Trent's RV14 Build: 43-08: Hanging the Engine (sort of!)

In order to run the engine on the engine truck, we need to use the engine mount from the kit. This means we will be sort of doing things backwards - instead of installing the engine mount to the airframe, then 'hanging the engine' in the traditional sense, I needed to install the engine mount to the engine first.

This will allow us to mount the engine to the engine truck for test running. My hope is that we can remove the engine / engine mount assembly from the truck and bolt it straight to the airframe.

Engine Mount Part Numbers

Some background on the engine mounts - firstly, the part numbers in the plans do not match the part numbers of the recieved parts.

The barry mount part numbers are as follows:

Mount 1 - 11900-71

Mount 2 - 11901-73

Spacer - 85-9217-02

Washer - 98-9074-11

These do not match ANY of the part numbers in the plans on page 43-08:

I posted a question on the forums, and it seems that most people are making the assumption that the final 2 numbers of the VIP mount is the same as the final 2 number of the Barry mounts as follows:

- VIP 50901-73 (HARD) = Barry 11901-73
-> This goes on the firewall side at the top, and the engine side at the bottom.

- VIP 50900-71 (SOFT) = Barry 11900-71
-> This goes on the engine side at the top, and the firewall side at the bottom

- VIP 50271-02 (Spacer tube) = Barry 85-9217-02

- VIP 50074-11 (Washer) = Barry 98=9074-11
-> This goes on the firewall side under the bolt head at the top, and on the engine side at the bototm between the engine at the mount (aka on the face of the HARD mount)

Trouble with the Engine Mounts

To install the engine mount to the engine, i pulled out the 4 boxes of Barry engine mounts from the shelves and laid them out:

Anyone see a problem?

As you can see from the above photo, the set of mounts second from the right, had 2 x 11900-71 (soft) mounts in the box instead of one 11900-71 (soft) and one 11900-73 (hard).

Frustrating! Check your engine mounts in their boxes when you inventory the FWF kit!

Moving on

Once i had returned the incorrect engine mount and recieved a new one, i was able to actually move on the install the engine mount to the engine. I followed the *very excellent* article written by Jim Norman (et al) called 'The Illustrated Guide to Engine Hanging'.

The TLDR is as follows:

Top Left and Right rubbers and bolts put loosely in and sit the mount on the engine.
Tighten TOP RIGHT to snug.
Tighten the TOP LEFT bolt to snug
Lift the engine mount, and slide BOTH the bottom left and right rubbers in place.
Install the BOT RIGHT bolt, and tighten this to snug
Install the BOT LEFT bolt and tighten this to snug
Torque all bolts!

This method worked perfectly - as you tighten one side you can see the other side come into alignment. I didn't even have to tap any of the bolts in.

A note is to make sure you get the correct rubbers in the correct spots - the -73 are the hard rubbers, and are the ones with the 'seam' around them. They are always matched with the large washer supplied in the engine mount box. They must be installed in compression - meaning at the top they go on the engine mount side under the bolt head, and on the bottom go against the engine.

At the bottom we install an additonal AN washer - this is just to lift the mounts off of the case, to clear a part of the casting.

I followed the instructions in Section 3 - Tools & Workspace (remember that?) and ground down a 5/8" spanner for the engine mount nuts - this worked great.

This is the top set of mounts - so the -73 (hard) mount goes in compression under the bolt head (along with the supplied barry washer).

Getting the nuts in on the top bolts was a challenge - no wonder a special spanner was needed!

The modified spanner

Only has to get through 4 bolts!

Initial tightening was done using 2 spanners

The nuts were initially snugged down using two spanners - for final torque i had to get a bit creative! The first issue is that you cannot torque the nuts - the torque wrench would not fit, so it is necessary to apply the torque to the bolt heads. There was hardly any running torque on these bolts (tested using a beam wrench), so i used the standard AN7 torque values.

For the lower bolts i was able to fit the torque wrench directly to the bolt heads using a standard socket.

For the upper bolts however, i was able to use a shallow socket on one side, and for the other needed to use an offset torque adapter. Luckily i was doing this at the engine shop and was able to raid some toolboxes! (if doing this at home, i will need to get a 3/8" drive 5/8" torque adapter).