Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210


 
Camshaft Installation Tips

The following basic camshaft installation tips have been drawn from experience and reflect the most common mistakes that result in premature camshaft failure. These are not meant in any way to replace the Original Equipment Manufacturers (OEM) installation procedures. These basic installation tips are intended to be used along with OEM procedures to help insure maximum camshaft life and performance.

  • Premature Cam or Distributor Gear Failure
    When replacing a camshaft that has failed prematurely, take the time to diagnose and correct the problem before installing a new camshaft, lifters and/or followers. For assistance in diagnosing distributor gear failures, please read our tech article on premature distributor gear failure. Thoroughly inspect the old cam and distributor gears, looking for improper wear patterns. We highly recommend having the stock distributor gear reconditioned and parkerized, or replacing with a high quality gear.

  • Keeping It Clean
    Once you've disassembled the engine and removed the old components, thoroughly clean the exposed portions of the engine. Excessive debris may not completely drain with the oil and could become lodged on other components in the engine– causing additional problems after the engine is reassembled. Finally, check all oil passages to make sure they are free of dirt and foreign particles. Remember, engine parts operate in tolerances as little as one thousands of an inch, and just one little speck of dirt could mean the difference between a job well done and a job you'll have to do again.

  • Inspection
    Inspect lifter bores for excessive wear. This usually shows up as an oblong or egg-shaped wear pattern. It is generally a good idea to check your valve springs for proper length, pressure, and to make sure they are square. Inspect the cam bearings for wear and signs of fatigue. Be especially concerned if you are replacing a camshaft that failed prematurely. The cause of the camshaft failure may have had an effect on the cam bearings. If you find the cam bearings need replacement, check the bores for size and alignment. We recommend that you replace the cam bearings whenever a new cam is installed, even if damage is not noted, as it is cheap insurance for a job well done.

  • Old Parts
    Make sure you remove the old cam pin as well as the spacer (behind the pin) as they will be needed when you install your new cam. If you fail to install the spacer on the new cam, the cam will bind up and won't turn once the gear is installed and the bolt is tightened down. If a new cam pin is supplied, use it, otherwise you can use your old pin. Just make sure you clean both parts thoroughly, before you install them on your new cam.

  • Pre-lube
    Lack of lubrication is one of the most common causes of camshaft failure during the initial start-up. If the camshaft and other valve train components are not properly pre-lubricated, they can be damaged within the first few camshaft revolutions. Once the damage has occurred, no amount of lubrication will prevent the impending failure of these parts. Always use a high quality break-in lube during assembly.

  • Installation
    Thoroughly coat the camshaft lobes, bearing journals and distributor drive gear with cam lube. Carefully slide the new camshaft into the engine block or head, taking precautions not to damage the cam bearing surfaces. When the new camshaft is installed, check that it turns freely in the engine.

  • New Lifters
    Because of the function and design relationship between the camshaft lobe and the lifter, it is extremely important that new lifters be used with a new camshaft. While cam lobes and lifter faces may appear flat to the naked eye, on all but a few applications, they are not. Cam lobes generally have a taper from .0007" to .001" across the face and are commonly ground to a domed shape with an approximate .002" crown. The offset, along with the taper of the cam lobe, causes the lifter to rotate as the cam turns. Before installing the lifters in the lifter bores, generously coat the lifter bores with cam lube. Coat the lifters and/or followers one at a time as they are installed, making sure to keep them clean and free of any dirt or dust particles. Once they have been installed, rotate the camshaft to check for binding or misalignment.
    Lifters should not be soaked overnight
    .

  • Reassembly
    Re-check all parts and gasket mating surfaces. Next, reassemble the engine to the proper OEM specifications using quality gaskets.

  • Valve Adjustment - Mechanical Lifters
    Set valve lash using OEM procedures and the proper specification for your camshaft.

  • Valve Adjustment - Hydraulic Lifters
    Although hydraulic lifters require no adjustment during normal service, it is important to check the lifter pre-load when lifters are installed and adjust as necessary. Lifter pre-load is the distance between the retaining snap ring and the push rod seat in the lifter when the lifter is on the heel of the cam lobe with the valve closed. A number of things can affect lifter pre-load:

    1. Resurfacing the heads and/or block deck
    2. Changes in camshaft diameter
    3. Changes in push rod length
    4. Changes in valve length
    5. Changes in rocker arm length or geometry
    6. Changes in head gasket thickness
    7. Changes in lifter height
    8. Valve job
    9. Different rocker arm stands or shafts

    When installing new hydraulic lifters, follow the proper OEM procedures for checking and adjusting lifter pre-load. Do not soak the lifters overnight. With manufacturing tolerance being so accurate, it is recommended that you use an oil pump priming tool to fill the lifters with oil after they are installed and prior to engine start up.

  • Engine Oil
    With the formulation of today's oils having evolved to favor roller cam applications, getting a flat faced camshaft and lifters through their critical initial break-in period is becoming more of a challenge. To meet current requirements, most oils have severely reduced zinc content. This has elevated the stresses where rubbing forces occur, leading to potential cam lobe, lifter, and gear failures. We highly recommend using an additive with zinc dithiophosphate during the initial oil fill (this is in addition to the moly-based lube that should have been applied to the camshaft, lifters, and gears during assembly). One such additive is Crane Super Lube (PN 99003-1), which was developed over 35 years ago. An 8 oz. container will provide the necessary additives to drastically reduce the potential for premature wear during the break in period. Some oil companies offer racing oils that have decent zinc content, however they may not be street legal. After break-in, change the oil and filter at normal intervals, as suggested by the manufacturer.

    Below is a list of oils with higher levels of wear preventive additives which may be more desirable during flat tappet camshaft break-in.

    Delo 400
    Delvac
    Rotella T
    Viscosity @100 15.95
    Viscosity @100 15.50
    Viscosity @100 15.12
    Magnesium 23
    Magnesium 419
    Magnesium 20
    Calcium 3343
    Calcium 2195
    Calcium 3322
    Zinc 1376
    Zinc 1231
    Zinc 1499
    Phosphorus 0
    Phosphorus 1120
    Phosphorus 1326
    Moly 0
    Moly 35
    Moly 0
    Boron 0
    Boron 61
    Boron 0

  • Initial Start-Up
    It is important that the engine starts as quickly as possible. Prolonged cranking may damage the camshaft, lifters and/or followers. Before starting the engine, top off the coolant level and make sure the ignition timing is properly set. After starting the engine, DO NOT let it idle. It is essential to run the engine at 1500-2000 RPM for at least 20 minutes. Because the camshaft and lifters are primarily lubricated by a splash-effect of oil from the crankshaft, any RPM below 1,500 may result in insufficient lubrication and will not rotate the engine fast enough to force the lifters to rotate on the camshaft. The rotation allows the lifters to properly seat against the camshaft during this critical break-in procedure. During the first 20 minutes, carefully monitor oil pressure. If any problems arise, shut down the engine immediately. Remember, do not let the engine idle for the first 20 minutes.
  • Finally,
    If the engine needed to be shut down for any reason during the initial start up, repeat the start-up procedures beginning with priming the oiling system, after the problem has been corrected.



Other related articles:

Understanding Lobe Centers
- Static vrs Dynamic Compression
How to Degree Your Cam - Adjusting Your Valves
Clay Smith Cam Cards - Clay Smith Cam Profiles





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