RING-BACKUP 1506344 - Caterpillar

1. Remove all bolts from the clutch bolt circle.2. Make sure No.1 cylinder is at top center position.3. Install two 7/16"-14 bolts one inch long (without washers) in the clutch bolt circle, one at the 9 o'clock position and the other at the 10 o'clock position as viewed from the rear of the engine.(A) Engine Speed
Vibration levels are not expected to vary significantly with engine speed for this test. It is recommended that the test be run at either the rated speed or an objectionable speed as determined from Table 2 of the In-Chassis Vibration Test. Record engine speed in the space provided on data sheet.(B) Probe Locations
Probe locations are the same as the five locations described in the In-Chassis Vibration Test. For this test however, it is not necessary to measure vibration in the cab.(C) Instructions For Table 3
Measure and record displacement amplitudes for all five probe locations as requested in Table 3. Overall (filter-out) displacement amplitudes and filter-in displacement amplitudes are required. For each order, compute and record the corresponding frequency. For example, if the engine speed is 1200 rpm, the frequencies are 600 cpm for 0.5 order, 1200 cpm for 1st order, 2400 cpm for 2nd order, 3600 cpm for 3rd order, etc.(D) Allowable Vibration Levels
On the chart Allowable Vibration Levels, plot the filter-in displacement amplitudes for all five probe locations for each frequency. Do not plot if the displacement amplitudes are less than 1 mil. Do not plot overall (filter-out) vibration data.(E) Interpretation Of Results
If all data points fall below the line, then the engine complies with Caterpillar's vibration limits. If the engine exceeds the vibration limits, refer to the table on pages 8 and 9 to determine the cause of the vibration. Consult your Service Engineering Product Analyst for advice on repair.Isolated Engine Vibration Test Use the graph below to plot all filter-in displacement data. The curve shown on the graph below is the allowable vibration level for an isolated Caterpillar engine. Example Problem
(A) History
A customer with a 3406 Engine in an International conventional cab truck complained about a vibration problem. The driver reported that the vibration was not present until after recent service work when the engine water pump was replaced. Naturally, the water pump was suspected as being the source of vibration; but close examination of the water pump revealed nothing abnormal. The procedure and test data sheets from this instruction were used to diagnose the vibration problem.(B) Filling Out Engine Vibration Questionnaire
The first step in diagnosing the vibration problem is to fill out the engine vibration questionnaire. The completed questionnaire is shown below. Notice that a bolt in the engine front mount was found to be loose. However, tightening this bolt did not eliminate the vibration. The questionnaire also shows that the vibration was most noticeable at 1200 rpm, which suggests the vibration is resonant related. Because the vibration was present with the vehicle stationary and no load on the engine (as shown by the answer to question 10), an