Anybody ever seen a front seal push out of the timing chain cover for no apparent reason? The whole seal, metal and all.

A little too much blowby?

They're brand new motors, 540's. About 75 hours, breathers in both valve cover. However, on a couple of occasions each of them have pushed the dipsticks out about a half inch.

Doesn't use any oil or drip from the breather.

i agree with mild,to much crankcase pressure can cause that.

Long story short. Rebuilt one motor put new valve cover breathers on both, two per motor. After long hard runs old motor lost oil out of rear main seal. Pulled old motor replaced seal, oil leak not so bad now and both dipsticks are up two inches. WTF!! Took the foam out of the new breathers and that fixed my problem.Good luck and be safe.

Are these motors boosted or naturally aspirated?

There is hardly any blow by at the valve covers. Are you talking pressure just from the displacement of the pistons? Why the hell would it push out a driven in seal before it could pop a valve cover breather out of its grommet, which on my motors just happen to fit loosely?

NA Matt.

Since you mentioned this the dipsticks have only been pushed out when the breathers have a few hours on them since being rinsed with Avgas.