OEM GMC Savana 2500 Timing Chain

GMC Savana 2500 Timing Chain Parts and Q&A

• Timing Chain
  12646386
  Q: How to replace the timing chain and sprockets on GMC Savana 2500?

  A:

  For the purpose of replacing the Timing Chain and sprockets, one must remove the Oil Pump and turn the Crankshaft until the timing marks on Crankshaft and camshaft sprockets line up, not to turn the Crankshaft assembly after the Timing Chain is taken out, to avoid damaging piston assemblies or valves. Next, exit the camshaft sprocket bolts, followed by the camshaft sprocket, and Timing Chain. Use the j 8433 pulley puller (J 8433), j 41816-2 Crankshaft end protector (J 41816-2) and j 41558 Crankshaft sprocket remover (J 41558) to remove the Crankshaft sprocket and, if required, remove the Crankshaft sprocket key. Clean and check out the Timing Chain and sprockets prior to fitting them. If the key was taken out, install in Crankshaft keyway in it, until both ends are secured. Install the Crankshaft sprocket at the front of the Crankshaft aligning the Crankshaft key with the sprocket keyway and bring into full contact with the Crankshaft flange using the j 41665 Crankshaft balancer and sprocket installer (J 41665). Tilt the Crankshaft sprocket aligning the alignment mark with the 12-hour point such that the location on the camshaft of sprocket is matched with the camshaft sprocket alignment hole and the sprocket tooth overlaps with the Timing Chain. Find the camshaft sprocket mark at 6 o'clock position, install the camshaft sprocket and Timing Chain, adjust camshaft or crankshafts sprockets if required to match the timing marks. Finally, install the camshaft sprocket bolts, and tighten them with 35 nm (26 ft. Lbs.), and install the Oil Pump back.
• Timing Chain
  14088783
  Q: How to service and repair the timing chain on GMC Savana 2500?

  A:

  To service and repair the timing chain, one should start with the removal of the engine front cover and crankshaft position sensor reluctor ring. To rotate the engine, it is necessary to put a 7/16-20 x 1 inch bolt on the end of the crankshaft that its tip is pointing up by not using the crank shaft balancer bolt (Crank shaft balance) nor a bolt longer than 1 inch to avoid stripping of the bolt head. Turn the crankshaft so that the marking on the rear sprocket align with the marking on the front sprocket and cylinder number four is at top dead center (Tdc) of the compression stroke. Next, you should undo the camshaft sprocket bolts, then camshaft sprocket and camshaft timing chain. Remove crankshaft sprocket and crankshaft balancer key with the help of the crankshaft gear remover (J 5825-a). Clean and inspect the timing chain and sprocket before installation. Place the crankshaft balancer key into the keyway of the crankshaft, ensuring the latter is almost parallel or slightly inclined. Key the keyway of the crankshaft sprocket with the balancer key on the crankshaft and then use the pinion bearing race installer - rear (J 5590) to install the crankshaft sprocket. Rotate the crankshaft so its sprocket alignment mark is placed at the 12 o'clock, and fill in the camshaft sprocket with its alignment mark positioned on the 6 o'clock and ensure the correct alignment on both sprockets. Use the camshaft sprocket bolts, and fix them with 25 nm, (18 ft, lbs). Finally put on crankshaft position sensor reluctor ring and line up key component of the ring with the crankshaft balancer key, use a hammer to fit it onto the crankshaft until it sits against the crankshaft sprocket, remove bolt from the end of the crankshaft, and replace the engine front cover.