4.6 romeo timing chain alignment
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4.6 romeo timing chain alignment
doing valve job on '97 F-150 4wd, Haynes manual is confusing.
According to manual:
Removal:
"When positioning the engine at TDC for number 1 piston, look at the keyways on the camshaft sprockets. Use a square to insure that each keyway is at 90-degrees to the valve-cover mounting surface of the cylinder head. then install the camshaft positioning tool on the rear of the camshafts."
Installation:
"The two timing chains should each have two bright or colored links.The links seperate the chain into two equal halves. If no colored links are present, lay the chain down, make a paint mark on a link, then count links and make another paint mark halfway around the chain"
"Install the left timing chain, aligning its colored link to the mark on the crankshaft sprocket and to the timing mark on the camshaft sprocket.
Install the right timing chain, and its crankshaft sprocket. When both chains are installed and all colored links and marks aligned, the keyways should be at 90-degree angle to the valve-cover mounting surface of the cylinder head."
Actual:
Removal:
Did not use the camshaft positioning tool but did insure that keyways were at 90-degrees to the valve-cover mounting surface of the cylinder head. After I took the tensioners off the chain was still under tension due to valve spring pressure, and when I took the chain off, the camshafts rotated slightly.
Assembly:
Put camshaft at near 90-degrees when heads were reassembled.
Put chain mark on crankshaft sprocket mark and placed sprocket on crankshaft. Crankshaft sprocket mark at 6:00.
Put camshaft sprocket on but when keyway is at 90-degrees the dimple in sprocket will not line up with mark on chain.
The dimple is at about 4:00 (keyway at 12:00) mark lines up with keyway but no tension is on chain. I can rotate the camshaft a tooth or two to put chain back under slight tension (so keyway is at 90-degree angle to the valve-cover mounting surface of the cylinder head) but marks do not line up.
How should I proceed? any and all help will be greatly appreciated.
According to manual:
Removal:
"When positioning the engine at TDC for number 1 piston, look at the keyways on the camshaft sprockets. Use a square to insure that each keyway is at 90-degrees to the valve-cover mounting surface of the cylinder head. then install the camshaft positioning tool on the rear of the camshafts."
Installation:
"The two timing chains should each have two bright or colored links.The links seperate the chain into two equal halves. If no colored links are present, lay the chain down, make a paint mark on a link, then count links and make another paint mark halfway around the chain"
"Install the left timing chain, aligning its colored link to the mark on the crankshaft sprocket and to the timing mark on the camshaft sprocket.
Install the right timing chain, and its crankshaft sprocket. When both chains are installed and all colored links and marks aligned, the keyways should be at 90-degree angle to the valve-cover mounting surface of the cylinder head."
Actual:
Removal:
Did not use the camshaft positioning tool but did insure that keyways were at 90-degrees to the valve-cover mounting surface of the cylinder head. After I took the tensioners off the chain was still under tension due to valve spring pressure, and when I took the chain off, the camshafts rotated slightly.
Assembly:
Put camshaft at near 90-degrees when heads were reassembled.
Put chain mark on crankshaft sprocket mark and placed sprocket on crankshaft. Crankshaft sprocket mark at 6:00.
Put camshaft sprocket on but when keyway is at 90-degrees the dimple in sprocket will not line up with mark on chain.
The dimple is at about 4:00 (keyway at 12:00) mark lines up with keyway but no tension is on chain. I can rotate the camshaft a tooth or two to put chain back under slight tension (so keyway is at 90-degree angle to the valve-cover mounting surface of the cylinder head) but marks do not line up.
How should I proceed? any and all help will be greatly appreciated.
Thread Starter
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Freshman User
Joined: Mar 2007
Posts: 28
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Continued with assembly, placing keyways at 90-degress to valve cover mounting surface and noticed that timing marks on camshaft were 180-degrees out, turned engine over by hand several rotations, and had no interferance. Since the camshaft rotates 180-degrees for every 360-degrees of crankshaft rotation I believe I will have no problems
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Hunter_D
1997 - 2006 Expedition & Navigator
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Oct 4, 2013 11:42 PM
