Valve Seals, Engine building

["Allan Weidenheimer" <allanw@domain.elided>]

For anyone thinking of changing the valve lift
(ala new cam) and/or installing valve seals,
you should assemble a head with ONE set of valves
using a WEAK spring.  Find some modelling
clay, and flatten it and place on top of the piston,
Put the head on the engine using either an old head 
gasket or no gasket, then put the pushrods and rocker
setup on.  HAND turn the engine through a few revs and
check for CLEARANCE to the valve seals at max lift
(both intake and exhaust, if so installed), and after 
removing the head, cut (section) the clay with a knife,
and measure the clearance.  Many hi-po engine building
books list suggested clearances, I can't recall any
exact figures right now.  The important thing is, DON'T
ASSUME things will clear.  Always check, building an
engine costs too much $$$ not to spend an hour to
make sure.

Allan Weidenheimer
72 1210 Pickup