Why Some Cars Have a Timing Chain Instead of a Timing Belt


rev up your engines, today I’m gonna talk
about timing belts versus timing chains inside your car’s engine, now for most
internal combustion engines the crankshaft which the Pistons are
connected to spins around and that’s connected to the camshaft which opens
and closes the valves, and there’s various ways you can connect it, now a
long time ago in my grandfather’s day the early engines they didn’t even use
timing belts or timing chains, they had timing gears, the bottom crank had a gear
and then gears went to the camshaft which spun the camshaft and then push
rods open and closed the valves, now that was a solid reliable system, you had
gears connecting them, but that two main disadvantages, one it costs a lot of
money to make good gears to put that together and the gears themselves had a
tendency of making whiny noises that people didn’t like, so then instead of
having gear on gear to spin it they decided to use a timing chain and
these engine designs the crankshaft sprocket teeth on it, then a timing chain,
then another sprocket with teeth that ran the camshaft all the old American v8
engines were made that way and some of them are still that way, you can see
these are thick hardy change this one came off a 350 Chevrolet they’re really
strong they lasted off a long time but of course it costs money to make hard
steel sprockets and expensive chains so they gave the idea of the timing belt
instead of a timing chain, the pulley on the bottom of the crank and the pulley
on a camshaft was connected using a rubber base timing belt and contrary to
what people might try to tell you, the only reason they went to tiny belts it’s
cuz it’s cheaper to make them when you have a sprocket that uses a timing chain
it has to be really strong steel, but the sprockets that run these rubber base
timing belts they can be a lot softer because they’re just pulling rubber
they’re not steel, so most of the manufacturers switched over the timing
belt, now with a car like this Toyota that’s well designed a 94 Celica, those rubber timing belt sometimes could last hundreds of thousands of miles they’d tell
you to change them every one thousand or 90 or so, they were pretty
reliable in the Toyota engine and there’s one big advantage of this design
almost every Toyota engine ever made is a non-interference engine, so off the
timing belt breaks the Pistons don’t hit the valve and do any damage, but when you
take cars like many of the Nissans, they were a faster engine racing design, so
the Pistons went higher and the valves came lower, so if those rubber belts ever
broke when you’re driving on the highway the Pistons hit the valves
they break the engine and destroy the engine, I’ve seen many people in the past few
decades with these timing belt Nissan’s have the belt brake ruined the engine
and they said, you’re telling me that this $30.00 belt broke made out of rubber and
it destroyed my engine, I’ll never buy another Nissan, well then respond to this
Nissan was one of the early companies to go from timing chains on their cars, to
timing belts and then back to timing chains, so that they wouldn’t have this
problem and unfortunately for Nissan and the people who bought them, a lot of
those early switchover that went from timing belts to timing chains had
problems with the timing chains cuz Nissan made them kind of poorly, but the
idea was correct and now many manufacturers have switched back to timing
chains and the main reason for that is the higher design capacity of smaller
engines, they’re making smaller engines put out more horsepower, putting variable
valve timing and other things inside and that strains the timing belt so much
that the rubber timing belts would have a tendency of breaking too often and to
get added horsepower to these smaller engines, a lot of the manufacturers had
used to make non-interference engines are now making an interference engine
but since they have a sturdy steel chain that’s driving it, they don’t have the
problems of a rubber belt snapping, take this matrix it’s twelve years old, it’s
got a timing chain inside the engine never had a problem, as quiet as can be,
and runs just as good as it did when it was brand new,
because really steel chains, they beat the heck out of a rubber base timing
belt any day of the week if the chains are
made correctly, and I know some guys maybe motorcycle guys are gonna say, but Scotty
chains need lubrication well guess what timing chain is inside the engine, it’s
coated with the engine motor oil it is inside the engine, so as long as you
change your engine oil regularly this chain is lubricated with nice clean engine oil and it can last a really long time, rubber hey it falls apart it’s over time, it’s going to stretch over time and yeah a chain
stretches a little over time but it takes a lot more time and mileage to
stretch solid steel than it does rubber and sure costs a lot more money to
manufacture a chain and build an engine that way but hey, they’re not giving away
modern car so you’re paying enough money you really want one that’s got a solid
timing chain in it, because I doubt they’ll ever go back to making gear
driven cams, that just costs way too much money and as I said earlier it does
make a reasonable amount of whining noise and people want quieter cars, they
don’t want louder ones, now of course the rubber base timing belts were really
quiet, but in a modern engine they just wouldn’t hold up, with all those extra
cams and variable valve timing and GDI direct injection, there’s a lot more
pressure, a rubber belt can’t take it but a chain can, so if you’re shopping
around for a new car hey, I’d make sure it had an engine with a timing
chain and not one of these flimsy rubber base timing belts, so if you never want
to miss another one of my new car repair videos, remember to ring that Bell!