[Healeys] Distributor vacuum units

[Eric Frenken]

Kees,

I have to disagree with you in that point. First it is most likely that
older, used vac units all leak or do not work properly unless they've been
rebuilt. Secondly the Lucas DM6A maxes out at about 4,000 rpm crank and last
but not least the vac unit on DM6As does not retard but advance the ignition
(right at the moment I don't know how much but I think it should be in the
region of 10-120), mainly under part load, when vacuum got to its max.

Dizzys on Cal. TR6s were equipped with 2 vac units, one for advancing, the
other for retarding the ignition. This was done for emission reasons, which
was never a concern as long as our Healeys had been built.

Eric
D

-----Urspr|ngliche Nachricht-----
Von: healeys-bounces at autox.team.net [mailto:healeys-bounces at autox.team.net]
Im Auftrag von Oudesluys
Gesendet: Dienstag, 8. Dezember 2009 08:57
An: richard mayor
Cc: healeys
Betreff: Re: [Healeys] Distributor vacuum units

There are plenty of used units about that can be used as a donor, e.g.
from Triumph, Mini, Morris, Landrover, MG etc. I do not know if they
differ a lot or at all in spring rate, but I would guess they are all
more or less the same. May be left and right handed units have different
vacuum units.
However if you set the ignition dynamically, e.g. at 2500rpm (about when
usually the max advance is reached) you can do away with it alltogether.
Most performance engines do not use them. They are there to retard the
ignition (about 4 degrees) when idling to reduce emissions somewhat.
Kees Oudesluijs
NL