walight01

what is a intake camshaft or exhaust camshaft???i am looking at buying these and was wondering exactly what they were.intake/exhaust camshaft

Sir Nuke

okay...for starters....considering you are asking this quesiton....do NOT attempt to install them yourself.

TWO....do NOT believe that you are actually going to get the CLAIMED horsepower gains that are on the page you linked to....there is NO WAY on gods green earth that you will get those kinds of gains on a stock motor....you MIGHT get some out of the two combined...but not 10 from one and 12 from the other for a combination of 22....so don't even think that....

NOW...to answer your question....the camshaft is the part of your engine that operates the valves in your cylinder head. and of course you know that you have INTAKE and EXHAUST valves...the intake valves allow the fuel/air mixture INTO the cylinder...and the exhaust valves allow the EXHAUST out of the cylinder and into the exhaust system of your car.....the camshafts have LOBEs on them....or BUMPS....and these lobes are excentric to the centerline of the shaft....thus as the camshaft spins the "bumps" go around and they are in contact with the tops of the valve stems...thus as they go around they push down on the valve stems opening them and then allowing them to close....this is all done in a very specific order......this is how they work for an engine like ours with DUAL OVER HEAD CAMS (one INTAKE cam, one EXHAUST cam) There are also SINGLE OVER HEAD Cam engines where you only have one cam and all the "BUMPS" or lobes are on one shaft......a Pushrod motor, on the other hand, has the cam down in the block and another part called a LIFTER rides on the cam....which in turn has the pushrod in it and it runs from the lifter to the head where it pushes on the rocker arm...which in turn pushes down on the valve stem to operate the valves....in a pushrod motor you only have ONE cameshaft where both the intake and exhaust lobes are located.....similar to a single over head cam motor.

BryanPendleton

Another take:

Cams/Camshaft - Cams orchestrate the valve train on your car. They dictate when and how much the valves on your car open to allow the motor to injest air. Then they dictate when and how much the valves open to let the exhaust gas escape the engine. Cams are driven by the crankshaft of the motor and are synchronized with the crankshaft via the timing belt or chain (2.0L FS uses a timing belt). Some cars come with a single cam which drives both intake and exhaust valves, and some cars have two seperate cams for opening and closing the intake and exhaust valves. The 2.0L FS is refered to as a dual overhead cam engine (DOHC). Cams have a very significant effect on a engines VE. A change in cams could change a motor from a low rpm torque strong truck engine to a high rpm screaming pocket rocket. Generally, tuners try to find a cam that is aggressive enough for some significant power gains, but mild enough so that the car is still street legal, passes emmissions, and does not reduce drivability too much. A change in cams generally changes the VE of the motor so much, that the fuel maps and ignition maps must be optimized for the motors new VE. The potential for cams is nearly endless, but the more aggressive route you take with the cams, often dictates other expensive modifications to accomodate them. So you are asking what is VE?

Volumetric Effeciency (VE) - This is a term that measures how effeciently your motor injests air through the intake and expells the exhaust gases out the exhaust side. This is a very important term to understand, because most engine modifications effectively change the VE of your motor, and hince why you decreases or increases in torque and power at various rpms. Mathimatically, VE is the percentage of air that the motor injests and expells vs the total volume of air the motor could potentially injest and expell. First the easy part. How much can your motor injest. Lets use the 2.0L FS motor as an example. Its total displacement is 2.0L's, and it has four cylinders, so each cylinder displaces approximately 0.5L's. Now if the motor were 100% effecient at all rpms it would injest 0.5L's of fresh air each cycle then expell 100% of the exhaust. Unfortunately, a 100% effecient motor is impossible. How effecient your motor actually is unknown, but as a general rule of thumb most dual overhead cam engines have maximum VE's around 85-90%. The actual numbers are not important though. What is important is the VE curve, or a chart of VE vs RPM. You VE curve will have the same trend as your torque curve, as measured on an engine dyno or a wheel dyno. So your peak VE will occur at peak torque. Without changing the displacement of the motor you cannot injest any more air, but you can change the VE of the existing motor. This takes on infinate degrees of modifications, from something as simply as changing the air filter or as complex as reworking the cylinder head with larger valves and ported runners. So we want to change the VE of the motor? Almost all performance modicafications will increase high rpm VE while sacrificing some low rpm VE. Recalling earlier statements, this means that the high rpm torque will increase and low rpm torque will decrease, and where torque increase, so does power. Learn this and understand it. Cams have a profound effect on your motor's VE. More lift and duration on the cams increase high rpm VE while decreasing low rpm VE. The key is doing lots of R&D to find good high rpm gains while minimizing low rpm losses, and still maintaining a good idle, emmissions, etc.

LOS-323

Thanks Bryan and Sir Nuke.... Threads like this one are the reason why I joined the forum.

Have a pleasant day.

LOS-323

One question....

In one of the posts you guys talk about the timing belt. I wanted to know if it is possible to simply remove the cover that protects the timing belt to check it (to see if looks like it´s about to break), or should I leave that to a mechanic?

I don´t want to replace it myself (unless it´s a very simple endeavor), I just want to know if I can see it and then place the cover back on without any problems.

I´m fairly illiterate when it comes to engines as you can tell (that´s why I started to come here).

BryanPendleton

You can remove the engine covers for T-belt inspection, but that involves removing accessory belts and crank pulley. At that point you are half finished with a timing belt swap.

Its my personal opinion, but removing the engine covers is the hardest dang part of swapping timing belts and cams. . . Sounds silly, I know, but the clearance is minimal and with my big hands, it so hard to reinstall engine cover bolts. Alignment of the lower engine cover was a pain too. First time I did it, after "jacking" with it for around 1/2 hour, I finally had my wife get the last few bolts started with her small hands. Don't laugh now.

Inspection of the timing belt is a good thing. You certainly want to replace damaged or frayed timing belts, but I would highly recommend that you replace timing belts on the manufacturers recommended milage intervals. If you t-belt has 60,000 miles on it, I would replace it. Its not worth gambling over $200-$250 timing belt change. . . The cost of it failing or slipping is SOOO much more, probably on the order of thousands of dollars. Timing belts are an elestomeric material which ages, weathers, looses it elasticity, becomes brittle, stretches, etc. Replace it if its time!

carguycw

You should also know that there's usually no way to tell if a timing belt is about to break just by looking at it. If it's got obvious signs of damage, then you should definitely replace it, but you should ALWAYS replace the belt at the manufacturer's recommended interval, regardless of how it looks. There is no reliable way to inspect one and accurately judge how much longer it's going to last.

LOS-323

I plan to replace them at the recommended intervals, but I thought that if it was an easy thing to check, then I could check it at 30,000 miles or so, to see if I should replace it before the scheduled interval. You never know when you might get a defective timing belt installed.

Thanks for the information guys.

Later,
LOS

walight01

thank you for the info guys, i wouldn't attempt to install those cams, i would get them and have them put on when i got my timing beltchanged. i've got 60kmiles already so it wouldn't be soon. also are the 10.7/1 pistons worth getting with a stock motor???

carguycw

IMHO they are not worth it by themselves. If you can't do any of the work yourself, the piston swap is going to be VERY expensive because it requires tearing down most of the engine; you'll be lucky if the job costs less than $1,000. In return, you will probably get less than 10 hp. There are better ways to spend the money.

jstand6

<<<<Green with envy!

Ambient

howstuffworks.com is the best

walight01

so what can i do to get a decent power increase for under a grand??? i've seen a computer you can get but its around 1k as well. if it requires professional instalation, i've got a bud who does that stuff so that part of the price isn't relavent.