Is this layover time okay? And will I have to go through security again?

Leaving Portland, arriving in MSP (Minneapolis) on 8:16 PM on a Sunday. Then my plane to London leaves MSP at 9:40 PM. Is 1 hour, 24 minutes a good layover time? Also, will I have to go through security again in MSP? The last time I flew to London I went through Philadelphia and did not have to go through security again, so I don't know if that's how it is in all airports or not.