Usage:
The 6V9450 Engine Pressure Group replaces the former 6V3150 Engine Pressure Group and 4S6553 Engine Evaluation Test Group. The contents of the 6V3150 Engine Pressure Group are still serviced. The contents of the 4S6553 Engine Evaluation Test Group are no longer serviced.
The 6V9450 Engine Pressure Group can be used to check the performance of diesel and natural gas engines, and to make operating adjustments to natural gas engines. Refer to the Service Manual of the engine being serviced or to the Fuel Setting and Related Information microfiche library for operating specifications.
The gauges in the 6V9450 Engine Pressure Group are gauge pressure instruments that indicate pressure relative to ambient atmospheric pressure. This type of instrument will read ZERO when the pressure port is open to the atmosphere.
Engine boost or manifold pressure is the difference between atmospheric pressure and the pressure in the engine intake manifold. The new 8T0840 Compound Pressure Gauge can read boost directly in kPa and inches of Hg. The new 8T0839 Differential Pressure Gauge reads directly in kPa and inches of H2O. All other gauges in the group read directly in kPa and psi. The chart in the lid of the case can be used to convert kPa or psi to inches of mercury as shown in the Fuel Setting and Related Information microfiche. No allowance for atmospheric pressure is needed in the conversion.
NOTE: The metric portion of the new pressure gauges is shaded in yellow.
List Of Components
1. 8T0841 Case
2. 8T0839 Differential Pressure Gauge
3. 8T0846 Pressure Gauge
4. 8T0840 Compound Pressure Gauge
5. 8T0848 Pressure Gauge
6. 8T0838 Bulkhead Fitting (eight) *
7. 8T0821 Tubing, 16 m (52.5 ft) **
8. 8T0837 Straight Connector (six) *
9. 8T0836 Elbow Fitting (six) *
10. 8T0835 Union (two) *
11. Optional 8T3153 Foam Block (case lid) ***
12. 6V6132 Cable Tie (five)a)
13. 6V6045 Accessories Case & SEES5575 Accessories Label
14. 6V6115 Packing Set Base
15. SEES5677 Conversion Chart b)
16. SEES5667 Title Decal (on outside of case lid)
17. Optional 8T0452 Water Manometer
*The 8T0835 Union, 8T0836 Elbow Fitting, 8T0837 Straight Connector and 8T0838 Bulkhead Fitting are reusable " tube fittings for applications in the pressure range of vacuum to 1720 kPa (250 psi) and in temperatures from -12°C to 200°C (10°F to 400°F).
**The 8T0821 tubing is a coil of 16 m (52.5 ft) of clear nylon tubing which allows the user to see the presence of any fluid before and during use.
***The optional 8T3117 Foam Block can be placed into the lid of 8T0841 Case to hold the optional 8T0452 Water Manometer in the case with 6V9450 Engine Pressure Group.
a)The 6V6132 Cable Tie can be used to tie tubing to the engine so the tubing does not contact hot surfaces. The ties are reusable. To loosen a tie after use, push back on the tang and pull out the strap. 2222
b)FORM SEES5677 Conversion Chart uses the SI unit kPa as its base unit and has been rounded to the nearest practical measure for fiel use. It allows conversion from kPa to psi, inHg, mmHg, cmHg, inHO, ftHO, cmHO, atm, bar, and kg/cm. The chart is printed on oil and water resistant material.
Optional Accessories
8T3047 Finger Release Buttons
The 8T3047 Finger Release Buttons snap onto the tube fittings. They allow removal of tubing without any tool. When the button is pressed down, the tubing can be pulled out of the fitting. For permanent mounting, the buttons can be glued to the fittings.
8T0452 Water Manometer
The 8T0452 Water Manometer is used to read static pressure, vacuum, or differential pressure over a range of 50 cmH2O - 0 - 50cmH2O (for a total range of 100 cmH2O)/
Specifications
Operating Temperature Range: - 1°C to 60°C (30°F to 140°F) for differential pressure gauges.
- 18°C to 71°C (0°F to 160°F) for all other gauges.
Gauge Accuracy: ± 2% of full scale for differential pressure gauge.
SAE Grade A (± 1.5% to 1% to 1.5% of full scale for all other gauges).
Vacuum and Pressure Ranges: 100 kPa (15 psi) for differential pressure gauge.
Full scale for all other gauges (vacuum below lowest reading and pressures above full scale will destroy accuracy of all such gauges).
Operating Position: Position has no effect on differential pressure gauge, if gauge has been mechanically adjusted to ZERO in the test position. On all other gauges, position has no effect on accuracy.
Pressure Media: Differential pressure gauge - clean air and gases only (no fluids).
All other gauges - air, gases and liquids (oil, water, antifreeze, fuel, etc.)
| NOTICE |
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Do NOT use any acids or other highly corrosive liquids in the gauges. Such liquids will destroy the gauges and accessories. |
Weight of Group: 6.8 kg (13.1 lbs).
Size: 390 × 310 × 190 (15.4" × 12.2" × 7.5").
Description Of Gauges
PRESSURE GAUGES
The 8T0848 Pressure Gauges (1) can be used to measure pressures of 0 to 400 kPa (0 to 58 psi). Typical uses for these gauges are the measurement of fuel pressure, intake manifold pressure on turbocharged diesel engines, cooling system pressure and the power balancing of diesel engines in a multiple engine application.
The 8T0846 Pressure Gauge (2) can measure pressures of 0 to 1000 kPa (0 to 145 psi). Typical applications for this gauge are the measurements of oil pressure and the cut-in and cut-out pressures on air compressors.
COMPOUND PRESSURE GAUGE
The 8T0840 Pressure Gauge (3) is a compound pressure gauge that can be used to measure pressures of 0 to 100 kPa (0 to 30 inHg) and a vacuum of 0 to - 100 kPa (0 to - 30 inHg). Typical uses for this gauge are the measurement of intake manifold pressure on turbocharged natural gas engines, manifold vacuum on natural gas and gasoline engines and the power balancing of natural gas engines in a multiple engine application. Valve (5) allows selection of one of the pressure or vacuum ports (6 and 7).
NOTE: The 8T0840, 8T0846 and 8T0848 Gauges are filled with glycerin lubricant which completely surrounds all moving parts. This lubricant greatly extends accuracy and the service life of the gauge. It also dampens input pressure pulses.
DIFFERENTIAL PRESSURE GAUGE
The 8T0839 Differential Pressure Gauge (4) can read the difference between two pressures. It has a range of 0 to 12 kPa (0 to 50 inH2O) and is accurate within ± .25 kPa (± 1.0 inH2O). The gauge has two inlet ports. One port is for the higher pressure and is identified by the word PRESSURE. The other port is for the lower pressure and is identified by the word VACUUM. The gauge will indicate the difference between the two pressures.
If one port is left open to the atmosphere, the gauge can be used to measure the difference between atmospheric pressure and the test pressure. If the PRESSURE port is connected and the VACUUM port left open, the gauge can be used to read a positive pressure (such as the exhaust back pressure caused by a muffler). If the VACUUM port is connected and the PRESSURE port is left open to the atmosphere, a vacuum can be read (such as the inlet restriction through an air cleaner). If both ports are connected to positive pressures (such as the gas delivery pressure and the inlet manifold pressure of a turbocharged natural gas engine), the gauge will read the difference between the two pressures.
This gauge has a zero adjusting screw. When necessary, adjust the screw so the gauge reads zero without any connections to the gauge fittings.
Connection Of Pressure Group To The Engine
1 The 8T0836 Elbow Fitting and 8T0837 Straight Connector are reusable tube fittings as described in the preceding "LIST OF COMPONENTS" on page 2 of this instruction. These fittings can be installed into 1/8" NPT ports on all Caterpillar engines with either 7/16" box or open end wrench. The 8T0837 Straight Connector can also be installed with a 7/64" Allen wrench, if access to the port is limited.
2 To connect 8T0821 Tubing to any fitting, simply push the tubing all the way into the fitting. An internal O-ring seals on the tubing O.D. and an internal slotted collet mechanism locks the tubing into the fitting. This provides an instant connection with total sealing. To remove the tubing from the fitting, press on the collet with the blade of a screwdriver and pull out the tubing at the same time.
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Be sure that there is no pressure in the tubing before disconnecting it from the fitting. Hot oil can spray out and cause personal injury. |
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Use Of Engine Pressure Group With Other Instruments
The 6V9450 Engine Pressure Group should be used with the 6V3121 Multitach Group and the 6V4060 Set Point Indicator (1) when checking engine performance (the 6V4060 Set Point Indicator is used with diesel engines only). Space has been provided inside the 8T0841 Carrying Case of the 6V9450 Group for storage of the set point indicator and the necessary components of the 6V3121 Multitach Group [such as the 6V2100 Multitach (2), 5P7366 Power Cable (3), 5P7362 Tach Cable (4), and 5P7360 Tach Generator (5), and 1P7446 Rack Contact Cable (6)]. For information on the use of the multitach group, see Special Instruction Form SEHS7807, "USING THE 6V2100 AND 6V3121 MULTITACH GROUP", and Form SEHS7931 "USING THE 6V4060 ENGINE SET POINT INDICATOR GROUP".
Use And Care Of The 8T0452 Manometer
The 8T0452 Manometer can be used to measure pressures of clean air and gases only. No liquid pressure media can be introduced into the manometer. To obtain accurate measurements, the manometer must be hung in a vertical position.
NOTE: The manometer cannot be used to measure pressures over 345 kPa (50 psi) and vacuum greater than -67 kPa (-20 inHg). If the manometer is filled with water, it must be protected from freezing at temperatures below 0°C (32°F).
The 8T0452 Manometer is equipped with a flexible steel metric scale and a sliding ZERO adjustment. The manometer can be filled with either mercury or distilled water. A bottle of Fluorescein green color concentrated wetting agent is included with the unit.
NOTE: The manometer cannot be used with .826 specific gravity red gauge oil. Mercury or distilled water are the only permissible measuring media.
FILLING
Using 1 quart distilled water, add 3/4 oz. bottle of Dwyer A-126 Fluorescein green color concentrate. Remove a tubing connector from the manometer and pour fluid in to mid-point level. Shake to remove air bubbles. Slide scale so zero mark is in line with the meniscus of the two fluid columns.
For readings in centimeters of mercury, fill with 13.6 SP. Gr. triple distilled mercury. When used with mercury, some discoloration of the vinyl tubing will normally occur.
READING
Connect the manometer to the source of pressure, vacuum or differential pressure. When the pressure is imposed, add the number of centimeters one column travels up to the amount the other column travels down to obtain the pressure reading. If the reading is desired in other units the conversion chart may be used.
Should one column travel further than the other column, due to minor variations in tube I.D. or to pressure imposed, the accuracy of the pressure reading thus obtained is not impaired. The U-tube manometer is a primary measuring device indicating pressure by the difference in the height of two columns of fluid. The fact that one column travels further than the other does not affect the accuracy of the reading.
Both sides of the manometer must be at the same level and should read ZERO before pressure is measured. Pressure safety traps in the top of both manometer columns prevent loss of fluid due to pressure surges or pressures exceeding the pressure range of the instrument. If the fluid in one side of the manometer is higher than the other side, the pressure safety trap is probably airlocked. Applying slight air pressure on one of the manometer input ports will usually release the air lock. If not, slide a small wire or other similar instrument into the input fitting and gently push down on the metal trap to release the air lock. Remove the wire or other instrument.
CLEANING
Cleaning can best be accomplished with a little pure soap and water. Avoid liquid soaps and solvents. Flush thoroughly with clear water to remove all soap. Dry completely before refilling with mercury.
When the manometer is not in use, plugs are placed into the 8T0837 Inlet Fittings to prevent fluid loss during storage. Four plugs are included with each group.
Accuracy And Calibration Of Gauges
8T0846, 8T0840, 8T0848 Pressure Gauges
The 5P8558 Calibration Group and 2D2825 Hydraulic Pump should be used to calibrate these gauges every six months as shown in the Service Quality Guide, Form No., SEBF3500 (Bulletin No. TC-1). Use five test points as reference to check the calibration of each gauge. Calibration tolerances are shown below.
8T0839 Differential Pressure Gauge
1 Use a water manometer as shown below and the following procedure to check the calibration of the differential pressure gauge.
2 Use the zero adjusting screw if necessary to make the 8T0839 gauge (1) read zero without any connections.
3 Connect the PRESSURE port of 8T0839 Gauge (1) to the tubing of the manometer as shown.
4 Apply a light pressure, approximately 7 kPa (1 psi), to the manometer tubing to cause the water column to read exactly 70.3 cm (28 inches) of water difference in pressure. The reading on the gauge should be 7.0 kPa ± .25 kPa (28 inH2O ± 1 inH2O).
5 Any gauges that are not within specification should be repaired or replaced.
Repair Of The 6V9450 Engine Pressure Group
If it becomes necessary to repair the engine pressure group, do not send the instrument or the gauges to Caterpillar Tractor Co. as this will only cause delay. In the U.S.A. and Canada, the gauges can be returned for repair to the addresses shown below. Outside the U.S.A. and Canada, it is more economical to replace the gauges than to return the gauges for repair.
Return the 8T0839 Differential Pressure Gauge to:
Dwyer Instruments Inc.Highway 212 at 12
Michigan City, IN 46360
Phone: (219) 872-9141
Return the 8T0840, 8T0846, 8T0848 Pressure Gauges to:
Carrier - Oehler Co.16965 Vincennes Avenue
P.O. Box 40
South Holland, IL 60473
Phone (312) 339-8200
Articles returned for warranty consideration or repair should be packaged in a manner to prevent damage in transit, and in accordance with the best commercial practice for fragile items. Instruments should not be shipped parcel post.
IMPORTANT: A common cause for failure of the gauges is overpressure (pressure beyond the maximum on the gauge scale). Overpressure can destroy the gauge in three progressive steps: 1) Loss of accuracy due to deformation of the Bourdon Tube, 2) failure of the mechanism, 3) rupture of the gauge. Failures caused by overpressure are not considered to be warranty, but abuse by the operator. Repairs to such gauges are on a time and material basis. Examination of the mechanism by the manufacturer will indicate a past overpressure condition.