740 ignition timing

Mr. V · 08-23-2021, 01:42 PM

'86 740 Turbo

I did a lot of work recently on it as I am restoring it / trying to cherry it out; among other things I replaced the distributor (rear mounted to cam).

It ran poorly.

I checked the timing with a timing light and it was way off, so I loosened the distributor and moved it til I showed 12 degrees before TDC, and now it runs great.

I was surprised to see that moving the distributor affected timing on this car, as I thought on this car timing was controlled entirely by the computer and that it couldn't be adjusted via spinning the distributor.

Live and learn, as they say.

2manyturbos · 08-23-2021, 01:50 PM

On LH 2.2 the base timing is adjusted using distributor body position. On LH 2.4 rotating the distributor body has no affect on timing unless you move it far enough for the spark to jump to the next terminal in the cap.

08-23-2021, 01:42 PM	#1
Mr. V Board Member Join Date: Jul 2004 Location: Portland, Oregon metro	740 ignition timing '86 740 Turbo I did a lot of work recently on it as I am restoring it / trying to cherry it out; among other things I replaced the distributor (rear mounted to cam). It ran poorly. I checked the timing with a timing light and it was way off, so I loosened the distributor and moved it til I showed 12 degrees before TDC, and now it runs great. I was surprised to see that moving the distributor affected timing on this car, as I thought on this car timing was controlled entirely by the computer and that it couldn't be adjusted via spinning the distributor. Live and learn, as they say.

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08-23-2021, 01:50 PM	#2
2manyturbos Moderator Join Date: Mar 2003 Location: Monroe, OR USA	On LH 2.2 the base timing is adjusted using distributor body position. On LH 2.4 rotating the distributor body has no affect on timing unless you move it far enough for the spark to jump to the next terminal in the cap.