.484 purple shaft grind info.

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T67POWER

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I forgot that I got this information and with some resent threads on cams I figured I would post it.

I called mopar performance parts many times in the past and have got to know some of the guy's pretty good
I called on the .484 purple shaft grind and they said he could not find any kind of cam card or information on the cam grind as far as intake and exhaust valve closing points.
I guess the engineers that designed these cams made the grind and then gave it to this company to manufacture.
Mopar parts told me the name of the company and gave me the number.
I guess I'm not really suppose to have it ,so i won't post it.

When i called the company,it was right before the holidays and i got some guy in his office.
It sounded like he was drinking a cup of coffee and relaxing.
He was very much in shock that i got to his desk.
They are a big company and because of it they where like who the hell are you.
I think they do a lot of oem stuff for the big three and still make some of the old purple shaft grinds.
I gave him the grind #p4120231 and he said he would call me back.
I guess these grinds are like the holy grail or something.lol

The guy calls me back with this information and after he gets done reading it ,i ask him for a date of manufacture and he says he has to go ,but then feels bad and says have a nice holiday and hags up.

Here is the info.
Company"s part#4220234 one digit off ///mopar part #p4120231 .484

.322 lift x add 1.5 rocker = .483 lift
239 @ 50 thousands lift.
108 LSA
Valve Events : @50
Intake opens 11 degrees btdc | Intake closes 48 degrees abdc

Exhaust opens 47 degrees bbdc | Exhaust closes 12 degrees atdc

I believe this is the .484 purple shaft.
When i called mopar parts back they where very surprised i got the information because when they tried they never could get any information out of them.
 
The (valve events) are not @ 50 in the victory info.
I believe it's S.A.E. \\\\ @ .006 thousands.

Modern cam company"s list the valve events @.006 and sometimes
@ 50, so this info. is somewhat useful in comparing cams.
It's nice to know when the intake closes @ 50. as far as cylinder pressure.
Just some information that i thought would be cool to post.
 
Intake Duration @ .050” 241° Exhaust Duration @ .050” 241°


second line down...has the .050
 
How rough an idle with this cam? what would be min comp reqiured?

Thanks
 
This all came about because of another thread on cam selection.
I was told about information on how mopar cam's are measured differently @ 50 according to a bit of information called victory tech papers.

In fact i had this information printed out and never really looked at the first page of the printout to try and understand it because it was about the size of the cam @ 50. as I originally printed it out for the intake valve closing events.

These events are listed and are measured at .006 lift.

After reading over the victory tech papers I have come to the conclusion that the author did not mean that the mopar cams could not be compared to other cams but WHEN comparing a cam @ 50 lift it should only be done with a performance cam and not with a OEM CAM GRIND.
I think he means to say only use the @ 50 lift measurment for PERFORMANCE CAMS (MP)IE>>MOPAR PERFORMANCE
AND OR IN GENERAL --ANY PERFORMANCE CAMSHAFT.

I see the .484 mopar cam as having a 284 advertised duration as being correct.
The intake valve closes at 70 degrees ABDC in the victory information.

If you compare this to a 284 advertised comp cam XE284H it has a intake valve closing point of 68 ABDC

Comp cams are measured at .006

If you want to be more accurate then you use @ 50 lift.
The mopar cam is 241 @ 50 and the comp cam is 240 @ 50.

Comparing the both of them is the same.
One is a mopar cam and other one is from comp cams.

I SEE NO DIFFERENCE IN THIS INFORMATION.


Given the inside information from the company that grinds the .484 cam (that i remembered i had) and in looking into it further,i see that mopar cams are no different then any other cam at how they are COMPARED TO OTHER CAM COMPANY'S.
 
To follow along with this do a google search >>(mopar tech papers) and scroll down to the 32nd line [[[[[ Chrysler MP Factory Data ]]]]]
Click on it<<<<<<
It brings you to Victory tech papers Chrysler Cam Data.
 
MAN WHAT A NIGHT....................:homework:
 
He kinda makes a similar reference in the MP engine manual. Still though, it is clear as a bell that MP uses one method of duration @ .050" and everybody else another. That's why you really need to do your homework when comparing. Because more likely than not what will happen is, you will end up getting a cam that you thought was better than a purple shaft that really ain't. The way I understand Larry Shepard, anything under .600 lift is "mild" and should not use .050" as a reference. At least, that's always been how I conveyed it.
 
Strokerscamp.
He does not mean what your saying.(victory tech papers)cam info.

How can (in my example) a mopar .484 PURPLE SHAFT and a comp XE284H have the save valve events---and the same @ 50 lift measurement--- plus the same advartised duration measurement and be on some other method of duration measurement???????
They are both 284 advertised cams.
241 @ 50 for the mopar cam \\\\ 240 for the comp cam
They are not exactly the same.
The mopar came has a 108 LSA and the comp cam has a 110 LSA.
These cams are being measured at .006 lift.for there valve events.
They are being measured at .050 lift for their duration.

Sometimes you have to look at things from a different angle to see the target.
Take a step back and look at the big pitcher.
I think your jumping to a conclusion, based on reading something from the wrong angle.
If you could explain the way you think mopar rated it's cams differently then just explain it.
I think you misunderstood the tech article.
He means to say, that it is RIGHT to use A @ 50 lift measurement ONLY FOR PERFORMANCE CAMSHAFTS......NOT OEM\STOCK GRINDS.
There are some stock grinds in that article.
This is why he said it.
 
Ran that .484 cam in a 340 years ago not impressed with it what soever.mopar performance cams are nothing to write home about..way better cams out there...
 
Had 9 to 1 360 with a 484 cam...ran 12 flat with it in Bakerfield kalifornia....
 
Mopar cams are great cams for factory stock heads because they where designed for those castings.
Saying there old is true ,but that has nothing to do with where the valves need to be in relation to the cylinder heads and short block for the valve timing.

If you still run stock heads on your engine, you could benefit by running a purple shaft cam.
They are set up to give you the most performance possible.
I have used the .474 and .484 cam and have been very happy with the performance they gave.
I have a friend of mine who runs a .557 solid in his dart with 308 factory stock cylinder heads.
If i was to ask what cam to run, how many people would say to run a purple shaft?????
How fast do most guys with a 318 run the quarter mile in a dart on pump gas with a factory steel head??????
The car goes 11.14 in the quarter.

Is this not a great running car.
How much faster is the car going to go with a so called modern cam????

I have not met to many people going 11.14 with a 318 on the street ,let alone on pump gas with nothing more then a carb.

If the cam gives the engine what it wants,then it's profile is right where it needs to be for max performance ,modern design or old.
 
Strokerscamp.
He does not mean what your saying.(victory tech papers)cam info.

How can (in my example) a mopar .484 PURPLE SHAFT and a comp XE284H have the save valve events---and the same @ 50 lift measurement--- plus the same advartised duration measurement and be on some other method of duration measurement???????
They are both 284 advertised cams.
241 @ 50 for the mopar cam \\\\ 240 for the comp cam
They are not exactly the same.
The mopar came has a 108 LSA and the comp cam has a 110 LSA.
These cams are being measured at .006 lift.for there valve events.
They are being measured at .050 lift for their duration.

Sometimes you have to look at things from a different angle to see the target.
Take a step back and look at the big pitcher.
I think your jumping to a conclusion, based on reading something from the wrong angle.
If you could explain the way you think mopar rated it's cams differently then just explain it.
I think you misunderstood the tech article.
He means to say, that it is RIGHT to use A @ 50 lift measurement ONLY FOR PERFORMANCE CAMSHAFTS......NOT OEM\STOCK GRINDS.
There are some stock grinds in that article.
This is why he said it.

It is in black and white in the MP engine manual ninth edition that the automotive industry uses .777 X advertised duration to come up with duration at .050". It goes on to say that aftermarket OTHER than MP uses .750 and MP uses .850. THAT'S what I am referring to. That is why you cannot compare .050" duration figures, because they are all different. It's in the book.
 
Some information is good, more is always better, but until the entire picture is seen, it's hard to make a solid comparison. The key to knowing a lobe shape is to profile it. You can't take data points on a curved shape and infer much.
If we simplify the cam lobe to a trapazoid (think a triangle or pyramid with the top point cut flat) and then plot similar lobes, like the MP 284/.484 lobe and the Comp PP284 lobe, and the Comp XE284H you can see they are similar in the specs as published. All 3 of them. Yet, the Comp advertises more area under the curve for the XE. Under the curve means the time the valve is open and the port is flowing. So how is that happening if the specs given show the same distance and duration? Well, two ways:
1. In that trapazoid, as both are hydraulic cams, the basic dimension of the top of the trapazoid will be the same. there has to be roughly the same area because of the lifter engineering. So that stays the same for both. However the total lift for these two are not the same.
The XE "pyramid" is taller. That means the rate of lift has to be faster to reach the same duration points while lifting the valve to an overall taller figure. This also means that the portion of the lobe above the .200" mark are longer duration.
2. That longer duration at higher than .200 means more duration so it will make more power provided the port can support it.

What is missing from the MP lobe info, and what makes that Victory statement about "85% for MP cams" vs "77% for stock type cams" is the lift and duration after .200" of lift. The final .100 or so forces the valve open longer, at the point in the flow curve where the port has almost reached maximum velocity. Interestingly, you'll almost never see the duration figures published for higher than .200 unless it's a custom cam. #2 is also why Lunati's VooDoo cams are bascially bigger for the same given advertised durstions, and why they make more power. There's not much difference in Comp and Lunati, but by leaving out the proprietary durations and lifts, they can say they are the more powerful and better when comapring the "268" cams.

My issues with MP is the quality control, which flat out sucks, and then the lobe designs, which are very dated. When you start to talk about rates of lift and valvetrain stability the MP cams are realy, really oldschool. Not bad, and certainly not bad on heads manufactured and designed in the same era, but I'd rather have modern that's tweaked where it counts.

Sorry. I had to edit after I re-read it...
 
Strokerscamp,
I under stand what your saying.


What cam do you think is bigger then.
The .484 mopar cam OR the XE284H Comp Cam???
 
Strokerscamp,
I under stand what your saying.

What cam do you think is bigger then.
The .484 mopar cam OR the XE284H Comp Cam???

It's hard to say. Because we really don't know what comp uses as a reference for .050". You can use the math and see real quick it works out using what Mopar says with .850. But, when you use .750 on the Comp, you come up with 213 @ .050", so somebody's stretching some numbers somewhere. So unless Comp has suddenly started grinding using .850 to figure their .050" duration figures, somethin is amiss. If you press me to make my mind up now, I'm stickin with Mopar as the "biggest", but that doesn't necessarily mean best.
 
Mopar performance has used two .484/284 cams. The original one is the -231 and is more aggressive. They later came out with a more "streetable" .484/284 grind.

They also give the centerline and lobe separation for the cam. The centerline is the angle that the intake is at max lift. To find the intake open/close, just take half of the duration (whether it be advertised or at .050) and add and subtract from the lobe centerline to find the intake open/close angles. Then take the lobe separation and that tells you the angle that the exhaust lobe centerline is from the intake centerline. Calculate the exhaust lobe centerline from this and then add/subtract half the duration (whether it be advertised or at .050) to find the exhaust open and close timing.

The "molder / Streetable" cam had less overlap than the -231 grind.

If you need any more info, I can try to look in my archive of old MP catalogs for the specs.
 
Let me use what your saying in this comparison of cams.

MOPAR PURPLE SHAFT>>.850 x 284 ADVERTISED DURATION =241.4 @ 50

COMP CAM XE284H>>.750 X 284 ADVERTISED DURATION=213.0 @ 50

The XE284H is not 213.0 @ 50 (WHY?) It's being measured the same way.

Some company's measure their cam at .750 still,and i understand that, and thanks for letting me be reminded of that.

I think what i picked for an example ,plus the information in the victory tech papers, somehow got us pulling the rope against each other.
Where both correct.
We just were getting are lines of communication messed up.:cya:
 
When I raced my Dart, I changed cams every week for 5 weeks, then went thru 3 sets a headers.. trying to beat my nemisis..

With 12.5 pistons, A crane 331 intake.. can't remember exhaust.. was the best.. 2nd was another breed but 3rd was early purple shaft.. as far as et's went..

That was in 1969/70...
 
........Its fairly rough in a 340.........u need 10.0 comp to take advantage of that cam........kim........

Thanks KIm

It would be for a 360, maybe the 213 would be better but when I am ready I will start another thread, do not mean to hijack this one.

GREAT INFO
 
Let me use what your saying in this comparison of cams.

MOPAR PURPLE SHAFT>>.850 x 284 ADVERTISED DURATION =241.4 @ 50

COMP CAM XE284H>>.750 X 284 ADVERTISED DURATION=213.0 @ 50
No... You cannot use arithmetic to calculate the Comp's druation at .050. Only Direct Connection suggested that.

The XE284H is not 213.0 @ 50 (WHY?) It's being measured the same way.
No it's not being measured the same way. Both brands list duration at .050. Only Direct Connection says you can calculate it off max lift. Comp is BEING MEASURED. Not calculated.

Some company's measure their cam at .750 still,and i understand that, and thanks for letting me be reminded of that.
No, no cam company uses math (meaning lift mutliplied by whatever) to determine lift at .050" other than Direct Connection.
I think what i picked for an example ,plus the information in the victory tech papers, somehow got us pulling the rope against each other.
Where both correct.
We just were getting are lines of communication messed up.:cya:

I disagree. You are taking one brand's recommendation and trying to universally applying it. Not to mention the fact that many modern cam lobes dont even have the same shape on the opening side vs the closing side.. So the duration at .050 it even less accurate.

PS - because the Comp has more lift (.507 vs .484) the Comp is a bigger lobe even with the same advertised numbers at .050.
 
Oh well. All I know is what's in the book and what the math says. Math does not lie and the math says somebody's numbers are off. Since it is broken down in the MP manual so a chimp can understand it, I am banking on Comp's numbers not being the same. Note I didn't say "not right", I said not the same. I am too tired and stupid to continue.
 
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