Cams-Design-Dynamics-and-Accuracy-Harold-A-Rothbart-1956

[SchmidtMotorWorks]

Saw this on ebay for $42, I paid about $80 for my copy.
A great book anyone wanting to learn about the math and history of cams.

It is a very hard book to find sometimes,

http://www.ebay.com/itm/Cams-Design-Dyn ... 58c72aa77c

[Kevin Johnson]

It will probably jump back up in price now that three ebay copies have sold. The book sellers are usually pretty good at tracking demand and rapidly adjusting prices.

[Stan Weiss]

Jon,
Have you ever seen the "Cam Design Handbook" by Harold A. Rothbart? Is it an good?

Stan

[SchmidtMotorWorks]

Jon,
Have you ever seen the "Cam Design Handbook" by Harold A. Rothbart? Is it an good?

Stan

Yes it is a good book but it is not particularly related to automotive cams.

It does have lots of useful formula for writing software.

By far the best reference for the basics of modern automotive cam design is:
Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms By J J Williams
That said, there are better ways to do what is described in JJ Willimas book.

https://books.google.com/books?id=os1ys ... am&f=false

[Stan Weiss]

Jon,
Thanks. I am not looking to design cams, but was searching for something the other day and this came up.

Cam Design Handbook - H. Rothbart (2004) WW.pdf (application/pdf Object)

ftp://air.zz.com/_manuals/Mechanics/Cam ... )%20WW.pdf

Stan

[SchmidtMotorWorks]

Jon,
Thanks. I am not looking to design cams, but was searching for something the other day and this came up.

Cam Design Handbook - H. Rothbart (2004) WW.pdf (application/pdf Object)

ftp://air.zz.com/_manuals/Mechanics/Cam ... )%20WW.pdf

Stan

That is also a good book, it does have a section by Dema Elgin.

[ninjakid]

Woah I snagged a rather beat up ex-library copy from a third party seller on amazon yesterday for $18 and there were a bunch more starting at $30 and today they all jumped up to at least $70.
Those went up fast.
Mine says it shipped so I'm hoping it shows up.

[SchmidtMotorWorks]

Woah I snagged a rather beat up ex-library copy from a third party seller on amazon yesterday for $18 and there were a bunch more starting at $30 and today they all jumped up to at least $70.
Those went up fast.
Mine says it shipped so I'm hoping it shows up.

Good find at 18!

Still worth it at $70.

[oldjohnno]

By far the best reference for the basics of modern automotive cam design is:
Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms By J J Williams
That said, there are better ways to do what is described in JJ Willimas book.

I imagine that as lobe design becomes more refined the benefits become progressively smaller. And how much of an improvement could one expect from using a state of the art lobe of today as compared to an average off-the-shelf design from say 20 years ago, assuming similar timing and lift? Do the modern designs materially improve performance, durability or both? And will we get to the point where the lobe refinements are too small to be "felt" by the valvetrain?

You can't help but feel just a little bit of cynicism sometimes when every cam designer claims his lobes to be technically superior to everyone elses, and they've been doing this for decades. Obviously they can't all be superior.

[pdq67]

I want to say that way back years ago that cam lobe masters were ground 1/360th at a time and the Grinder would hand smooth the final lobes little-bitty 1/360 steps using a really fine die-makers stone.

Is this true?

pdq67

[wyrmrider]

or a file

[ingram]

Many cam grinders that do not have any CNC machines or that want to keep their cam profiles in house still make the master plates the same way that was used years ago. The process consists of making a cam model in a milling machine from the profile lift table. The model is smoothed by hand or with a polishing belt in a machine similar to a crankshaft polisher. The model is then used to make the master plate in the manual cam grinding machine.

[CamKing]

In the 80's, we would design a lobe, and make a model of the lobe on the bridgeport, by using a rotary table, and cutting each degree. We would then use the Berco cam grinder to follow the model lobe, and grind the master Lobe.
Now we design the lobe in 1/4 degree increments, run it thru a program that adds the rocker table geometry of the cam grinder, and smooths it, then we CNC machine the master.

[SchmidtMotorWorks]

By far the best reference for the basics of modern automotive cam design is:
Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms By J J Williams
That said, there are better ways to do what is described in JJ Willimas book.

I imagine that as lobe design becomes more refined the benefits become progressively smaller. And how much of an improvement could one expect from using a state of the art lobe of today as compared to an average off-the-shelf design from say 20 years ago, assuming similar timing and lift? Do the modern designs materially improve performance, durability or both? And will we get to the point where the lobe refinements are too small to be "felt" by the valvetrain?

You can't help but feel just a little bit of cynicism sometimes when every cam designer claims his lobes to be technically superior to everyone elses, and they've been doing this for decades. Obviously they can't all be superior.

Very few cam designers 20 years ago were even considering the things that the JJ Williams paper explains how to compute.

[oldjohnno]

Very few cam designers 20 years ago were even considering the things that the JJ Williams paper explains how to compute.

Do these new techniques translate into gains on the dyno or timeslip? What I'm getting at is if the current designs are already near the current limits as set by lifter diameter then what are the benefits of these latest methods?