We had a consulting partner who did the same for our company. This is his procedure and worked great:

How to migrate ovirt management engine
Packages
Ensure you have the same packages & versions installed on the destination hostas on the source, using 'rpm -qa | grep ovirt'. Make sure versions are 100%identical.
Default setup

Run 'engine-setup' on the destination host after installing the packages. Use
the following configuration:
1.    Backup existing configuration
2.    On the source host, do:
a.    service ovirt-engine stop
b.    service ovirt-engine-dwhd stop
c.    mkdir ~/backup
d.    tar -C /etc/pki/ovirt-engine -czpf ~/backup/ovirt-engine-pki.tar.gz .
e.    tar -C /etc/ovirt-engine -czpf ~/backup/ovirt-engine-conf.tar.gz .
f.    cd /usr/share/ovirt-engine/dbscripts
g.    ./backup.sh
h.    mv engine_*.sql ~/backup/engine.sql
3.    You may also want to backup dwh & reports:
a.    cd /usr/share/ovirt-engine/bin/
b.    ./engine-backup.sh --mode=backup --scope=db --db-user=engine --db-password=XXX --file=/usr/tmp/rhevm-backups/engine-backup --log=/tmp/engine-backup.log
c.    ./engine-backup.sh --mode=backup --scope=dwhdb --db-user=engine --db-password=XXX --file=/usr/tmp/rhevm-backups/dwh-backup --log=/tmp/engine-backup.log
d.    ./engine-backup.sh --mode=backup --scope=reportsdb --db-user=engine --db-password=XXX --file=/usr/tmp/rhevm-backups/reports-backup --log=/tmp/engine-backup.log
4.    Download these backup files, and copy them to the destination host.
Restore configuration
1.    On the destination host, do:
a.    service ovirt-engine stop
b.    service ovirt-engine-dwhd stop
c.    cd backup
d.    tar -C /etc/pki/ovirt-engine -xzpf ovirt-engine-pki.tar.gz
e.     tar -C /etc/ovirt-engine -xzpf ovirt-engine-conf.tar.gz
f.     tar -xvjf engine-backup
g.     tar -xvjf dwh-backup
h.     tar -xvjf reports-backup
 
Restore Database
1.    On the destination host do:
a.    su - postgres -c "psql -d template1 -c 'drop database engine;'"
b.     su - postgres -c "psql -d template1 -c 'create database engine owner engine;'"
c.     su - postgres
d.     psql
e.      \c engine
f.      \i /path/to/backup/engine.sql
NOTE: in case you have issues logging in to the database, add the following
      line to the pg_hba.conf file:
     
       host    all    engine    127.0.0.1/32        trust

2.    Fix engine password:
a.    su - postgres
b.     psql
c.    alter user engine with password 'XXXXXXX';
Change ovirt hostname
On the destination host, run:

 /usr/share/ovirt-engine/setup/bin/ovirt-engine-rename








NB:
Restoring the dwh/reports database is similar to steps 5-7, but omitted from
this document due to problems starting the reporting service.