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Re: 25d4 advancer distributer on a 68 B

To: HolePuncher <hoops@owt.com>
Subject: Re: 25d4 advancer distributer on a 68 B
From: Bill Schooler <schooler@erols.com>
Date: Wed, 09 Dec 1998 12:51:02 -0500
Note also that, as Larry specified, all of the figures give advance in
distributor degrees; to obtain total crankshaft advance, double that
number.

-- 
*Bill Schooler      *Check the MGCC Wash DC Centre Web Page
*Woodbridge, VA     *http://members.aol.com/mgccwdcc/
*schooler@erols.com 
*53 TD
*60 MGA 
*69 MGB/GT

HolePuncher wrote:
> 
> Ever notice how clarity can come a microsecond after you've hit the "send"
> button?
> 
> The first number is the onset of advance, the second number is the point at
> which maximum advance takes place, and the third number is the total advance
> provided by the vacuum unit.
> 
> Lonn Howard
> rocket scientist
> 
> "We are but temporary custodians with an obligation of preservation."
> ----- Original Message -----
> From: HolePuncher <hoops@owt.com>
> To: MGs <mgs@autox.team.net>
> Sent: Tuesday, December 08, 1998 10:37 PM
> Subject: Re: 25d4 advancer distributer on a 68 B
> 
> >Something seems to be missing in this equation.  I may be wrong, but it
> >seems very unlikely that the vacuum advance is designed to produce such a
> >linearly progressive advance, such that 1inch of mercury equals 1 degree of
> >advance.
> >
> >I'm going to put a vacuum pump on my distributor so that I can plot the
> >advance.  It's got me curious...
> >
> >Lonn Howard
> >'70 TR6  -mine
> >'71 TR6  -in my garage, therefore it's mine  (dad might disagree)
> >'70 MGB GT  -mine, mine... all mine
> >
> >"We are but temporary custodians with an obligation of preservation."
> >----- Original Message -----
> >From: Unger, Larry G <larry.g.unger@lmco.com>
> >To: 'Rene van Maanen' <renevm@support.neth.hp.com>; <mgs@autox.team.net>
> >Sent: Wednesday, December 09, 1998 6:45 AM
> >Subject: RE: 25d4 advancer distributer on a 68 B
> >
> >
> >>Rene van Maanen wrote:
> >>
> >>> Does someone know what the number of degrees is that the
> >>> vacuum advancer creates for the ignition?
> >>>
> >>> It's a 25d4 advancer distributer on a 68 B.
> >>
> >>Rene,
> >>
> >>Here is info that Kelvin posted awhile back ...
> >>
> >>
> >>> MGB     Dist#    Vac.#  Vac.Adv.  Type
> >>>
> >>> 18GF    40897  54411230 5.13.10  ported
> >>> 65-67   41288  54411985 5.13.10
> >>> 67      41290  54412170 5.11.7
> >>> 68      41288  54411985 5.13.10
> >>> 69      41264  54415625
> >>> 70      41288  54411985 5.13.10
> >>>
> >>> 71 18GK 41339  54414868 7.13.5   manifold
> >>> 72 18V  41370  54423989 7.13.3
> >>> 73-74   41491  54425359 10.15.5
> >>> 75      41599  54425516 10.15.5
> >>>
> >>> Note the change in advance characteristics in 1971.
> >>> The later units come in at a higher vacuum and gives
> >>> less advance.
> >>>
> >>> 10.15.5  = Movement starts at 10 ins of Mercury
> >>>            Movement stops at 15 ins of Mercury
> >>>            5 distributor degrees advance at maximum movement
> >>>
> >>
> >>Hope this helps ...
> >>
> >>**********************************************************
> >>Safety Fast! ... larry.g.unger@lmco.com
> >>'61 MGA 1600 MkII
> >>
> >
> >

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