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techtalk:ref:tools148 [2018/08/24 17:58] hippysmack [Interpreting the Readings] |
techtalk:ref:tools148 [2024/01/24 21:55] (current) hippysmack |
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| ====== REF: Tools - 148 ====== | ====== REF: Tools - 148 ====== | ||
| - | ====== Cylinder Leak-Down Tester ====== | + | ====== Cylinder Leak-Down and Compression Testers ====== |
| + | ====== Leak Down Tester ====== | ||
| + | |||
| + | See also [[techtalk:ref:svcproc21|Performing a Cylinder Leak-Down Test]] in the REF section of the Sportsterpedia. \\ | ||
| This is basically a flow meter showing the differential pressure between the two gauges. \\ | This is basically a flow meter showing the differential pressure between the two gauges. \\ | ||
| - | Simply put, the left gauge measures incoming pressure from the air tank and the right gauge measures the pressure lost thru leakage in the cylinder. | + | Simply put, the left gauge measures incoming pressure from the air tank and the right gauge measures the pressure lost thru leakage in the cylinder. \\ |
| + | Some have dual psi gauges for which you can induce a dedicated 100 psi of air into the system which makes deducing percentage easy. \\ | ||
| + | Others will have a percentage based gauge on the right (with a lighter calibration) using a pre-determined amount of air via the regulator. | ||
| + | |||
| + | |||
| + | * When using the differential pressure gauge set, ((SHIPCHIEF of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/29105-cylinder-compression-and-leakage-tests-for-your-ironhead?t=48311)) | ||
| + | * The first gauge shows the regulated pressure. | ||
| + | * Then, the air passes thru an orifice (a smaller hole inline between the two gauges to restrict the flow between them) to the second gauge. | ||
| + | * The air then leaves the second gauge to the cylinder via the spark plug adapter. | ||
| + | * This pressure (end to end) would ideally be the same if there is no cylinder, valve or head gasket leakage. | ||
| - | ===== Setting up the Gauge ===== | + | This test will also tell you what to look for at the top end of a tear down: worn exhaust valves, worn intake valves, leaky head gaskets, or worn rings. ((IronMick of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/29105-cylinder-compression-and-leakage-tests-for-your-ironhead?t=48311)) |
| + | - Turn on the compressor, connect the gauge to the air pressure, and adjust the gauge. | ||
| + | - Thread the adapter into the spark plug hole and attach to the gauge. | ||
| + | - The gauge now shows the amount of leakage. | ||
| + | - Interpreting the readings | ||
| + | - Hunt down the source of leaks | ||
| - | * **Before attaching the gauge to an air supply**: Turn the regulator all the way to the left (off). \\ Failure to do so can result in damage to the gauge(s). \\ | ||
| - | * Most gauges are subject to damage from dropping / abuse. \\ | ||
| - | * The pic below demonstrates how easy this one from Harbor Freight can get out of calibration. \\ The face dial is driven by air pressure thru a flattened copper tube with down-weight from a long armed gear that actuates a spring loaded mechanism to the dial. \\ The copper tube lifts up on the end under pressure while actuating the gear arm. \\ One good hit and the weight can ping the spring out of calibration. \\ Driving the air pressure past zero and enough to ping against the dial stop can also damage the spring. \\ The gauge will still work, but the dial will stop at various unusable locations. | ||
| - | |{{:techtalk:ref:tools:hf_leakdown_tester_1_by_hippysmack.jpg?direct&300|}}| | + | |{{:techtalk:ref:tools:hf_leakdown_tester_5_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:tools:hf_leakdown_tester_7_by_hippysmack.jpg?direct&300|}}| |
| + | ^ Commercially available leak down tester (from Harbor Freight) ((photos by Hippysmack)) ^^ | ||
| - | * **Slowly, turn the regulator valve to the right to increase the pressure thru the tool**. | + | |{{:techtalk:ref:tools:homemade_leakdown_tester_by_cjburr.jpg?direct&300|}}| |
| - | * **Stop turning the valve when the right gauge reaches '0'**. \\ The regulator gives air to both gauges at the same time. \\ Both gauges will increase together. However, these two gauges are not calibrated the same. \\ The right gauge will increase all the way to the zero mark before the left gains much pressure. \\ With this particular tool, the left gauge will be near 1 bar (14.5 psi) although it may vary slightly. | + | ^ Homemade Leak-Down Tester ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/32811-compression-check-how-to?t=56497)) ^ |
| - | |{{:techtalk:ref:tools:hf_leakdown_tester_2_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:tools:hf_leakdown_tester_4_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:tools:hf_leakdown_tester_3_by_hippysmack.jpg?direct&300|}}| | + | ====== Compression Tester ====== |
| + | {{techtalk:ref:svcproc:checking_compression_1_by_mathormell.jpg?direct&250|}} ((photo by MatHormell of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/183888-hammerperf-90-in-the-works/page71?t=1976997&page=71)) {{techtalk:ref:svcproc:checking_compression_2_by_mathormell.jpg?direct&250|}} ((photo by MatHormell of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/183888-hammerperf-90-in-the-works/page71?t=1976997&page=71)) | ||
| - | * **Install the short air hose via a 12mm adapter into the spark plug hole**. | + | ====== Spark Plug Hole Adapters for an Air Hose ====== |
| + | These are used in place of the spark plug to hook up diagnostic tools (compression tester, leak-down tester etc.). \\ They can also be used to adapt a 14mm TDC whistle or piston stop to a Sporty engine. | ||
| + | ===== Commercially available ===== | ||
| + | * 14mm fittings are most commonly found at auto parts stores. | ||
| + | * 12mm adapters are usually supplied along with compression and leak down kits. \\ They are also available at some auto parts stores and online tool companies. | ||
| + | * If you, by chance, have bought a 'kit' in the past only to find your gauges no longer work properly, keep the fittings that came with it before tossing out the defective parts. \\ These may prove to be invaluable when they are needed. | ||
| - | **Now, your ready to start the test**. | + | |A few adapters including a tall one (which is great for some V-8's). \\ Add the small 14mm-12mm adapter on the long one and it'll work for 12mm plug holes.|| |
| + | |{{:techtalk:ref:tools:spark_plug_thread_adapters_1_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:tools:spark_plug_thread_adapters_2_by_hippysmack.jpg?direct&300|}}| | ||
| + | ^ Spark Plug Hole Thread Adapters ((photos by Hippysmack)) ^^ | ||
| - | ===== Test the Cylinder for Leaks ===== | + | ===== Homemade ===== |
| + | An old spark plug with the ceramic removed can be used to make an adapter for air hose fittings. \\ | ||
| + | Ceramic is too hard to drill and it's easier to just break it off flush with the metal and cut the compression lip off the plug. \\ | ||
| + | With the plug hollowed out, an air hose nipple can then be welded brazed, threaded or epoxied in the hole to connect a regulated air supply. \\ | ||
| - | During the leakdown test, when you apply the air pressure to the cylinder, the piston will be driven downward thereby turning the rear wheel. So secure the wheel by applying brakes or some other method or it will just turn over the engine and open the exhaust valve. ((skyboltdan of the XLFORUM http://xlforum.net/forums/showthread.php?t=48311)) | + | **Welded**: \\ |
| + | |{{:techtalk:ref:tools:compression_test_adapter_by_fearlessfrisbee.jpg?direct&300|}}| | ||
| + | ^Homemade air nipple welded into the plug. ((photo by FearlessFrisbee of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/136487-valve-job-shop-nearby?t=1481141))^ | ||
| - | * **Note the pressure reading on the left gauge during set-up** by memory or by making a mark or with a piece of tape. \\ You'll need to adjust the pressure later back to this point. | + | **Brazed**: \\ |
| - | * **Attach the engine side hose to the gauge and watch the readings**. \\ Both gauges will have lower readings due to the tool filling up the cylinder. \\ The closer the piston is to TDC, the less area to fill and the gauge will rest at it's static residual pressure on the gauges. \\ Likewise, the lower the piston, the more volume of air is needed to fill the chamber. \\ Then, more pressure will drop but it will catch back up when the cylinder is pressurized and you'll see the gauges bounce back up to a static number. | + | |
| - | |{{:techtalk:ref:tools:hf_leakdown_tester_5_by_hippysmack.jpg?direct&300|}}| {{:techtalk:ref:tools:hf_leakdown_tester_6_by_hippysmack.jpg?direct&300|}}| | + | This adapter was made using the same concept of removing the ceramic and brazing a male hose coupling to the end of a spark plug. |
| + | |{{:techtalk:ref:tools:homemade_12mm_hose_adapter_by_screw_loose_dan.jpg?direct&400|}}| | ||
| + | ^ Homemade Hose Coupling ((photo by Screw Loose Dan of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/32811-compression-check-how-to/page2?t=56497&page=2)) ^ | ||
| - | * **Now increase the pressure**. Turn the regulator valve up to get the pressure on the left gauge back to the same point as before it was attached to the engine side hose. \\ (in this case, near 1 bar) | + | \\ |
| - | * **Note the right gauge reading**: This gauge should now show a lower reading than it did when the tool was set up: | + | |
| - | |Before testing|After testing| | + | **Threaded**: \\ |
| - | |{{:techtalk:ref:tools:hf_leakdown_tester_3_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:tools:hf_leakdown_tester_7_by_hippysmack.jpg?direct&300|}}| | + | This is a homemade adapter (1/4" NPT to 12mm) that's relatively simple to make if you are having trouble finding the adapter you need. |
| - | | This test was done on a 1250 engine with less than 1,000 miles || | + | |A used spark plug is already threaded for the plug hole. You can grind the electrode off and remove the \\ insulator. Then thread the internal hole for the threads you'll be needing from your hose / apparatus ((photos by cjburr of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/32811-compression-check-how-to?t=56497))|| |
| + | |{{:techtalk:ref:tools:homemade_12mm-to_quarter_npt_hose_adapter_1_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:tools:homemade_12mm-to_quarter_npt_hose_adapter_2_by_cjburr.jpg?direct&300|}}| | ||
| - | ===== Interpreting the Readings ===== | ||
| - | A mechanics stethoscope [with the probe removed for this test] makes a good listening device, as does a length of oil / gas line hose. \\ | ||
| - | There will always be some audible leakage, especially past the rings and even on a healthy engine. \\ | ||
| - | Greater leakage results in a sound of lower pitch. ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=48311)) | ||
| + | You'll need to tap threads into the gutted out portion of the plug. In order to get good threads in the plug body you need a bottoming tap (no taper). \\ | ||
| + | Or, you will have to grind down a 1/4" NPT tapered tap and make it shorter until it is able to go deep enough into the plug body to cut threads in the sides. | ||
| + | |Break the porcelain off with a hammer (eye protection required). Take a small screwdriver and break up the porcelain under the crimp (portion that holds the \\ porcelain in the plug body ), this will let you grind the crimp only and the job will go faster as the porcelain is harder to grind. Then pull the rest of it out. \\ You now have to tap threads in the gutted area for 1/4" NPT (national pipe thread)in the plug body and you are ready to go. ((photos by cjburr of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/32811-compression-check-how-to?t=56497))||| | ||
| + | |{{:techtalk:ref:tools:homemade_12mm-to_quarter_npt_hose_adapter_3_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:tools:homemade_12mm-to_quarter_npt_hose_adapter_4_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:tools:homemade_12mm-to_quarter_npt_hose_adapter_5_by_cjburr.jpg?direct&300|}}| | ||
| + | ^ Homemade 1/4" NPT to 12mm Spark Plug Hole Adapter ^^^ | ||
| + | \\ | ||
| - | * **Listen at the exhaust pipe or exhaust port on the head**. | ||
| - | * Excessive hissing here indicates the respective exhaust valve is not sealing. | ||
| - | * **Listen at the A/C intake or intake port of the head**. | ||
| - | * Excessive hissing here indicates that the intake valve is not sealing. | ||
| - | * **Listen at the timing plug hole with the plug removed**. | ||
| - | * Excessive hissing here indicates the rings are not sealing. | ||
| - | * **Listen around the cylinder to head connection**. | ||
| - | * Excessive hissing here indicates the respective head gasket is not sealing. | ||
| \\ | \\ | ||
