OEM GMC Savana 1500 Timing Chain

GMC Savana 1500 Timing Chain Parts and Q&A

• Timing Chain
  12458911
  Q: How to service and repair the timing chain on GMC Savana 1500?

  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.
• Timing Chain
  12646386
  Q: How to replace the timing chain and sprockets on GMC Savana 1500?

  A:

  To change the Timing Chain and the sprockets, first take off the Oil Pump and then rotate the Crankshaft until there is a proper response between the marks on the Crankshaft and the camshaft, make sure not to turn the unit on Crankshaft once the Timing Chain will have come out so as not to damage the piston assemblies or valves. Next, remove the bolts of camshaft sprockets and then the camshaft sprockets as well as the Timing Chain. When removing Crankshaft sprocket, use a j8433 pulley puller (J8433), j41816-2 Crankshaft end protector (J41816-2), and j41558 Crankshaft sprocket remover (J41558). Remove Crankshaft sprocket then get the Crankshaft sprocket thoroughly removed. In case of necessity remove the Crankshaft sprocket key and clean check and sprockets. Treat it just like when installing a pinion bearing, put the key in the crank keyway and tap it into place up to where both ends are seated. Mount the Crankshaft sprocket on the front of the Crankshaft, putting it in alignment with the keyway in the Crankshaft key using the j41665 Crankshaft balancer and sprocket installer (J41665). Installs the sprocklet completely into the position against the Crankshaft flange. Turn the Crankshaft sprocket so the alignment is placed at the 12 o'clock, making sure that the locating pin on the camshaft sprocket aligns correctly with a hole created in the sprocket, the teeth of the sprocket are in mesh with Timing Chain, and aligning marks placed on the camshaft and Crankshaft sprockets align, and camshaft sprocket alignment mark is at the 6 o'clock. Put on the camshaft sprocket and the Timing Chain, tweak the camshaft or Crankshaft sprockets to have the appropriate timing marks align on them. Finally, install the camshaft sprocket bolts and screw them to 35 nm (26 ft. Lbs.) and then reinstall the Oil Pump.