Genuine Chevrolet Astro Camshaft Bearing

Chevrolet Astro Camshaft Bearing Parts Questions & Experts Answers

• Bearing, Camshaft
  12453171
  Q: How to remove and reinstall Camshaft Bearing,Camshaft and Lash Adjuster in V6 engine on Chevrolet Astro?

  A:

  To measure camshaft lobe lift the first step is to remove the Rocker Arm covers to enable checking the number one piston at TDC on the compression stroke to determine wear. Slacken the rocker arm nuts on the number one cylinder valves and rotate the rocker arms to their highest position and fit a dial gauge pointer to the first push rod plunger so that it will bear on the top of the push rod at right angles to the centre line of the cylinder. Zero the dial indicator and slowly turn the crankshaft until the indicator needle stops and turns the other way, this is the maximum cam lobe lift. Note this down and set the piston back at TDC and do the same check to the other valves but should make sure that each piston should be at TDC on the side of the cylinder that you are about to check. This calls for inspection of lobes whereby their lift is checked against the camshaft specifications; if the lobe lift is below this value then the camshaft has worn and thus requires replacement. For removal-destroy the Intake Manifold with rocker arms with push rods and Timing Chain as well as the sprocket of the camshaft together with the crudities like the fan shrouds, water pump, radiator, and A/C condenser. They can be removed by use of a tool or a magnet if small; do not use pliers except when replacing the Lash Adjusters. Some of the roller Lash Adjusters require removal of the retainer and restrictors before withdrawal can be made. Provide a small box where you will store all your Lash Adjusters to ensure that they retain their positions for reuse. If the engine has a balancer shaft the drive gear is removed from the camshaft. Again observe the direction of the camshaft retainer before you unscrew it and, using bolts which are fitted into the camshaft sprocket bolt holes, pull out the camshaft from the block carefully without damaging the bearings. Generally, different camshaft bearing demand unique sort of tools in their replacement and it is highly advisable to undertake this process at the automotive machine shop. For installation, it is required that before installing the camshaft, the camshaft bearing journals and lobes must be lubricated, to later slide the camshaft into the engine, it has to be rotated until the dowel pin is at the 3 o'clock position while being supported. Place back the camshaft retainer in place and tighten the bolts that are holding it, then put in the balancer shaft drive gear such that the marks touch perfectly. If the timing chain has been replaced, or if any of the sprockets have been removed, put the new or cleaned and refurbished timing chains and sprockets in the engine compartment. If the Lash Adjusters have been removed for cleaning, lubricate them with fresh engine oil and put them back in their original positions if possible. As with any other assembly work, complete the remaining steps in the reverse order, and prior to starting the engine turn it over by hand to prepare for the installing a new oil and new oil filter.