|
Hi Joseph,
Are you sure you're up for this T belt job? Those are pretty basic questions that we all asked at some point, but your asking them now suggests that you don't have a service manual (I recommend the Bentley over Haynes), or haven't yet looked in the 700/900 FAQ at all tips and info there on this job (same engine as 240), such as THESE PICTURES.
Anyhow, on to your questions...
• 1) How do I rotate crank and what is #1 0° TDC Compression?
Rotate the crank in the normal direction (CW as viewed from the front) with a 15/16" (or 24mm) socket and ratchet wrench on the pulley bolt.
Identify Top Dead Center (TDC) for the #1 piston, on its compression stroke, by stopping the crank rotation when the small notch on the crank pulley outer edge is aligned with the 0° [unmarked] reference line/ridge on the flat surface of the Timing Belt Cover (lower half).
Be aware that the notch and 0° mark are also aligned whenever the #4 piston is at its TDC position, so you should check the position of the two cam lobes for #1 cylinder—which will only be as described at #1 TDC. On your 240 you could also take the distributor cap off and make sure the rotor is pointing toward the #1 plug wire.
NOTE: The outer (belt drive) part of the pulley has been known to slip on the rubber that bonds it to the inner hub that's secured to the shaft — another reason to verify the TDC position by cam lobe or distributor rotor position. If you find your outer pulley has slipped, the whole thing should be replaced before it causes damage.
• 7) Tighten bolt the same way, but start with crank about 90° before #1 TDC Comp, ......Do I get the crank 90° before #1 by continuing to turn
another 180°?
This would be after you have removed the rope, the new T-belt is on, and you've rotated thru a couple of turns to make sure all three timing marks are still in sync. [The pulley or a spacer has to be in place so you can use the bolt head to turn the crank.]
I think at this point I usually snug the pulley bolt a bit tighter by smacking the ratchet by hand, so I can rotate everything about 90°back from 0° while eye-balling the notch on the pulley.
Then, with the lower cover and pulley in place, stuff the rope in again for the real bolt tightening. [If you don't have a torque wrench, use a moderate one-arm pull for the initial 44 ft lbs. Then use a 2' pipe on your 18" breaker bar for that additional 60° of tightening. I have to brace myself on the left fender, use both arms and my back, and give it all I've got. But then, I'm an old codger now.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
|
