact STC #. Also I understand that this engine is a post WWII engine designed to be used as an APU. What information can your readers and members provide on this engine. Can this engine STC, if found, be approved as an LSTC to include the Lycoming 180HP? Has it been achieved by anyone? The Lycoming 0-340 A1A was paired with a now antiquated Hartzell Prop the HC 82 XL-10B. Apparently it has an AD calling for an overhaul every year or 250hrs airtime which ever comes first. Does anyone have the Lycoming 0-340 paired with a different propellor such as a newer Hartzell 2 blade matched with the Lycoming 0-360 180 HP? The project boils down to cost...it would be affordable to rebuild the 0-340 and prop combo than it would be to buy the entire 0-360 STC...I would save 25 thousand. The other option is to buy a half time 0-360 if there is one around and the STC separately. Anyone know of a half time 0-360?
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Re: STC # for the Lycoming 340 A1A

Postby blueldr » Wed Jun 02, 2010 5:15 am

The last C-170B with a Lyc. O-340 that I worked on was a "Doyn" (sp) conversion according to the paperwork in the log. I do not believe they are any longer in business.
BL
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Re: STC # for the Lycoming 340 A1A

Postby gahorn » Wed Jun 02, 2010 2:51 pm

I strongly urge you to obtain a copy of the official aircraft record from FAA-OKC which you can order online. www.faa.gov
That record may have a copy of the Form 337 which lists the particular STC under which that engine was installed.

The veracity of the following information may be suspect:
Robert (Bob) and Barbara Williams owned several STCs of this nature under several names. Their reputation for response and fiscal responsibility is not good, according to many commenters on many aviation websites. (You can do your own search on the Internet.)
The last contact information I have is:

Bush Conversions is located at Po Box 341 Udall, KS. Phone: 620-782-3851

Avcon Conversions,PO Box 654,Udall KS 67146,316-782-3317
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight.
An originality nut (mostly) for the right reasons. ;)
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Re: STC # for the Lycoming 340 A1A

Postby Guardian Aerospace » Wed Jun 02, 2010 6:04 pm

Thanks for the information. I will track that down. I understand once proven that the STC applies, Hartzell may have a replacement prop for that engine which is newer and does not require the re-occurring SB or AD be followed.

Eric
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Re: STC # for the Lycoming 340 A1A

Postby Blue4 » Wed Jun 02, 2010 9:34 pm

I looked at purchasing a 170B with a 170 hp O-340 engine, so I did a little homework on it. It is my understanding that there are several versions of the Doyn / Doyne conversion. (I've seen it spelled both ways so many times I haven't a clue which is correct -- much less the proper pronunciation!)

If the airplane I was looking at had the sole sin of an O-340 engine, I would have bought it. Money well-spent on a prebuy, however, had me pass. 2 airplanes later, I'm very happy with the one I bought (with an O-360).

The prop is a major headache. The number I've heard quoted for new propeller is $19,000. Yes, $19k. Its my understanding that there is not another prop available with the STCd engine. Parts such as cylinders are available, but they are rare. Neither of these are a show stopper, but its not going to be easy.

My final and important point is this: once you locate the exact STC your airplane was converted under, look hard at the paperwork. _SOME_ of the Doyn conversions allowed for EITHER an O-340 or an O-360. Well, wouldn't that be nice? O-360s aren't cheap, but they're ubiquitous. In pilot-speak, that means you can find a lot of 'em easy. An O-360 would solve your propeller problem as well. I wish you the best of luck, we're curious as to your results!
-Scott
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Re: STC # for the Lycoming 340 A1A

Postby Guardian Aerospace » Thu Jun 03, 2010 5:30 pm

Thanks Scott,

I'll post my developments. Off to the FAA to see if a historical copy of the STC was filed.

Eric
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