What does this cam specifications mean?
02-15-2002, 08:00 AM
#1
Burning Brakes
Thread Starter
What does this cam specifications mean?
Duration 290 !!, Lift: 0.48
I was told it is made by Comp Cams....
I know to what the data refers, but I donīt know what type of cam it is.
Duration seems much to me, lift too, so.....is it a wild cam?
Any input appreciated.
I was told it is made by Comp Cams....
I know to what the data refers, but I donīt know what type of cam it is.
Duration seems much to me, lift too, so.....is it a wild cam?
Any input appreciated.
02-15-2002, 08:11 AM
#3
Burning Brakes
Thread Starter
Re: What does this cam specifications mean? (Ganey)
Yes, itīs a hydraulic lifter cam, this info is all I have....
it was hard enough to find that out!!
I was told that this cam isnīt strretable without a torque converter such as holeshot 2000...
it was hard enough to find that out!!
I was told that this cam isnīt strretable without a torque converter such as holeshot 2000...
02-18-2002, 03:04 AM
#5
Safety Car
02-18-2002, 07:25 AM
#6
Burning Brakes
Member Since: Nov 2001
Location: Toronto Ontario
Posts: 787
Likes: 0
Received 0 Likes
on
0 Posts
Re: What does this cam specifications mean? (Jvette73)
I have the comp cam with 292 duration at .05 lift on my 73-454 Auto. I would "NOT Recommend" this cam for street use on an auto vette. It might work a bit better on a 4-speed. I suggest you call Com cam tech. line and ask for their recommendation. Word on the street is no more the a 262 duration for street use with and auto.
02-18-2002, 09:08 AM
#7
Race Director
Member Since: Apr 1999
Location: CORVETTE 77 385 C.I. TEXAS
Posts: 11,520
Likes: 0
Received 12 Likes
on
12 Posts
Re: What does this cam specifications mean? (MARKUS_P)
If used, the lifters need to go back on the same lobes. If you cannot be sure then the whole discussion is moot. Cam is critical, best to have the correct one for your setup.
:cool:
:cool:
02-18-2002, 10:13 AM
#8
Safety Car
Re: What does this cam specifications mean? (Ganey)
I went with XE268. But I already had a 2400stall with a th400 and 3.08. Comp Cams catalog says the 268 is the biggest cam for auto without higher stall. But they also suggest lower rear gear. If your gonna run a stock stall speed convertor, I wouldnt go over XE262. Actually with the 3.08, the 262 would also work better with a slightly higher than stock stall speed. If I had run the 268 without a higher stall along with my th400 and 3.08's, I doubt there would have been any gain. Of coarse the top end would have been better, with the sacrifice on the botom end. From a dead standing start race, weak launch, no wheel spin to even think of. But from a highway blast from 50 to 100mph. There is where it would feel better.
02-18-2002, 11:05 AM
#9
Pro
Member Since: Jan 2002
Location: FL
Posts: 534
Likes: 0
Received 0 Likes
on
0 Posts
Re: What does this cam specifications mean? (73-454)
Here's a collection of random cam rules of thumb borne from experience...
Cam specs alone don't define a cam's behavior, though given a particular cam type and engine displacement they can give you some idea.
Cams come in "solid lifter", "hydraulic lifter", "hydraulic roller", and "solid roller" varieties (perhaps there are others, I dunno). The lifter type generally implies the shape of the valve event curve. Roller varieties tend to slap open and slam closed the valves faster, with steeper sides on the curve. Rollers generally need stiffer springs so these more violent valve events are kept under control.
There is also a matter of how cam specs are presented... Some cams durations are advertised as "off the seat", while others list 'duration at 0.050" lift'. These numbers cannot easily be compared, because they depend on the curve shape.
Overall cam lift is important. It defines how far open the valve is pushed, and the rocker arm geometry can affect this as well. Most cams advertise lift assuming the "stock" rocker arm ratio (i.e., 1.5:1 in a Chevy small block, if memory serves).
Another factor in determining how a cam will run is the lobe separation. In other words, the rotational relationship between the timing of the intake valve and exhaust valve opening. A wider lobe separation implies the exhaust valve will open later as compared to the intake valve, and will generally give better idle and mid-range torque.
Last but certainly not least, a given cam that might be considered wild for a small engine will run as though it were a milder one in a larger displacement engine.
For example, I have a solid-roller cam advertising 245/245 degrees duration at 0.050" lift, with 0.575/0.572 lift and 113 degree lobe separation. It probably has something like 290 degrees "off the seat" duration. This might be a really "wild" cam in a 350, but it actually idles pretty well down to about 800 RPM and delivers excellent mid-range torque in my 418.
Perhaps the best you can hope for, when selecting a cam, is to find someone who's used a particular cam of interest in an application similar to yours, and ask them how it worked and what they'd do different. George's and Jvette73's posts, for example, are valuable in this regard.
-Noel
[Modified by Noel Carboni, 3:11 PM 2/18/2002]
Cam specs alone don't define a cam's behavior, though given a particular cam type and engine displacement they can give you some idea.
Cams come in "solid lifter", "hydraulic lifter", "hydraulic roller", and "solid roller" varieties (perhaps there are others, I dunno). The lifter type generally implies the shape of the valve event curve. Roller varieties tend to slap open and slam closed the valves faster, with steeper sides on the curve. Rollers generally need stiffer springs so these more violent valve events are kept under control.
There is also a matter of how cam specs are presented... Some cams durations are advertised as "off the seat", while others list 'duration at 0.050" lift'. These numbers cannot easily be compared, because they depend on the curve shape.
Overall cam lift is important. It defines how far open the valve is pushed, and the rocker arm geometry can affect this as well. Most cams advertise lift assuming the "stock" rocker arm ratio (i.e., 1.5:1 in a Chevy small block, if memory serves).
Another factor in determining how a cam will run is the lobe separation. In other words, the rotational relationship between the timing of the intake valve and exhaust valve opening. A wider lobe separation implies the exhaust valve will open later as compared to the intake valve, and will generally give better idle and mid-range torque.
Last but certainly not least, a given cam that might be considered wild for a small engine will run as though it were a milder one in a larger displacement engine.
For example, I have a solid-roller cam advertising 245/245 degrees duration at 0.050" lift, with 0.575/0.572 lift and 113 degree lobe separation. It probably has something like 290 degrees "off the seat" duration. This might be a really "wild" cam in a 350, but it actually idles pretty well down to about 800 RPM and delivers excellent mid-range torque in my 418.
Perhaps the best you can hope for, when selecting a cam, is to find someone who's used a particular cam of interest in an application similar to yours, and ask them how it worked and what they'd do different. George's and Jvette73's posts, for example, are valuable in this regard.
-Noel
[Modified by Noel Carboni, 3:11 PM 2/18/2002]
