!!!!!CALLING CAM EXPERTS!!!!!

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duster360

duster360

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Curious about something. Seems most performance cams are ground on a 110* lobe separation, some even tighter. Generally they have a very lopey idle. Let’s say we have a cam ground on a 110* lsa, 240ish duration at .050 and .570 lift at the valve. Let’s say I have a cam ground with exactly the same duration and lift, but changed the LSA to 112* or even 114* for smoother idle and better vacuum. What would happen? Lose power? Any other side effects?
 
From what these guys say here is that changing the LSA to 114 gives more mid range torque. It is what Chevy does with their well-sorted out LS engines with closed chambers, roller cams, and high flow heads
 
I might be wrong but the tighter LSA gives the torque curve on the dyno more of a peak. Maybe more initial torque from idle as well. I think the timing between the intake/exhaust valves open/close is more crucial for pressure/max charge
 
I would expect that the typical or generic mentality of average cam companies is that the average consumer wants some lump in their idle, to show off their car/engine/build. The tight LSA's serve that function-despite whatever the cam was designed for in rpm range. The most dedicated to power members of FABO are adamant about getting a custom grind for just a few dollars more for those last pounds of torque and few horses -for ANY build. The FABO guys want the build info too though, gear ratio in the axle, car weight, car usage, engine stroke, bore, heads, induction...
 
With 240 or 250 @ .050", you're gonna have a lope no matter what.
 
112 lsa will give more low-end torque. 112 is a good all around street lsa. And will perform well at the track also. That's what I have read in just about any performance cam articles. Depends on what your gonna due with the vehicle. This is one of those questions you ask 5 different people . you will have 5 different answers.
 
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Any cam question or recommendation will have 5 people give 5 different answers.

A lower number, say a 106 vs a 110 will show more top end pop. This is desirable at the end of a drag race to edge out your competitors. M
There has been a move recently to a wider 112 or 114 for getting off the line better. Being first out is the idea and trying to stay there to fend off the top end charge of the 106 line cam car.

All else being equal, some feel this is the way to go. Now matter which way you choose, Max it out for that thought train.
 
The cam I actually had ground for my 512 build b block Trick Flow 270 head 10.3 comp motor is a cam motion cam. He ground it to my specification to the tee. It's a solid roller .674 lift 296 duration ground on a 112 lsa. With a 1.6 rocker. 72 dart full car. Ss springs. Assssin bars. 5500 stall from jw performance. Pump gas motor plan on running in the 9's with it in the 1/4 6.30 or so 1/8 . plus drive this dude as often as I can . work / play / travel to some car shows. And do some street racing.
 
Rmoore said:
The cam I actually had ground for my 512 build b block Trick Flow 270 head 10.3 comp motor is a cam motion cam. He ground it to my specification to the tee. It's a solid roller .674 lift 296 duration ground on a 112 lsa. With a 1.6 rocker. 72 dart full car. Ss springs. Assssin bars. 5500 stall from jw performance. Pump gas motor plan on running in the 9's with it in the 1/4 6.30 or so 1/8 . plus drive this dude as often as I can . work / play / travel to some car shows. And do some street racing.
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So if this car doesn't run what I think it should !! Well I pointing the finger of the cam designer on this dude. I'm pointing the finger at him. Cause when you point your finger at someone you got four more fingers pointing back a me !!
 
greymouser7 said:
I would expect that the typical or generic mentality of average cam companies is that the average consumer wants some lump in their idle, to show off their car/engine/build. The tight LSA's serve that function-despite whatever the cam was designed for in rpm range. The most dedicated to power members of FABO are adamant about getting a custom grind for just a few dollars more for those last pounds of torque and few horses -for ANY build. The FABO guys want the build info too though, gear ratio in the axle, car weight, car usage, engine stroke, bore, heads, induction...
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When I get my cam custom ground it's for many dollars less than buying one new.
I think most people have in their head that a custom grind is going to cost more when reality is the cam is already there, it just gets reground and doesn't cost much.
 
^^^^also you get to talk to the custom cam grinder. He probably does this 50 times a day for hundreds of different applications. With 20-30 or more years experience....
my last comment on this is to call an expert and NOT call on a bunch of Knuckleheads for 10, 000 different answers LOL
 
duster360 said:
Curious about something. Seems most performance cams are ground on a 110* lobe separation, some even tighter. Generally they have a very lopey idle. Let’s say we have a cam ground on a 110* lsa, 240ish duration at .050 and .570 lift at the valve. Let’s say I have a cam ground with exactly the same duration and lift, but changed the LSA to 112* or even 114* for smoother idle and better vacuum. What would happen? Lose power? Any other side effects?
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David Vizard has an excellent book called "How To Build Horsepower" that covers LSA as well as all the other areas of camshafts and how it affects an engines characteristics. He's just one source (of many) for in depth theory and testing that backs it up and if you were going to educate yourself to make your own choice it might be worth a look into some of his writings. I've been reading his stuff for 35 years and applying what I can, and chose my cams specs based on his various formulas. The companies I called when looking for a cam for my stroker spec'd LSA's of 110-112. Using the Vizard theory and formulas as applied to my build pointed to a 106LSA so that's the route I went. Otherwise, why buy the books if I wasn't going to apply the teachings?:rolleyes: And I like the explosive power and lumpy sound of the 106 :lol:
 
A couple more side effects for the OP:
  • Wider LSA gives for fuel mileage. Narrower LSA with more overlap allows more unburned fuel to go right out the exhaust at the lower RPM's.
  • Wider torque band applications also call for a wider LSA.
  • Turbo engines are usually better off with a wider LSA to get a better peak pressure on the exhaust pulse, which can help the get the turbo spooled up at a lower RPM
 
j par said:
^^^^also you get to talk to the custom cam grinder. He probably does this 50 times a day for hundreds of different applications. With 20-30 or more years experience....
my last comment on this is to call an expert and NOT call on a bunch of Knuckleheads for 10, 000 different answers LOL
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Well yes and no.. I emailed Jones cams on their form with very complete info on engine and application, plus what I was looking to do application-wise, and got a cam grind anyone would have picked out of a catalog. When I asked a straightforward question, I got no answer. Not impressed at all.

To be fair, I'll give it a few more shots with other custom grinders and will hope for a better outcome, but I know far more about cams from direct experience, readings, and by reading posts by experienced 'knuckleheads' like here on FABO.
 
I learned it like this... Camshafts with tighter LSA numbers like a 106 or 108 are used when you want a tighter, narrow powerband, where peak torque occurs earlier in the powerband. A good example of an application for this would be a circle track car that needs to drive off the corner as quickly as possible. Generally speaking the tighter the LSA is, the peakier the powerband and torque curve will be. Wider LSA's, like 122 -116 degrees will result in a flatter torque curve, with peak torque occuring at a higher RPM. They also have a much smoother idle, and are good for engines using some form of boost. Lots of times a pro stock car will use a wider LSA cam to help control traction early in the run.
 
Garry in AZ said:
I learned it like this... Camshafts with tighter LSA numbers like a 106 or 108 are used when you want a tighter, narrow powerband, where peak torque occurs earlier in the powerband. A good example of an application for this would be a circle track car that needs to drive off the corner as quickly as possible. Generally speaking the tighter the LSA is, the peakier the powerband and torque curve will be. Wider LSA's, like 122 -116 degrees will result in a flatter torque curve, with peak torque occuring at a higher RPM. They also have a much smoother idle, and are good for engines using some form of boost. Lots of times a pro stock car will use a wider LSA cam to help control traction early in the run.
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Gotta agree with this for sure.
 
I have found that a wider LSA kills 60 foot times compared to say a similar cam ground on a 108.
Wider also likes more compression, and might make more mph.
The above on a typical 5k stall bracket race motor
 
I noticed a lot of old school Crane cams are like that. Even if the cam is on the smaller side, they have wider LSA’s and call for 12-1 ratios.
 
nm9stheham said:
Well yes and no.. I emailed Jones cams on their form with very complete info on engine and application, plus what I was looking to do application-wise, and got a cam grind anyone would have picked out of a catalog. When I asked a straightforward question, I got no answer. Not impressed at all.

To be fair, I'll give it a few more shots with other custom grinders and will hope for a better outcome, but I know far more about cams from direct experience, readings, and by reading posts by experienced 'knuckleheads' like here on FABO.
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Give Ken the owner of Oregon cam grinding a call. No computer necessary no waiting time just call him and say hello he's an old-school guy who will talk to you. If he's not there leave a message and he'll call you back. I doubt there's an online application but there could be. I know there's a website. I know he has one other employee that may answer the phone. but it's not like calling Comp Cams or something like that where you're going to get one of ten thousand employees giving you some generic anwser..
 
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