'68 177's with RG Engines

One of the most common questions I get is whether it is possible to install a 200 HP IO-360 engine into a 1968 177 fixed gear. At times folks propose a similar change to other years of FG, which would share the same challenges.

It has been done to a very few '68 Cardinals. So the simple answer is yes, but doing so is not simple. There is no STC available, although at least one was done under a one time STC (which can't be used as data for another installation.)

Based on stories shared across history, at least these following challenges need to be addressed:

Cooling dynamics are very different at slower FG speeds. Cardinals which have been converted (see below) usually struggle with heat.

The fuel pressure required for an RG is 10PSI, where the FG runs around 3PSI, requiring signification changes to the FG fuel system.

Fuel flow requirements would be higher, perhaps requiring a redesign of the FG fuel paths.

Substantial changes are required to the airframe to covert the FG front end to an RG front end, with differences in things like rudder trim and steering.

Certification has become more difficult since the time when the existing aircraft were signed off.

Some theorize that a strict reading of FAA regulations leaves room for such an upgrade, as long as the power increase is within 10%. However what's needed is not just compliance, but also someone within the FAA who agrees and is capable of approving, plus willing to accept the career risk which we have learned comes with that approval.

Perhaps the most important question is whether you would really want to do this change? A new engine will weigh more, and won't increase the gross weight of the airframe, which is lower than later (or RG) Cardinals. There are often reported issues with heat, and many have found that certification can be a very significant challenge.

The more accurate answer to the question is that it would be difficult, and the resulting airplane would not be particularly desirable.

To my knowledge there are 5 Cardinals which have this modification made, and one rumored mystery ship we have not yet found. The information below captures what I can find about these aircraft from my records in 1/2022. With luck and over time I hope we can capture the details of all of these Cardinals as well as possible on this page.

If you have one of these and can add more info, or have information about one not listed here, please let me know.

As an interesting aside, there is also one '68 with an injected engine which is not 200 HP. It has an IO-360-B1B engine, a parallel valve 180 HP injected engine. That engine was originally built as an IO-360-B1E, installed in a Piper. Then later it was converted to an IO-360-B1B and installed in a Beech Travel Air. That Cardinal is N30157, serial 17701086.

Keith Peterson

Current known 1968 Cardinal 177 aircraft with a 200 HP injected engine:

(Most recent information first)

N68VV (Serial: 17700898)

Listed for sale in Trade A Plane January 2022.
From the owner in 2022: This cardinal started its life in Canada under registration CF-WVU and stayed there until 1995 when is was parked (indoors) and sat until it was rescued in 2005. In 1984 an STC was filed with transport Canada to install an IO360 from a 1974 Cardinal 177RG (C-GUNY) SN-RG475 donor aircraft and it was approved. It was transferred to the United States in 2006 and the work began on restoring the entire airframe/engine.
Owned by Chad Vanderhoof in Elk, WA in the 2006 timeframe
Owned by Mark White (West Virginia) in the 2022 timeframe

N2347Y (Serial: 17700147

Owned by Keith Proctor as of 8/2022 in PA
As of 2022 was listed as being in Paint Lick, KY
Listed for sale in Hurricane, UT in the 2020 timeframe
Owned since 2000 (at least) by Mark J Perini
Seen in the Seattle area in the 2006 timeframe.
Owned by Noel Keefer around 1998

C-FWXO (Serial: 17700648)

Owned by Michael Anderson in Calgary, Alberta in 2006
Owned by John Cardiff in Calgary, Alberta around 1998, asking about W&B issues.

C-GELB (Serial: 17700865)

Owned by Glen Wright in 2022
Information from the owner in 2022:

It started life as N29402 serial number 17700865 and appears to have spent much of its life in Texas. It was apparently imported to Canada in 1998, and from what we can tell it was disassembled at some point for unknown reasons.

A fellow named George Pohl purchased it in 2004. At that time, Transport Canada allowed some discretion with respect to the "more than 50% rule" and he managed to reassemble and re-register this aircraft as amateur-built at that time. In 2008 TC issued a staff direction which basically ended conversions of commercially built aircraft to amateur-built.

It was renamed on it's aircraft registration as part of the conversion and is now known as a "Pohl 177 Canary" serial number 001. Aircraft registration is C-GELB. TC also allowed an increase of the gross weight up to 2600 pounds. It has a modified cowl for the IO-360 and a constant speed prop but otherwise looks like a '68.

N30208 (Serial 17701121)

As of 2022 based in Key West FL.
Owned by a Community College in Iowa for some time.
Based for a while in Clovis, CA.
Sold by John Lawson in 2001
Had a hard landing, bending the firewall and boot cowls, (perhaps around 1996?)
Owned at one point by John Lawson (who had a hook for his right hand.)
Said to have an engine from a Mooney in 2004.
Reported to have been initially done by Horton around 1980.

N???? - the mystery ship

Listed for sale in TAP in August of 2017
Reportedly built by a tech school in Colorado.
Rumored to be approved completely through 337s.

These pages are a collection of the ideas and impressions of the Cardinal pilots who frequent this site. This information is anecdotal, informal and may not be completely accurate. The Cardinal Flyers are not certified mechanics and do not guarantee the accuracy of the contents of these pages. Please research and confirm anything that is referenced on these pages with the experts appropriate to your situation.

As always, the Cessna maintenance, operations and flight manuals, and the advice of a certified mechanic and flight instructor, should be your primary sources of information regarding safe maintenance and operation of your aircraft.