What type Carburetor Seat guide does engine use? | Форум

zjautopartsnetLee Апр. 14 '16

 

Now consider Carburetor Seat guides. Used to position valves and guide valves as move up and down. Extreme heat around valve makes hard to lubricate guide. If not enough oil available, excessive friction will wear down guide. If more oil present than needed, oil will be baked onto valve head; could build up and block valve openings.

Valve guide wear refers to clearance between stem and valve guide. As guide wears, valve begins to open side to side as opens and closes. Side to side movement can cause valve to seat improperly. For this reason, guides must be checked, and replaced or repaired if beyond manufacturer’s specifications.

Valve guide wear measured in different ways. One way to measure inside diameter guide and compare to outside diameter stem. Since inside diameter guide quite small, small bore gauge required to measure. Outside micrometer can be used to measure diameter valve stem. Stem diameter subtracted from guide diameter to find clearance. Calculated clearance compared with manufacturer’s specifications in service manual.

Another way to measure guide wear to insert valve with correct stem diameter into guide. Once inserted, hold valve slightly up off seat (as if valve were open). Then move head of valve side to side. Amount movement can be measured with dial indicator or other precision instrument and compared with specifications in service manual.

Some technicians rely on judgment to evaluate guide wear. Guide should allow only slight side to side movement. If can feel movement when move good valve side to side, guide probably worn, should be repaired or replaced.

REPLACING AND REPAIRING THE VALVE GUIDES

Consider construction Carburetor seat valve guide zjautoparts.net. Valve guide located either in cylinder block (in L-head engine) or cylinder head (in OHV and OHC engines). Guides made soft metals like bronze or aluminum to reduce friction against stem. Guide may be separate piece press fitted into block or head, or as in aluminum engines, guide may be built into engine.