illbird, a cause of timing problems is the harmonic damper on some 240's. When I replaced my last timing belt, found the rubber insert between the inner and outer parts was slipping. Since the timing marks are on the outer part of the balancer, it can slip and give you a wrong starting reference. The dealer wanted $180. for the part, got it from Pelican for $60. with free shipping!

If you don't get a timing light, try this as an approximate, temporary setting:

1) Put the crank at 0° per pulley and belt cover marks.

2) Remove dist cap, rotor, and plastic dust shield.

3) Put rotor back on and compare its centerline position to 0° notch on dist body. If 15° advanced, the rotor CL will probably be more than 5/16" past the 0° notch mark (CW rotation).

4) Loosen the adjustment lock bolt and rotate the dist body CW to reduce the rotor CL distance past the 0° notch mark to 1/4" (no less, or it will be too retarded). Make a reference mark for this setting at the base of the dist where it meets the block.

5) Tighten dist lock bolt, replace dust shield, rotor, and cap. See how it drives. If needed, rotate dist (using reference mark) CW to advance, CCW to retard more.

From the Grasping At Straws Dept. at Anal Engineering
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.