Exhaust System

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

Post Reply
User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Exhaust System

Post by 170C »

On our O-300 engines, the exhaust clamps used between the cylinder exhaust pipe and the exhaust manifold. What is the correct description of those clamps (could not find them on Spruce)? The four bolts & nuts that secure the two halfs of the clamps above, what size are they?
Thanks!
OLE POKEY
170C
Director:
2012-2018
User avatar
GAHorn
Posts: 20968
Joined: Fri Apr 12, 2002 8:45 pm

Re: Exhaust System

Post by GAHorn »

Frank, here's what you are asking:
https://awi-ami.com/partfinder/product/ ... COMPONENTS

The bolts are AN3-4A and if you prefer AN4C will be corrosion-resistant. The nuts are MS20365-1032C.

Here's the "whole enchilada": https://awi-ami.com/cessna-170-a-b-172a.html

Tell Charlie Field I said hi...and he'll either give you a real nice discount...or he'll charge you more... one or the other.. :lol:

(TIC170A discounts apply)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
n2582d
Posts: 2808
Joined: Mon Apr 29, 2002 4:58 am

Re: Exhaust System

Post by n2582d »

Wag-Aero E-505-007 See also Cessna p/n 0550157-50 and 0550176-50
EF187911-B01D-4F57-A56C-06D3E4FA023D.png
Fig. 51-6 calls for AN365-1032C nuts to attach the exhaust riser clamps. When I see “AN365” I automatically think “elastic stop nut”. As we all know elastic stop nuts should not be seen in the engine compartment; they are for low heat applications. AN365-1032C however is different than AN365C-1032. The former is an obsolete p/n for an all metal locknut. The latter is a stainless steel locknut with an elastic insert - you don’t want to use that here. I believe the number George gives, MS20365-1032C, supersedes the obsolete AN365-1032C. MS20365-1032C is what Cessna calls for in the ‘75-86 C-172 IPC. It’s good up to 450°F. I’d recommend using AN363C1032 (MS21046C3) all metal stainless locknuts which can be used in applications up to 800°F.
MS21046C3
MS21046C3
F754C215-E87D-49E1-8458-1C1C571D90B1.jpeg (18.7 KiB) Viewed 12168 times
Although Cessna continues to use regular AN3-4A bolts on later 172’s I’d consider using AN3C4A corrosion resistant steel bolts and AN960C10 washers which are used in applications up to 800°F according to Genuine Aircraft Hardware Co. Typical egt’s are well over 800°F though so if you gotta have the top of the line hardware - good for up to 1200°F - use MS20033-1 bolts, NAS1587-3 washers, and MS20500-1032 or 990FR12-1032 nuts. Whatever you use slather on some Permatex high temp anti-seize to keep the expletives to a minimum for the next guy removing the clamps.
Last edited by n2582d on Sat Aug 05, 2023 2:46 am, edited 2 times in total.
Gary
User avatar
cessna170bdriver
Posts: 4059
Joined: Mon Apr 22, 2002 5:13 pm

Re: Exhaust System

Post by cessna170bdriver »

I love this different design that only requires two bolts! It’s worh $64 to not have to tighten the inboard ones...
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
User avatar
Stankasica
Posts: 16
Joined: Tue Oct 18, 2016 9:08 am

Re: Exhaust System

Post by Stankasica »

Especially on the #3 and #4 risers
Stan Kasica N2458D
KSNC. Chester,Ct
User avatar
johneeb
Posts: 1520
Joined: Thu Jun 26, 2003 2:44 am

Re: Exhaust System

Post by johneeb »

cessna170bdriver wrote:I love this different design that only requires two bolts! It’s worh $64 to not have to tighten the inboard ones...
Miles they are even better at the $50.64 price Gary found at Wag-Aero

https://www.wagaero.com/engine-parts/ex ... pma-d.html
John E. Barrett
aka. Johneb

Sent from my "Cray Super Computer"
User avatar
flyguy
Posts: 1057
Joined: Mon Apr 22, 2002 6:44 pm

Re: Exhaust System

Post by flyguy »

Wag Aero . . . Some of their stuff can be less than top drawer. Just sayin.
OLE GAR SEZ - 4 Boats, 4 Planes, 4 houses. I've got to quit collecting!
Post Reply