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Cloyes: How To Service Timing Components 2.7 Chrysler Engine


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    • By OReilly Auto Parts
      Free Check Engine Light Testing | O'Reilly Auto Parts
    • By Counterman
      The VVT category continues to grow in the automotive aftermarket. These systems are becoming more and more common as manufacturers try to meet tightened fuel-economy standards. When it comes to meeting those standards, variable-valve timing (VVT) is just one piece of the puzzle. As these vehicles exit the factory warranty period, there’s a huge opportunity for counter pros to serve customers’ repair needs.
      Variable-valve timing is the process of altering the timing and/or duration of a valve lift event, to improve performance, fuel economy and emissions.
      On a conventional engine, the opening and closing of the valves is based on their fixed position relative to the timing chain or belt, which is driven by the crankshaft. Without VVT, the valve timing remains the same for all conditions. This means that certain compromises must be made by manufacturers; this is achieved by selecting a specific cam profile. The cam profile affects the valve lift and duration.
      However, an engine equipped with VVT can make additional adjustments, so it isn’t constrained by the cam profile. VVT systems allow for improved performance over a broader operating range. The ability to alter valve timing at any engine speed gives manufacturers the ability to tune for optimal performance and efficiency. The camshaft’s timing can be advanced to produce better low-end torque, or it can be retarded to have better high-end torque as directed by the ECU.
      System Overview
      It’s important to point out that VVT is not just a single part or component – it’s an entire system. There are a number of components that all need to work hand-in-hand in order for the system to function. Let’s talk about some of the components that make up the entire system.
      The part that actually controls the position of the camshaft is the phaser. Cam phasers may feature a piston-type construction, or a vane-type construction. Regardless of construction, they use engine-oil pressure to push against a strong internal spring. A VVT solenoid is used to adjust the engine-oil pressure into the phaser.
      While early VVT systems were active only in higher rpm ranges or under specific conditions, modern systems are actively adjusting the intake and exhaust camshaft positions for the best possible efficiency at all times.
      VVT systems have caused one emissions system to become all but extinct: exhaust-gas recirculation (EGR). Since VVT is able to control the way gasses enter and exit the combustion chamber, there’s no need for EGR systems.
      EGR systems were designed to reduce nitrous oxides (NOx) by recirculating exhaust gasses back into the intake manifold. This causes the combustion temperature to drop below 2,500 F, preventing the formation of these harmful gasses. EGR systems did work, but lacked the reaction time and precision offered by VVT systems.
      Failure Points
      In many ways, engine oil is the lifeblood of the VVT system. Inadequate oil pressure or contaminated oil will hamper system performance. It’s very important that customers are following the manufacturer’s maintenance schedule, and using only the specified type, grade and viscosity of engine oil in their vehicle.
      Clean engine oil is critical to VVT-system operation. The oil passages of a VVT system are like a dead end, and the oil doesn’t flush out the passages all the time. If a piece of debris finds its way into a phaser or oil-control valve, it could be there for a while. Most manufacturers use a metal-screen filter to prevent debris from reaching the variable-valve timing system. Some manufacturers make the screen serviceable but, on some vehicles, it could be inside the oil-control solenoid and almost impossible to inspect or even clean.
      The relationship between the camshaft and crankshaft is critical in today’s VVT systems. The ECU relies on information from the camshaft position sensor and the crankshaft position sensor to determine ignition and valve timing. If either of these sensors produces a faulty signal, the VVT-system performance will suffer. A loose or stretched timing chain or timing belt, or a worn timing guide or tensioner, all could negatively affect the VVT system.
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    • By Counterman
      Westar Industries, a Columbia, Maryland-based supplier of aftermarket engine and transmission mounts and air-suspension components, recently announced the release of 58 new engine and transmission mounts.
      These newly released items are all in stock and ready for immediate shipment.
      The 58 items serve more than 30,569,261 registered vehicles currently in operation, according to the company.
      For more information, contact [email protected] or visit
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    • By Counterman
      Camshafts are one of those components that can define an engine. Cams can have a direct effect on the efficiency, power curve, sound and even attitude of the engines they are installed into. Muscle cars and race cars are two examples of vehicles that are immediately recognizable by a loping, rumbling idle that builds into a deafening roar as they’re pushed harder and higher through their rpm range. 
      A “stock” camshaft usually is designed as a compromise between performance and drivability, with considerations for emissions and fuel economy, while performance cams trade much of the “politeness” of a stock camshaft in favor of brute horsepower. 
      If you were to open any of the major speed catalogs (or look up the information on their website), you’ll discover three things: Performance parts aren’t cheap; there are a LOT of cams to choose from; and each one is accompanied by a list of specifications including duration, lift, lobe separation and recommended rpm range/usage. But what makes one cam any different from another, and what do some of the terms used to describe a performance cam actually mean?
      Duration refers to the amount of time (expressed in degrees of crank rotation) that an intake or exhaust valve is “off” of its seat. This equates to the amount of time the valve is open, allowing air to enter or exhaust to escape. Generally, a longer duration means a “deeper breath” (or exhalation), although the amount of overall airflow through the cylinder is also affected by “lift.”
      Lift, or more specifically, “valve lift,” is the distance the valve travels as a result of the action of the camshaft. As the cam rotates on an overhead-valve (OHV) engine, the eccentric lobes act directly upon the lifter, raising it (and the pushrod above) a specified distance. The pushrod transfers this “lift” to a rocker arm, which in turn presses down on the valve, releasing it from its seat. Valve-spring pressure helps the valve close at the end of its cycle, and keeps the valvetrain components from clattering as they return to a resting position.
      In an overhead-cam (OHC) design, the cam lobe contacts the rocker arm directly, or against the valve itself when paired with a “bucket tappet,” which protects the valve stem from wear. The design of a rocker arm also multiplies the lift imparted by the cam lobe, creating more lift at the valve than at the lobe. Performance rocker arms use this advantage to improve lift without altering the existing cam profile.
      Us old-timers sometimes refer to camshafts as “bump-sticks,” as they seem to have lobes poking out in every direction. They are, however, precisely engineered to open and close multiple valves in a perfectly timed sequence to maximize their effectiveness. Lobe-separation angle (LSA) is a fancy name for the distance (again in degrees) between the centerlines of the exhaust and intake lobes on a shaft. This distance, along with the duration of the cam, will determine the amount of “overlap” in the movement of the intake and exhaust valves.
      Let’s look at a “racing” cam, and how its design affects performance. Intake valves open slightly before the engine begins pulling in air on the intake stroke. Call it a “head start,” but it helps promote airflow through the cylinder. As the piston reaches the bottom of its stroke, the intake valve is still open – pulling as much air as it can into the cylinder – then closes as the piston begins compression. Exhaust valves also open a bit before the power stroke is completed, with the pressure of the expanding gas helping “push” the spent exhaust out of the cylinder.
      With both valves slightly open at top dead center, more cool air is drawn in as the hot exhaust is expelled. This phenomenon is called “scavenging,” and at higher rpm can further boost horsepower. The smaller the separation between lobes (and the more duration) the more overlap will occur. Unfortunately, at idle and low rpm, it also causes a lumpy rumble, low engine vacuum and a lack of low-end power. Although many people (myself included) enjoy hearing this signature sound at the race track, it isn’t very useful in a daily driver! Choosing the right camshaft for your intended purposes begins with defining your intended purposes!
      Every camshaft design has a “sweet spot” – the rpm range at which it performs the best. Camshaft manufacturers’ rpm recommendations are a result of dyno-testing the unique combination of lift, duration, lobe design and separation engineered into each particular grind profile. If you aren’t going to be consistently operating in a cam’s specified rpm range, it may not be the best choice for your project. Your mostly stock, daily driven street vehicle won’t benefit much from a race-ready cam that really needs to rev up around 5,000 rpm to make maximum power. As with any other performance-part purchase, it pays to do your research before buying … no matter how cool the stickers will look on your toolbox!
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    • DIY like a pro! Shop from over 1,000,000 Repair Manuals at eManualOnline.com! As low as $14.99 per manual. Shop now.


      DIY like a pro! Shop from over 1,000,000 Repair Manuals at eManualOnline.com! As low as $14.99 per manual. Shop now.


      DIY like a pro! Shop from over 1,000,000 Repair Manuals at eManualOnline.com! As low as $14.99 per manual. Shop now.

    • By Counterman
      Arnold Motor Supply recently purchased Sioux City, Iowa-based Motor Parts Central and its sister company Northern Auto Parts.
      The purchase will allow the company to expand its inventory and distribution in the region.
      “The move from our old location in Sioux City to the Motor Parts Central building increases our retail and distribution space by 130,000 square feet,” says Eric Johnson, president and managing partner for Arnold Motor Supply. “The Sioux City location will now serve as a distribution hub for our surrounding parts stores.”
      Northern Auto Parts will continue to operate within the same building and is a different type of expansion for the company. Northern is a national online retailer, specializing in engine-rebuild kits and engine parts.
      “For years, we’ve provided engine rebuilding and restoration through our machine shops, so adding the expertise of the Northern Auto Parts team is a great addition for our customers,” Johnson said.  
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