Estimating timing chain wear
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==Effects of changing cam timing== | ==Effects of changing cam timing== | ||
| + | When advancing/retarding the cam, be sure to check valve to piston clearance. Each degree of change effects valve clearance approximately 0.010". Example: If you advance the camshaft 4 degrees, you will '''lose''' about 0.040" clearance between the intake valve and piston, and you will ''gain'' about 0.040" clearance between the exhaust valve and piston. It will be the opposite if the camshaft is retarded. | ||
===Advance timing=== | ===Advance timing=== | ||
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====Ford retarded timing sets==== | ====Ford retarded timing sets==== | ||
| − | ;According to Crane<nowiki>:</nowiki> | + | ;According to [[Media:Crane roller cam instruct.pdf|Crane (page 3)]]<nowiki>:</nowiki> |
<blockquote> | <blockquote> | ||
'''Note:''' Many 1972 and later Ford-Mercury V-8 engines are originally equipped with a retarded crankshaft sprocket. This may cause idling and performance problems when installing aftermarket camshafts. Eliminate this problem by installing a pre-1972 crankshaft sprocket, (the non-retarded sprocket will have the alignment dot and keyway slot directly in line with each other), or by degreeing in your camshaft, or with appropriate Crane timing chain and gear set. | '''Note:''' Many 1972 and later Ford-Mercury V-8 engines are originally equipped with a retarded crankshaft sprocket. This may cause idling and performance problems when installing aftermarket camshafts. Eliminate this problem by installing a pre-1972 crankshaft sprocket, (the non-retarded sprocket will have the alignment dot and keyway slot directly in line with each other), or by degreeing in your camshaft, or with appropriate Crane timing chain and gear set. | ||
</blockquote> | </blockquote> | ||
| − | An aftermarket performance timing set | + | An aftermarket performance timing set is a good choice (Cloyes, etc.). Regardless of the timing set that's used, it is always best to degree the cam. That way you will know ''for sure'' where the cam is in relation to TDC. Degreeing the can will also show if the cam or timing set was made wrong, and will give the opportunity to correct for any errors/tolerance creep that can make the cam slightly out of phase. |
| − | On a non-adjustable timing set having just one keyway, if it's | + | *On a non-adjustable timing set having just one keyway, if it's a '''straight up''' timing set (no cam retard built into the timing set) the dot on the crank gear will be in alignment with the keyway. |
| + | *A set having the dot offset to the right of the keyway (as seen if you were standing in front of the vehicle looking over the radiator at the engine) will give '''advanced''' timing. | ||
| + | *A set having the dot offset to the left of the keyway (as seen if you were standing in front of the vehicle looking over the radiator at the engine) will give '''retarded''' timing. See the drawing below, left for an example of a retarded timing gear. | ||
| − | On a timing set having various keyways for advancing or retarding the cam timing, use the keyway that has the dot or pip mark directly above the keyway, not offset to either side if you want the timing to be straight up | + | On a timing set having various keyways for advancing or retarding the cam timing, use the keyway that has the dot or pip mark directly above the keyway, not offset to either side if you want the timing to be straight up (having no advance or retard), like the 1972-back and 1987-newer timing sets. |
| + | |||
| + | {| | ||
| + | |[[File:Retarded ford cam1.jpg]] | ||
| + | |[[File:Straight up fprd cam1.jpg|thumb|300px|Example of Ford timing set adjusted to the "straight up" position]] | ||
| + | |} | ||
==Effects of changing lobe separation angle== | ==Effects of changing lobe separation angle== | ||
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===Wider (larger number) LSA=== | ===Wider (larger number) LSA=== | ||
| − | *>/= 112 degrees | + | *Generally >/= 112 degrees |
*Raises torque to higher RPM | *Raises torque to higher RPM | ||
*Reduces maximum torque | *Reduces maximum torque | ||
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===Tighter (smaller number) LSA=== | ===Tighter (smaller number) LSA=== | ||
| − | *</= 110 degrees | + | *Generally </= 110 degrees |
*Moves torque to lower RPM | *Moves torque to lower RPM | ||
*Increases maximum torque | *Increases maximum torque | ||
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[[Category:Engine]] | [[Category:Engine]] | ||
[[Category:Adjust valves]] | [[Category:Adjust valves]] | ||
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[[Category:Camshaft]] | [[Category:Camshaft]] | ||
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