Camshaft install tips and tricks

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(→Adjusting the cam timing or "phasing": add text)
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==Lubrication==
 
==Lubrication==
 
That pencil-point of contact between the camshaft lobe and lifter crown is under somewhere between 250,000 and 300,000 pounds per square inch of pressure, so it should come as no surprise that extreme pressure lubrication is required, especially at break in where the contact point between lobe and lifter is irregular. The break in grease applied to the bottoms of the lifters and to the cam lobes is all the lubrication there is during the initial 5 to 10 seconds of operation, until motor oil reaches the interface.
 
That pencil-point of contact between the camshaft lobe and lifter crown is under somewhere between 250,000 and 300,000 pounds per square inch of pressure, so it should come as no surprise that extreme pressure lubrication is required, especially at break in where the contact point between lobe and lifter is irregular. The break in grease applied to the bottoms of the lifters and to the cam lobes is all the lubrication there is during the initial 5 to 10 seconds of operation, until motor oil reaches the interface.
 +
 +
===Comp Cams's position on break-in additive and nitriding===
 +
<blockquote>
 +
''"Due to federal legislation, motor oils no longer contain certain anti-scuffing agents that played a critical role in flat tappet camshaft break in. While incorrect valve spring pressure and not following proper break-in procedure are often the culprits, the changes in oil formulation have brought about a need for additional steps to be added to the break-in process.''
 +
<br><br>
 +
''COMP Cams has two ways to ensure proper break-in of flat tappet cams. COMP Cams Engine Break-In Additive (part #159) ensures that the camshaft will have the lubricants that it needs to seat the camshaft journals and lobe/lifter surfaces. This lubricant is poured into the engine crankcase after the camshaft and lifters have been coated with the initial break-in lubricant (molybdenum disulphide) supplied with the camshaft.''
 +
<br><br>
 +
''Another option for increasing flat tappet cam longevity is nitriding. Recently COMP Cams invested in a nitriding machine, the first of its kind owned by a major U.S. aftermarket camshaft manufacturer. Nitriding actually hardens the surface of the camshaft and tappet face by injecting nitrogen “needles” into the metal. The result is an ultra-hard surface on the face of the camshaft lobes and lifter face, which greatly improves the performance and break-in process for flat tappet cams. This process is an additional charge for COMP Cams camshafts, but for many extreme duty applications, it virtually ensures proper break-in and increased durability."''
 +
</blockquote>
  
 
===Racer Brown's position on oil level during break-in===
 
===Racer Brown's position on oil level during break-in===
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''"Overfill the crankcase by at least 4 or 5 quarts of oil so that the oil level comes to within an inch of the top of the oil pan. Install a set of fairly hot spark plugs with a gap of 0.050" to 0.060" to prevent oil-fouling of the plugs, which is otherwise inevitable under no-load conditions with all the extra oil aboard. During this operation, we want near-maximum oil flow, together with a maximum of oil vapors and liquid oil thrashing about in the crankcase so that the cam lobe and lifter interface lubrication is considerably better than marginal."''
 
''"Overfill the crankcase by at least 4 or 5 quarts of oil so that the oil level comes to within an inch of the top of the oil pan. Install a set of fairly hot spark plugs with a gap of 0.050" to 0.060" to prevent oil-fouling of the plugs, which is otherwise inevitable under no-load conditions with all the extra oil aboard. During this operation, we want near-maximum oil flow, together with a maximum of oil vapors and liquid oil thrashing about in the crankcase so that the cam lobe and lifter interface lubrication is considerably better than marginal."''
 
</blockquote>
 
</blockquote>
 +
 +
===Lubrication requirements after break in===
 +
For the same reasons break in oil or break in oil additives are used to break in the cam and lifters, '''''after''''' cam/lifter break in, only oils formulated for flat tappet equipped performance engines should be used. Also acceptable is using additives like ZDDPlus, etc. (in the correct quantity- less than for initial break in) added to over the counter motor oil.
  
 
===Lubricants===
 
===Lubricants===
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*[http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=159&Category_Code= Comp Cams Engine Break-In Oil Additive]
 
*[http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=159&Category_Code= Comp Cams Engine Break-In Oil Additive]
 
*[http://www.hotrodders.com/forum/assembley-lube-good-anything-174183.html#post1239633 Hotrodders forum thread on cam and assembly lubricants]
 
*[http://www.hotrodders.com/forum/assembley-lube-good-anything-174183.html#post1239633 Hotrodders forum thread on cam and assembly lubricants]
−
 
−
===Comp Cams's position on break-in additive and nitriding===
 
−
<blockquote>
 
−
''"Due to federal legislation, motor oils no longer contain certain anti-scuffing agents that played a critical role in flat tappet camshaft break in. While incorrect valve spring pressure and not following proper break-in procedure are often the culprits, the changes in oil formulation have brought about a need for additional steps to be added to the break-in process.''
 
−
<br><br>
 
−
''COMP Cams has two ways to ensure proper break-in of flat tappet cams. COMP Cams Engine Break-In Additive (part #159) ensures that the camshaft will have the lubricants that it needs to seat the camshaft journals and lobe/lifter surfaces. This lubricant is poured into the engine crankcase after the camshaft and lifters have been coated with the initial break-in lubricant (molybdenum disulphide) supplied with the camshaft.''
 
−
<br><br>
 
−
''Another option for increasing flat tappet cam longevity is nitriding. Recently COMP Cams invested in a nitriding machine, the first of its kind owned by a major U.S. aftermarket camshaft manufacturer. Nitriding actually hardens the surface of the camshaft and tappet face by injecting nitrogen “needles” into the metal. The result is an ultra-hard surface on the face of the camshaft lobes and lifter face, which greatly improves the performance and break-in process for flat tappet cams. This process is an additional charge for COMP Cams camshafts, but for many extreme duty applications, it virtually ensures proper break-in and increased durability."''
 
−
</blockquote>
 
  
 
==Roller cams are '''not''' immune==
 
==Roller cams are '''not''' immune==
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|[[File:Bad lifter rollers.jpg|thumb|center|500px|Heavily chipped/pitted/galled lifter roller]]
 
|[[File:Bad lifter rollers.jpg|thumb|center|500px|Heavily chipped/pitted/galled lifter roller]]
 
|}
 
|}
−
 
−
==Adjusting the cam timing or "phasing"==
 
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Cam phasing is the relationship of the camshaft position to the crankshaft position in reference to TDC. A change of 2 degrees at the cam gear equals 4 degrees at the crank.
 
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{{NOTE1}}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.
 
−
 
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The cam timing, or phasing, can be changed at the time of installation by using a multi-keyway timing set, or an adjustable cam gear like [http://www.cloyes.com/HighPerformance/Products/HexAJustTrueRollerSets/tabid/383/language/en-US/Default.aspx Cloyes Hex-A-Just].
 
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On timing sets that have no built-in adjustability, the cam phasing can still be adjusted in many cases. This is done by drilling the dowel pin hole of the cam gear oversize in order to use a bushing to advance or retard the cam gear. On engines where this isn't practical, an offset crank gear Woodruff key can often be used instead.
 
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{|
 
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|[[File:Cam bushings.jpg|thumb|center|280px|Cam gear bushing selection]]
 
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|[[File:Offset crank keys.jpg|thumb|center|250px|Crank gear offset key selection]]
 
−
|}
 
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In the majority of cases, installing the cam "straight up" (without any advance/retard added by the installer) is the correct way to install the cam and timing set. Many cam makers have already advanced (in most cases) the cam timing when the cam was made to suit the application. Unless the builder has access to an engine dynamometer or has advanced knowledge of the dynamics involved, advancing/retarding a cam is nothing but a shot in the dark as to whether it will result in any benefits at all. And there's the chance the engine output could be adversely affected by indiscriminately changing the phasing of the cam. The piston to valve clearance can be reduced enough to cause damage in some cases.
 
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==Effects of changing cam timing==
 
−
 
−
===Advance timing===
 
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*Open Intake Valve Sooner
 
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*Builds more low-end torque
 
−
*Decreases piston to intake valve clearance
 
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*Increases piston to exhaust valve clearance
 
−
 
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===Retard timing===
 
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*Keeps intake valve open later
 
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*Builds more upper RPM power
 
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*Increases piston to intake valve clearance
 
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*Decreases piston to exhaust valve clearance
 
−
 
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==Effects of changing lobe separation angle==
 
−
The lobe separation angle (LSA) is ground into the cam at the time of manufacture and cannot be changed by the installer.
 
−
 
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===Widen (larger) LSA===
 
−
*Raises torque to higher RPM
 
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*Reduces maximum torque
 
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*Broadens power band
 
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*Reduces maximum cylinder pressure
 
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*Decrease chance of engine knock
 
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*Decrease cranking compression
 
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*Decrease effective compression
 
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*Idle vacuum is increased
 
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*Idle Quality improves
 
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*Overlap decreases
 
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*Natural EGR effect is reduced
 
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*Increases piston-to-valve clearance
 
−
 
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===Tighten (smaller) LSA===
 
−
*Moves torque to lower RPM
 
−
*Increases maximum torque
 
−
*Narrow power band
 
−
*Builds higher cylinder pressure
 
−
*Increase chance of engine knock
 
−
*Increase cranking compression
 
−
*Increase effective compression
 
−
*Idle vacuum is reduced
 
−
*Idle quality suffers
 
−
*Overlap increases
 
−
*Natural EGR effect increases
 
−
*Decreases piston-to-valve clearance
 
  
 
==Resources==
 
==Resources==

Revision as of 14:11, 20 February 2013

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