After putting about 50 miles on a newly rebuilt B21F, I inspected the underside and discovered I was leaking quite a bit of oil out of the front crank seal. While running, it will actively drip a drop every few seconds. This is coming from a newly installed seal on a new engine.

I pulled the front pulley's and timing gear off the crank to inspect the seal. It was indeed clearly leaking from the inner diameter, where it touches the crank shaft. I carefully inspected the seal itself (pink silicon) and found no obvious tears, punctures, or damage. In fact, carefully prodding around the ID showed that it appeared to be tightly clinging to the crank OD just fine. I can't see any obvious damage to the crank surface either.

Short story, I can't see an obvious reason for leakage here. Oil weight is 15-40 Mobile 1. No leaking anywhere else I can see. I've confirmed oil pressure with a mechanical gauge to read 4 bars when cold, 1 or so when warm and idling.

I can blindly replace this seal, but I worry that the new one will leak as well. Any advice about what else could be going wrong here?