Crankshaft Service Flashcards
Threads on crankshaft should be discarded if?
Half of the threads are damaged.
Removing a wear sleeve you should look out for?
Hitting the flange and stay away from bolt holes.
Critical areas of the crank shaft are?
The fillet, oil holes and webs
When measuring rod and main journals you should stay away from?
oil holes and fillet radius.
Where is dial indicator placed when checking run out?
90 degrees to journal on either side of oil hole.
After re grinding where is the new measurement located?
Front counterweight.
Can mains and rod journals be ground to the same size?
They can differ rods usually wear more but if grinding all respective journals must be the same. .010,.020,0.30”
Difference between undersize bearings and oversize bearings?
Undersize is for if shaft/journals get ground (material on the front), oversize is for bores. (material on the back)
Where would this new measurement of bearing undersizing be located?
On engine plate or backside of bearing.
Removing a flywheel you will need to?
Heat it up and drive it off with a hammer and blunt chisel, Don’t use cutting torch.
Installing flywheel?
use a oven, or steel plate to evenly heat up and let cool slowly to room temp.
Rubber type Damper index lines on hub should not move more then?
1/16th of an inch, indicates bond has broken from rubber and inertia mass. this can cause it to wobble, discard.
Viscous type damper should be replaced when?
during any major overhaul, check for cracks, and runs on small tolerances any dents will cause binding of inertia mass.
Bending load crankshaft failures?
critical areas such as fillets and webs.
- misaligned main bearing bores.
-bearing failures.
-excessive loads.
-to tight of belt.
-poorly mounted components (flywheel, damper, transmission)
Torsional load crank shaft failures?
Most likely in con rod journals.
-excessive engine speed.
-excessive engine loads.
- a loose, damaged or defective damper.
-loose flywheel.
Maximum measurement a fillet radius can be ground too?
.030. radius should be round not sharp, sharp will break easier.
Lack of Lubrication causes metal to metal contact, what are causes?
-low oil level.
- low oil pressure.
-oil film breakdown (excessive heat)
-plugged passages from foreign material.
-improperly installed bearings.
Bearing failures?
-loss of oil film
-contaminated oil
-excessive loading
-improper installation
is a bearing with minor wear of overlay and light exposure of copper inner layer reusable?
Yes, this is a sign of normal wear.
Bearing failure due to lack of lubrication?
-low oil pressure
-low oil level
-plugged passages.
- not installed properly
Bearing with wiping on face is due to?
Metal-to-metal contact, bearing will seize and be destroyed quickly. discard and replace.
Bearing contamination can be from?
-poor maintenance intervals.
- poor handling when doing assembly.
-deep scratches, abrasive wear, small particles embedded.
Fuel diluted bearing failure?
reduces the viscosity of oil which allows metal to metal contact, if ran for long period of time will destroy.
Corrosion bearing failure?
- combustion by-products (blow by gases containing Sulphur)
- ## water (condensation or coolant leaking into oil
