Dave,
Do you have the right numbers stamped on your TR4A distributor parts? Vacuum
advance should be stamped 2-6-3 (near neck). Distributor base should be
stamped 40795 with date stamp something between '65-'70.
Your photos look normal. The advance stop arm should have a 10 (degrees)
number stamped on it. The smashed washer on the post ain't right - get rid of
that. Your weights look ok.
I bought the correct weight springs from Moss, listed specifically for a
40795 dizzy. They are two identical light springs for $8.00/pair. Moss also
sells
a 5-pack of assorted springs for modifications but why not just get the 2
correct ones? Ideally you would bring your rebuilt dizzy to a shop to run up to
speed on a SUN or similar machine to check vacuum/advance weight calibrations
against your Factory Manual tables (see ELECTRICAL section ) - lacking that, at
least make sure you have the right vacuum unit 2-6-3, distributor #40795, and
new 40795 advance springs.
The typical problem (besides having incorrect items installed over the years)
is after many miles the main shaft bearing wears and you end up with a sloppy
cam and rotor (more than .010" play is worth rectifying), a roving cam
affects your dwell and idle and even running. I opted to find a tight used
housing
for $10.00 at Brit yard to rebuild rather than buying/installing the $60.00
bearing.
Good luck,
Carl
'63 TR4 since '74
----------
On my distributor rebuild,, it seems one of the mechanical advance springs
has disappeared completely. Like somebody took it out missing.. I checked
the vacuum advance and it works OK using a vacuum pump and holds the vacuum
for long enough to rule out a slow leak. Are these springs available? I
found a suspicious break on the movable part of the mechanical advance that
looks to me like it broke off. Although it could be a stop for the
mechanical advance too. I have a picture of it on my website in the
engine/distributor section. Maybe somebody can shed some light on it.
Thanks in advance,
Dave Connitt
'67 TR4A
http://home.fuse.net/davestr4a
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