Re: Aluminum heads
 

Big,
I agree. I was addressing GPM's question on what will happen and I get drug into a confrontation. I appologize to the board. I addressed GPM's question with what I know is fact. I deal with top engine builders everyday in all realms of motorsport. Each a different sport that the engine is intended to help win but a commonality among all engines; Each is designed to make power within a certain rpm range of running. And each motorsport has participants that are passionate about what they as does any other sport, so I think referring to another "go fast" motorsport that there participants are "circle jerks" is really uncalled for.

Chris

Re: Aluminum heads
 

Hi Chris,

Thanks for the link... :p

Bill,

I'm in your neck of the woods. Say we get together and I'll explain how things work in the real world of engine building? You say you are an engine builder correct? Well then, how can you not know that E/I ratio is very key in the design of any camshaft profile? The camshaft is the brain of the engine and not knowing how to use all the information available to design one is just poor service to a customer!

Every camshaft designer, (short of the 1-800 telephone people) will ask for things like flow figures and other "cylinder head/intake manifold/exhaust system" information in order to make a proper decision. If they don't, then a consumer should look elsewhere for their custom engine or stick to "crate" engines. (and their "crate" performance)

Some engine builders may or may not agree with the "catalog" pieces and their configurations but they do ask the right questions if they are top shelf people.

Here's just one of the forms I ask for my customers to fill out along with a few other "cam people" that ask similar questions. These I found find pretty quickly too so anyone with a computer can do the same. The last one is even a competitor of mine in the Ford market yet he still has a "form" to fill out...;)

Makes for some good reading....

Cam Form

Elgin

Comp Cams

Crane

Lunati

Camshaft Innovations

Also ask for a catalog from people like Reed, Isky, Crower and others. In their "hard copy" catalogs, there are forms to fill out. See a trend here?

What Chris has stated is fact. The references he provided are valid people in this industry, Pick up the telephone and ask them.

Ed

Re: Aluminum heads
 

Sorry, we kind of drifted off the subject. You might want to look at the flow numbers on several brands before making a decision. Match the head flow to the potential of your cubic inch.

Re: Aluminum heads
 

Sorry guys didn't mean to start a war. I was just thinking about trying another cam. Thought I might try something a little different.

Re: Aluminum heads
 

No matter what I may say, or what my experience is, it will not matter to Bill. He has his mind made up that cylinder head parameters play no role in camshaft design.

However, since this is not correct, I provided the links to various places that do "ask" for this type of data.

You're correct, I am a friend of Chris' as well as a few others mentioned in this thread, however, all I did provide were sources of information that do show the importance of the cylinder head data, a topic being discussed here. All while not insulting or condescending anyone's credability. :eek:

Take the info provided and do whatever you want with it. While reading through it, I'll be busy working on various combinations for my customers that "do work" extremely well. (whether I'm well known on this site or not.. ;) )

Laters...

Ed

Re: Aluminum heads
 

I helped Brett install my supercharging systems over the phone and discussed another engine build with him. He seemed like a nice, knowledgable guy, but I don't think that observation is going to prove anything in this discussion.

I don't understand heads and cams the way I would like to. My dumb impression is that all the good heads are a big improvement over stock and the differences between them in air flow and I/E ratio call for different cam specs to optimize, so there is maybe no such thing as the best head or the best cam.

Different builders pledge allegiance to different heads and cams based on hard won experience, and the guy that really tries all the different combinations is not going to share the answer because he needs to recover that investment in sales. If he did his homework then his stuff whups ass and word of mouth does the rest.

Re: Aluminum heads
 

The duration split of a camshaft is determined by I/E ratio. That is what I have stated. I have not stated that biased exhaust duration cams are not correct. I believe the best engines are built as a combination.

I won't limit any engine builders capabilities with a label. Each has a right to specialize in what they may prefer to do but that doesn't mean that they can't build an engine that will be competitive in some other sport.

Chris

Re: Aluminum heads
 

Say what you want all day about head flow, particularly on the exhaust side and the fact remains most boat headers aren't flowing as good as automotive counterparts. The fact is on many boat motors great flowing exhausts ports are being used with short tube headers or even manifolds!!! Now if truely custom headers i.e primary tube diameter and length along with collector design were built for a particular motor and they are run dry I could see running a single pattern with no problem. We put a single pattern cam in our 66 Vette that has GM oval aluminum heads on a 468 and the performance was OK. We then put headers on the motor and the gain was unreal!! My opinion is if we chose to run the HP manifolds the single pattern cam would need to be replaced. The split would be needed to crutch the exhaust system, not the heads!

Re: Aluminum heads
 

cstraub all i hear is head head head from you what about boat ,exhaust system water in the exhaust system i have used both types of cams in blower motors with good heads junk heads and real good heads and more then one type of blower and everytime i push the exhaust nbs.the motor makes more power on the dyno and in the boat .we can argue heads all day there is more going on here then a air pump and a head in the real world not all things are perfect like in a computer we have to overcome the rest of the system

Re: Aluminum heads
 

The worst part is when getting a cam ground one of the questions will be what type of exhaust. In the boating world we spend 3+ grand on systems and in reality many of us should be telling the cam grinder our exhaust really suck compared to true headers and flow more like HP manifolds. Instead I'll bet a lot of guys tell the cam grinder "my exhaust system is top of the line and flow great" and then end up with an incorrect custom ground cam! :drink: My advice is to buy a cam from a reputable marine engine builder who knows what CMI E-top, Gils, etc. exhaust systems are. :rolleyes:

Re: Aluminum heads
 

you are right and with these exhaust systems you need to help even a good set of heads the cam may get it out of the head and that is it also on a blower motor pushing the exhaust also helps in cooling the exhaust valve and we all know that is a weak link with the heat of a blower motor

Re: Aluminum heads
 

Anybody ever flow the big buck headers, I wasn't impressed. That's the reason I asked about a 12 to 14 degree seperation between intake and exhaust.

Re: Aluminum heads
 

Give it a shot GPM!! At the RPM levels you turn you may just be on to something. I could see the added exhaust duration allowing some cylinder pressure to be lost in the lower RPM's, but at 7500 there isn't much time for too much to sneak out!!

Re: Aluminum heads
 

you might be surprised it works on my deal tried it both ways

Re: Aluminum heads
 

I'm done. I'll just keep doing what I have been doing.

Chris

Re: Aluminum heads
 

Ah yes.. we have a winner!

However, to some, since it's not in any catalog, a camshaft with 12*-14* of exhaust bias must be wrong!

:rolleyes:

Ed

Re: Aluminum heads
 

Hey Mike: We talked several times in Miami, and I know your stuff works. Maybe you have tested a combination that answers my question from above.

Suppose you have good aftermarket heads with the kind of exhaust that most of us a using, e-tops or maybe sport tubes. Your flow numbers are in the 375/250 CFM range at .600 lift on intake/exhaust. You try increase exhaust flow by:

a) porting
b) duration
c) both porting and duration

What has been your experience if you have done this back to back? Of course I'm thinking blower engine. Not after specific trade secrets here, just whatever you can share.

Re: Aluminum heads
 

Tomcat,
You may also want to try www.speedtalk.com there is always good info on there with some of the HP gurus's frequenting the board. The board owner Don, is an X cup engine man.

Chris

Re: Aluminum heads
 

IF you're still interrested in Canfield Heads, let me know. I can get you a good price on them. I have 2 sets of 310 CC Intake, 119CCC Cumbuston Chamber, Inconel Exhaust Valves, all Feria valves, 2.25 Intake, 1.90 Exhaust in stock, ready to go, 1 year warranty. I can even deliver as far as Buffalo, or even meet you near closer to Rochester. They are as cast with a CNC'd Combustion Chamber. Good price. Better than edelbrock.

Re: Aluminum heads
 

Not wanting to fuel any fires here. I was looking through the cam books today, and I noticed a lot of the Nitrus cams run 14 to 20 degrees between intake and exhaust. I'm guessing it's because of everything that's being forced into the cylinder needs to get out. My question is, what would be the difference between, Nos adding 400 hp, or boost adding 400hp.

Re: Aluminum heads
 

a.lift and b. duration sometimes we try 1.8 rockers on the exhaust but we have had good luck with adding duration to the exhaust. Also if you go to the 1.8s and it picks up what does that tell you.

Re: Aluminum heads
 

That's a good way to test; doesn't take too long to change rockers.

Re: Aluminum heads
 

I tried 4 cams last spring, 2 on the dyno and 2 in the boat, what's another one. Keeps life interesting.

Re: Aluminum heads
 

Just an honest qestion here----what added amount of duration does a 1.8 ratio rocker give over the standard 1.7 ratio rocker arm? Thanks

Re: Aluminum heads
 

hehe, you caught em. good one

Re: Aluminum heads
 

Well, actually not trying to catch anyone really. I just really want to know. I think it's common knowledge among most of of us that a 1.8 ratio adds so many thousandths of valve lift over a 1.7 ratio rocker----but I was just wondering about the duration they add (if any) since rocker arm ratio was brought up.

Re: Aluminum heads
 

Kaama,
No duration increase @ seat and approx effective duration increase +2*- 4* @ .200"
Bob

Re: Aluminum heads
 

I have also heard that advancing or retarding the cam can tell you something about what the engine needs. Is that true?

Re: Aluminum heads
 

i never said the 1.8 changed the duration it does but not anought to mater it isthe lift that changes