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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