No idea what application a 41147 is for but the vacuum advance almost
certainly works the same as any other. I say 'almost' as some people claim
that the vacuum capsule on some dizzies on some engines *retards* the timing
whereas all those for the MGB advance it, ported vacuum or manifold.
However your biggest problem is likely to be the curves on the 41147 will be
different from what your engine requires. If the two dizzies are both the
same type i.e. both 25Ds or both 45Ds then just swap the vacuum capsule over
and retain the dizzie body. That way at least you will keep the centrifugal
advance as it was. The vacuum capsules usually have the advance details
stamped on them somewhere in the form 5-13-10 which means the vacuum advance
starts at 5 in. Hg. and reaches a maximum of 10 dizzie degrees (20
crankshaft degrees) at 13 in. Hg.
According to the Leyland Workshop Manual the 41339 is for the 1971 8.8:1
compression engine, i.e. high compression.
If you have the 18V 672/673 (CB) engine you should have the 41491. If you
have the later 18V 836/837 (RB) engine I cannot find that listed in any of
my sources so don't know what it should be. The 41491 has a higher max
centrifugal advance than the 41339 and requires more vacuum to give the same
amount of vacuum advance.
----- Original Message -----
From: "Bill Mills" <williem@mindspring.com>
To: <mgs@autox.team.net>
Sent: Sunday, May 26, 2002 3:56 AM
Subject: Dizzy help
> I had to pull the dizzy on my '74 BGT with HIF4's because the vaccum
advance
> was leaking. I got a 41147 to put in there. This number does not match
> with ones on paul's chart at
>
> http://www.teglerizer.com/mgstuff/advance_curves.htm
> any ideas what a 41147 was from, would it work with a manifold vaccum
> source???
>
>
> I've also got a 41339 in the shop that may have a good vaccum advance unit
> on it. It is listed as appropriate for a '71 low compression and manifold
> vaccum source which is what I have with the HIF4's.
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|