Camshaft lobe design

[Cammer]

You guys should have started with Mercedes' dropping quality ratings!

http://money.cnn.com/2006/11/17/autos/p ... /index.htm
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David Redszus,

What years did you build BMW engines for the Firehawk IMSA series? Where is your engine shop located?

[kirkwoodken]

A few years ago, one of the Mercedes Directors said he didn't know how much longer they could build a car with the same materials and craftmanship as everyone else, and charge twice as much for it. He was fired.

At the time they bought Chrysler, they were unable to get financing from German banks, and scooped up Chrysler's cash in a bogus deal. Mercedes has been a management disaster for years. When Chrysler was bought, Forbes mag rated it as the 16th most efficently run business in America. After the Germans took over, they said Chrysler had the worst management on Earth. Who would you believe? In 1994, Chrysler had made more money than any car company in history.

[bobqzzi]

David Redszus,

What years did you build BMW engines for the Firehawk IMSA series? Where is your engine shop located?

I'm curious as well- I used to run an M3 in the Firehawk series. Did you work with Kormann?

[David Redszus]

So if cam lobes are designed to be used with specific valve sizes, flow coefficients and rockers, would not a change in any of the above necessitate the use of a completely different camshaft?

By looking at a camshafts specifications, how could anyone tell which valve train components it should be used with?

[CamKing]

So if cam lobes are designed to be used with specific valve sizes, flow coefficients and rockers, would not a change in any of the above necessitate the use of a completely different camshaft?

By looking at a camshafts specifications, how could anyone tell which valve train components it should be used with?

Just have your intake and exhaust profiles designed for you engine. Then you won't have to guess.
I only charge an extra $1,000 for that option.

[David Redszus]

By looking at a camshafts specifications, how could anyone tell which valve train components it should be used with?

It might be useful for engine builders to know that an accurate camshaft measurement system (called the EZ Cam) is available from Andrews Products, Andrews-Products.com. Call Dave Olson, (847) 759-0190. It can accurately measure and plot cam lift and all derivatives for each lobe. It permits the determination of cam wear, lobe consistency, out of tolerance mfg, and allows the engine builder to determine the true difference between advertised data and reality.

Also, new analysis software is available that can reverse engineer any camshaft lift curve, to determine the exact lobe profiles, all derivatives and valve train characteristics. In camshaft mfg and design, there are no longer any secrets.

These two items are worth their weight in gold, since they permit one to cut through the fog of folklore.

[panic]

[af2]

"Germans took over, they said Chrysler had the worst management on Earth"

Given what Germans used as models 70 years ago I wouldn't be too upset.

Being of German desent I have to agree!

[UDHarold]

The Andrews EZ cam is a great machine, and fills a real niche in the market. It IS very accurate. I bought 2, the $28000 model for Lunati, and a $8000 model for Holley, at least they were on order when I left.
The trouble with measuring a cam depends a lot on the accuracy of the master(Landis 3Ls can make very accurate cam masters for manual machines, John Andrews has 2 Landis 3Ls, and made a number of my designs as masters for Lunati's Bercos).
The Petersen-Berco is the only modern manual cam grinding machine available in America, AFAIK. There might be some from Asia, I know there are some CNC cam grinders from Asia.
Manual cam grinders depend upon the maintenance quality of the machine, the accuracy and wear on the masters, and the mental ability and concentration of the machine operator. At UltraDyne, most of my operators were with me for 10 to 13 years, and a few longer. My shop foreman, who made all my models and masters, was with me for 19 years, and is now in charge of the cam-grinding shop at Lunati. He taught all my machine operators how to grind cams.
Looking at a symmetrical cam design, or ONE side of an unsymmetrical cam, the software that I use can design 2.457X10 to the 14th different math equations for the same duration from top of the ramp to the nose of the cam.
Most of these are too close to each other to matter, some are too soft and easy to be of interest, and some are even impossible to make(Think of a cam with such a negative radius-of-curvature that it cuts through the middle of the lobe---A teardrop suspended over the base circle!!!).
Simple cams may have only 2 math equations, a ramp from the base circle to the valve lash point, and the flank, the rest of the cam. The numbers we talk about are generally just the flank.
I have been doing cams with 8 to 12 math equations since 1980, these "Multi-Segmented Polynomial" equations were what I started UltraDyne on. Later, I found out that they were called 'Spline Fits' or even 'Knots'. Little did I know.......
So far, it has taken multiple iterations on an $800,000 Adcole to find where I 'knot' the strings, and what 3 derivative values each 'knot' has.
It does not tell you how to design the next future family, only what someone did.
Computers do not think, they only do calculations much faster, and let us humans think a little faster. Making the right cam for a particular engine is as much an Art as it is a Science.

UDHarold

[David Redszus]

The Andrews EZ cam is a great machine, and fills a real niche in the market. It IS very accurate. I bought 2, the $28000 model for Lunati, and a $8000 model for Holley, at least they were on order when I left.

I'm pretty sure the starting price for an EZ Cam is about $2500, which is easily affordable to every engine builder. While an EZ Cam will not design a cam for you, it will tell you what you have and what condition it is in.

Computers do not think, they only do calculations much faster, and let us humans think a little faster. Making the right cam for a particular engine is as much an Art as it is a Science.

Harold, I would agree with you completely. A computer, any computer is only a tool and nothing more. Why is it then so many folks are terrified of computers and are reluctant to learn what the tool can do for them.

Due to the advances of technology, it iseasier to make a cam than ever before. In the early days, did you use a slide rule, desktop calculator, or graph paper, pencil and ruler? I am in awe at what our predecessors were able to accomplish without the tools we have today.

The last frontier seems to be how to decide what cam to make for a given application. In the past, experience (trial and error, and error) was the only path. Computer simulation programs are now available that will bring science to the task camshaft specification. And to inlet and exhaust system design. The major factories already have them, the racers are a ways behind.

With all due respect to both cam grinders and engine builders, my 35 years of engineering involvment have indicated the following:
Cam grinders do not know much about engines. Engine builders do not know much about cams. Perhaps it was always that way, perhaps it always will be.

[UDHarold]

David,

the EZ cam does start somewhere around $2500, We thought we needed the one with all the bells and whistles.
I started on analog computers in 1966, working in the oil fields after 6 years in the military(22 months Turkey, 38 months Germany). In September 1969, I started back to college, and got a job with the State of Mississippi's Central Data Processing Agency, on the largest digital computer in the state. For 2 1/2 years I put out every Motor Vehicle Registration, every Driver's Liscense and tag renewal notice.
While there, I taught myself Fortran programming, and later Basic, and cam design.
I sold my first profile in December 1972, for $125.00. It is still offered for sale today.
I used Rothbart and Stoddart to learn the basic theory of cam design, and Jess Nourse's SAE paper on how to adapt the computer for cam design.
My first job at a cam company was at General Kinetics, August 1974. At that time, I had already designed the future 1975 Daytona 500 winner, and the 1974 NHRA Funny Car National Champion's cam.
General Kinetics taught me how not to run a cam company, and my next job, as Competition Cam's original cam designer, taught me how to run a cam company. Both experiences were very valuable to me.
When I started UltraDyne, I bought a 2000 model Tandy HD2000, which I used to design UltraDyne's cams until 1995, when it self-destroyed.
At that point, I bought a nice Gateway, and some commercial cam-design software. The same identical software has been sold to hundreds, if not a thousand or more, people who wanted to design cams.
I think of the computer and the software as I do a carpenter's hammer and saw. Some carpenters build mansions, some just build doghouses.
They all use hammers and saws, and it is their skill that makes the difference.
In 1982, Comp Cams asked me to make a programming change to the program I had written them. My Tandy was out of service, and I needed a new design for the Daytona Trade Show.
After I finished the programming changes, I verified them by running some data through the programming. I took the printouts back with me and they became my UR30 and UR31. The program I had written them was always capable of designing every UltraDyne designed through 1995.
Comp Cams designed Competition Cams on their program, I designed UltraDynes on mine, and on theirs.
Designing is all in the mind of the designer.
I am still using the software I bought in 1995, and designing better cams than ever.
Cam copiers have been around at least since the 1950s. Isky used to complain about them. Cam curves cannot be patented. However, mechanical copies are never perfect, because what they are copying is probably not perfect either. The thing is, cam copiers have to wait to see what is successful, and are always behind, on the curve. They are just like a pesky insect that will not go away. I've learned a long time ago, Don't Sweat the Small Stuff!!!

UDHarold

[David Redszus]

The thing is, cam copiers have to wait to see what is successful, and are always behind, on the curve. They are just like a pesky insect that will not go away. I've learned a long time ago, Don't Sweat the Small Stuff!!!

Once upon a time, a well known road racer, Bob Tullius gave a presentation in which he revealed a great many speed secrets that he was using to make Group 44 (Quaker State) successful. Afterwards, I asked him if giving away information would hurt his success. He said, "sonny boy, what I have told you is what I learned yesterday. But tommorow I will know more and you'll still be stuck in yesterday. So you'll never beat me."

Enzo Ferrarri is alleged to have said, "I have never lost a Formula 1 race because of the information I have given away."

All three of you gentlemen are right.

[OldSStroker]

Cam grinders do not know much about engines. Engine builders do not know much about cams. Perhaps it was always that way, perhaps it always will be.

Perhaps the wave of the future is the engine builder (designer) who understands engines and cams and who uses the modern tools available to do a "Bob Tullius". I believe there are some younger designers/builders coming along who will do this. They often face reluctance to change from (us) old farts, but the proof is in the puddin'. They may even be able to inspire an experienced OF to think out of the box. That may be a synergy that leads the parade.


Jon

[panic]

[CamKing]

Cam grinders do not know much about engines. Engine builders do not know much about cams. Perhaps it was always that way, perhaps it always will be.

Try googling, Dick Jones champion spark plug west coast racing facility.
The camshaft design equation I use is just part of a total engine design equation Dick Jones came up with.
He was arguably one of the greatest racing engine minds of the 20th century.
I started working on racing engines long before I designed camshafts.