Diesel
Once the gear is heated, how is it normally installed?
At the required temperature the gear can be dropped over the shaft and allowed to air-cool
Valve Lash is a gap between the rocker arm and the valve stem. WHY is this required to be at a specific setting?
If they aren't right the valves would stay constantly open
How are timing gears commonly fitted to shafts?
Keys
What are 6 visual inspections that can very easily determine if a cam is bad?
Pitting, scoring, peeling of lobes and scoring, wear, blueing of journals, uneven wear
What is a cam CPS and what is it used for?
a cam position sensor, signal shaft speed and position data to the engine control module
What is a "follower" and /or what is it used for?
a lifter to the pushrod
The camsaft profile actuates which of the following parts?
a. Injection Pumps b. Unit Injectors c. Valvetrains
Timing gear Backlash is important, Its the movement between gears also called play between the gears. How do you check gear backlash?
dial indicator or thickness gauge
What 2 things are timing gears responsible for in a diesel engine(What do they do for the engine)?
driving the camshaft. most of the engine accessories on a diesel-powered truck engine
How does a rocker know when to actuate the component its used to operate?
either push rods or cams
When a timing gear needs to be replaced how do you remove it from a shaft?
hydraulic puller or press
What are the 2 different mounting locations of Camshafts?
in the head or in block
What can happen if you overheat the gear during installation?
overheating a gear will be to destroy the heat treatment and possibly the surface hardening resulting in premature failure
Where are timing gears located on the engine? There are 2 different locations
rear and front mounted
What is the process for repairing any cam defects that you might have found during the inspection process?
should be replaced
What are keepers used for?
split lock fitted to a peripheral groove at the top of a cylinder valve stem. holds the spring retainer in position
What part is used to rotate the valve when the engine is running? And why do valves need to rotate while the engine is running?
the flexibility is required so that at engine can adapt to different operating condition
What is Camshaft Endplay? AND what is the procedure to measure it?
the movement of the cam from front to front to back in the engine. Dial indicator on the front of the cam with the cam installed and move it back and forth
What is the cams OBC?
the portion of a cam profile with the largest radial diameter
What is the BC of a cam?
the smallest radial dimension of an eccentric (base circle)
How do you know if the cam gear and other gears are in the correct postion?
they are index with stamped markings
What are "Pushrods" and where do they fit into the valvetrain?
they are rods that ride on the cam and push on the rockers. they go in-between.
What are "Valve Bridges" used for?
to push on 2 valves at once
What are "Rockers" used for?
to push on the valves opening and closing
How do you measure Cam Lift
using a dial indicator place it on the cam lobe and spin the cam
What should you place the Cam on during inspection?
v blocks
What are valve and injector trains used for?
valve and injector trains transmit the effects of cam geometry to the cylinder valves and injector assemblies
What are valves used for?
valves provide the means of admitting air into, and discharging exhaust out of, the engine cylinders.
How are Valve Springs tested to make sure they are still within spec.? ALSO what is the spec.?
with a tension gauge should be within 10% of the original
