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AirCooled Engine Technology
Roth 9 th Ch 15 Cylinders Pages 277 286
AirCooled Engine Technology 1. Engines removed from the implement are easier and safer to work on if
mounted on an ____________ stand. However, most service work doesn’t involve full removal because “time is money”.
Engine Transmission Music
AirCooled Engine Technology 2. A __________ _________ (paper or electronic) is an important reference
that must be used when servicing engines and implements because every model is built to different specifications & dimensions.
AirCooled Engine Technology 3. A technician should look for causes of engine problems ________ removing
the engine from the implement (piece of equipment). This can save time and lead to better problem solving & repair.
Before During After
AirCooled Engine Technology **Use the procedure known as the 3 C’s when repairing.
Complaint Cause Correction
Listen to and then Verify the Customer Complaint
Use Diagnostic Procedures & Tests to Determine the Cause of the Problem
Make the Correction & Be Sure the Problem is Solved to the Customer’s Satisfaction
AirCooled Engine Technology 4. Marking parts can be done with _______ marks, __________ ______ flags,
number or letter punches and even paint. Flags are used mostly for hose and wiring identification.
Scratch mark at arrows Punch, Masking Tape Punch, Cookies Stamp, State
AirCooled Engine Technology 5. ___________________ a repair or service job increases success & saves you time and effort.
Organizing
AirCooled Engine Technology 6. Cylinders can be separate parts that are removable from the crankcase or
can be _______________, which means “onepiece with” or “a part of ”. Integral components are not removable from one another.
Integral Internal International
AirCooled Engine Technology
AirCooled Engine Technology
Removing an integral head & cylinder assembly from a 2 stroke cycle engine block.
AirCooled Engine Technology 7. Pistons are removed through the _________ of the
cylinder on an integral block & crankcase engine.
Bottom Side Top
AirCooled Engine Technology 8. The unworn area above ring travel in the cylinder (1/8”1/4”) is known as a
______ _________ and must be removed with a ring ridge reamer or with abrasive paper before taking the piston out through the top of the cylinder. This prevents ring breakage and possible piston skirt damage.
Ring Ridge Ring Land Ring Groove
AirCooled Engine Technology
Using a ridge reamer to remove a cylinder ring ridge
AirCooled Engine Technology 9. Cylinder wear is greatest on two “thrust surfaces” located 90 degrees to
the ________________ and wrist pin centerline. This will cause an oval or outofround shape to the worn cylinder.
Crankshaft Camshaft Balance Shaft
AirCooled Engine Technology
2.506”
2.500”
2.506” – 2.500 = 0.006” Taper
AirCooled Engine Technology
AirCooled Engine Technology 10. Increased wear at the top of the cylinder is due to a lack of ____________
because of the diluting effect of raw gasoline on the engine oil, excessive heat, and the high pressure buildup behind the piston rings which greatly forces them out against the cylinder wall.
Air & Fuel Nourishment Lubrication
AirCooled Engine Technology 11. There is a gradual ____________ in most worn cylinders. Bores maintain
original size below the area of ring travel and tend to wear bigger at the top of the cylinder.
Taper Wafer Gouge
AirCooled Engine Technology
Difference between A & B determine outof round
Difference between 1, 2, 3, 4 determine taper
AirCooled Engine Technology 12. Cylinder service needs are determined by cylinder wall condition.
If the bore is not damaged and the taper & outofround dimensions are within tolerances, only a light ________________ may be needed.
Deglazing Oversizing Sleeving
AirCooled Engine Technology 13. ______________ plated aluminum cylinders and pistons should be
discarded if they are at all worn.
Chrome Steel Cadium
AirCooled Engine Technology 14. Cylinder __________ or liners may be of the flanged type, removable type
or may be of the integral type which are cast right into the block as a permanent piece.
Hems Legs Sleeves
AirCooled Engine Technology 15. Worn cylinders may be _________ (bored out) in steps of .010” and fit with
new pistons which are available in standard + .010”, +.020”, and + .030” sizes. The .010” increments make it easier for parts suppliers and service facilities to stock the correct parts on their shelves. (parts in stock = money)
Oversized Capsized Revised
AirCooled Engine Technology 16. Cylinder oversizing or boring out may be done with a rigid ____________
tool driven by a heavy duty, slow speed, electric drill or drill press.
Honing Reaming Drilling
AirCooled Engine Technology 17. ____________ or deglazing is an abrasive finishing process that removes
boring tool marks from the cylinder wall.
Honing Moaning Loaning
AirCooled Engine Technology 18.The honing process places a fine, _______ ________ surface finish
on the cylinder wall.
Crosshatch holds oil on the cylinder wall Oil will Lubricate, Clean, Cool & Seal
The piston rings seal better with the addition of oil!
AirCooled Engine Technology 19. The crosshatch in a cylinder is just deep enough to hold ________ which
lubricates the cylinder wall as the piston & rings glide up & down. Oil also seals the piston rings to the cylinder wall. A cylinder with little or no crosshatch will have poor compression.
Air & Fuel Oil Graphite
AirCooled Engine Technology The difference between dry compression test readings & wet compression test readings will be greater on cylinders with little or no crosshatch pattern.
Big Difference between dry & wet = need for rings Low Compression & no change dry to wet = valves, head gasket, etc. No Compression = damaged parts or outoftime valves
AirCooled Engine Technology Crosshatch can be destroyed by abrasive ingestion either with the incoming air or in the oil.
AirCooled Engine Technology
AirCooled Engine Technology 20. The smoothness of cylinder finishes depends upon the _____ of the stones
used during honing.
Grit # Grout # Gage #
