1966 mustang 289 timing - Ford Mustang Forum

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post #1 of 6 (permalink) Old 04-17-2011 Thread Starter
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1966 mustang 289 timing

hi going to replace dis-what should the timing be set at??? is this vary hard too do???? do i block off the vacume hose when i do this??? thanks so much.you ford guys are the best in the west

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post #2 of 6 (permalink) Old 04-17-2011
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Set timing at 6 degrees below top dead center with the vacuum line detached.

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post #3 of 6 (permalink) Old 04-17-2011
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You have to know how much timing is built in to the distributor in order to decide where to set the initial timing. The easiest way is to have a shop find out what the timing curve is inthe distributor and then set the initial timing to provide for an overall maximum advance of 34 degrees before top dead center.
The cheap way is to disconnect the vacuum advance hose and plug it and then set the timing at 34 degrees with the engine running at 3500 rpm. Check it at idle and that is where it should be set at an idle. Be sure to reconnect your vacuum advance after setting it up.

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post #4 of 6 (permalink) Old 04-18-2011
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Although you should set the timing without the vacuum advance I have never owned a 289 (all were stock) that had any vacuum advance at idle. If that is the case for you then disconnecting it will have no effect up timing at idle. That is somewhat fortunate since an original 289 setup does not have a vacuum hose but a steel line threaded into the vacuum advance which is more difficult to disconnect.

Is it hard to do? No, as long as you have a timing light and I think its a 9/16" wrench. I always set the timing at idle since it easier especially since the timing marks on a stock balancer only go to 12 degrees. If you have the proper scale marking and a way to maintaining a high idle PaulS method is also valid.

If everything you have is stock the idle timing should be 6 degrees BTDC. If you look in the shop manual there are about 15 different distributors for a 289 with slightly different total advance curves. They are all supposed to have 6 degrees at idle except the HiPo which was 12 and the Thermactor cars which were Zero. The Thermactor cars were intentionally mis-tuned from the factory for emissions and I doubt that many people ever really sets 289 timing at Zero after the cars were sold.
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post #5 of 6 (permalink) Old 04-18-2011
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Thank you. ..as I said.

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post #6 of 6 (permalink) Old 04-19-2011
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I have seen that manuals set at 6 BTDC and automatics are 10 BTDC. Mine runs great at 10, but 6 was a different story.

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