2-28. In a two-stroke cycle engine with aluminum  pistons,  what  is  the maximum wear limit for the liner? 1. 0.0015   in.    per   inch   diameter 2. 0.0025   in.    per   inch   diameter 3. 0.0030   in.    per   inch   diameter 4. 0.0050   in.    per   inch   diameter 2-29. Which  of  the  following  conditions will NOT cause cracks on an engine cylinder  head? 1. Obstruction  in  the  combustion space 2. Restriction  of  cooling  passage 3. Addition of hot water to a cold  enqine 4. Improperly  tightened  studs 2-30. What  valve  casualty  is  usually caused  by  resinous  deposits  left by improper lube oil or fuel? 1. Burned  valves 2. Sticking  valves 3. Weak  springs 4. Bent  valves 2-31. After  inspecting  the  engine  intake valves,  you  discovered  that  the surface of the valve head has damage. Which  of  the  following casualties  is  the  most  probable cause? 1. It is sticking 2. It has a weak spring 3. It is bent 4. It has a loose valve seat 2-32. Which  of  the  following  valve casualties  will  cause  the  valve  to fail  to  close  completely? 1. A burned valve 2. A  valve  float 3. A  sticking  valve 4. A valve that has a weak spring 2-33. Failure  to  properly  prepare  the counterbore  area  before  placing  a valve seat insert in it will cause what  problem? 1. Uneven  heat  transfer  between the seat and the counterbore 2. Scratching  of  the  insert 3. Misalignment  of  the  valve  head in the seat 4. Loose fit of the insert in the counterbore 2-34. When  replacing  a  valve  seat insert, which of the following procedures  should  you  follow? 1. Plan the operation so that the insert is placed slowly and precisely 2. Use boiling water to heat the valve  seat 3. Drive the insert down with a special tool 4. Shrink the valve guides or counterbore  with  dry  ice 2-35. Minor pits and flaws may be removed from the valve seat by what  method? 1. Buffing 2. Hand  grinding 3. Insert  replacement 4. Rubbing  with  prussian  blue 2-36. How are valves refaced? 1. On a lathe 2. Against  the  valve  seat 3. By  machine  qrinding 4. Each of the above 2-37. Which  of  the  following  conditions will cause valve springs to break? 1. Compression  and  corrosion 2. Misalignment  and  compression 3. Corrosion  and  fatique 4. Fatique  and  compression 12