Thread: BBC Main Seal

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Embarrassed to ask but... I'm putting together a BBC 427 - 2 piece rear main seal and I cannot remember which way the rear main seal goes in. Does the lip point to the transmission or to the front of the engine ? ... or does it matter ?
Thanks,
Ron D.

Just remember that the seal relies on crankcase pressure to push it against the shaft, so it has to "lean in" to that pressure.

Originally posted by DennyW
Pcv system, neg pressure in crankcase.

there is none in mine.