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Holy crap another cam question!
https://www.slantsix.org/forum/viewtopic.php?t=13460		 Page 1 of 1
Author:  argentina-slantsixer [ Fri Jun 24, 2005 9:36 pm ]
Post subject:  Holy crap another cam question!
Well, I know I shouldn't, but I couldn't help it.

So doc and others agrees I got a shibby hyd cam lobe profile on my custom cam.... GRRRR! :evil:

I'm considering to use an off the shelf cam like comp 252 or 264. I don't fully understand how those 2 slightly diffrent profiles would affect my car behavior. So, I thought I'd open with my car specs

225 - mildly ported head (stock valvles for now) and shaved .07 off . decked block. steel gasket. 1 7/8" primaries 2" sec true dual headers, 2 small free flow mufflers near the end of each pipe. No balance pipe whatsoever. 3.07:1 rear end ratio. torqueflite 904. Stock convertor. bored 0.20 over at the pistons, 0.05 under at the crank. Nice forged connecting rods. Flat top pistons. 3000 plus lbs car. My dist is recurved. I have dual electrofans, MSD 6 AL relabeled mopar performance EI, blaster 2 coil. I use NGK jap BP5 spark plugs, no fouling.
what I wanna do: have plenty of pep off the line, strong running rice eater car in the city, not wanting to rev the holy crap outta it, my cruising speed usually is in between 75 and 85.
Soon to be replaced: my induction sys would be a 350 cfm speedshop worked holley 2300. No bottom mani heatup. I'd consider to upgrade my rearend ratio to 3.31:1

So here it goes the main q:

Would you go with comp 252 or 264?

here's main data comparision:
adv duration @0.5 lift lobe sep dur.@.02
comp 252 215 .435 110 252
comp 264 220 .440 110 264

both cams are to be lashed .010 in .012 ex

and one more q... does anyone have purchased comp's complete kit? how good is their timing set? thnx. Juan
Author:  emsvitil [ Fri Jun 24, 2005 9:48 pm ]
Post subject: 
With an automatic the 252, stickshift 264.

My reason being that you need the lower torque, and when just putting around in the city, the engine is below 2000 rpm, so the lower torque and efficiency is better with an automatic.


Personally I like the MP244, but that is unavailable (unless there is a stash of em down there). (What I'd really like to see is a higher lift roller cam version of the MP244.....)
Author:  emsvitil [ Fri Jun 24, 2005 9:50 pm ]
Post subject:  Kit....
Haven't gotten a kit, but comp cams timing chain is not a double roller, so you'd probably be better off piecing it together....


BTW, I found out on this forum that the slant 6 truck engines used a double roller, so that should be a good way to cross reference the timing chain.
Author:  Dart270 [ Sat Jun 25, 2005 7:13 am ]
Post subject: 
If you want HP, the 252 is not going to do it for ya. It is only a very small step over a stock cam, as is the MP 244.

Ideally, the 264 with a 2500 stall converter would really wake the car up. Even w/o a stall, you should be able to make the 264 work pretty well. I little more head/block milling (higher static comp) would give you better low end with that cam. You can run more comp with the 264 on regular gas since the longer duration bleeds off some comp.

Lou
Author:  SlantSixDan [ Sat Jun 25, 2005 7:20 am ]
Post subject: 
Quote:
Personally I like the MP244, but that is unavailable
I like the MP244 a lot, too. That's why I sent my new-in-box MP244 to Doug for his cam grinder to profile and archive.

New MP244s are an e-mail to Doug away...
Author:  argentina-slantsixer [ Sat Jun 25, 2005 7:53 am ]
Post subject: 
hey folks thanx for the replies.

I'm already running a higer duration cam, but the lobe profile's a bitch. Harder to lash right, etc. I'm running 9.3:1 static compression but my cam eats away a lot of that. When lashed per cam grinder's specs, my comp # are 120-130 PSI. On 0.05 that's 150-165 so go figure...

So I figured, lets' get a really nice lobe profile high lift high duration cam, and hopefully with a sl6 matched lobe profile.

As far as for timing set, I saw that coming. I'm getting a huges double roller timing set.

About low end torque, how about advancing the 264? maybe I can get it to work on both sides, or it runs outta breath quickly? BTW, my driving style is "get away from my path"... over 2k rpm runs in town are not scarce ;) so when I'm in the city, it's just gramma style (If my wife is with me) or kinda 1/4 mile drag race. Also note that I'm planning to raise the rear end ratio... so maybe that would compensate for the low end loss on the 264... :?: :?: :?:
Author:  Slant6Ram [ Sat Jun 25, 2005 8:23 am ]
Post subject:  My custom cam design
I was reading the 'cams sanitized' post a while back. I used that info to design a cam that is wilder than the ones comp sells off the shelf. I haven't ordered the cam and might not get to install and test it until next racing season:cry:

I want to be able to keep the stock converter for a little while (saving up for a good one), so I am hoping it has good idle (as has been suggested that it can)

All this stuff is using comp cams online catalog
Using a standard 64-000-5 cam blank (for a slant six)

From their custom lobe pages
MH solid 6252
duration: 262
dur at .5: 236
dur at .2: 149
lift: .346
Lift at 1.5 rocker ratio: .518

This is an agressive lobe for a ford lifter, but the mopar lifters are bigger than ford, so I'm feeling O.K. about my chances. All the agressive lobes for mopar have far too much duration for a street driven slant six. I've picked the largest of the 3 lobes that I thought might work. If you want to go milder here are two others you can look at. Compare them to the standard 252 lobe and you will see that they are very interesting, but still considered very mild.
lobe - 6053
MA 259-1

O.K. you say the 262 is more than you are comfortable with having in an automatic. Well, the rumor is that lobe separation and intake centerline can be modified for a wild lobe to tame it back to street car status, but still take some of the gains of the bigger lobe.

The trick for full range of power may be lobe separation. I'm going to try 112* of separation to give it street manners.
To keep compression tame and allow for reasonably priced pump gas, I've read that overly advancing the Intake center line is no good. This will make the engine only generate high rpm power. High revs is not really a slant sixes strong point anyway, so I'm taking a chance to ask for a 102* intake center line.

It sounds like we have similiar goals, but slightly different breathing setups. I wish I could say I KNOW THIS WILL WORK GREAT, but the truth is, I am just trusting the word of a forum member who I have never met. Am I crazy? I guess we'll find out.
Author:  panic [ Sat Jun 25, 2005 10:10 am ]
Post subject: 
"agressive lobe for a ford lifter, but the mopar lifters are bigger than ford, so I'm feeling O.K. about my chances"

The larger lifter won't have any effect on life expectancy, you're just as safe as a Ford here. The diameter only controls where the edge contacts the lobe. This will need more spring than the smaller Mopars with the same duration.

"This will make the engine only generate high rpm power"

Backwards - increase low speed power.

112 sounds like a good choice, just a guess.
Author:  emsvitil [ Sat Jun 25, 2005 3:30 pm ]
Post subject:  Info and a ?
Comp Cams has 2 measuring systems for solid lifter cams....

.015 tappet lift and .020 tappet lift. The .015 seems to be for streetable, and .020 for raceable....

Now with that said check this out:

Xtreme Energy Solid 6052
Advertised 256 @ .015
218 @ .050
129 @ .200
Lobe Lift .311
1.5 lift .467
Tappet Lift TDC .057 @ 106CL
.046 @ 110CL

XTQ Solid 6275
Advertised 248 @ .020
218 @ .050
129 @ .200
Lobe Lift .310
1.5 lift .465
Tappet Lift TEC .057 @ 106CL
.046 @ 110CL

There may be some ramp variations, but they are essentially the same lobe with a 8 degree difference in advertised duration.

Just for fun I plotted out the curves(I added 0 @ 298 on both for the ramps )with Excel using the XY scatter and the curve function (it fits a nice curve for the points) and the curves looked like they were about 99.9% identical.

Also remember that lash settings will vary the duration.


Now the ???
At what tappet lift are the Mopar cams advertised duration at??????
Author:  argentina-slantsixer [ Sat Jun 25, 2005 6:49 pm ]
Post subject: 
whoa.... i ended up more confused... :oops: :lol:

I think I'm sticking to my lumpy cam unless some ligth brighten my brains.
Author:  brent [ Sat Jun 25, 2005 7:19 pm ]
Post subject:  comp cams
I have run both the 264s and the 252s i have a 252s for sale i gave the 264 away the stock cam makes more low end power that i wanted
Author:  emsvitil [ Sat Jun 25, 2005 9:05 pm ]
Post subject: 
Quote:
whoa.... i ended up more confused... :oops: :lol:

I think I'm sticking to my lumpy cam unless some ligth brighten my brains.
I just wanted to point out that when comparing cams, look at all the specs so you're comparing apples to apples....... a 256 is not necessarilly longer duration than a 248 if they are measured at different lifts.....


Which is why I'm curious to what the Mopar cams are measured at...
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