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...according to Don Foster's post from the archives, below:
Re: replacing the timing belt -- CAUTION with "the rope trick"?/91] posted by Don Foster on
Saturday, 18 September 1999, at 1:19 p.m.
>>>First, when loosening the pulley bolt, you must set the engine to #1 TDC, and then turn the crank about 90 degrees clockwise. Stuff in the rope. Then, when you start loosening the bolt, the rope compresses against CLOSED valves (the cylinder's in the power stroke).
To tighten 'n retorque the pulley, bolt -- again set the engine to #1 TDC, but turn the crank 90 degrees counterclockwise. Stuff in the rope and tighten and torque. Again, the rope is compressed against CLOSED valves (the cylinder's in the compression stroke).
Two things are important -- making sure you're setting TDC for #1, and making sure you stage the piston to push UP against rope.
If you simply turn the crank "...so the piston is about half way down the barrel..." you have a 50-50 chance of timing on #4, and a 50-50 chance of catching #1 headed down (not up). So you have a 75% chance of bearing against an open valve, and maybe doing something very expensive.<<<
I do it with even less than 90° rotation each way.
You'll be at #1 TDC when the HB mark is at 0° and the distributer rotor points at the #1 tic mark on the distributor body. Cam sprocket marks will also line up, assuming only the HB has been removed.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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