I know a little bit about cams but I'm always looking to learn more. Here is what I know (let me know if I am correct).

- The duration is the amount of time that your valves remain open. Running more duration keeps your valves open longer, thus the need for a higher compression ratio when running higher duration cams. Keeping the valves open longer allows more air/fuel to enter the cylinder while also allowing more exhaust to exit.

- The lift is how far your valves open. Running a higher lift cam allows your engine to push more air/fuel into the cylinders while also allowing more exhaust to escape (same principle behind duration ?).

I'm a little lost when it comes to lobe seperation. Could someone please enlighten me :) ?

Cams also have effective RPM ranges, I've noticed that more duration appears to be condusive to better mid-range to high-end horsepower. When selecting a cam do you want a cam that fits into your target RPM range? If you only plan to run an engine to 6000RPMs what good would a larger cam (with an effective RPM range of 2300-6500)do for your setup? Wouldn't you be better off going with a cam that would pull from 1800-6000?

What advantages do solid lifter cams have over hydraulic cams? The only advantage that I can see is the lack of valve float with a solid lifter cam. I have been told that they rev faster, but I would tend to think that that would deal more with the lobe seperation (:confused:).

Any help is greatly appreciated :cheers:

 

http://www.newcovenant.com/speedcrafter/
try this



[Modified by clem zahrobsky, 6:33 PM 10/19/2001]

 

Clem:
Thank you so much for introducing me to that site. It offers gobs of information about cams and answer a lot of the questions that were troubling me. I have decided upon my cam (the same cam my buddy with the 454 Camaro is using).

Comp Cams Magnum 282S Solid Lifter Cam : 2000-6000RPMs, 110 Lobe Seperation, .561" Lift.

I guess solid lifter cams due rev quicker than hydraulic camshafts. I'll talk to my buddy tonight and see what he thinks.

Once again thanks Clem!

 

bence,
Let me make a suggestion. Instead of choosing a max rpm that you want to turn, choose the hp level that you want to achieve, and put together a matched combination of parts from the carburetor to the rear end gears that will work together. It's unbelievably easy to chase one area, miss the ball in another, and end up with a cranky dog setup. 6000rpm for a well built big block is a walk in the park.

 

The thing of it all is I'm going with cast rods, which would be the weak point in my setup. I can afford to go with a larger cam because of the 4 speed and the 3.70 gears but I am unsure if my setup will handle 6500RPMs.

The next step up is the Comp Cams Magnum 294S and pulls from 2500-6500 RPMs and has a .595" lift. I know that I DO want to go with a solid lifter cam.

I realize that my intake of choice (Torker II) is a POS, but it's the only intake that will come close to fitting under my hood. If it doesn't fit under my hood, I'm selling the intake and going with an intake that has more potential and buying a cowl induction hood.

I should also mention that my target horsepower range is 500 + horsepower. If I can reach 500 horsepower I'll be happy. :)


[Modified by bence13_33, 10:03 AM 10/20/2001]

 

bence - are you sure you've got cast rods?

As far as I know all of 'em are forged...

 

Both my crank and rods are cast. They are out of a '73 Corvette 454. I'm most certian that they are cast.

I'm not worried about the crank, I believe it can handle 6500RPMs with very little trouble. The rods are what worry me, they will most likely be the weak point. Does anyone know if my cast rods will handle the RPMs that I speak of? Obviously I wouldn't be running it to 6500RPMs on a regular basis. I would only be running it to those RPMs while racing, and only for a very brief second and then I would shift gears.

 

bence,
The rods from your 454 should be forged with 3/8" bolts. All rods are forged with the exception of the newer PM rods, billet steel or aluminum. Check out the dividing line on the side of the rod; if it's wider than 1/16" or so, it's forged. With a good set of bolts, your rods will handle 6500rpm fine. To hit the 500hp mark, you won't have to get too radical in the cam dept., but a hydraulic roller might be a good choice. Fit as much oil pan sump as possible; many BB's have died from sucking the pan dry under high rpms.

 

dually4wd:
Well I went and I measured my rods out of the 454. The rods have 3/8" studs to hold the caps in place. The line down the side of the rod measures about 2/8" in width. So this means I have forged rods? Did all big blocks come with forged rods? What about small blocks, my buddy pulled a 350 out of a pickup truck (short deck motor), would it have forged rods? You learn something new every day :)

I think I'll probably go with the 294S that pulls up to 6500RPMs.

 

bence,
No more worrying about cast rods; yours are forged. The big blocks came with several rod configurations depending on the hp, but all are forged. Some even had 7/16" rod bolts, such as the LS-6 454. As for your buddies motor, I'm not sure what years have the PM (powdered metal) rods, but they are likely forged as well.

 

bence13_33

I'm curious as to why you chose a solid cam over a roller cam? With the roller, there's less friction, and you can run a more agressive duration. Another concern is that with a solid cam is that it will pull the rpms until the engine blows. So this means if your racing and you miss a gear in that 4 speed, it will rev to 9,000 rpms and blow. With a hydraulic you have float, but it will not float to 7-7500rpms depending on the cam and lifters.
You can get the same if not more power out of a roller, it will rev faster, less friction, more duration, plus you don't have to set the valves every 10K miles, and still have a safty net incase you miss a gear.

I have to admit, nothing quite sounds like a solid cam, but it sucks when you miss a gear and blow an engine in front of a crowd.

Just something to think about.

 

That's all anyone around my area runs is a solid lifter cam. I don't really want to go to a roller cam, I don't know enough about them and I'm not sure about their overall longevity.

Yea, over-revving the engine would be bad mojo. I suppose I could get a MSD 6AL box that has a built in rev limiter that you can adjust. Pop in the 7,000 RPM rev limiter chip and I'd be set.

 

There you go, getting sucked into the racing equipment again. Who told you you need a solid lifter cam? I hope you enjoy adjusting valves, again and again. Here's a question for ya: what cam comes in a GM 502/502 crate motor? How about a hydrolic roller. When was the last time that anyone put a solid cam in a production motor? If you can afford it, go with a hydrolic roller, otherwise, go with a good hydrolic grind. Again, if your going racing and need every tenth of a horse power and dont mind taking the valve covers off every few passes to adjust valves, sure, do the solid. I'm afraid your going to build a street pig and you won't enjoy driving it any more. And speaking of valve dynamics, this stuff is bounded by hydrodynamics that envolves flow rates, air velocity and voodoo. When you think about it, the optimum valve cycle would be that the intake valve fully opens instantly at the top of the exaust stroke. It would then close instantly at the bottom of the intake stroke and so on. The roller cam comes closer to this optimal valve timing because the leading ramps can be ground so much more steeper. Someone that knows more about this can elaborate.


[Modified by BubbaJJ, 4:47 PM 10/20/2001]

 

BubbaJJ:
I'll try to respond to your comments to the best of my ability, please don't think I'm trying to flame you or anything. My buddy with the 454 Camaro has the same exact solid lifter cam in his engine and it performs quite nicely (11.66s consistantly at the track)-I'm building a setup similar to his-. He adjusts his valves twice a month which isn't too bad, I can handle that to have a quicker revving engine. Yes, the hydraulic roller cams come as stock equipment in the new 502 engines. If you ask me 502 horsepower out of a 502ci engine doesn't do anything for me....the old 427s were putting out that kind of power and they were using solid lifter cams. Ideally yes, a roller cam is the way to go...but the price is rather steep. The 3.70 gears and the wide ratio 4 speed will help out with my bottom end. I'm shooting for 500+ horsepower, I think that this cam is a step in the right direction.

 

No flame taken, you will have to eventually live with what you create. All I'm doing is urging caution and common sense. I have built cars that I simply didn't enjoy driving because I stepped over the line between drivability and performance. Cams have come a long way, I dont think you will get the performance benefits out of a solid that will outweigh the practicallity of a hydrolic. There simply isn't that much horsepower to be had from substituting a solid for a hyd. If you want to go wicked quick, find a second car that you can race and leave your vette stock, and then go nuts. You wont have to drive your race car so it won't matter how nutty you make it.

 

Well, I agree with BubbaJJ. My father builds race motors in his shop, eveything from 540ci offshore racing boats to 502 air boats, bracket racers, and tractor pull motors. We have done it all. In the '60's solid was all there was really, but now the technology has progressed enough that you can have a roller cam, and make MORE power without the headaches of a solid. Less friction means more HP and less wear and tear. If it's an all out race car, sure go solid, but if it's used on the street, you may regret it.

First off, if you want a high reving motor, you want a 427, not a 454ci. The 454 make loads of torque, but the 427 revs like all hell. The shorter the stroke the faster and higher the revs. The rule of thumb is build TORQUE and horspower will take care of itself, after all horsepower is a byproduct of torque.

The 498 I'm building will have in the neighborhood of 600hp+ with a 200hp-300hp shot of Nitrous to accompany it. All this with a roller cam.

"Torque gets you down the track, horsepower is what keeps you there"

 

Well, I'm gonna toss in my two cents in and irritate everyone...

bence - I think what you're doing is fine. Guys seem to be trying
to push you towards roller, which is totally fine. I'll never build
another engine without a roller. BUT, the cam costs, the rollers
cost, the cam button and whatever you use to keep that button
in place costs. I'm too lazy to look anything up, but I'd guess
at LEAST 600 bucks more?

So, let's say a roller is out. Now, what's better - a solid or hyd?
I'd say a solid anyday. I've run solids for years. Solids have better
ramps, better idle, and give more vacuum for similar specs.

I don't run on the strip, so I don't know about that, but mine
hardly ever get out of whack. If you think about it, what makes the tolerances change? I think a quick check at oil changes is more
than enough. Face it - if you like playing with you car checking
your valves is just plain fun...

So, anyway - I like watching your build. I see too many ricers
so it's just great fun seeing you build up a GREAT car.
If you pay for a roller that's cool, but I don't know if the cost/
payback is really worth it for you right now.

 

Hey bence - I'm on a roll...

If you go with a solid cam what I've found to work pretty well
is to glue the valve cover gaskets to the covers. That way
when you do your valves the covers just pop off and the gaskets
are solidly stuck to 'em. Studs instead of bolts are cool too -
it makes putting the covers back down real easy.
I don't think you need to pay for the ARP studs. I use them,
but if you think about it those things have almost no stress,
so cutting off some bolts and rounding off the tops on a grinder
would be totally fine and cost like two bucks...

 

Bence you do realise that twice a month is every other weekend?

Don't mess around, do it right, get a Lunati Hyd roller cam and show them what an engine can do...

It kinda sounds like you really want to be just like your buddy, but no better

:U


[Modified by 427V8, 9:39 PM 10/20/2001]

 

Oh, by the way, I believe your confusion about rods has to do with the difference between forged iron and forged steel. Can you make a rod any other way then by forging? Can you imagine, pot metal rods? Yuck!