rev up your engines, today I'm going to talk about VTEC engines, how they can get
more power and better gas mileage out of the same engine, now variable valve
timing engines, are an interesting phenomena that's been around for quite
some time and Honda was really the first company that perfected them, granted the
first mass-produced variable valve timing system was in 1980 with the
Italian company Alfa Romeo, but if you know Italian cars, hey they didn't hold
up that well over time and the engine wasn't that reliable, but in 1989 Honda
made the Honda Integra, it wasn't sold in the United States, it was called an
Acura here, but it was the first VTEC engine that Honda made and it proved to
be extremely reliable, now here's my cute little model that
shows how valve timing works, this is the cam, as it spins around, the lobes open
and close the valves, letting the air and fuel come in to fill a cylinder, and then
once it fires, letting the exhaust gas come out of the engine, and in older cars
the camshaft here was connected to the crankshaft by a gear which was not
adjustable, it only worked one way, so the cam timing was not adjustable
except for race cars, as you can see here, this is a race rocket for a camshaft,
and you can loosen these bolts and then you could set the timing by the degree
wheel on the top to advance or retard it, now you do this to get more power out of
an engine, of course that would get worse gas mileage, but racing guys don't care
they want power, but as I said in 1989, Honda came up with a brilliant idea, they
had an engine that by itself could change the valve timing and the valve
lift automatically by itself as you drove, in the Honda system, not only could
it change the timing of the cam to advance or retard it, it can also change
the lift, so it would open wider to get more power, but open smaller to get better gas
mileage, in Honda the VTEC stands for variable valve timing and lift
electronic control, through electronic computer control and hydraulic control
using the oil pressure of the engine, not only can the Honda system advance or
retard when the valves open and closed, but it can also make them open wider for
high rpm power and open less wider so they get better gas mileage when you don't
need all that power, and in 1996 Toyota came up with their version which they
call vvt-i, which is a similar system of course for patent reasons they couldn't
copy them exactly, but it's the same basic principle, electronics and the
hydraulic fluid of your oil pressure allows the valve timing to be changed by
computer, now both the Honda system and the Toyota system have proven to be extremely
reliable, but there are some companies out there that have extremely unreliable
variable valve systems as they age, for example I've worked on a lot of Mazdas
with their variable valve systems, that broke even before the engines had a
hundred thousand miles on them, the ones that I saw problems with on Mazdas, they
were using a motor craft actuator on the front of the cam and those actuators
break down all the time on those Mazdas, and it's an expensive repair taking the
engine apart and changing all those parts, plus if they do break under high
rev situations, you can bend valves in the engine then you pretty much say
goodbye to the engine because everything inside gets bent, so when it comes time
to buying a car that has a variable valve timing engine, there's two things
you have to understand, the first thing is you want to go with a company that
makes quality engines that hold up over time, do a little research before you
plunk down 30 40 thousand or more for a car that is a variable valve timing
engine with history of problems, and number two is, change your oil and use
the correct oil for VVT valve engines, that's very important, being
electro-hydraulic they operated, they use oil pressure to run themselves, there's
lots of tiny little holes it all has to flow through, you got to use the right
weight oil, if yours says use 0w 20, use that don't put a heavier oil in,
and to be honest, a lot of the VVT failures I see, don't have to do with the
engine themselves, they have to do with the owner of the car, because a large
amount of the VVT engine failures I see are due to contaminated dirty oil the
oil just wasn't changed enough, then it destroys these systems, so if you pick
the right engine, with the right manufacturer, and change your oil
frequently, you could have a great time with the VVT valve engines, but make sure
you do both of those things, so if you never want to miss another one of my new
car repair videos, remember to ring that Bell!