ok, I know that this is a completely stupid question but to be honest, Im new to cars so: what exactly are the "valves" that are reffered to when people say "its a 2 valve 4.6L V8" or its a "4 valve 4.6L V8?" I know cobras are very fast and they are 4 valves so can someone clear this up for me?

 

They are the valves that let the air into combustion chamber and let the exhaust out. A 2v engine has two valves, 1 exhaust and 1 intake, a 4v will have 2 exhaust valves and 2 intake valves.

 

Also that is per cylinder. I don't know if you knew or not, just wanting to clear it up. The valves are on the bottom of the cylinder head, so as 4600cc was saying 2v head is one exhaust one intake, (per cylinder) and the 4v head is just that. 2 intake 2 exhaust valves per cylinder. 16vlave motor vs. 32 valve motor.

 

And of course the 05/06 Has a 24V 4.6L that has two intake valves and one exhaust.
They use a Variable Valve timing, much refered as an import ideal for a long time but Ford is using it now.

Ford is the First American car company to change ALL of their production engines over to the OHC (Overhead Cam) design, Again concidered an Ideal of imports. That means that there is one came over each head, if its a DOHC then there are two cames over each head.

OHC was a huge step for Ford and it helps to increase economy, performance and reliability. Just as most Asian manufacturors went over to a Hemispherical Head (Hemi- A Ford/Chrysler/Dodge invention)

Well I hope that helps a little bit, everyone here has a great wealth of knowledge so never hesitate to ask, and there is no stupid question.


-Eric-

 

Here

http://auto.howstuffworks.com/engine.htm

Check this out. This is a page that has all sorts of diagrams that explains how an engine works. This should answer any questions youvbe got about the basic operation of an engine... anythingelse, just ask us, somebody is bound to know.

Jim

 

Yeah, i love that website. thats actually where i learned how manual transmissions work . anyway, one more question: is there any way to convert a 16 valve GT to a 32 valve like a cobra? if so, how much work/extra parts would be involved; would it be expensive; and would there be a significant power gain?

 

You may check this out Fastest Modulars There are alot of people on there that are doing the 4V swap. You would need a new manifold (off of a 4V motor) I guess there is also an adapter plate you can get to use your 2v manifold if you wish to. Obviously 4V heads. Other small misc parts. It would take basic knowledge of your motor to do the swap.

 

would I see much hp or acceleration increase?

 

Yeah, I want to go over to an 03/04 Cobra head and KB supercharger swap on my engine. I just bought a 2005 F150 Fx4 with the 5.4L triton in it, I havnt really seen flow charts for either head but I would assume that the Cobra heads flow better being an extra valve and double cams and all.

Then if I get the 4V cobra heads then I can get a sick set of Hooker Super Comp headers for it and have one whicked dual exhaust setup on it. I want dual side exhaust like the Roush F150 has but on both sides of the truck, not just the pass side.

I love my new F150 ^_^ They say its a work truck

 

In 2v engines valves are the major bottle neck. 4v engines resolve that bottle neck by introducing two more valves. These two additional valves have greater area than valves in 2v engine, greater area mean lower velocity, and thus it is harder to fill the cylinder with air at lower engine speed. This all amount to 4v engine being less powerful at lower RPM. However, the trade of is that you get more power at higher RPM. Thus overall 4v engines make more power, but because of their design they make that power at higher RPM.

An introduction of 3v engine is a compromise between 2v and 4v design. 3v makes more power at lower RPM than the 4v does, but less power at higher RPM than the 4v engine.

A 4v is better, since it has more potential. Right of the shelf, power of 2v vs 4v is 260 vs 300. However, it is more expensive.