Monday morning I transferred some EUR from a Finish bank to my EUR Revolut account. When can I expect to see the amount in my Revolut account?
Now waiting 4 days.
At what time did you wire it on Monday? There is a chance it was sent only on Tuesday and with a day or two it might show up today.
Transferred at 10.15 am.
Should be today,or tomorrow 
Worst case scenario would say is monday …
You can clarify it with your bank but given it was relatively early I would assume it really was wired on Monday and hence should have already shown up. Maybe give it a day more - to be generous - but if it is still not there tomorrow something went wrong.
Are you absolutely sure all the details were correct, particularly the BIC?