(* cont.)
VACUUM ADVANCE
Ins. of merc. vacuum degs disributor advance degs. crankshaft advance
min max min max
<2 ----------- no advance to occur --------------
3 0 1.0 0 2.0
4 0 2.7 0 5.4
6 2.5 5.5 5.0 11.0
8 4.8 7.8 9.6 15.6
10 6.5 8.9 13.0 17.8
11 7.0 8.9 14.0 17.8
20 7.0 8.9 14.0 17.8
Whilst I find the above information intriquing, for my own TR4 ('63 open
breather but with 4A in & out manifolding) I am sticking with the Lucas 40795
with
vacuum unit 2-6-3 and carb needles spec'd just prior to final smog driven
choices.
Regards,
Carl
'63 TR4 since '74
ps; Randall regarding Greg's numbers shown below his 'degree crank advance'
should read 'degree distributor advance' according to my official factory
workshop manual.
> Inches Hg Degree Crank advance
> 2.0 0
> 3.0 1
> 4.0 1.75
> 5.0 2.5
> 6.0 2.75
--
-------------------------------------------------------------------------------------------
The data I have for a 40795A is that it should have a 54413565 vacuum unit,
with specs of 2-6-3 (normally marked on the unit). Meaning that advance
starts at 2 inches of mercury, and ends at 6 inches of mercury with a total
of 3 cam degrees (6 crankshaft degrees) advance.
YMMV ... if anyone knows different, please let me know.
Randall
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