Camshaft install tips and tricks
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'''DISCLAIMER:''' | '''DISCLAIMER:''' | ||
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| + | THE FOLLOWING INFORMATION WAS GLEANED FROM MANY DIFFERENT SOURCES OVER A 50 YEAR PERIOD AND IS PRESENTED HERE IN MY OWN WORDS. SOME OF IT MAKES SENSE TO ME AND SOME OF IT DOESN'T. USE WHAT YOU THINK IS REAL AND THROW OUT THE REST OF IT. I HAVE NOT USED ALL OF THE SUGGESTIONS LISTED HERE. THROUGH THE YEARS, I HAVE ACCOMPLISHED MANY SUCCESSFUL FLAT TAPPET CAMSHAFT BREAK-INS, BUT I HAVE ALSO ROACHED A FEW. USE THIS LIST AS A GUIDELINE SO THAT YOU REMEMBER TO CHECK ALL THESE THINGS WHEN INSTALLING A NEW FLAT TAPPET CAMSHAFT. DO NOT TAKE EVERYTHING POSTED HERE AS GOSPEL. IF THE MANUFACTURER OF THE CAMSHAFT YOU'RE USING RECOMMENDS PROCEDURES THAT DIFFER FROM WHAT IS SHOWN HERE, USE THE MANUFACTURER'S RECOMMENDATIONS AND DISREGARD THIS INFORMATION. | ||
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| + | ==Mistakes that may "frag" a flat-tappet camshaft and lifters.== | ||
===Cleaning=== | ===Cleaning=== | ||
| + | 1. Failure to remove all rust-preventative from cam and lifters with solvent once you get them home. (This advice does not include removing coatings applied at the factory such as phosphates. It is only suggesting to remove rust-preventative grease that may or may not have been applied to the cam/lifters to prevent rust in storage. This grease will not have the extreme pressure characteristics that Molybdenum Disulphide has and should be removed so that MD can be applied properly. MD is the black, tar-like extreme-pressure grease that is recommended by some camshaft manufacturers to be applied to the lifter crowns/cam lobes for initial flat tappet camshaft break-in). | ||
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| + | 2. Failure to wash the cam and lifters with hot soapy water to remove the remainder of rust-preventative not removed with solvent. CAUTION; WASH ONLY THE CROWN OF THE LIFTERS. (THE VERY BOTTOM OF THE LIFTER WHERE IT CONTACTS THE CAMSHAFT LOBE). DO NOT ALLOW WATER TO GET INTO THE INTERIOR OF THE LIFTER BODY. BE VERY CAREFUL HERE IF THE LIFTER HAS AN OILING HOLE THAT HAS BEEN EDM'D INTO THE CROWN TO PROVIDE OIL FROM THE INTERIOR OF THE LIFTER BODY TO THE CAMSHAFT LOBE. Dry the cam and lifter crowns thoroughly with hot air from a hot air gun or hair dryer to remove all traces of moisture before applying Molybdenum Disulfide. | ||
| + | WARNING: DO NOT USE ANY ABRASIVE MATERIALS SUCH AS SCOTCHBRITE PADS OR SANDPAPER OF ANY KIND TO ACCOMPLISH THESE SOLVENT AND SOAP CLEANING OPERATIONS. USE ONLY SOFT, CLEAN RAGS. THE WHOLE INTENT OF CLEANING THE CAMSHAFT IS SO THAT WE CAN REMOVE RUST-PREVENTATIVE OILS AND GREASES THAT MIGHT HINDER GETTING DOWN TO THE BASE METAL IN ORDER TO PERFORM OPERATION #3 SHOWN HERE. | ||
===Pre-Lube=== | ===Pre-Lube=== | ||
| + | 3. Failure to properly massage an extreme pressure lubricant such as Molybdenum Disulfide into the pores of the metal on all lobes and lifter faces. Moly will actually bond with the metal and give maximum protection to the lifter crown/lobe. | ||
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| + | 4. Failure to use an extreme pressure lubricant additive in the engine oil for camshaft break-in. Each cam grinder has his own specific product to facilitate valid cam break-in. The aftermarket has also come to our rescue with many different formulations of ZDDP. Here are a couple of offerings for your approval....Most of them will 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. | ||
| + | *http://www.zddplus.com/ | ||
| + | *http://www.eastwood.com/underhood-e...CFRmjagodmX1aKw | ||
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| + | ==Here's the Lube I use== | ||
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| + | *http://www.sfrcorp.com/product/sfr-...m-oil-fortifier | ||
==Valve springs== | ==Valve springs== | ||
| + | 5. 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 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 pretty "spendy", these are available from 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 accomodate the shorter pushrod cup to pivot dimension and maybe alter the slots in your guide plates as well. | ||
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| + | 6. Failure to check for valve spring coil bind at max lift. If you cannot tell by eye, verify by inserting a .010- inch feeler gauge between the coils. A .010" space between five coils would give a total of .050" safety margin before stacking the spring solid. If you cannot pass the feeler gauge between the coils, the spring is either coil bound or dangerously close to this condition, and you have probably overshimmed the spring (the fitted dimension is too short). | ||
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| + | 7. Failure to check for retainer to valve guide/seal clearance. 1/16"-1/8" clearance at full valve lift is considered sufficient. This is the limiting lift factor with the stock L31 Vortec heads. Most uninformed fellows will say they can run a 0.500" lift cam with them stock. That leaves ZERO clearance between the retainer and the seal. Not good. GM says the limit is about 0.420" with the stock pieces. Ricky Racer down the street will tell you differently, but the GM engineers say 0.420" lift allows 0.030" retainer-to-seal clearance. | ||
==Checking clearances== | ==Checking clearances== | ||
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| + | 8. Failure to check for binding at the rocker/stud interface with stamped steel rockers. Long slot rockers are made specifically to cure this problem. Quality roller rockers with a needle bearing trunnion are as good as it gets with a stud-mounted rocker. | ||
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| + | 9. Failure to check for piston/valve clearance..... 0.080" on the intake and 0.100" on the exhaust is considered by many to be the minimum clearance acceptable. You will probably find the closest near-miss at the exhaust valve on overlap, when the piston is chasing the exhaust valve back onto its seat. | ||
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==Engine RPM for break in== | ==Engine RPM for break in== | ||
| + | 10. Failure to run the motor at high rpms (2500 or higher, alternating 500/1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for the first 40-45 minutes of its life. NO IDLING. NO IDLING. NO IDLING. The motor should not be run at less than 2500 rpm's for a minimum of 40 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 the crankshaft at speed, drainback 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. | ||
| + | 11. Failure to clearance lifters in their bores so that they spin freely. Lifter clearance should be 0.0012" to 0.002", with 0.0015" (one and one/half thousandths) considered close to ideal. Too loose is as bad as too tight. One more way to "bulletproof" a flat tappet installation is to groove the lifter bores for oiling the cam lobes. See the first tool in this link.... | ||
| + | *http://www.compcams.com/products/335-353.pdf | ||
| − | =VIEWPROD&ProdID=25140 | + | |
| + | 12. Failure to initially adjust the valves properly. Using the "spin the pushrod until it feels tight" method will normally result in valves too tight. Holding the rocker arm tip down against the valve stem tip with one hand, jiggle the pushrod up and down with your thumb/forefinger of your other hand until all play is removed, then turn the rocker nut the number of times specified by the lifter manufacturer to set the preload. (Another good reason to buy lifters from someone you can talk with about them on the phone instead of buying them in a white cardboard box with no name on it). Builders who have done hundreds of engine builds may have the "feel" to do the "twist" method, but those fellows who are doing their first few builds lack the experience to do this and will have better results with the "jiggle the pushrod up and down" method. | ||
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| + | 13. 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. | ||
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| + | 14. Failure to have everything ready for the motor to fire on the first few turns. Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum 40 minutes of uninterrupted running. Ignition timing set. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER. I don't know who started this 20 minutes business, but the motor needs to run uninterrupted for a minimum of 40 minutes at a speed high enough to sling a good quantity of oil off the crank and rods to lube the cam and lifters. (Not under 2500 rpm's). | ||
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| + | 15. 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 sure pressure is registering. Priming will aid lubing the valvetrain at initial startup. 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 unless you use either the distributor or the tool to block off the oil galley under where the distributor bolts down. Here is an example of a tool for use with a Chevrolet..... | ||
| + | *http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=25140 | ||
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| + | 16. Failure to use new lifters on a used cam. Used lifters should only be used on the very same cam, in the very same block and in the very same positions they were removed from. Chances that the lifter bores will be machined on the very same angles on a different block as the block the lifters came out of are about equal to you hitting the lottery. If you purchase a used flat tappet cam from a swap meet or yard sale, plan on using it for a doorstop. | ||
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| + | 17. Here's some interesting verbage from CompCams..... | ||
| + | "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. | ||
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 disulfide) supplied with the camshaft. | 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 disulfide) supplied with the camshaft. | ||
| − | + | 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." | |
| + | Now, this last bit of advice comes from Racer Brown, world-renowned camshaft manufacturer/engineer who ground the hot cams for Chrysler Corporation during the horsepower wars of the 60's. | ||
| + | "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." | ||
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| + | This advice from the Racer is too scary for me, but I included it so that you know someone, somewhere has done it. | ||
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| + | Just a note to make you aware of the loading between the camshaft lobe and lifter crown. That pencil-point of contact, if carried out to a square inch, would be somewhere between 250,000 and 300,000 POUNDS PER SQUARE INCH. | ||
==New Tool Innovations== | ==New Tool Innovations== | ||
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| + | As new innovations in flat tappet technology show up, they will be addressed here. One such newbie on the scene is the lifter bore grooving tool that allows pressurized oil from the lifter galley to be squirted directly onto the cam lobe/lifter interface. | ||
| + | http://www.compcams.com/products/335-353.pdf | ||
[[Category:Engine]] | [[Category:Engine]] | ||
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