J 38822 Cam Chain Tension Holder
IMPORTANT: Do not mix the camshaft bearing caps between positions or between heads. Each cap must be reassembled in the position from which it was removed and in the original orientation (arrow pointing toward the front of the engine).
Remove the camshaft cover. Refer to Camshaft Cover Replacement (Left) and Camshaft Cover Replacement (Right).
Set the engine at base timing (top dead center number one piston).
Align the timing marks to the correct position. Refer to Setting Camshaft Timing for the correct timing mark alignment.
IMPORTANT: The sprocket-to-chain relationship must be maintained throughout this procedure or the camshaft timing will be lost and require further engine disassembly for retiming.
Secure the camshaft sprocket to the secondary timing chain using tie-straps through the camshaft sprocket holes. Use two tie-straps per sprocket.
Working behind the sprockets, install the J 38822 between the chain tensioner and the chain guide. Apply tension by tightening the tool adjusting screw.
IMPORTANT: When using J 38822 on the right hand cylinder bank, remove the wiper motor in order to gain access for the tool usage.
Remove the camshaft sprocket bolts. Note the relative location of the camshaft drive pins in the ends of the camshafts.
Work the sprockets off of the camshafts using the play in the chain.
Alternately loosen the camshaft bearing cap screws a few turns at a time until all valve spring pressure has been released.
Remove the camshaft bearing cap bolts and caps.
Remove the camshaft.
Inspect and measure the camshaft lobes and valve lifters. Measurement can be performed with the camshaft still in the engine. Refer to Camshaft Clean and Inspection.
Replace the camshaft if any of the following conditions exist:
Excessive lifter wear
Excessive scoring on the lifters and/or camshaft
Excessive flaking on the lifters and/or camshaft
Scored or burned bearing journals
J 38822 Camshaft Chain Tension Holder
Apply GM approved camshaft prelube, P/N 1052365, to the face of each camshaft lobe and journal.
Install the camshaft.
Position the camshaft bearing caps to the cylinder head.
Each cap is identified for position and direction.
The arrow should point toward the front of the engine.
These caps are stamped for identification. The E indicates a cap for the exhaust camshaft. The I indicates a cap for the intake camshaft. The E1 or 11 is the first cap at the front of the engine.
Loosely install the camshaft bearing cap bolts.
Alternately tighten each bearing cap bolt a few turns at a time against the valve spring pressure until all bolts are snug.
Tighten the bolts to 12 Nm (106 inch lbs.).
NOTICE: Refer to Fastener Notice in Service Precautions.
Slide the camshaft sprockets onto the camshafts. Using the hex cast into the camshaft, rotate the camshafts until the drive pins are in the correct position to engage the camshaft sprockets over the camshafts.
Install the camshaft sprocket retaining bolts.
Tighten the sprocket bolts to 120 Nm (89 ft. Lbs.).
Remove the J 38822.
Remove the tie-straps from the camshaft sprockets.
Install the camshaft covers. Refer to Camshaft Cover Replacement (Left) and Camshaft Cover Replacement (Right).
Friday, May 4th, 2012 AT 2:19 AM