Don't know how different an 18R-C is from a 22R/RE
Oil pump is on right now? If so, align the pulley's mark with TDC and check that both cam followers are on each's cam lobe's base. If either one is not, go around a full turn and see how that looks.
With the pulley @ #1 TDC, the tooth with the mark under it (drilled divot usually) on the cam sprocket should be at the top. Some chains have two bright side plates, one goes on the crank pulley tooth with the drilled divot marker, the other goes on the cam sprocket tooth with the mark. The drilled divot tooth on the crank sprocket is opposite of the keyway, so when the crank is at TDC #1, the keys are up and the divot is down.
If the oil pump leaks at the balancer you'll want to replace the seal. The black ones I've had fail on me for no appearent reason. The rusty red ones seem to work much better. If there is a groove or any roughness on the damper's seal surface you need NAPA p/n 600-2501 "Redi-Sleave". There are possibly other true Redi-Sleaves out there to fit here, but this p/n has been known to be particularly (surprisingly) inexpensive.
The pump O-Ring can fall out of the pump body groove and cause a leak. I use heavy grease to hold it in while installing the pump.
