wide lobe center vs narrow

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wide lobe center vs narrow

Post  cheatham on October 4th 2010, 2:02 pm

I've been wondering what the advantage is to a wide lobe center, say 112 vs 110 or 108 ? Talked to Blake before and I think he said the factory iron heads seem to like a narrower lobe center. What does a wider lobe center do for you and in what application would someone consider it ?
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Re: wide lobe center vs narrow

Post  The Pope on October 4th 2010, 3:28 pm

From CompCam's site. http://www.cpgnation.com/forum/comp-cams-top-10-tech-faqs-3773.html

4. What is the difference between different Lobe separations?

Tighter lobe separation tends to narrow the power band and typically increase the peaks. Tighter separation will also increase cylinder pressure and increase bottom end torque. Narrow also reduces piston to valve clearance, hence too narrow creates many issues with fitment. Also, narrow will decrease engine vacuum at idle and may cause issues with misfire. And, wider lobe separation will do the opposite of the points on tighter separation.

Lobe Separation = (Intake Centerline + Exhaust Centerline)/2
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Re: wide lobe center vs narrow

Post  Lem Evans on October 4th 2010, 7:43 pm

cheatham wrote:I've been wondering what the advantage is to a wide lobe center, say 112 vs 110 or 108 ? Talked to Blake before and I think he said the factory iron heads seem to like a narrower lobe center. What does a wider lobe center do for you and in what application would someone consider it ?
1] If you have talked to Blake about this you already know what you need to know.
2] A wide lsa takes overlap out of the cam timing. Less overlap [with smaller cams] is good for drivablity and produces more vacuum for power brakes etc. As strange as it seems it is used in racey high compression engines that demand bigger/high duration lobes.....the huge duration cams need a wider lsa too keep the overlap within a exceptable range.
3] Because of mechanical things in certian cyl. heads..........one cam does not serve all cyl. heads the same.

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Re: wide lobe center vs narrow

Post  cheatham on October 4th 2010, 9:47 pm


[/quote]
1] If you have talked to Blake about this you already know what you need to know.
2] A wide lsa takes overlap out of the cam timing. Less overlap [with smaller cams] is good for drivablity and produces more vacuum for power brakes etc. As strange as it seems it is used in racey high compression engines that demand bigger/high duration lobes.....the huge duration cams need a wider lsa too keep the overlap within a exceptable range.
3] Because of mechanical things in certian cyl. heads..........one cam does not serve all cyl. heads the same.[/quote]

I'm just now starting to get a grasp on this, probably gonna have to read this a few more times.
Thanks Pope. Thanks Lem.
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Re: wide lobe center vs narrow

Post  cool40 on October 4th 2010, 11:51 pm

i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
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Re: wide lobe center vs narrow

Post  jm on October 5th 2010, 2:58 pm

one thing i have noticed and tryed, is that when you stroke your BBF, it will like a wider lsa. Neutral wheather you use iron heads or not. the beauty of the torque of the BBF Smile

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Re: wide lobe center vs narrow

Post  cool40 on October 9th 2010, 12:14 am

cool40 wrote:i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
now i know how it worked.i went from a 278/292@.050-807/814 on 112 to 270/276@.050-722/722 on 108.it's not realy apples to apples but i can say the torque realy picked up but the rpm and mph went to hell. Very Happy
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Re: wide lobe center vs narrow

Post  richter69 on October 9th 2010, 12:23 am

cool40 wrote:
cool40 wrote:i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
now i know how it worked.i went from a 278/292@.050-807/814 on 112 to 270/276@.050-722/722 on 108.it's not realy apples to apples but i can say the torque realy picked up but the rpm and mph went to hell. Very Happy



the numbers on the last one is what we run in our 306"............but with only .600 lift lol.
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Re: wide lobe center vs narrow

Post  cool40 on October 9th 2010, 12:46 am

richter69 wrote:
cool40 wrote:
cool40 wrote:i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
now i know how it worked.i went from a 278/292@.050-807/814 on 112 to 270/276@.050-722/722 on 108.it's not realy apples to apples but i can say the torque realy picked up but the rpm and mph went to hell. Very Happy



the numbers on the last one is what we run in our 306"............but with only .600 lift lol.
that should work on a 306.lol it wont turn a dam lick over 6800 in my 526! realy done at 6500.it does make a slick tnt track hard to work with Laughing it did muster a 5.74 spinnen bad and then i had other problems with fuel and only got worse.fucken waste of time realy.this fuel i tried made my plugs yellow?and made my shit slow down 2 tenths.i think it was c25?or some shit.
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Re: wide lobe center vs narrow

Post  richter69 on October 9th 2010, 11:18 am

quit f-ckin with the gas if its not what your gonna run lol.
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Re: wide lobe center vs narrow

Post  rmcomprandy on October 9th 2010, 2:16 pm

For some reason, most people just seem to forget all about the exhaust side as if it doesn't exist.
On anything but, a smaller street type camshaft, it ALL plays a part in how an engine combination will act as "lobe seperation" is merely a tuning tool to get the other valve events close to the places which will be correct..

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Re: wide lobe center vs narrow

Post  J.Toney on August 23rd 2015, 12:14 pm

Bump for some good basics insight.
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Re: wide lobe center vs narrow

Post  rmcomprandy on August 23rd 2015, 7:09 pm

cool40 wrote:
cool40 wrote:i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
now i know how it worked.i went from a 278/292@.050-807/814 on 112 to 270/276@.050-722/722 on 108.it's not realy apples to apples but i can say the torque realy picked up but the rpm and mph went to hell. Very Happy

Almost a hundred thousandths in valve LIFT probably had a little something to do with it.

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Re: wide lobe center vs narrow

Post  cool40 on August 23rd 2015, 8:49 pm

rmcomprandy wrote:
cool40 wrote:
cool40 wrote:i just went back to a smaller cam with a 108 and will know soon how it works out. Suspect
now i know how it worked.i went from a 278/292@.050-807/814 on 112 to 270/276@.050-722/722 on 108.it's not realy apples to apples but i can say the torque realy picked up but the rpm and mph went to hell. Very Happy

Almost a hundred thousandths in valve LIFT probably had a little something to do with it.
after flowing the heads it was more obvious. I remember the peak number was 363?? Been 5years ago so......
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Re: wide lobe center vs narrow

Post  res0rli9 on August 23rd 2015, 9:50 pm

Think I can hear Randy's or Lem's phone Ringing. Smile

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Re: wide lobe center vs narrow

Post  Mark Laczo on August 24th 2015, 8:28 am

cool40 wrote:after flowing the heads it was more obvious. I remember the peak number was 363?? Been 5years ago so......

I am gonna guess that you had pretty well out of the box Ford motorsport A460 heads on that 526" ? What did you end up going with on the cam deal ?

I am considering a similar cam change the other way around.
500" w/A460's out of the box flow was 360ish @ .800"
Current cam is .735" int & exh 276/286 on a 108.

Got heads ported this spring and now flow 440 @ .800" switched from 1.73 rockers to 1.80 also(.030" increase in vlv lift) and knocked off .15 sec in the 1/8.

Got this cam sitting on shelf .814" Int .780" exh 277/290 on a 112.

I wonder if this will pick up another 1/10th or so ??

Mark
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Re: wide lobe center vs narrow

Post  cool40 on August 24th 2015, 9:12 am

Mark Laczo wrote:
cool40 wrote:after flowing the heads it was more obvious. I remember the peak number was 363?? Been 5years ago so......

I am gonna guess that you had pretty well out of the box Ford motorsport A460 heads on that 526" ? What did you end up going with on the cam deal ?

I am considering a similar cam change the other way around.
500" w/A460's out of the box flow was 360ish @ .800"
Current cam is .735" int & exh 276/286 on a 108.

Got heads ported this spring and now flow 440 @ .800" switched from 1.73 rockers to 1.80 also(.030" increase in vlv lift) and knocked off .15 sec in the 1/8.

Got this cam sitting on shelf .814" Int .780" exh 277/290 on a 112.

I wonder if this will pick up another 1/10th or so ??

Mark
I did port the heads and get them to flow 420 range. I also cut them .100 and changed Pistons to a small dome from a flat top. I didn't run it with the smaller cam but put the 112 back in and it ended up making pretty good power. I found that the fuel system may have been inadequate as the switch to alky injection picked up more et than anything I did to it.
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Re: wide lobe center vs narrow

Post  Straubtech on August 31st 2015, 6:50 pm

Lobe Sep is a sum of numbers. If the events and lobe area are correct the LSA is what it is.

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Re: wide lobe center vs narrow

Post  rmcomprandy on August 31st 2015, 6:58 pm

Mark Laczo wrote:
cool40 wrote:after flowing the heads it was more obvious. I remember the peak number was 363?? Been 5years ago so......

I am gonna guess that you had pretty well out of the box Ford motorsport A460 heads on that 526" ? What did you end up going with on the cam deal ?

I am considering a similar cam change the other way around.
500" w/A460's out of the box flow was 360ish @ .800"
Current cam is .735" int & exh 276/286 on a 108.

Got heads ported this spring and now flow 440 @ .800" switched from 1.73 rockers to 1.80 also(.030" increase in vlv lift) and knocked off .15 sec in the 1/8.

Got this cam sitting on shelf .814" Int .780" exh 277/290 on a 112.

I wonder if this will pick up another 1/10 or so ??

Mark  

Maybe not a whole tenth however, if the flanks have similar aggressiveness ... it WILL help horsepower.
The question becomes whether or not your vehicle can take advantage of it.

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Re: wide lobe center vs narrow

Post  Lem Evans on August 31st 2015, 7:35 pm

The "LSA" in and of it's self does not mean much unless one is using the same intake and exh. lobes. , which is the context of most of my statements.

Changing the LSA does change the 'events' ....no shit Sherlock Smile

Given the same lobes and a package that does work very well, small changes to the installed icl, lash and lsa are very good tools.  

It almost sounds like a pencil can tell an engine how to perform...foot brake, trans brake, 2,100# or 3,700#, 1/4 mile or a 150 ft. pit....LSA does matter given the same lobes.

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Re: wide lobe center vs narrow

Post  Straubtech on September 1st 2015, 9:27 am

Lem Evans wrote:The "LSA" in and of it's self does not mean much unless one is using the same intake and exh. lobes. , which is the context of most of my statements.

Changing the LSA does change the 'events' ....no shit Sherlock Smile

Given the same lobes and a package that does work very well, small changes to the installed icl, lash and lsa are very good tools.  

It almost sounds like a pencil can tell an engine how to perform...foot brake, trans brake, 2,100# or 3,700#, 1/4 mile or a 150 ft. pit....LSA does matter given the same lobes.

I'll stand by the statement that LSA is meaningless..... A sum that is it. It's one of the numbers that cam companies have selected to "market cams" to the customers.

Lash is the most important tuning tool in the tool box. It will tell you what the engine is wanting. Advancing or retarding the cam will also. Now if you have to change lash and move the cam around too much then that also tells you the cam is not correct for the engine

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Re: wide lobe center vs narrow

Post  gt350hr on September 1st 2015, 12:30 pm

We all have our own way of doing things , that doesn't mean it's wrong.

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Re: wide lobe center vs narrow

Post  Straubtech on September 1st 2015, 12:49 pm

gt350hr wrote:   We all have our own way of doing things , that doesn't mean it's wrong.

We are all individuals your correct.

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Re: wide lobe center vs narrow

Post  supervel45 on September 1st 2015, 6:47 pm

So a cam with a 106LSA will run as good with a SuperCharger or Nitrous as one with a 114LSA with the same static compression ratio?

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Re: wide lobe center vs narrow

Post  Straubtech on September 1st 2015, 7:10 pm

supervel45 wrote:So a cam with a 106LSA will run as good with a SuperCharger or Nitrous as one with a 114LSA with the same static compression ratio?

The events and lobe area are determined by the build and rpm desired rpm range of power. The LSA is a result of what is needed in the timing events and lobe area.

Blower cams one need to pay attention to where the piston is and always think about how can I "help" it.

NOS cam, that's a Unicorn. Do nothing different until NOS levels being used are over 500HP capability and at this level it is about EVO.

The greatest Marketing Campaign in this industry by far has been that of NOS Cams. I can remember in the late 80's when the 5.0 Mustangs were being sold to the secondary market and guys were bolting on stock 75 to 150HP plate kits and putting 5.7 IROCs in the LOOSER bracket every week at Ohio Valley. I think back and said damn those Ford Engineers in the late 70's were really smart to know that some guy would have a plate NOS system in the mid 80's and that the little 302 with its 600 Holley needed to have a NOS friendly hyd roller cam in it.

I think the Marketing guy at a cam company in Memphis was the smart one when he said...we need a NOS Cam Line.

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