Cam?

[Big Turkey]

Alright so I was checking out Vanirtech and I came across some cams. I've heard that with the 4.0 OHV engine, you can pull a good 250hp with a good street cam, and personally, I don't have a clue what that means. LOL.

So my question is, what exactly does a cam do? How much does it cost with labor? Because damn, if it gives you that much hp gains in that OHV engine, then I think that'll be my next step. The only thing is.. how come I don't hear everyone doing it as their "basic mods" such as intake/exhaust/headers? Someone clear me up please!

 

[Kontrol-Trak]

Originally posted by Big Turkey
Alright so I was checking out Vanirtech and I came across some cams. I've heard that with the 4.0 OHV engine, you can pull a good 250hp with a good street cam, and personally, I don't have a clue what that means. LOL.

So my question is, what exactly does a cam do? How much does it cost with labor? Because damn, if it gives you that much hp gains in that OHV engine, then I think that'll be my next step. The only thing is.. how come I don't hear everyone doing it as their "basic mods" such as intake/exhaust/headers? Someone clear me up please!

OHV engine does not use cams.

 

[SteveVB]

No cams?

Well the OHV does use A cam. The 4.0 OHV uses a single cam in the block which has lifter that pushes a rod(push rods) into the rocker arm which inb turn activates the OverHead Valves (OHV) in the cylinder heads.

No one talks about them because it takes some knowledge of the engine to install them, and in the 4.0 its a bear. It is not a bolt on mod, it requires a good deal of engine disassembly, and checking and measuring to install. Cost is in the 700 range with all of the needed accessories. Do a search of this site- cam upgrades have been covered before.
I would recommend a cam change during a rebuild when everything is apart anyway and you have to replace the lifters, springs push rods and cam anyway- the incremental cost is not a big deal at that point maybe a hundred bucks or so.

hope that clears things up.

 

[DOGMAN]

Like SteveVB said, the 4.0 OHV (OverHead Valve) is an old pushrod style motor with the cam in the block. Kontrol-Trac, you are probably thinking of the Single Overhead Cam (SOHC) motor, where the cam is situated over the valves.

In an OHV motor, an aftermarket cam can be installed, but again like SteveVB said, it's far from a simple plug and play mod. Yes, you can gain HP with a different cam profile, but where that HP occurs at is something to be considered. Do you want your powerband to occur at a higher rpm? Do you want your torque curve to be flat, or peaky? Will you want a lopey low rpm idle? Is the vehicle to be used as an everyday driver? These are all factors to consider before swapping cams.

One person who I found helpful with discussing 4.0 OHV cams is Dennis Hilliard at Central Coast Mustang www.centralcoastmustang.com

Be aware that with most HP mods, there are tradeoffs to consider. And there must always be a balance. For example, a larger bore throttle body will allow more air into the intake than a stock one will, but without other mods to make it worthwhile, it will actually hinder performance at low rpm by decreasing velocity of airflow into the intake. Now if you upgrade the cam, heads, intake, and fuel system, and say install a blower, then yes, a larger bore throttle body may be just what you need. So check out the big picture and think about what you're trying to accomplish before jumping into what can be a rather expensive search for HP. Learn before you buy!

 

[Kontrol-Trak]

Ah, so it does have a cam. lol sorry, I don't know alot about OHV engines

 

[Kontrol-Trak]

Since it's not an Over Head Cam, What is the cam in an OHV engine called?

 

[Big Turkey]

Hey guys, thanks alot. I've decided that I'll wait until this engine goes bye-bye before I do a cam swap or any heavy work. This is my daily driver, so mpg is going to be sacrificed by hp gains, and that's not a good thing. All my money is going to be wasted on this ****. But when I do waste the engine (I still have awhile to go.. only 45k on this one) I'm going all out :smoke: I think my search for hp has gotten to a stale, and I don't feel like I'm going to be able to make this car any faster without really putting alot of money, which sucks. Cause I don't have any.

 

[SteveVB]

Originally posted by Kontrol-Trak
Since it's not an Over Head Cam, What is the cam in an OHV engine called?

Uh- its called a cam. Cam is short for camshaft. Camshafts do the same thing in all engines they activate the valves letting the fuel/air mix in and the exhaust out. OHV.OHC its just a matter of where they(cams) are located.
OHC have a cam right over the valve and actuate the valves directly, while OHV cams have a cam in the block and use the lifter/pushrod/rocker to activate the valves

 

[DOGMAN]

Well put Steve.