Private lending using self directed 401k

[Julia Trudeau]

I presently have a 401k. I am wondering if I wanted to set it up to do private lending out of it and so set it up to be self directed, how do I handle the portion of funds that I don’t want to lend out? 

For example, If I wanted to use 1/2 of it to do private lending, but not all of it, can I just conservatively invest the other 1/2? How does this look?