The Cessna 120-140 Association Forum

I ran into an IA at the airport while I was working on the airplane and he started peeking under the hood. He wasn't too happy with how the exhaust was mounted for my engine. The STC doesn't call out any specific instructions for mounting the exhaust, so he asked me to post here seeing if anyone had any experience with mounting the exhaust for the O-290-D.

Any input?

As usual thanks for all the help, this place has been a real gold mine of information.

Yes, you can contact Reddoch Williams in Fort Walton Beach, FL and Tom Julian at Julian's Aircraft Repair in Holt, FL.

Reddoch has a 140 with the 0-290 installation. Tom did the conversion for Reddoch.

If you have an association membership book both Reddoch and Tom's numbers are listed.

Tamer, my exhaust isn't mounted to anything but the engine. The rest of the assembly just hangs out under the engine. No attach brackets or anything. I can take off the bottom cowling if you need better photos but here is some from the top and bottom.

I sent some photos of my exhaust to Custom Aircraft Parts in El Cajon, CA. They came highly recommended from my IA. They recommend a crossover exhaust system for the lycoming. He sent me photos of a 120 (O320) with their crossover system. Just curious if that member is on here? Wondering how much louder it is without mufflers. He said I can do with or without mufflers. Losing a few more pounds on the nose would be nice if it's not significantly louder.

Anyone know the owner of this aircraft?

O-320!!! WANT! That thing has got to be silly. I'm curious about our 50 hour exhaust AD and if that exhaust system will dispose of it. Our company got an AMOC for a 50 hours exhaust AD on the TSIO-520 by installing Knisley exhaust. At $1800 it had better have no AD, make me 10 knots faster, and weight 20 pounds less.

Joshua

8340 wrote: ↑Tue Feb 26, 2019 7:37 pm I'm curious about our 50 hour exhaust AD and if that exhaust system will dispose of it.

Do you mean the 25 hour exhaust AD? If so, it only applies to the "pancake" mufflers originally installed on '47 and '48 planes. If you have an O-290 you don't have them any longer.

6643 wrote: ↑Tue Feb 26, 2019 7:48 pm

8340 wrote: ↑Tue Feb 26, 2019 7:37 pm I'm curious about our 50 hour exhaust AD and if that exhaust system will dispose of it.

Do you mean the 25 hour exhaust AD? If so, it only applies to the "pancake" mufflers originally installed on '47 and '48 planes. If you have an O-290 you don't have them any longer.

No, the McKenzie STC for the O-290-D2 installation has AD 62-24-03. 50 hour intervals.

8340 wrote: ↑Wed Feb 27, 2019 2:01 pm No, the McKenzie STC for the O-290-D2 installation has AD 62-24-03. 50 hour intervals.

Ah! Lucky you. No mention of specific exhaust systems (or a particular engine, for that matter) and no terminating action. I think you're stuck with it unless you can get the FAA to approve the new exhaust as a terminating action (or the exhaust manufacturer has already done that.)

Exactly my hope. If the maufacturer hasn't accomplished that, maybe I can get an alternate method of compliance from the FAA.

Joshua

Joshua,

I've gotten two AMOCs from the FAA. If you have a FSDO that will work with you it is not all that hard. I got the approval to remove ( or not install) the primer line shielding on the firewall for the 1946 aircraft that have the pancake and 150 exhaust.

Bil