Single or Dual Pattern Cam

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The problem with the other 45 "318 cam" threads is that they all come to the same ridiculous conclusions:

1- use the stock .400 lift cam because nothing is better unless-

2- use a .500-.600 lift cam with .300 duration and get 4.56 gears and a 3500 converter or-

3- build a stroked 360 with a solid roller instead.


Seems like for any other displacement, there are threads with comprehensive analysis that lead to 3 or 4 good choices.

We had one 318 cam thread with some promise where a couple of very knowledgeable members started to do that type of analysis but for some reason it just stopped.

Although I have no experience with either and can't crunch the numbers to tell anyone why the math works or doesn't work with a stock or basically stock 318 setup (maybe assuming dual exhaust and a 600 CFM 4 BBL), my money is on either the Comp "256" XE (or Lunati equivalent) or the Summit 690x (which ever is the lower lift, split pattern).

So far the only real analysis I've gotten from members on those is that "they are smaller than the stock 340 cam", which is actually a positive, sine the 318 is a smaller displacement engine. My addition to that would be that AFAIK, both cams I mentioned are "more modern" grinds.
 
YY1 said:
The problem with the other 45 "318 cam" threads is that they all come to the same ridiculous conclusions:

1- use the stock .400 lift cam because nothing is better unless-

2- use a .500-.600 lift cam with .300 duration and get 4.56 gears and a 3500 converter or-

3- build a stroked 360 with a solid roller instead.


Seems like for any other displacement, there are threads with comprehensive analysis that lead to 3 or 4 good choices.

We had one 318 cam thread with some promise where a couple of very knowledgeable members started to do that type of analysis but for some reason it just stopped.

Although I have no experience with either and can't crunch the numbers to tell anyone why the math works or doesn't work with a stock or basically stock 318 setup (maybe assuming dual exhaust and a 600 CFM 4 BBL), my money is on either the Comp "256" XE (or Lunati equivalent) or the Summit 690x (which ever is the lower lift, split pattern).

So far the only real analysis I've gotten from members on those is that "they are smaller than the stock 340 cam", which is actually a positive, sine the 318 is a smaller displacement engine. My addition to that would be that AFAIK, both cams I mentioned are "more modern" grinds.
Click to expand...
:lol::lol:

theyre-right-you-know.jpg
 
YY1 said:
The problem with the other 45 "318 cam" threads is that they all come to the same ridiculous conclusions:

1- use the stock .400 lift cam because nothing is better unless-

2- use a .500-.600 lift cam with .300 duration and get 4.56 gears and a 3500 converter or-

3- build a stroked 360 with a solid roller instead.


Seems like for any other displacement, there are threads with comprehensive analysis that lead to 3 or 4 good choices.

We had one 318 cam thread with some promise where a couple of very knowledgeable members started to do that type of analysis but for some reason it just stopped.

Although I have no experience with either and can't crunch the numbers to tell anyone why the math works or doesn't work with a stock or basically stock 318 setup (maybe assuming dual exhaust and a 600 CFM 4 BBL), my money is on either the Comp "256" XE (or Lunati equivalent) or the Summit 690x (which ever is the lower lift, split pattern).

So far the only real analysis I've gotten from members on those is that "they are smaller than the stock 340 cam", which is actually a positive, sine the 318 is a smaller displacement engine. My addition to that would be that AFAIK, both cams I mentioned are "more modern" grinds.
Click to expand...

Building a 340 - 360 is fairly straightforward. 273 -318 are not that's why these threads go on forever and comes up with no conclusion but also why they get more views.

!st problem should build a 360 crowd starts and cause that argument, thing is their right but if someone wants to do a 318 there a very capable engine and that's their choice.

2nd is most are just looking for mild cam 4bbl and exhaust which your recommends are perfect, but you get not enough cr and displacement crowd talking them out of any mod.

3rd is if you want more power than the 2nd will provide, you got to do something about the heads and cr which most want to do on the cheap so it becomes a problem.

4th way is to build like it's a 340, with a little more gear and stall, which it becomes a pretty straightforward build.


And to the OP if this is for a 318 why the 108 lsa??
 
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Hmm, I thought I was posting in the most recent 318 cam thread.

I stick to my statements, though.
 
273 said:
Building a 340 - 360 is fairly straightforward. 273 -318 are not that's why these threads go on forever and comes up with no conclusion but also why they get more views.

!st problem should build a 360 crowd starts and cause that argument, thing is their right but if someone wants to do a 318 there a very capable engine and that's their choice.

2nd is most are just looking for mild cam 4bbl and exhaust which your recommends are perfect, but you get not enough cr and displacement crowd talking them out of any mod.

3rd is if you want more power than the 2nd will provide, you got to do something about the heads and cr which most want to do on the cheap so it becomes a problem.

4th way is to build like it's a 340, with a little more gear and stall, which it becomes a pretty straightforward build.


And to the OP if this is for a 318 why the 108 lsa??
Click to expand...
The tighter lsa is good for low to midrange torque. From what I've read and heard, a 112* lsa is to wide. A few guy's on here have recommended a lsa of under 110. I just read last night that a 108-109 lsa is highly recommended for low to midrange torque
 
Here’s a David Vizard method of selecting LSA: Engine C.I./8/Intake valve diameter = X

Example:

318/8 = 39.75

39.75/1.92 = 20.70

20.70 on the graph shows: 109 LSA

In his books he recommends rounding up if it falls somewhere in between The more common even numbered LSA’s

1ADCEE9B-831F-40AE-B353-AC8D04870DD9.jpeg


Change around with cubic inches and intake valve diameters can you can see the various LSA’s It comes up with. Obviously there’s more to it, but if you read some of his books and his theories on camshaft selection it all makes sense
 
12many said:
Here’s a David Vizard method of selecting LSA: Engine C.I./8/Intake valve diameter = X

Example:

318/8 = 39.75

39.75/1.92 = 20.70

20.70 on the graph shows: 109 LSA

View attachment 1715832459

Change around with cubic inches and intake valve diameters can you can see the various LSA’s It comes up with. Obviously there’s more to it, but if you read some of his books and his theories on camshaft selection it all makes sense
Click to expand...

Do you have the isbn numbers for the book? Id love to buy a copy to read.
 
Dan the man said:
The tighter lsa is good for low to midrange torque. From what I've read and heard, a 112* lsa is to wide. A few guy's on here have recommended a lsa of under 110. I just read last night that a 108-109 lsa is highly recommended for low to midrange torque
Click to expand...

This is true but what powerband you plan in operating in ?

Aka street motor
Idle - 5000 rpm
hot street engine
1500-5500 rpm
Street strip
2000-6000 rpm
2500-6500 rpm
Race anything above
 
Dan the man said:
The tighter lsa is good for low to midrange torque. From what I've read and heard, a 112* lsa is to wide. A few guy's on here have recommended a lsa of under 110. I just read last night that a 108-109 lsa is highly recommended for low to midrange torque
Click to expand...

That's generally true, but the amount of overlap changes with duration. That's why many members say 'lsa doesnt matter' - because with the same LSA, but a 20 degree difference in duration, you'll have 20 degrees more overlap... Focus on the Ica (intake closing angle) which will determine your dynamic compression, and secondly on the amount of overlap. Too much overlap will soften the low end too much.

I would recommend reading this.

After that, I would seriously consider a Howards 255/261 cam - it's ground on 110, but should be stout with headers, an airgap intake, and 3.2+ gearing, even with a stock trans/converter. I also would assume a solid 9.5-10:1 compression with a zero-deck piston in order to overcome the later closing angle of the intake valve. Otherwise it's going to need even more advance than the 4degrees they recommend.
 
Dan the man said:
I'll research on what cam I need for my application, then I'm going to contact the cam company and see what compression ratio I need to get the best performance from the cam. If need be I'll ask the cam company about a custom grind cam.
Click to expand...
With a 318 this is backwards. You don't have a lot of options when it comes to compression ratios without spending piles of money.
If your pockets are deep, then you can follow the usual protocols, and make a darn nice streeter. But it won't be budget friendly.
 
I read the entire thread and I still don't know anything about the engine, operating elevation, the car, the gears, trans, tires, stall; the budget, the must-haves, the don't care abouts, and what's that ugly thing under the back seat
 
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AJ/FormS said:
I read the entire thread and I still don't know anything about the engine, the car, the gears, trans, tires, stall; the budget, the must-haves, the don't care abouts, and what's that ugly thing under the back seat
Click to expand...

crystal ball.jpg
 
Dual pattern cam. Best with a restrictive exhaust? Correct me if I'm wrong.
 
Dan
Look up in the top right corner of any thread that you have open. There you will see your name. Click on it and find "signature"; click on that. Anything you type in that dialog box will appear at the bottom of every post in every thread you ever wrote or ever will.
I got an idea, howbeit you tell us about your car in that box. You can even go back and make changes any time you want.
And you'll never have to keep on telling everyone of us one atta time, what we're working on. I'm pretty sure this will cut out out dozens of chit-chat posts.
Dan you can even put some of it in your Avatar under your picture.
Look at my Avatar and My signature, and see what I mean.
 
toolmanmike said:
Dual pattern cam. Best with a restrictive exhaust? Correct me if I'm wrong.
Click to expand...
Mike Jones once spec’d me a single pattern cam when using headers, single plane intake, etc but when I gave him my option “B” build with a dual plane and slightly lower max power rpm (all else the same) he cam back with a dual pattern. So......
 
toolmanmike said:
View attachment 1715832657
Click to expand...
Hey man, fill that thing about 45 % with water, toss in some heavy rocks or sand, and small floating mats, then stick the whole thing in your kitchen sink and fill the sink with water until just before the sphere wants to float. Does that remind you of anything?
 
...and once again, no one mentions that 67 to 69 and 83-ish to 91 are 9.2:1 compression from the factory (with the 83 and up LA roller blocks being pretty close to advertised) while the 71-ish to 83-ish are supposedly 8.8:1 but likely lower.

My guess would be putting in a factory replacement LA roller piston would get you more squeeze, although I don't know how much the closed chambered 302 heads accounted for.
 
273 said:
Building a 340 - 360 is fairly straightforward. 273 -318 are not

4th way is to build like it's a 340, with a little more gear and stall, which it becomes a pretty straightforward build.


And to the OP if this is for a 318 why the 108 lsa??
Click to expand...
Smaller engine respond *better* to a wider LSA.
(*street-street/strip, in certain parameters)
Building a 273/318-318 for this discussion, is straight forward. Building it like a 340 is fine for the most part. Certain caveats apply.

Dan the man said:
The tighter lsa is good for low to midrange torque. From what I've read and heard, a 112* lsa is to wide. A few guy's on here have recommended a lsa of under 110. I just read last night that a 108-109 lsa is highly recommended for low to midrange torque
Click to expand...
Normally speaking a tighter LSA will make more low end torque and peak earlier in HP.
12many said:
Here’s a David Vizard method of selecting LSA: Engine C.I./8/Intake valve diameter = X

Example:

318/8 = 39.75

39.75/1.92 = 20.70

20.70 on the graph shows: 109 LSA

In his books he recommends rounding up if it falls somewhere in between The more common even numbered LSA’s

View attachment 1715832459

Change around with cubic inches and intake valve diameters can you can see the various LSA’s It comes up with. Obviously there’s more to it, but if you read some of his books and his theories on camshaft selection it all makes sense
Click to expand...
Thank you!!!

toolmanmike said:
Dual pattern cam. Best with a restrictive exhaust? Correct me if I'm wrong.
Click to expand...
Correct. But also, the extra exhaust extends the power band. How much and how long are completely build dependent.
 
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