1. 708 Engine failure
The 708 came from SSYD with a # 2
Equipment Blower problem. When
started to check # 2 blower the diesel
was found to be making unusual
noises, it was immediately shut down
and inspected.

2. The inspection reveal that the R6 forward cam flange and R6 cam
journal had broken and separated.

3. Further inspection revealed that the R7 cam bearing had failed and
turned in the bore.

4. Measurement of the damaged R7 cam bore revealed the diameter to
be 5.492”-5.496”. GEK29341F specifies that this dimension should be
5.4985”-5.501”

5. An automotive cylinder hone was used to resized the R7 bore to
5.4995”. New bearings were installed in the R6 & R7 positions. Bore
misalignment was indicated as shown and found to be .005” vertical
and .003” horizontal. GEK 29341F specifies this tolerance to be .0045”
with the block supported at 4 points. These measurements were taken
with the rear of the assembled engine supported by the alternator.

6. New journals and cams were then installed in the engine. The cam
spins freely. Measurements of the oil clearance between the R7 cam
and journal were taken with feeler gauges passed between journal and
bearing on the crankcase and gear side. These measurements reveal
that the restored #7 cam bearing bore and subsequently the bearing
are “out of square” by as much as .010” with the cam and the rest of
the bearings. There is no tolerance specified in GEK 29341F to
address this condition.

7. There is .010” clearance at the 6 o’clock position on the crankcase side
of the #7 bearing and essentially none at the 12 o’clock position. On
the gear side there is .008” clearance at the 12 o’clock position, and .
002” at the 6 o’clock position.

8. Reference marks were filed in the R6 & R7 cam bearings to provide an
indication of the condition of the press fit of the new bearings installed
at these locations.

9. The repaired engine was installed in Locomotive 700. Initial start and load test
has revealed no unusual noises. The cam bearings at R6 & R7 have remained
in place so far.

10. The repaired engine was installed in Locomotive 700. Initial start and load test
has revealed no unusual noises. The cam bearings at R6 & R7 have remained
in place so far.