RH Eckensberger

Have loud engine knock on startup that quiets down, not entirely, upon warmup. Dealership replaced oil pump but noise is still there. Sounds like piston slap, but could it also be due to a bent pushrod? Went to pick it up this morning and techs came out to hear what I was talking about. They're going to hold it overnight and check again tomorrow. Seems to be a semi-common problem with this motor from what I see online. Anybody on this forum familiar with this, know someone who had it repaired, and what was done?