Camshaft install tips and tricks
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Most ZDDP additives recommend a specific quantity in the oil for break-in, and then half that amount for each subsequent oil change. Yes, it is possible to get too much ZDDP in the oil and generate spalling of the cam lobes. So, do your research, or use roller lifters where this stuff is not required. | Most ZDDP additives recommend a specific quantity in the oil for break-in, and then half that amount for each subsequent oil change. Yes, it is possible to get too much ZDDP in the oil and generate spalling of the cam lobes. So, do your research, or use roller lifters where this stuff is not required. | ||
| − | ====ZDDP resources==== | + | =====ZDDP resources===== |
*[http://www.zddplus.com/ ZDDPlus.com] (includes various tech briefs) | *[http://www.zddplus.com/ ZDDPlus.com] (includes various tech briefs) | ||
*[http://www.sfrcorp.com/product/sfr-100-petroleum-oil-fortifier/ SFR 100 Oil Fortifier] | *[http://www.sfrcorp.com/product/sfr-100-petroleum-oil-fortifier/ SFR 100 Oil Fortifier] | ||
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*[http://www.zddpforum.com/forum/ ZDDP forum] | *[http://www.zddpforum.com/forum/ ZDDP forum] | ||
| − | ==Installation== | + | ===Installation=== |
'''5. Actual installation of the camshaft into the block.''' | '''5. Actual installation of the camshaft into the block.''' | ||
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'''6. Failure to verify "lifter spin" on flat-tappet lifters.''' | '''6. Failure to verify "lifter spin" on flat-tappet lifters.''' | ||
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With the camshaft and lifters installed, but before the timing chain is attached or the pushrods are installed, mark each lifter and lifter bore with a "Sharpie" or other marker. A simple stripe on the lifter bore aligned with a dot on the visible part of the top of the lifter is fine. Rotate the camshaft several revolutions, and assure that the lifters spin in the bores, as noted by the increasing misalignment of the dot on the lifter relative to the stripe on the lifter bore. The lifters may not all spin the same amount--some will spin more than others--but they must all show some rotational movement as the cam spins. The only exception to this that I'm aware of is Buick "Nailhead" V-8s, which (at least in OEM form) have no crown on the lifter foot, no taper on the cam lobe, and no offset between lifter bore and cam lobe. The Nailhead lifters are NOT intended to spin. | With the camshaft and lifters installed, but before the timing chain is attached or the pushrods are installed, mark each lifter and lifter bore with a "Sharpie" or other marker. A simple stripe on the lifter bore aligned with a dot on the visible part of the top of the lifter is fine. Rotate the camshaft several revolutions, and assure that the lifters spin in the bores, as noted by the increasing misalignment of the dot on the lifter relative to the stripe on the lifter bore. The lifters may not all spin the same amount--some will spin more than others--but they must all show some rotational movement as the cam spins. The only exception to this that I'm aware of is Buick "Nailhead" V-8s, which (at least in OEM form) have no crown on the lifter foot, no taper on the cam lobe, and no offset between lifter bore and cam lobe. The Nailhead lifters are NOT intended to spin. | ||
| − | + | ===Valve springs=== | |
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'''7. Failure to use the proper valve springs for cam break-in.''' | '''7. Failure to use the proper valve springs for cam break-in.''' | ||
You can't use the 300 lb over-the-nose springs that you'll eventually use in the motor, and expect the cam to live at break-in. Assemble the heads with stock or weak single springs (if those springs will accept the amount of valve lift and the retainers will clear the valve seals/valve guides) to break in the cam, then use one of the many tools available to change the springs with the heads on the motor. Those without shop air to hold the valves up through this operation can feed some clothesline cord through the spark plug hole and then bring the piston up to smash the rope and hold the valves up. Alternately, assemble the heads with the springs you will run and use reduced-ratio break-in rockers, then change out the rockers after break-in. Although expensive, these are available from [http://crower.com/ Crower] in different ratios for different motors. A popular ratio for a small block Chevy would be a 1.3:1 rocker. In other words, let's say the lift at the cam is 0.350" and the theoretical lift at the valve with 1.5:1 rockers is 0.525". Using the 1.3:1 rockers would result in lift at the valve of only 0.455", thus reducing stress at the camshaft/lifter interface during the crucial break-in period. Of course, you would have to elongate the pushrod holes to accommodate the longer pushrod cup to pivot dimension and maybe alter the slots in your guide plates as well. | You can't use the 300 lb over-the-nose springs that you'll eventually use in the motor, and expect the cam to live at break-in. Assemble the heads with stock or weak single springs (if those springs will accept the amount of valve lift and the retainers will clear the valve seals/valve guides) to break in the cam, then use one of the many tools available to change the springs with the heads on the motor. Those without shop air to hold the valves up through this operation can feed some clothesline cord through the spark plug hole and then bring the piston up to smash the rope and hold the valves up. Alternately, assemble the heads with the springs you will run and use reduced-ratio break-in rockers, then change out the rockers after break-in. Although expensive, these are available from [http://crower.com/ Crower] in different ratios for different motors. A popular ratio for a small block Chevy would be a 1.3:1 rocker. In other words, let's say the lift at the cam is 0.350" and the theoretical lift at the valve with 1.5:1 rockers is 0.525". Using the 1.3:1 rockers would result in lift at the valve of only 0.455", thus reducing stress at the camshaft/lifter interface during the crucial break-in period. Of course, you would have to elongate the pushrod holes to accommodate the longer pushrod cup to pivot dimension and maybe alter the slots in your guide plates as well. | ||
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===Checking clearances=== | ===Checking clearances=== | ||
'''Note:''' More info on checking clearances at [[Valve train points to check]]. | '''Note:''' More info on checking clearances at [[Valve train points to check]]. | ||
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'''8. Failure to check for valve spring coil bind at max lift.''' | '''8. Failure to check for valve spring coil bind at max lift.''' | ||
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| − | '''12. Failure to clearance lifters in their bores | + | '''12. Failure to clearance lifters in their bores.''' |
| − | Lifter clearance should be 0.0012" to 0.002", with 0.0015" (one and one half thousandths) considered close to ideal. Too loose | + | Lifter clearance should be 0.0012" to 0.002", with 0.0015" (one and one half thousandths) considered close to ideal. Too loose can be as bad as too tight. One way to provide a flat tappet cam and lifters with additional lubrication is to groove the lifter bores. One tool for doing this operation is the Comp Cams p/n 5003 [http://www.summitracing.com/parts/CCA-5003/ lifter bore grooving tool] sold by Summit. Solid lifter flat tappet lifters are available with a small machined hole in the lifter foot that feeds pressurized oil to the interface between the cam and lifter. But having that hole is no guarantee... |
| − | + | [[File:Bad cam and lifter edm.jpg|thumb|left|500px|Bad cam and EDM hole-equipped lifter]] <br style="clear:both"/> | |
===Engine RPM for break in=== | ===Engine RPM for break in=== | ||
| − | '''13. Failure to run the motor at high rpm (2500 or higher, alternating 500/1000 rpm up and/or down to allow the crank to throw oil in different places at different revs) for a minimum of 20 minutes. | + | '''13. Failure to run the motor at high rpm (2500 or higher, alternating 500/1000 rpm up and/or down to allow the crank to throw oil in different places at different revs) for a minimum of 20 minutes.''' |
No idling! The motor should not be run at less than 2500 rpm for a minimum of 20 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off of the crankshaft at speed, drain back from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection. | No idling! The motor should not be run at less than 2500 rpm for a minimum of 20 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off of the crankshaft at speed, drain back from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection. | ||
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| − | '''15. Failure to inspect the distributor drive gear for wear.''' Too much wear can allow the cam to walk in its cam bore and contact an adjacent lifter. The builder is also responsible for using a distributor gear that is compatible with the camshaft gear material. Coordinate this with the cam grinder before you ever begin assembling the motor. Hardly anything will make you feel more stupid than finding one or the other of the gears eaten up, necessitating an engine tear-down to clean out all the shrapnel. | + | '''15. Failure to inspect the distributor drive gear for wear.''' |
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| + | Too much wear can allow the cam to walk in its cam bore and contact an adjacent lifter. The builder is also responsible for using a distributor gear that is compatible with the camshaft gear material. Coordinate this with the cam grinder before you ever begin assembling the motor. Hardly anything will make you feel more stupid than finding one or the other of the gears eaten up, necessitating an engine tear-down to clean out all the shrapnel. | ||
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'''17. Failure to prime the oiling system prior to firing the motor.''' | '''17. Failure to prime the oiling system prior to firing the motor.''' | ||
| − | Prime until you get oil out of the top of each and every pushrod. Observe the oil pressure gauge to be certain that pressure is registering. Priming will aid lubing the valve train at initial start up. It's the last area of the motor to get lubed on dry start. You can make a tool by disassembling an old distributor and removing the gear, or just grinding off the gear teeth so that the teeth don't engage the cam teeth. Or, you can spring for 20 bucks and get a very nice priming tool that will be a nice addition to your tool chest. In either case, you will NOT get oil to the passenger side rockers of a Chevrolet-designed V-8 unless you use either the distributor or the tool to block off the oil galley under where the distributor bolts down. | + | Prime until you get oil out of the top of each and every pushrod. Observe the oil pressure gauge to be certain that pressure is registering. Priming will aid lubing the valve train at initial start up. It's the last area of the motor to get lubed on dry start. You can make a tool by disassembling an old distributor and removing the gear, or just grinding off the gear teeth so that the teeth don't engage the cam teeth. Or, you can spring for 20 bucks and get a very nice priming tool that will be a nice addition to your tool chest. In either case, you will NOT get oil to the passenger side rockers of a Chevrolet-designed V-8 unless you use either the distributor or the tool to block off the oil galley under where the distributor bolts down. An example of a tool for use with a Chevrolet engine is the [http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=25140 Proform oil pump prime tool]. |
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Engines with an oil pump that is not driven by the distributor like the GM LS-series, Vega 2.3L, some later Buick V-6, etc. can be primed by injecting pressurized oil into the oil pressure gauge port. A hand-pumped garden-sprayer-type pressure vessel will work if you can adapt the end of the hose to appropriately-threaded fittings to suit the port in the block. Put the engine oil into the pressure vessel, pump the handle, squirt all the oil into the oil sender port. The pressure used doesn't really matter--if the oil squeezes into the engine at two or five psi...that's just fine. | Engines with an oil pump that is not driven by the distributor like the GM LS-series, Vega 2.3L, some later Buick V-6, etc. can be primed by injecting pressurized oil into the oil pressure gauge port. A hand-pumped garden-sprayer-type pressure vessel will work if you can adapt the end of the hose to appropriately-threaded fittings to suit the port in the block. Put the engine oil into the pressure vessel, pump the handle, squirt all the oil into the oil sender port. The pressure used doesn't really matter--if the oil squeezes into the engine at two or five psi...that's just fine. | ||
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| + | Priming is not intended to initially lubricate the internal engine components. Every moving part should have received lubrication when the engine was assembled. Priming the oil system is a process to remove air from the pressurized portions of the oiling system, i.e. the oil pump, the oil filter, and some of the oil galleries (the oil galleries will begin to drain the oil as soon as the priming stops but the oil pump and filter are likely to remain full.) Priming is "done" when you see oil pressure on the gauge, plus about ten or fifteen seconds additional. Often the crank will also be rotated two revolutions while the priming is being done to allow all the lifters to see pressurized oil from the lifter oil gallery. | ||
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| + | With engines that use a submerged oil pump (Chevrolet big- and smallblocks, Oldsmobile V8, Pontiac V8, etc.), priming is usually done in ''less than one minute''. Engines with non-submerged oil pumps (Buick V8, big Cads for example) may take longer due to the difficulty in pulling oil through the long pickup tube to the remote-mounted pump. However, once you show pressure on the gauge, another ten or fifteen seconds is entirely sufficient. There is NO need to prime until the oil squirts over the fender; in fact some engines won't show oil at the rocker arms until it's running. | ||
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''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."'' | ''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."'' | ||
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==Roller cams are not immune== | ==Roller cams are not immune== | ||
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