intermittent spark knock and nyb timing chain stuff

["mike sutton" <mikanlin62@xxxxxxxxxx>]

It appears the consensus on the spark knock has already hit most of the
common culprits.  Check the dist mechanical advance springs to see if one
has broken or has stretched.  You wont catch that at idle necessarily
depending on idle speed, it may or may not have begun to swing out with
centrifugal force against the other spring.  Its not hard to check, just
pull the cap and look down under the advance plate and visually check them.
I would guess vac advance issue perhaps or one of the other conditions
already mentioned.

On the subject of the 78 NYB timing chain.  You need not worry about turning
the engine over after you remove the chain and gears.  These engines are not
an interference type so unless someone has installed a HUGE  lift cam in the
thing youll never get the valves that close to the pistons.  Also, the
reason the problem can exist with the cam hitting the welch plug is from
driving the cam gear onto the cam can push the cam rearwards, and the
distributor / oil pump drive shaft isnt going to totally eliminate the cam
from moving rearwards. If one was to push the cam that far back to dislodge
the welch plug then there will be some other issues Id rather not think
about....one of which will be an absolutely horrendous oil leak at the back
of the engine.

 Find a piece of hard plastic, nylon, really anything that wont let it move
and use it as a lever to keep some forward pressure on the cam as you put
the gear on. zDont use something thats either so brittle it breaks and falls
inside the engine or something so small that it just falls down inside.
Careful using metallic stuff incase you happen to slip and nick a cam lobe.
I  have replaced numerous cam gears and never had to use that much force to
get one on anyway.  Light tapping with a mallet or hard plastic hammer has
always done the trick,  if its going on that hard theres probably something
wrong otherwise.


Mikey
62 Crown Coupe