456 Cam selection

[747mopar]

O.K guys, looks like I'm going to be in the market for a new cam and since I had my motor built before joining this FBBO I didn't get to pick your brains. I'll do my best to break down the motor and it's intended use. I want a serious street motor leaning more towards street and has to be happy cruising at 1,900-2,100 rpm. Starting at the bottom, 400 BB, 440 forged crank, resized rods, KB 280 pistons with floated pins and the step milled to a flat top, 9.8:1 comp, heads are ported 452's with 1.81, 2.14 Ferra valves flow test show they're good up to .550 lift, Comp 911-16 springs, intake is a Eddelbrock Performer RPM, Comp magnum rockers, and a Holley 870 Avenger. For now I'll be running a 727 with a 2,500 stall and 3.55's but like I said "for now", I'm more concerned that it's suited for the future T56 that will bring the RPM's down in the 2,000 ballpark. I originally chose Comps 21-224-4 but because of 2 bad sets of hydraulic lifters and the fact that everything will likely be replaced under warrantee I'm looking to get a solid lifter cam to end the nonsense. They have no problem letting me switch to a solid cam and lifter under warrantee so hear we are, what do you think. I'm looking at Comp 21-230-4 at the moment. Looking forward to your replies.

 

[benno440]

http://www.lunatipower.com/Product.aspx?id=1568&gid=279

bit milder
http://www.lunatipower.com/Product.aspx?id=1567&gid=279

tad milder again
http://www.lunatipower.com/Product.aspx?id=1580&gid=287

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screw comp cams man,

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oh solids nvm,

 

[m79ded]

give bullet cams a call they will spend time with you and get you the right cam. If you do reconsider a hydraulic the Lunati voodoo cam works very well. seen it on a street car and it behaved exceptionally well. With your combo it's right on. I did notice that you said you want a serious street motor leaning more towards street and has to be happy cruising at 1,900-2,100 rpm. well you need a cam that will make very good low end torque but still be happy around 5500 rpm.
The others are just too big for your intended usage. Be careful not to overcam because it will make the car feel lazy with 3.55 and 2500 stall.

 

[cdr]

because the are warrantying the other cam & you have to go with a comp,this is what i would go with,it might seem to big but you will lose some of the lift & duration because of the valve lash
21-232-4 or this would be better with the t56 21-231-4

 

[Meep-Meep]

Your target RPM range pretty much decides what you will end up with. Low overlap (112 lobe separation) will be a good place to start looking.

 

[451Mopar]

What problem did you have with the lifters? If you wiped out a cam lobe because the lifters were not rotating correctly, you may want to get the Hughes lifter bore burnishing ball.
http://www.hughesengines.com/Index/...W5n&searchmode=partnumber&page=3&partid=11372

The cam you have would be OK for the lower RPM range, but you could go a step hotter with a cam around 240 @ 0.050" duration range.
The 21-231-4 looks better to me (236/242 @ 0,050"), 0.502"/0.511" lift.

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because the are warrantying the other cam & you have to go with a comp,this is what i would go with,it might seem to big but you will lose some of the lift & duration because of the valve lash
21-232-4 or this would be better with the t56 21-231-4

I just read this CDR, and I was thinking the same thing. The engine would likely make best power with the larger 21-232-4 cam, but it is a bit too much for the lower stall speed and gearing. The 21-230-4 is just too small, and may create too much cylinder pressure increasing the chance of the engine pinging on pump gas.

 

[747mopar]

What problem did you have with the lifters? If you wiped out a cam lobe because the lifters were not rotating correctly, you may want to get the Hughes lifter bore burnishing ball.
http://www.hughesengines.com/Index/...W5n&searchmode=partnumber&page=3&partid=11372

The cam you have would be OK for the lower RPM range, but you could go a step hotter with a cam around 240 @ 0.050" duration range.
The 21-231-4 looks better to me (236/242 @ 0,050"), 0.502"/0.511" lift.

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I just read this CDR, and I was thinking the same thing. The engine would likely make best power with the larger 21-232-4 cam, but it is a bit too much for the lower stall speed and gearing. The 21-230-4 is just too small, and may create too much cylinder pressure increasing the chance of the engine pinging on pump gas.

The 21-224-4 that is in it didn't seem to have any issues with pinging but then of coarse I never got to put it under load either.

 

[lewtot184]

first, you will not lose lift or duration because it's a solid lifter. people who say this don't know how to read cam specs and have never tested their rocker ratios. the fact of the matter is, you will pick up duration on those extreme energy solids. they are rated at .015" lobe lift which equates to .022" lash with a true 1.5 rocker. comp gives a recommended lash of .016" and .018". .016" at the valve is .0106 at the lobe with a true 1.5 rocker. thats picking up .0054" on both sides of the lobe which increase seat timing probably 8 degrees. so a 268 lobe may actually be 276 on the seat. the other factor is rocker ratio. never believe that an adjustable rocker is what it's rated at. every 1.5 rocker i've measured is higher than 1.5, usually 1.6. 1.6's i've measured are around 1.65. this compensates for any lash loses and can make things get complicated on hydraulic cams. an example; i have a comp 282-.495 magnum laying around that i stuck in a block and measured it at the valve with a crane ductile iron 1.5 rocker. net lift at the valve with lash was .505, do the math. i have an engle k65 in one of my engines. rated lift is .510 but it has .525 at the valve with lash on crane gold 1.5 rockers. the 911 springs, very stout single springs, and a higher rocker ratio is probably a contributor to killing the hydraulic tappets.

 

[cdr]

first, you will not lose lift or duration because it's a solid lifter. people who say this don't know how to read cam specs and have never tested their rocker ratios. the fact of the matter is, you will pick up duration on those extreme energy solids. they are rated at .015" lobe lift which equates to .022" lash with a true 1.5 rocker. comp gives a recommended lash of .016" and .018". .016" at the valve is .0106 at the lobe with a true 1.5 rocker. thats picking up .0054" on both sides of the lobe which increase seat timing probably 8 degrees. so a 268 lobe may actually be 276 on the seat. the other factor is rocker ratio. never believe that an adjustable rocker is what it's rated at. every 1.5 rocker i've measured is higher than 1.5, usually 1.6. 1.6's i've measured are around 1.65. this compensates for any lash loses and can make things get complicated on hydraulic cams. an example; i have a comp 282-.495 magnum laying around that i stuck in a block and measured it at the valve with a crane ductile iron 1.5 rocker. net lift at the valve with lash was .505, do the math. i have an engle k65 in one of my engines. rated lift is .510 but it has .525 at the valve with lash on crane gold 1.5 rockers. the 911 springs, very stout single springs, and a higher rocker ratio is probably a contributor to killing the hydraulic tappets.

i am so glad i am stupid,the cam specs @ .050 DO NOT TAKE valve lash into consideration, & the amount of valve lash comes right off the top of the lift......

 

[lewtot184]

i am so glad i am stupid,the cam specs @ .050 DO NOT TAKE valve lash into consideration, & the amount of valve lash comes right off the top of the lift......

you never mentioned .050 in your initial reply. i stand 100% behind my comments.

 

[cdr]

you can stand anywhere you want

 

[747mopar]

Your target RPM range pretty much decides what you will end up with. Low overlap (112 lobe separation) will be a good place to start looking.

Was looking around on Comps sight, looks like most solids I'm seeing are 110.

 

[747mopar]

Got my cam out tonight, everything looks great except the lifters that aren't pumped up of coarse.