Don't understand cams

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I guess you had better NOT call a cam manufacture either. THERE GIVING FREE ADVICE AS WELL!!!! :BangHead:

I guess your right, after all they will probably give me a bunch of options and then argue with themselves about each one being wrong. People are better off not giving advice if they are going to begrudge giving it out.
 
I guess your right, after all they will probably give me a bunch of options and then argue with themselves about each one being wrong. People are better off not giving advice if they are going to begrudge giving it out.

You keep lumping me into that pile and there'll be no need to send me a PM. I have NOT begrudged you a ******* thing. I am STILL trying to help you.
 
So tell me, who's advice was good yours or the person you claim was wrong. DUDE
I'm sorry that I wasted your time, asking for free advice, but if you don't want to share what you had to pay for, then why bother responding. I guess its like my poor old deceased Daddy used to say,
Advice is only as good as you pay for it.




DUDE, there IS more than one way to skin a cat. Just because I say I don't do something a certain way, it doesn't make that way wrong. Just DIFFERENT. I'm pretty secure in what I say because I have done it that way, and still do it that way. That doesn't make it the only way, or even the right way. Again, it's all about the combination. If I did your engine it would certainly be different that if others did it. How we get to the end product may be by different roads, but the end result is what counts.

I'll give you an example. I was building an engine for a customer. It was a 408 inch deal, with ported eddy heads, a custom Cam Motion HRT cam, 10.8:1 compression, T&D rockers, 1 7/8 headers and a Mallory ignition. I told the guy it would make 500 HP falling off a log. At that time I had never even seen a place like FABO. Hell, I didn't know they existed. Everyone on the web was telling him that if it made 425 HP to be happy. I said if that's all it makes, I'll smash it with a sledge hammer. All try keyboard builders hated most everything I did. By the way, FABO was not the site making the trouble.

Anyway, on a third party dyno, it made 565 HP, I forget the torque and it did it all by 5200 RPM. I sent the dyno sheets to the cam grinder, and they figured if we used a bit more cam, spun the engine to a modest 6000 RPM, it probably would have broke the 600 HP mark. But the customer didn't want to turn it "that tight".

My point is, other do the same thing, but with different parts etc.

The reality of all this is, while many of us don't agree on such minutiae as LSA, IVC how much compression you can actually run on pump gas and other stuff that guys who have been doing this crap for decades argue about, I think if you go back and look, we ALL agreed that the cam you posted was NOT for what YOU needed.

So, the cut of it all is that we did agree on what you asked. We did not necessarily agree on other cam timing events. But we did agree that that cam was JUNK, for YOU.


What I see in all this is guys of various experience, backgrounds and education levels did their very best to help you to understand a very difficult, extremely complex internal combustion engine component.

One more thing and then I'm DONE trying to help someone who again, is unwilling to READ what is being given to you, for FREE. You can call 10 different cam grinders, with exactly the same specs and get exactly 10 different sets of cam specs. All THEY all wrong? Nope. It's the same thing. They all have their ways, their understanding, their ways of conceptualizing of what the correct cam timing events SHOULD be. They are not all wrong, just different.


Go back through this thread and read the discussion that is happening. No one here is calling you stupid. No one here expects you to understand everything we wrote. Go read the links RRR posted. Then read this thread, again. You'll start picking the concepts out of all the fluff. It's there.

Your attitude is holding you back. I don't want to speak for the whole of FABO, but I will say no one posted in this thread to confuse you, belittle you or do anything of th sort but help you.
 
GO AHEAD AND LUMP ME INTO THAT PILE! I'M BECOMING EXACTLY WHAT YOU THINK I AM!!!!! :mob:
 
I guess your right, after all they will probably give me a bunch of options and then argue with themselves about each one being wrong. People are better off not giving advice if they are going to begrudge giving it out.


Who the hell begrudged you ANYTHING?

Your attitude blows dude. You are beyond helping.
 
Who the hell begrudged you ANYTHING?

Your attitude blows dude. You are beyond helping.
Reread post 139. he got all butt hurt because I told him that it took over 90 post to get all the info out of him to help.:realcrazy:
 
The information in post 139, had nothing to do with my original question. And to my point the real crazy gesture is just childish and not called for. OHH wait you guys don't belittle anyone. right.
 
I told you, i have become the guy you think i am!!!!!:mob:
 
I can understand Norton's frustration. Yes LOTS of good advice here. I was looking forward to reading and learning on this subject (and still will) I have quite a few engine performance books but havent read them all yet.
Ya gotta admit (or dont) this thread turned into a very high tech.pissing match fast!
Yes its free, most on the internet is.
 
RRR, he didn't look at the first 3 link you gave him. What make you think he will now...........

OK over my rant.
So you want a STock stock stock 72 340 rebuild. Buy a complete overhaul kit with piston and cam.
The End.
 
Yeah I can understand the frustration as well - people chiming in with somewhat complicated and lengthy discussions on the subject at hand... but not necessarily related to the original question.

This thread should have been over right about post 9 on page 1.

- boingk
 
There is no need to be frustrated. OP expected a simple answer ("can I use this cam... will it have a lumpy idle"), and that started the , err, discussion.

Quote of the day is again YR: 'You can call 10 different cam grinders, with exactly the same specs and get exactly 10 different sets of cam specs. All THEY all wrong? Nope. It's the same thing. They all have their ways, their understanding, their ways of conceptualizing of what the correct cam timing events SHOULD be. They are not all wrong, just different.'

As easy as that.
 
I know there was a lot that got frustrated, including the OP, with the heavy debate between YR and other. BUT! When someone decides, to do a search, and sees a title "
Don't understand cams
Someone who wants to understand cam better, THIS, WILL BE A THREAD WORTH CLICKING ON.
There was a lot of good, DEEP, information that was brought out. On how a cam works and why! For those that were/are interested, this IS a great thread.
There was several post that i printed off so that i could read a few more time to get the whole picture. There was vary good info and links, in this thread for those that wanted to learn.
 
Not long ago I actually queried Maxwell, a camshaft tech at Comp cams on the process of determining the right camshaft for any given engine combination.

Giving him the two opposing viewpoints as mentioned earlier in this thread as such

"One first of us believes that the camshaft technician Determines which duration and lobe separation figures specifically will be optimal. without looking specifically at valve timing event specifically unless trying to design on the ragged edge of detonation in a competitive racing application.

This person believes that the technician employs his knowledge and experience of the relationships which duration and lobe separation angle both have on an engine's performance in a variety of configurations and applications.

That valve timing events are incidental to duration and lobe separation angle. That Valve timing events are mostly used as a way to check or make sure that the finished camshaft is installed in the correct position relative to the crankshaft.


The second of us believes that instead, the technician will first determine all the optimum valve timing event numbers specifically. That the cam technician employs his knowledge and experience of altering each valve timing event and their relationship with an engine's performance in a variety of configurations and applications. That it is instead duration and lobe separation which are incidental, since they are only selected as a means of achieving the desired timing events.

Which parts did we get right?
Which parts did we get wrong?"

And his response was as follows.

"I can mainly speak about my methodology, which is shared by many at COMP(I was taught by the best). I have been at this for almost 14 years, so I believe I can speak with some experience.

You are both right to an extent. The first guy is more correct for choosing a cam on a fresh engine combination.
Once an engine combination has been run with a specific camshaft, then the second approach can be taken to taylor and improve the performance.

It is pretty difficult to explain to an outsider. The only way to get really good at camshaft design is to work at a camshaft company. After full immersion for 8 hours a day for a number of years, duration and lobe separation angle numbers come to mind automatically. It's kind of like becoming fluent in a second language.

Once, I decide on duration, then I will search for a lobe with the proper amount of lift to accommodate the cylinder head flow, and valve spring package. Also, the aggressiveness of the lobe must taken to account depending on the engine's application. For instance, a softer, smoother lobe must be used for an endurance application. On the other hand, a heads-up drag racing class where every last horsepower counts would require very aggressive profiles.

I hope that helps answer your question."

So there you have it, some expert insight into the process and methodology of determining the correct camshaft for a given application.
 
the aggressiveness of the lobe must taken to account depending on the engine's application. For instance, a softer, smoother lobe must be used for an endurance application.

This is an interesting spec that up until recently I used to neglect. You may see 2 cams with identical specs. Check the specs at .020 and compare them. If the cam has the same duration at .050 but one has more at .020, that cam has a more aggressive lobe or ramp angle.
 
You may see 2 cams with identical specs. Check the specs at .020 and compare them. If the cam has the same duration at .050 but one has more at .020, that cam has a more aggressive lobe or ramp angle.

Wouldn't the one with a smaller .020 duration have a steeper, more aggressive angle if the .050 numbers were the same?
 
Wouldn't the one with a smaller .020 duration have a steeper, more aggressive angle if the .050 numbers were the same?


The best way to see how agressive a lobe is, other than a cam doctor or spending time with a degree wheel, is to look at the seat timing numbers, the @.050 number and the @.200 number. Most of the time, you don't get the .200 number but you can ask for it.

I have a cam now that is seat to seat 281*. The @ .050 is 255* and I can't remember the .200 off the top of my head, but it's a fairly fast lobe. So my example sucks because I can't remember the .200 number.

Anyway, if you don't have the .200 number, you can look at the the other two numbers and get a feel for how fast the ramp it.

An example of that is to find a Chrysler lobe that has 255*@.050 you would have to have about 300* of seat timing. My lobe is 19*'s faster just to .050.
 
Someone who wants to understand cam better, THIS, WILL BE A THREAD WORTH CLICKING ON.
There was a lot of good, DEEP, information that was brought out. On how a cam works and why! For those that were/are interested, this IS a great thread.

23266068.jpg
 
Fast lobes on a streeter a pretty good deal too


I guess, I actually chose my cam with a slightly slower lobe because it was for a primarily street car. 2 identical roller cams with exception to the ramp angle.
 
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