>Thanks everyone....
>one more ill-cross-referenced confusion remains...
>I have two dists.
>1) a 41288 body with a 54411985 vac adv attached which operated correctly
>this is the one I have the XR700 elec ign. in and was using on OB
>2) a 41491 body with a 54425359 vac adv attached which is blown
>I screwed up and can't remember which dist. body had which weights and
>springs
>I have two weight sizes, and two spring sizes. The Burgess book 'How to
>Power Tune MGB
>4 Cylinder Engines" shows a picture on page72 of the dist. and weights
>the smaller of the two weights is trimmed off at the end that is furthest
>away from the pivot.
>The photo in the book looks like the heavier of the two weights.
>One of these two dists. had two heavier springs (appear equal in size)
>and one had one heavy and one light spring.
>
>QUESTION : Which weights and springs go with which dist?
>
>I tried running the vac of the manifold and for the first time all the
>little items related to balancing the carbs, pushing up the pins to hear
the
>speed change, etc etc WORKED PERFECTLY
>It' tuned up great.
>
>PROBLEM: I believe my vac advance and the screwed up weight configuration
is
>limiting my useful power curve under this setup on OB WHAT SPRINGS AND
>WEIGHTS DO I NEED?.
>
>
>Paul Tegler
>OB - 1973 MGBGT (Blaze Red, (orange))
>YB - 1973 MGBGT (Primrose Yellow)
>wizardz@amdyne.net
>http://www.amdyne.net/~ptegler/mgmain.htm
>-----Original Message-----
>From: Bill Schooler <schooler@erols.com>
>To: wizardz <wizardz@amdyne.net>
>Cc: MG list <mgs@triumph.cs.utah.edu>
>Date: Sunday, January 10, 1999 2:29 PM
>Subject: Re: Advance timing and stumble
>
>
>>wizardz wrote:
>>>
>>> I presently have a 19 degree advance plate in my distributor.
>>> Using the heavier weights, one heavy and one light spring,
>>> I'm dynamicly timed at 14-16 degrees BTDC at 1200 rpm
>>> it dynamically times at 12 degrees BTDC at 650-700 rpm
>>> The vacuum advance unit come in at 5 HG of vac. and will
>>> give a full vac adv of 10 degrees at 15 HG of vac.
>>> This 19 degree plate means I'm getting 38 degrees of
>>> timing advance at max (mechanical limit) plus a possible
>>> 10 more degrees from the vac advance.
>>> This seems like too much to me. TRUE OR FALSE?
>>
>>FALSE. Per John Twist, the 73-74 18V engines used a distributor with 39
>>degrees of total advance (close enough to your 19 degree plate). Vacuum
>>advance was to be taken from the manifold and provided 10 degrees
>>maximum.
>>
>>>
>>> I think for a ' 73 BGT I should Only have a 10 dgree advance
>>> (mechanical limit) plate in the dist. TRUE OR FALSE?
>>
>>FALSE. See above.
>>
>>>
>>> QUESTION? Could the light spring, and heavy wieght be
>>> adding too much adv at at lower speeds and then too much
>>> as well at higher speeds, and this is the reason the vac adv
>>> seems to have such a powerful impact on the timing at
>>> cruising speeds? (ie stumble at crusie)
>>
>>Pass on this one.
>>
>>>
>>> I thought the 73 should have had a vac advance unit that came in at
>>> 5 to 7 HG and only added 5-7 degrees? TRUE OR FALSE
>>
>>Don't know the curve, but the latter spec is not correct. Should be a
>>total of 10 degrees vacuum advance. By the way, Paul Hunt gave you the
>>correct timing information, according to John's book. Static is 6
>>degrees BTDC, dynamic is 12 degrees BTDC at 1500 rpm
>>
>>--
>>*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
>>
>
>
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