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techtalk:ref:svcproc23 [2019/02/02 05:52] hippysmack [Cam Lift] |
techtalk:ref:svcproc23 [2024/01/22 21:07] (current) hippysmack |
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| ====== Degree-ing Cams ====== | ====== Degree-ing Cams ====== | ||
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| Degreeing cams is an expression used to mean measuring certain characteristics of the cam movements (cam specs). \\ | Degreeing cams is an expression used to mean measuring certain characteristics of the cam movements (cam specs). \\ | ||
| The act of degreeing cams doesn't change anything but gives you an understanding of what the cams are doing and when. \\ | The act of degreeing cams doesn't change anything but gives you an understanding of what the cams are doing and when. \\ | ||
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| * You can also degree the cams to eliminate errors in; | * You can also degree the cams to eliminate errors in; | ||
| * General manufacturing of the cams. | * General manufacturing of the cams. | ||
| - | * Proper cam installation. | + | * Proper cam installation. \\ A compression test will also immediately point out a cam timing problem. ((aswracing of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/97704-so-i-put-my-bike-back-together-got-a-dyno-tune-not-happy/page3?highlight=degree#post2030753)) \\ See also [[techtalk:ref:svcproc20#cylinder_compression_test|Performing a cylinder compression test]] in the REF section of the Sportsterpedia. |
| ====== Setting up the Equipment ====== | ====== Setting up the Equipment ====== | ||
| - | + | {{:techtalk:ref:tools:degreeing_cams_by_povertyflats.jpg?direct&400|}} ((photo by povertyflats of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/130556-fitting-buell-xb-cams-551-e-grind-to-xl/page2?s=03729fd1877416d73eb9535bdf896822#post4051327)) | |
| - | {{:techtalk:ref:tools:degreeing_cams_by_povertyflats.jpg?direct&400|}} ((photo by povertyflats of the XLFORUM http://xlforum.net/forums/showthread.php?s=03729fd1877416d73eb9535bdf896822&p=5503895)) | + | |
| * You'll need to [[techtalk:ref:svcproc22#finding_tdc_of_the_piston|Find True TDC of the Piston]] for precise measurements. | * You'll need to [[techtalk:ref:svcproc22#finding_tdc_of_the_piston|Find True TDC of the Piston]] for precise measurements. | ||
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| * Or, for spot checking cam installation, a dial caliper placed in the spark plug hole and a degree wheel will do to find TDC. | * Or, for spot checking cam installation, a dial caliper placed in the spark plug hole and a degree wheel will do to find TDC. | ||
| * See also [[techtalk:ref:svcproc22#find_true_tdc_using_a_dial_indicator_and_a_degree_wheel|Finding True TDC Using a Dial Indicator and a Degree Wheel]] | * See also [[techtalk:ref:svcproc22#find_true_tdc_using_a_dial_indicator_and_a_degree_wheel|Finding True TDC Using a Dial Indicator and a Degree Wheel]] | ||
| - | * By using only a dial indicator on top of the piston, the point where the indicator falls off it's high point will be different. \\ (depending on which direction you rotate the engine to find the high point). ((rivethog of the XLFORUM http://xlforum.net/forums/showthread.php?t=1507847)) | + | * By using only a dial indicator on top of the piston, the point where the indicator falls off it's high point will be different. \\ (depending on which direction you rotate the engine to find the high point). ((rivethog of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/138903-ccing-my-combustion-chambers?t=1507847)) |
| * There will be a few degrees of interpretation before the piston rolls back down. | * There will be a few degrees of interpretation before the piston rolls back down. | ||
| * However, a cam gear off by a tooth will show much more of a degree change than the caliper dwell at TDC. | * However, a cam gear off by a tooth will show much more of a degree change than the caliper dwell at TDC. | ||
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| ===== Equipment Specifics ===== | ===== Equipment Specifics ===== | ||
| + | \\ | ||
| ==== Dial Indicator for Measuring the Cam Lobe Lift ==== | ==== Dial Indicator for Measuring the Cam Lobe Lift ==== | ||
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| A dial indicator is set on top of the lifter body to measure the lift on each cam lobe, \\ | A dial indicator is set on top of the lifter body to measure the lift on each cam lobe, \\ | ||
| As well as the start and end times of the lobe lifts (corresponds to opening and closing of valves). \\ | As well as the start and end times of the lobe lifts (corresponds to opening and closing of valves). \\ | ||
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| |{{:techtalk:ref:tools:dial_caliper_by_jorgen.jpg?direct&300|}}| | |{{:techtalk:ref:tools:dial_caliper_by_jorgen.jpg?direct&300|}}| | ||
| - | |Dial caliper mounted over lifter bore ((photo by Jorgen of the XLFORUM http://xlforum.net/forums/showthread.php?t=761410&highlight=degreeing+cams&page=4))| | + | |Dial caliper mounted over lifter bore ((photo by Jorgen of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/92792-cam-choices/page4?t=761410&highlight=degreeing+cams&page=4))| |
| ==== Piston Stop Tool ==== | ==== Piston Stop Tool ==== | ||
| |{{:techtalk:ref:tools:piston_stop_by_jorgen.jpg?direct&300|}}| | |{{:techtalk:ref:tools:piston_stop_by_jorgen.jpg?direct&300|}}| | ||
| - | |Commercial Piston Stop Installed ((photo by Jorgen of the XLFORUM http://xlforum.net/forums/showthread.php?t=761410&highlight=degreeing+cams&page=4))| | + | |Commercial Piston Stop Installed ((photo by Jorgen of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/92792-cam-choices/page4?t=761410&highlight=degreeing+cams&page=4))| |
| - | ==== Degree Wheel ==== | + | |
| + | ==== Degree Wheel ==== | ||
| |{{:techtalk:ref:tools:degree_wheel_by_jorgen.jpg?direct&300|}}|{{:techtalk:ref:tools:degree_wheel_by_hippysmack.jpg?direct&300|}}| | |{{:techtalk:ref:tools:degree_wheel_by_jorgen.jpg?direct&300|}}|{{:techtalk:ref:tools:degree_wheel_by_hippysmack.jpg?direct&300|}}| | ||
| - | |Degree wheel mounted on primary side ((photo by Jorgen of the XLFORUM http://xlforum.net/forums/showthread.php?t=761410&highlight=degreeing+cams&page=4))|Degree wheel mounted to the pinion shaft ((photo by Hippysmack))| | + | |Degree wheel mounted on primary side ((photo by Jorgen of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/92792-cam-choices/page4?t=761410&highlight=degreeing+cams&page=4))|Degree wheel mounted to the pinion shaft ((photo by Hippysmack))| |
| ====== Cam Spec Definitions and Measuring ====== | ====== Cam Spec Definitions and Measuring ====== | ||
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| It also closes the valve at 46° after the intake stroke ends (or 46° degrees after bottom dead center). \\ | It also closes the valve at 46° after the intake stroke ends (or 46° degrees after bottom dead center). \\ | ||
| Each stroke is 180° long. \\ | Each stroke is 180° long. \\ | ||
| - | |||
| The duration can be calculated from the published timing figures. \\ | The duration can be calculated from the published timing figures. \\ | ||
| - | ===== Cam Lift ===== | + | |
| + | ===== Cam Lobe Lift ===== | ||
| The actual cam lift is any amount of lift greater (taller) than the base circle. \\ | The actual cam lift is any amount of lift greater (taller) than the base circle. \\ | ||
| This corresponds to how far the valves are open. \\ | This corresponds to how far the valves are open. \\ | ||
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| Check all four cams and compare the results. \\ | Check all four cams and compare the results. \\ | ||
| - | You can also measure cam lobe lift with the cams removed by using a caliper. ((rocketmangb of the XLFORUM http://xlforum.net/forums/showthread.php?s=73d24db8f0756ef41c6215fd92ad0055&p=4726240)) \\ | + | You can also measure cam lobe lift with the cams removed by using a caliper. ((rocketmangb of the XLFORUM https://www.xlforum.net/forum/vendors/hammer-performance/160789-gaterman-lifters-now-available-from-hammer-performance?s=73d24db8f0756ef41c6215fd92ad0055#post3437771)) \\ |
| The base circle is the smallest dimension of a cam lobe. \\ | The base circle is the smallest dimension of a cam lobe. \\ | ||
| If you measure the largest dimension of the lobe and subtract the smallest dimension you get the lobe lift. \\ | If you measure the largest dimension of the lobe and subtract the smallest dimension you get the lobe lift. \\ | ||
| Multiply that by the rocker ratio and you get the valve lift. \\ | Multiply that by the rocker ratio and you get the valve lift. \\ | ||
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| ===== Duration ===== | ===== Duration ===== | ||
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| | 30° before \\ TDC Exhaust \\ or (BTDC) | 180° | 46° after \\ BDC \\ or (ABDC) | 52° | 180° | 24° | | | 30° before \\ TDC Exhaust \\ or (BTDC) | 180° | 46° after \\ BDC \\ or (ABDC) | 52° | 180° | 24° | | ||
| | Calculated Intake Cam Duration: 30+180+46 = 256° ||| Calculated Exhaust Cam Duration: 52+180+24 = 256° ||| | | Calculated Intake Cam Duration: 30+180+46 = 256° ||| Calculated Exhaust Cam Duration: 52+180+24 = 256° ||| | ||
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| * To measure advertised duration: | * To measure advertised duration: | ||
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| Simply note the start degree before the initial lift and the end degree after the last fall of the indicator. \\ | Simply note the start degree before the initial lift and the end degree after the last fall of the indicator. \\ | ||
| Then calculate the distance in between as in the example above. \\ | Then calculate the distance in between as in the example above. \\ | ||
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| ===== TDC Lift ===== | ===== TDC Lift ===== | ||
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| TDC Valve Lift is calculated by multiplying the cam lobe lift, at TDC exhaust, by the rocker arm ratio. \\ | TDC Valve Lift is calculated by multiplying the cam lobe lift, at TDC exhaust, by the rocker arm ratio. \\ | ||
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| Valve to piston clearance has nothing to do with maximum lift (which occurs with the piston well down the bore). \\ | Valve to piston clearance has nothing to do with maximum lift (which occurs with the piston well down the bore). \\ | ||
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| |{{techtalk:ref:svcproc:2_cam_outside_gear_position_1_by_hippysmack.jpg?direct&500|}}| | |{{techtalk:ref:svcproc:2_cam_outside_gear_position_1_by_hippysmack.jpg?direct&500|}}| | ||
| |#2 Cam, Outside Gear Location (91 and Up Models) ((photo by Hippysmack))| | |#2 Cam, Outside Gear Location (91 and Up Models) ((photo by Hippysmack))| | ||
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| [[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]] | [[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]] | ||
