Well , since you had to ask..........................................
The specs shown are an abrieviated version , what's missing is the timing of events , intake closing , exhaust opening etc. Not a big deal though , that information is not often shown in a catalog. Let's compare the three cams with the Comp cam that is so popular.First let's look at what they do show us.
The advertised duration
#P4529228AB = 240 / 240 degress
#P4529229AB = 248 / 248 degrees
#P4529230AB = 256 / 256 degrees
Comp Cams #68-232-4 = 250 / 256 degrees
All three Mopar cams have the same duration and are known as single pattern , meaning the intake and exhaust duration #'s are the same for each cam.
The Comp Cam is a dual pattern , simply put , the additional exhaust duration is to promote scavenging. Towards the end of the exhaust stroke , when the piston is on the way up and near the top , the intake valve opens , the exhaust valve is open as well and has been for some time , this , in terms of valve timing events , is known as overlap. The amount of overlap is one of the most critical of events in valve timing , in particular , the point where the intake valve opens , critical to throttle response , vacuum , fuel economy and emissions.
Confused ? you shouldn't be , yet , often the confusion begins when trying to understand the difference between intake centerline and lobe separation angle.
Lobe separation angle is the number of degrees separating the peak lift point of the intake and exhaust lobe , established when the cam is ground at the time of manufacture. This can not be changed.
Intake centerline can be described as the position of peak lift of the intake lobe in relation to piston top dead center. This can be changed , if desired by the installer , using a timing chain / sprocket set that has a crank sprocket which is machined to provide three positions for the woodruff key. The procedure used to mess with this is called "degreeing the cam " , enabling the installer to advance or retard timing events . As mentioned multiple keyway sprockets or offset keys are used to adjust valve timing from a straight up install. An example of a timing chain / sprocket set that allows timing changes ( degreeing the cam ) is Mopar #P5249519 , a well built double roller chain , high quality kit that includes detailed instructions.
For the purpose of what you are doing , the above is not all that important , these cams are usually installed straight up , the installer would not bother with advancing or retarding the valve timing. Just cuz I know you might ask about altering timing , here's the deal on that.
Advancing valve timing increases bottom end torque , while retarding valve timing boosts top end horsepower. There are trade offs to altering timing , advancing timing causes overlap to occur earlier , the result of that ? , the engine is not as efficient.
I like knowing the point of intake closing , this affects compression ratio , nice to know , when messing around with altered reciprocating parts like strokers or high compression pistons.
The lift of the cams being discussed are as follows
The three Mopar cams............
.430" / .430" , .440' / .440" , .450" / .450"
Comp cam
.460" / .476"
Obviously the comp cam is more aggressive than any of the Mopar #'s , there's no denying that it works well in a 4.0 l six, so to answer your question , yes the Mopar cam ( hottest one ) would be a good choice. Looking through some catalogs today , I realized not all of the information is listed , there is enough data to make an intelligent choice. My choice would be the Comp cam 68-232-4 .
You will need to do the springs with either cam , remember this , the Mopar P5249464 spring ( 318 / 360 ) spring is a quality chrome silicon spring , it is .110" larger in diameter and will need the corect retainers & locks , not to mention the limited room under some valve covers.
Topic: Lifter Replacement (Read 3594 times)