Engine mount to Firewall bolt torque for N1320D

[Psmith]

I have a 51 170A. What is the criteria for replacing the rubber pads (engine mount to firewall) and what is the bolt torque. Also there are 2 slotted tabs on copilots side, cabin side of the firewall, what are/were they for? Thanks.




Pete Smith N1320D
Lewistown, MT

[n3439d]

The cessna 172 manuals cover this subject well, the mounts and torque values are listed.

ken

[GAHorn]

I have a 51 170A. What is the criteria for replacing the rubber pads (engine mount to firewall) and what is the bolt torque. Also there are 2 slotted tabs on copilots side, cabin side of the firewall, what are/were they for? Thanks.


Pete Smith N1320D
Lewistown, MT

The "Cessna 100 Series, 1962 and prior, Service Manual" (available from Aircraft Spruce 877/477-7823) says to tighten the mounts until the rubber mounts "bulge out slightly". The mounts should be replaced whenever they are dry rotted, cracked, sag excessively or are excessively age-hardened.
Some mounts (not usually found on 170's) have a steel bushing within the mount itself, and those should be torqued according to the torque tables found on page 1-8 in the service manual.

[Psmith]

Are the rubber firewall mount pads typically replaced before the plane is 52 years old?


Pete

[mit]

Are the rubber firewall mount pads typically replaced before the plane is 52 years old?


Pete

Probably. 48's don't have any except at the eng. to mount.

[N170BP]

Mine were trashed, and I suspect they were the originals.
I was looking for a torque value as well but only found
the blurb in the 100 series service manual saying to tighten
them until they bulge slightly. I suppose over-tightening
them could lead to cracking / failure....

The bushings were relatively inexpensive (got them
from http://www.iwantcessnaparts.com).

Bela P. Havasreti
'54 C-170B N170BP