Thursday, November 15, 2012

4-stroke engine valve clearance adjustment and bearing replacement

Valve clearance adjustment: gasoline engine work after a period of time or cleaning is not just a pile of parts assembled back can guarantee that it will smooth functioning. YS, OS, Thunder Tiger four-stroke engine factory as this topic to share please correct me if any linguistic errors.
   
A: Open the valve cover, remove the spark plug, the rotation spindle top dead center (piston walked usual propeller bushing there is a mark will be exactly aligned with the gasoline engine chassis directly above the cylinder most vertex Next to that point), this time shaking valve rocker will have a certain gap (if the intake and exhaust are very tight like him to turn the spindle lap); this point you adjust valve clearance.
   

B: Open the engine side two screws Timing gear cover, you can see the the spindle above fit a gear gear called "Timing gear with a clean cloth to wipe gear front you can see there is an approximately 0.8MM dots, please pay attention to the subject of this dot that according teeth is just above front spindle or timing gear cover (depending on the original manual prevail).
   

C: come up with the valve to adjust the gap-chip 0.04 and 0.1, two, I'm used to the intake tune 0.04MM; exhaust (near side) exhaust pipe tune 0.1MM; clearance tablets advancing to the contact point of the valve top and rocker not be pushed into the gap is too small; (the piston pushed to the outbreak of the system on the dead point, this point is not entered into the system / exhaust top dead center) relax fixing nut counterclockwise rotation of the adjustment screw until the gap piece can be pushed go re-adjustment screw clockwise to the gap piece again during sliding left hand leaning on the adjustment screw, the right-hand turn to tighten the fixing nut either. With 0.1MM gap chip to adjust the exhaust gap. (This adjustment is into fast row slow, the advantage of a strong power output. Drawback is idling unstable, and prone to overheating. Depending on personal preference I are adjusted to row fast into slow, the advantage is idling stable and difficult to overheating, fuel-efficient. drawback is that average power output of 140 aircraft is sufficient.) Timing gear cover back cover locking view steam door packing paper are not damaged (especially YS rc model gas engines Please do not can leak) or else you'll have an "the next elimination" (no force) how to tune the troubled rc aircraft model gasoline engine; packing paper is broken, do not tense, a put do not need to find a thick brown paper bags according to the shape of the shear to spend money to buy.
   

Replace the engine bearing the timing: the ordinary engine work should not exceed 9500 rpm speed 1500-10000 rpm high speed best flight after a period of time, bearing gap, if you use a balanced propeller launched engine Special Ma (experience) (or turned by hand crank, not smooth or foreign body sensation). This is the opportunity to change the bearing because of the large gap to a degree of wear (leak) produces piston side (the engine will have a very big shock, after the crankshaft will be bending phenomenon can not see with the naked eye.) forces could not get ready to get a new engine. When you have the engine apart to clean, it is recommended that bearings with replace.
   
Steps:
    A: (two-stroke rc gasoline engines) Remove the cylinder head, rc gasoline engine cover, cylinder liner, piston, propeller pad (this part is commonly known as the force monkey bearing exit) pulled out from the front of the the fixed latch, spindle front bearing ( I remember after looking for a hard wooden stick from behind, gently tapping the front bearing spindle), the entire aircraft model gasoline engine with efficient hair dryer or gas torch (the kind used by the plumber) heating the rc aircraft gasoline engine DLE30 to a certain extent, the hand I remember wearing cotton gloves to avoid burns, the engine cover down in the rear bearing can withdraw a knock on wood. Bearing note of ID such as 6903,1600 X, R6X .... If you can not see the ID when the amount of outer diameter and thickness to the bearing shop to buy back change.

(Four-stroke gasoline engine) Remove the the steam valve cover, rocker (bird), cylinder head, plunger, top tube, Timing gear cover, cylinder liner, piston shaft, piston rod (dog bones), propeller lining pad (which parts need to be commonly known as force bearing exit monkey) pull out from the front of the, fixed latch, spindle (remember the spindle to knock before propeller fixed bolts in the front spindle and then plastic hammer to knock out this method can avoid the spindle thread knocking bad); remaining steps with the two-stroke.
   

B: buy bearings engine by demolition anti-step parts - Replace.
    C: (especially any screws lock rc model gasoline engine cylinder head) locking method of diagonal three sections: first all the screws all the bolt on the locking screws turn tight semi-circle in 12:00, 6:00, 2:00 , 8:00, 4:00, 10:00; then in accordance with the the above angular position locking screws (unless gasket this method lock cylinder head to ensure airtight).

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