You can disable journaling on a non-startup volume. Open the Terminal application in your Utilities folder. At the prompt enter and press RETURN:
df
You should see something like this:
Filesystem 512-blocks Used Available Capacity Mounted on
/dev/disk0s2 324779648 176462256 147805392 55% /
devfs 210 210 0 100% /dev
fdesc 2 2 0 100% /dev
map -hosts 0 0 0 100% /net
map auto_home 0 0 0 100% /home
/dev/disk0s3 65008352 27592336 37416016 43% /Volumes/Snow
You are interested in an entry like the one I have set in bold. At the end you should see a "/" followed by the name you have assigned to the disk you want to modify. In the above example it's /Volumes/Snow. Now, select the disk you are going to modify on your Desktop, then select Eject from the Finder's File menu. Next enter the following pressing RETURN at the end:
sudo diskutil disableJournal force /dev/diskID (from df output, such as disk0s3)
You will be prompted to enter your password which will not be echoed. If the operation succeeds you should receive a line of output indicated that journaling is now disabled on the selected drive.