1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16694 Metered Oil Flow Rate (MOFR) of Valve Stem Seals Copyright 2012 General Motors Company All Rights Reserved January 2012 Originating Department: North American Engineering Standards Page 1 of 6 1 Scope Note: Nothing in this standard supercedes
2、applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. Measure by collected weight, the oil flow rate (Q) due to gravity alone (Procedure A) or due to gravity and absorbed with a special pape
3、r (Procedure B) off the valve stem, guides, etc., after ten (10) hours. See paragraphs 5.2.3 and 5.2.4 for procedure usage guidelines. Results (optional) may be converted to a volume per 5.1.2. 1.2 Foreword. A function of valve stem seals is to control the passage of oil (flow) between the reciproca
4、ting valve stem, valve guide, and the seal lip. Insufficient lubrication leads to abrasion, abnormal valve noise, and in the worst case, valve burnout. Validation of seal design factors is accomplished by precise measurement of oil leakage using actual engine components. 1.3 Applicability. Intake an
5、d exhaust valve stem seals. After long term engine lab or field testing, leakage can be remeasured. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM D573 ISO 6194-1 ISO/IEC 17025 SAE J1901 IEEE/ASTM SI 10 ISO
6、 16949 SAE J946 2.2 GM Standards/Specifications. GMW15827 2.3 Additional References. None. 3 Resources 3.1 Facilities. Test laboratory with temperature and humidity control. See paragraph 4.2.1. 3.2 Equipment. 3.2.1 Leakage Rate Apparatus. Ahaus Tool and Engineering, Richmond, IN or equivalent. Each
7、 unit consists of one (1) to two (2) heads, with four (4) test specimens per head. This apparatus can be adapted for push rod or overhead camshaft applications. A pulley, belt, and electric motor drive the camshaft. The oil system includes collection devices, heater, controller, sump, pump and filte
8、r. A vacuum pump connected to the combustion chamber aids in oil collection. The machine controls camshaft speed, oil pressure and temperature, and vacuum pressure. Gauges measure oil temperature, oil pressure and combustion chamber pressure (vacuum). Head orientation effects are optional. Productio
9、n heads are optional. 3.2.2 Balance. Single pan analytical with readability to 0.0001 g and repeatability to 0.1 mg. Pan must have a cover or be enclosed. 3.2.3 Calipers. ncremented to 0.02 mm. 3.2.4 Desiccating Cabinet or Desiccator. Sufficiently sized to prevent contact between weighed specimens.
10、3.2.5 Optical or Video Comparator. Capable of measuring valve stem and seal dimensions per detail drawing, ISO 6194-1, or SAE J946. 3.2.6 Oven. Air-circulating oven conforming to ASTM D573, Type IIA. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for Re
11、saleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16694 Copyright 2012 General Motors Company All Rights Reserved January 2012 Page 2 of 6 3.2.7 Profilometer. Capable of measuring valve stem surface finish per detail drawing. 3.2.8 Filter
12、Paper, 5.5 cm, Grade 4 White. Coarse porosity, fast flow with 20 to 25 micron particle retention (Procedure B). 3.3 Test Vehicle/Test Piece. Test only seals compliant with the drawing requirements. 3.3.1 Randomly select 32 seals to be tested. 3.3.2 Seal. Measure the lip inner diameter (ID) and the l
13、ip contact load (LCL) per SAE J1901, and visually inspect the seal for defects. Record these measurements. Confirm the measurements meet the product drawing specifications. 3.3.3 Stems and Guides. Obtain production release intent valve stems and guides. Measure outside diameters and stem finish and
14、confirm they meet the product drawing specifications. Customer supplied stems and guides may be used. 3.3.4 Springs. Obtain production release intent springs. Confirm they meet the drawing specifications. Customer supplied springs may be used. 3.3.5 Head. At the requesters option, the intended produ
15、ction part is modified to permit oil collection from each valve. 3.4 Test Time. These times are typical for scheduling information once test parts are received. Calendar time: 20 days (32 seals on 1 unit) Test hours: 10 hours Coordination hours: 1 to 2 hours 3.5 Test Required Information. MOFR (Q) f
16、or each valve stem seal tested in specified fluid(s) Seal ID at start of test (SOT) Lip Contact Load (LCL) at SOT Seal ID at end of test (EOT) LCL at EOT Guide outer diameter (OD) at SOT Stem OD at SOT Surface Finish at SOT 3.6 Personnel/Skills. The test technician shall be trained to correctly oper
17、ate the devices and measurement tools described in this procedure. 4 Procedure Follow Procedure A or B using this sequence (see paragraphs 5.2.3 and 5.2.4). Only the differences between procedures are marked, using the letters A or B where appropriate, and bold font to emphasize Procedure B or added
18、 requirements. 4.1 Preparation. Follow the steps in this section for cleaning the leakage rate apparatus and weighing oil collection test cups. Note the change in steps between break-in and retest (paragraph 4.3.4.3). 4.1.1 Test Cups. Cover hands with clean latex gloves, or wash and dry them before
19、handling the test collection cups. 4.1.2 Using a lint free cloth, wipe the oil collection test cups with a residue free, technical grade safety solvent/cleaner (e.g., isopropyl alcohol). Place the cups in a cabinet or desiccator with anhydrous calcium sulfate until dry (see paragraph 4.1.3). In addi
20、tion, for Procedure B, place filter paper in the desiccator. 4.1.2.1 If the cleaner/solvent has a slow evaporation rate, store the collection cups in the lab oven for 30 minutes at 60 C. 4.1.2.2 Remove test cups from the oven and wipe dry with a suitable lint free product. 4.1.3 Verify that the indi
21、cating anhydrous calcium sulfate desiccant in the desiccating cabinet is active (moisture absorption produces a visible color change). Store the collection cups in the desiccator for 20 minutes. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleN
22、o reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16694 Copyright 2012 General Motors Company All Rights Reserved January 2012 Page 3 of 6 4.1.4 Leakage Collection Assembly. Using a lint free cloth, remove and wipe down the following with a res
23、idue free technical grade safety solvent/cleaner: test guides, stems, springs and the tester surface directly above the collection cups. Allow these items to dry. Install the clean items in the test unit. Clean this assembly before the first two (2) hour break-in (paragraph 4.3.5). Do not re-clean t
24、hese assembly items after the first run of four (4) to eight (8) seals. Test 32 seals (paragraph 3.3.1). 4.1.5 Procedure A: Remove the collection cups from the desiccator or cabinet, and weigh them on the analytical balance. Measure to 0.0001 g and record the results. Procedure B: After washing and
25、drying hands, remove one filter paper for each cup from desiccating cabinet and place in the cups. Weigh filter paper/cup assembly on the analytical balance. Measure to 0.0001 g and record the results. 4.1.6 Do not install the test cup into the leakage rate apparatus until the initial two (2) hour b
26、reak-in is completed (paragraph 4.3.4.3). 4.1.7 At the end of each test, concluding with the final weighing, clean the used collection cups as described in 4.1.1 to 4.1.5. 4.2 Conditions. 4.2.1 Environmental Conditions. Conduct leakage rate apparatus testing at facility temperature and humidity cond
27、itions. Labs with weighing apparatus should be at 30% to 70% relative humidity (RH) and 20 C to 30 C. All test conditions must be within 2 minutes or hours, and 2 C of a specified temperature. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such
28、requirements shall be specified on component drawings, test certificates, reports, etc. 4.2.2.1 Standard Test Fluids. See GMW15827. 4.2.2.1.1 Use GMW15827 Synthetic SAE 5W-30 oil. Other engine oils specified between the tester and requester must be identified by the appropriate industry standard or
29、GMW specification. Dedicated fixtures for each test oil will minimize flow measurement errors. 4.3 Instructions. Follow Procedure A or B using this sequence. Only the differences (steps) between instructions are marked, using the letters A or B in bold font where appropriate. 4.3.1 Select the cleane
30、d and measured valve stems and guides for testing (paragraph 3.3.3). 4.3.2 Set the valve stem seal leakage rate apparatus (Ahaus or equivalent) to the conditions found in Tables 1 and 2. Table 1: Intake Seals Condition Settings Oil Temperature: 120 C Pressure: Gasoline: 400 mm 60 mm Hg Diesel: 0 mm
31、Hg Camshaft Speed: 1500 rpm 75 rpm Stem Stroke: 8 mm to 12 mm Table 2: Exhaust Seals Condition Settings Oil Temperature: 120 C Pressure: Gasoline: 35 5 kPa Diesel: Pressure Corresponding to Maximum Torque Camshaft Speed: Gasoline: 1500 rpm 75 rpm Diesel: Speed Corresponding to Maximum Torque Stem St
32、roke: 8 mm to 12 mm Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16694 Copyright 2012 General Motors Company All Rights Reserved Janua
33、ry 2012 Page 4 of 6 4.3.3 Confirm the new valve stem seal, cleaned stem, guide, and spring are properly installed and conform to paragraphs 3.3.2 to 3.3.5. 4.3.3.1 For consistent results, all 32 valve stem seals are to be run on the same leak test apparatus including stems, guides and springs. 4.3.4
34、 Each test unit shall have a clear transparent head cover or one with observation window(s) for viewing to confirm the oil flow pressure and direction on the stems. 4.3.4.1 For the initial two (2) hour break-in, install un-weighed collection cups. After the break-in or ten (10) hour test run and one
35、 (1) hour wait (paragraph 4.3.5), wipe clean the area immediately above the collection cup. Before all subsequent runs, install the weighed collection cups. 4.3.4.2 Turn on the oil pump, without cam motion. Visually confirm that adequate oil flow rate is directed at the stem surface above the valve
36、stem seal. 4.3.4.3 Initial Break-In Only. Procedure A: Start the leak rate apparatus and run for two (2) hours. At the end of two (2) hours, stop the apparatus and install the weighed collection cups. This step ensures consistent oil exposure between the first set of valve stem seals, and seals test
37、ed in subsequent runs. Procedure B: Start the leak rate apparatus and run for two (2) hours. At the end of two (2) hours, stop the apparatus and install the filter paper and cup assembly into the tester. 4.3.5 Start the tester and run for ten (10) hours. At EOT, wait a minimum of one (1) hour to per
38、mit any gravity fed oil to reach the collection cups. 4.3.6 Procedure A: Remove the collection cup from the test unit. If immediately starting another test, place cups in a cabinet or desiccator for at least 20 minutes. Procedure B: After washing and drying hands, remove filter paper/cup assembly, f
39、old filter paper in half, and fold ends to retain any oil that has collected. Place filter paper back into cups and set the assembly back in the test chamber. 4.3.7 Disassemble the rocker and push rod or camshaft assembly in the leak rate apparatus. Remove the tested valve stem and seal, valve sprin
40、g, retainer and keeper assembly from the apparatus and install a new seal. 4.3.8 Procedure A: Wipe oil off all valve stem seals with a lint free cloth. Retain seals for measurements. Procedure B: Wipe oil off all valve stem seals with a lint free cloth. With one hand, remove the tested valve stem, v
41、alve spring, retainer, and keeper assembly from the test unit. After removal, immediately turn the components horizontal to prevent oil from running down the stem. Do not let the stem make contact with the valve spring ID. 4.3.8.1 Procedure B: With the other hand, wrap filter paper around stem benea
42、th the valve spring. Wipe off oil from beneath valve spring to the end of the stem. Do not make contact with the filter paper and the valve spring. 4.3.8.2 Procedure B: Lay valve stem, valve spring, retainer, and keeper assembly down and return the filter paper to the cup. 4.3.9 Procedure A: Repeat
43、paragraphs 4.3.6 to 4.3.8 (Procedure A) for all positions in the tester. Procedure B: Repeat paragraphs 4.3.6 to 4.3.8 (Procedure B) for all positions in the tester. 4.3.9.1 Procedure B: With seals remaining on the guide fixture, wipe off the top of the seals at each position with a lint free cloth.
44、 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16694 Copyright 2012 General Motors Company All Rights Reserved January 2012 Page 5 of 6
45、 4.3.9.2 Procedure B: After washing and drying hands, wrap filter paper around the stem of a cotton swab. Stick filter paper and cotton swab though the seal and wipe the entire surface of the guide ID. 4.3.9.3 Procedure B: Push filter paper through the bottom of the guide. Catch filter paper with th
46、e opposite hand and return to the cup. 4.3.9.4 Procedure B: Repeat paragraphs 4.3.9.1 to4.3.9.3 (Procedure B) for all positions in the tester. 4.3.9.5 Procedure B: Place collection cup and filter paper in a cabinet or desiccator for at least 20 minutes. 4.3.10 Begin the next run of test valve stem s
47、eals. Reassemble the test unit following paragraph 4.3.4.1. 4.3.11 Restart the test following paragraph 4.3.5. Repeat 4.3.6 (Procedures A and B) through 4.3.10 until all valve stem seals are tested. 4.3.12 Take the test collection cups (paragraph 4.3.6, Procedures A and B) from the desiccator or sto
48、rage cabinet. 4.3.13 Procedure A: Weigh each collection cup on the analytical balance. Measure to 0.0001 g and record the results. Procedure B: Weigh filter paper/cup assembly on the analytical balance. Measure to 0.0001 g and record the results. 4.3.14 Seal. At EOT remeasure paragraph 3.3.2 items.
49、Record these measurements. 4.3.15 Procedure B: After weighing, properly dispose of all used filter paper. 5 Data Note: All data must be generated by an ISO/TS 16949 or ISO/IEC 17025 accredited lab. 5.1 Calculations. Calculate oil leakage using the formula: Q = W2 - W1 Where: Q = Oil leakage rate (g/10 hours) W2 = Weight (g) of cup at EOT W1 = Weight (g) of cup before SOT 5.1.1 Calculate
