You probably have heard of them, or heard somebody
else tell a horror story about theirs, but lets talk about timing belts
for just a moment. All four-cycle internal combustion engines currently
require the use of a "camshaft". This shaft has several eliptical shaped
"cams" that push open the intake and exhaust valves. In years gone by, the
camshaft (which is driven by the crankshaft) was either gear-driven or driven
by a timing "chain". "Ahhh" you say, " I've heard of that before". Well,
starting (locally) with the Pontiac Tempest inline overhead cam six-cylinder
sport engine in 1966, timing belts have been employed with increasing numbers
every year. The belt has rounded "teeth" that engage with sprockets on the
crank and cam. The main advantages in utilizing a timing belt as opposed
to a chain is that there are fewer moving parts, less weight, no need to
lubricate anything in the belt area and less noise. And, Oh yeah, less cost
to produce. The belts tend not to stretch as much as chains when they age,
maintaining the valve timing more precisely. The down-side to these belts is that there could be some fairly nasty problems when one breaks. For this reason, most manufacturers, including Honda, suggest replacement of the timing belts at regular age or mileage intervals, before they break. If the belt breaks, the syncronization between the crankshaft (what the pistons are connected to) and the camshaft (what operates the intake and exhaust valves) will be lost. The engine cannot operate under these conditions and will cease function, right now, with no warning whatsoever. To make matters worse, as the engine is grinding to a halt, the possiblity exists that the pistons and valves will actually contact and bend an unsuspecting valve or valves. This event usually causes the cost of the repairs to be increased by the power of four since the cylinder head(s) must be removed and disassembled for repair.
Replacement of the timing belt is not especially difficult although there is usually quite a bit that requires removal to gain access to it. We like to suggest that the outer drive belts and water pump be replaced at the same time since most water pumps are now driven by the timing belt and the outer belts must be removed anyway. It is in your (the client's) best interest to do these items together as it represents the best use of your repair dollar. Since this function is critical to the life and operation of the engine, we strongly reccommend using only original parts as they represent the best valve to you. This is not an area of the car to scrimp on.