The International Cessna^® 170 Association

This is my first post.

My recently-acquired 170B has the above Doyn O-360-A1D engine conversion. The 337 refers to STC ISA421CE. I find STC (no leading "I") SA521CE on the FAA web site, with owner in Udall KS about, about whom posts on this site don't speak kindly.

Does anybody have drawings for this conversion? The installation instructions attached to my 337 are almost illegible, but seem to mention drawings 1099, 1199, and maybe others. I have no problem paying costs for copying large size drawings, shipping, etc.

My manifold pressure/fuel flow guage does not indicate correctly (11gph at idle) and also may be marked incorrectly. It may not even be the correct part.

Does anybody have proper drawings so I can make sure my engine conversion is done correctly using correct parts? I'm also interested in reconfiguring the instrument panel for center radio stack, subject to engine STC requirements (instrument locations, switch locations, etc.). I probably have a "T" control yoke, but am willing to replace it, and need guidance here (STC, drawings, parts, etc.).

Thanks!

Give me a call, I have drawings, 345-7370

You seem to have your drawing requirement solved. As for the center stack radios as with most subjects it's been discussed here before in length. These links discuss the subject as well as a few others. Do a search on "center and stack".

http://www.cessna170.org/phpBB2/viewtop ... ntre+stack
http://www.cessna170.org/phpBB2/viewtop ... highlight=

If you have any more questions feel free to add to the older threads or start a new one.

Welcome to the forum.

What a surprise! All of the Doyn conversions I've ever seen used the Lycoming O-340 engine which is kind of an orphan.
Check with DelAir for the center stack STC.

I'll be coming to the convention with another oddball Doyn orphan(o-320).

It turns out that Green Bean's drawings are Avcon, not Doyn, so I still need drawings. I talked to Harry Dellicker at Delair about panel stuff, and he's sending me out info. He also knows a lot about Doyn/Avcon/etc. and says that Doyn conversions always had seperate MP and fuel flow guages. I have a combined one (MP on left, fuel flow [which also has a red "10.0 psi" marking at the top]) on the right, which I guess is more Avcon-like than Doyn-like. Could it be that I really have Avcon and the paperwork says Doyn? The logs show that the big engine was taken off another 170 and installed in mine in 1983. Interesting, it then shows that my airplane's N# was changed to the N# of the donor airplane!

I also left voicemail at (620)782-3317, the # shown on faa.gov for STC SA421CE in Udall KS. The outbound message there gave no indication of a company or person name, so I don't know if faa.gov has current info or what. Maybe FAA Wichita keeps copies of stuff and I can get drawings from them?

LakeHood170B wrote:I talked to Harry Dellicker at Delair about panel stuff, and he's sending me out info. He also knows a lot about Doyn/Avcon/etc. and says that Doyn conversions always had seperate MP and fuel flow guages. I have a combined one (MP on left, fuel flow [which also has a red "10.0 psi" marking at the top]) on the right, which I guess is more Avcon-like than Doyn-like.

It sounds like the gauge you have is intended for a fuel-injected engine. The "fuel flow" side is actually a pressure gauge measuring metered fuel pressure (usually measured at the distribution spider), but calibrated to read in gallons per hour. It wouldn't be usable on a carbureted engine. Were there any Avcon or Doyn conversions for the 170 that used fuel injected engines? The only fuel injected conversion for the 170 that I'm aware of is the TCM IO-360.

Miles

Awesome. I don't know anything about fuel injection, and am pretty sure my engine has a carb; it has a carb heat control. Does anybody know what's different among Doyn, Avcon, and whatever conversions so I can figure out what I really have? My 337 says my engine is an O-360-A1D. Did Avcon come after Doyn?

LakeHood170B wrote:This is my first post.

My recently-acquired 170B has the above Doyn O-360-A1D engine conversion. The 337 refers to STC ISA421CE. I find STC (no leading "I") SA521CE on the FAA web site, with owner in Udall KS about, about whom posts on this site don't speak kindly.

Does anybody have drawings for this conversion? The installation instructions attached to my 337 are almost illegible, but seem to mention drawings 1099, 1199, and maybe others. I have no problem paying costs for copying large size drawings, shipping, etc.

My manifold pressure/fuel flow guage does not indicate correctly (11gph at idle) and also may be marked incorrectly. It may not even be the correct part.

Does anybody have proper drawings so I can make sure my engine conversion is done correctly using correct parts? I'm also interested in reconfiguring the instrument panel for center radio stack, subject to engine STC requirements (instrument locations, switch locations, etc.). I probably have a "T" control yoke, but am willing to replace it, and need guidance here (STC, drawings, parts, etc.).

Thanks!

Let me know if you sell your "T" control yoke, I know someone who is looking for one. Thanks.

Joe

I'm thinking that what Harry meant was that Doyn had seperate manifold Px and fuel pressure gauges. Also theyhad as most of these conversions an electric fuel pump, a back-up to the mechanical fuel pump (is this over kill or what)and hence the requirement for the fuel PX gauge. I could be wrong here as well in that I think most of the Doyn conversions were straight mount and Avcon 's are dyno mounts.

I have an extra T yoke i would be willing to part with. pm me with what your looking for. nick

LakeHood170B wrote: I have a combined one (MP on left, fuel flow [which also has a red "10.0 psi" marking at the top]) on the right, which I guess is more Avcon-like than Doyn-like.

Interesting, it then shows that my airplane's N# was changed to the N# of the donor airplane!

I also left voicemail at (620)782-3317, the # shown on faa.gov for STC SA421CE in Udall KS. The outbound message there gave no indication of a company or person name, so I don't know if faa.gov has current info or what. Maybe FAA Wichita keeps copies of stuff and I can get drawings from them?

(some clips in the above, Dave)

I'll bet it is fuel pressure, not flow. Mine says Avcon right on the face. A green band from about 2 to 6 lbs I think.

The N number swap raises questions of data plate, logs and such and most importantly legality of the installation. The STC goes with the airframe not the N number. The data plate and serial number usually belongs to the fuselage. My conversion was a FWF from a wrecked A model and It took 3 months and $125 to get Bob Williams in Udall to send me an STC with my plane shown. A very long story and lots of frustration.

Look for a data tag on the engine mount. Mine is on a cluster near the oil filler neck (lower rear right)

I believe that those engine conversions that required an electric fuel pump on conversions utilizing a carbureted engine were predicated on the basis of horse power versus fuel line size, similar to the situation on the
C-170 which required the engine driven pump. Installing an electric boost pump was easier than re-piping the fuel system to larger size. The C-170 inherited its fuel system from the C-140 but due to the fuel line size it was required to have a fuel pump. In the C-170A and C-170B they increased the fuel line size and the fuel pump was no longer required for certification.

Did you look for a sticker on the motor mount? or door frame?

LakeHood170B wrote:... Could it be that I really have Avcon and the paperwork says Doyn? The logs show that the big engine was taken off another 170 and installed in mine in 1983. Interesting, it then shows that my airplane's N# was changed to the N# of the donor airplane!

... so I don't know if faa.gov has current info or what. Maybe FAA Wichita keeps copies of stuff and I can get drawings from them?

Ralph, that logbook entry, coupled with the registration number change hints of legality troubles. The modification should have been logged to the airframe serial (not the registration number alone), and the STC paperwork should also be identified to serial number.

As for the FAA having copies of STC info,....it's unlikely. STC's are registered to their owners, but the FAA does not keep copies of the modification procedure itself, but only who the FAA registered as owner of the STC and the basic description of the mod. (I.E. "Conversion of 170B to Hydrogen-Peroxide Rocket Power, Miles Bowen, Tehachapi, CA." No details of the installation instructions would be kept. The engineering details would be stamped with FAA approval and kept by the owner of the STC. The owner would then include the installation details to any purchaser of that STC, which would be licensed only to that purchaser and his airframe (identified by serial.) The one copy of that STC would only be applicable to that one serial-number airframe. Even if the airframe were junked out at the salvage yard, and I came by and purchased the pile of salvage, the STC could not be used on my other 170B without approval of the STC holder and issuance of new paperwork, ...for which he'd likely want to be paid. Think of an STC as being sort of like a patent. Any modification of an airplane according to that STC would have to pay the owner a "licensing" fee.
The FAA considers the data "proprietary" and does not wish to have it in their possession, is how it was explained by the FSDO near me.