I do not use any type of software or computer program to generate valve events.

I don't think in terms of duration let alone LSA.

I think in terms of valve events. Overlap to me is where the intake valve opens and the exhaust valve closes. It's not even a number to me. It's an opening and a closing event.

I don't ever think in terms of LSA either. I see center lines of the intake and exhaust lobe where the lobe will reach maximum valve lift in relation to ATDC or BTDC.

I don't even think or care about duration or center lines until I have worked out the valve events from trends I see in specifying camshafts and testing different valve events.

Once I've generated the valve events I know the combination needs, then I use a "camshaft calculator" to compute the durations and center lines that correspond with those valve events.

Then based off cylinder head data, cylinder head flow, valve train parts, RPM, and many other factors I choose the lobes that I know will work best for the application based on testing, experience and trends.

Then and only then do I care about duration and center lines and I still don't think in terms of LSA even though you see me frequently list LSA when someone asks for a cam spec or recommendation. This is because 90% of people do not think in these terms.

Hopefully this sheds some light as to how I specify a camshaft. Maybe some others will chime in shortly to share their methods as well.

I think you will find that the true guru's and cam grinders that know what they're doing follow the exact same methods as I do as it's really the only "right" way to do it IMO.

 

I've got to say... I love your post, there is so much truth here, and yet funny all at the same time.

As I read your post I thought about the years that I've been doing cams, I started as the Catalog junky in 1993 when I became a dealer for Ultradyne. That was the year I started TEA and we already had some very quick cars using their cams.

In 1994 I landed a job at Holley in Product Development by which time I had purchased every piece of software made. That software collection was complete when Holley purchased Dynomation. Dynomation had the ability to load Cam Pro and Flow Pro files directly from the cam checker and the flow bench, at which time I became the Computer Nerd. It didn't take too much real world dyno testing (Holley had 2 engine dyno cells) to become disenchanted with the computer software.

By 1997 I was self employed again building engines and porting heads at which time I guess I would be the Engine Builder

By 2001 I bought the 5 axis CNC machine, chassis dyno and had everything else imaginable, so I became the Speed Shop Owner

By 2004 when Summit bought TEA I became so consumed with CNC porting heads and developing new products that I didn't have time for spec'ing cams.

In 2010 when I built my 454 I once again became very interested in cam specs. I took the time to make a spread sheet, enter lots of cams that had good results and start looking for trends in IVC, EVO and overlap. This probably over simplified what's really going on, but knowing how runner length, valve diameter and other factors affected airflow, it gave us some decent direction for what to do, and what not to do. Through the years I've had help from Geoff at EPS, Shawn at Va Speed, Ron at Vengence and others.

So now I guess I've become the Salty Dog, with experience being the primary thing that I can hang my hat on.

I do think there is something to be said for computer software, and I'm sure it's come a long way since I used it 20 years ago. But we all know that real world, back to back testing is the only way to know for sure what a engine likes and what it doesn't.

 

It wasn't my intention to imply deception on the part of any "cam guru" on this thread. My point was , a cam from any "in the know" cam spec expert would most likely perform so closely that you wouldn't see a noticeable difference in any of them. The "smoke and mirror" term way a poor ending to what I was trying to say in the post.
I think, in all honesty, the only real problem I see with having a "guru" grind a cam for you is, their thought on what the end result should be. I think that most cam guys and customers on this site are drag racers and are looking to maximize their combo for shooting down a straight away as quickly as possible. A much smaller group of people are wanting to get the best grind for something different like a cruiser, auto X , or any other driving style that doesn't require, or even want, a max effort cam. I think a good percentage of cam spec gurus automatically go for the max effort profile. Understandable , because they have spent a long time perfecting that design. If I could give any advise to the cam spec experts on this site, it would be to listen closely to what the guy on the other end of the phone is saying about the intended use for the car. It can be pretty discouraging for a broke car guy to find out the car needs more converter or gears to let the cam do its thing, if that wasn't the plan for the car in the first place. I send a lot of business to the cam pros on this board and I always tell them to make sure to make your intended use of the car well known and make sure the cam guy understands before the phone goes click.

 

I have been a head porter my entire life. 20 years ago I started actually designing and then helped to manufacture various types of heads and intake manifolds. I am going on my 30th year in this industry. I can safely say that I am a mixture of the various stereotypes. First and foremost I identify myself with the “Salty Dog” stereotype because I know that experience is the key to success in this industry. The second stereotype I identify with is the computer nerd. I am a HUGE computer nerd and have been since I built my first 486 computer in the early 90s. With that being said I must stipulate that computer simulation software is dangerous and dare I say worthless without one key component. Experience! I use EAPro, PipMax as well as 20 spread sheets I have built over the years and love all of them. I am not however a proponent of using such software to design a cam. Granted, the software might show a trend or give insight into a trend that may produce more power but I would never take that data at face value until it was proven on the dyno and ultimately the race track. That’s THE main problem with any simulation software. People take the data at face value and that’s not what it was designed for.


So, I guess I am a “Salty Computer Nerd Dog”.
LOL


My personal view on cam design is this. I dont believe in "shelf" cams for street vehicles. No two people are alike or have the same driving style, needs or wants. I think that in this particular field a persons personality, driving style, likes and dislikes will dictate some of the camshafts design specifications. Out of the last 20 grinds I have spec'ed out for LS engines not one of them has been the same due to the fact that people wanted different idle and power band characteristics. We now have the ability to specify the exact lobe intensity's, duration, asymmetries, and a host of other variables then have it ground on a CNC and delivered in three days time. I dont see a reason to keep cams on the shelf.

 

I have been most of those things from one time or another myself as you may have guessed. That is where all this silliness came from. When I first started going to the races in the 70s, I was 8 years old. I was my dads shadow. I studied everything he did as if he was the god of racing. So, I guess I started out as a nut hugger.

In the 80s, I also became a catalog junkie. I had every one I could get my hands on and I never threw any out. I studied them until I could quote from them. I also studied car magazine dyno tests. The idea that these products were tested back to back with hard data showing the results became what I considered the ultimate resource.

I the late 80s my family bought a Corvette specialty shop. It was at this point when I really started to get some real experience. So, that was my specialty shop owner period.

During that same times, the Buick Grand Nationals came out. I immediately bought one and started tweaking. I was one of the first guys in the central Florida area go turn up the boost and start messing with cams and head porting on them. Simultaneously, we were racing the new at the time Tuned Port engines in the Vettes. We had a 383 stroker tuned port with welded up runners going 12.50s on the stock rear gears and stock torque converter. So, I got to see what if felt like to be the famous racer for a short period of time.

During the development of the Tune Port car, I teamed up with the prominent local machine shop owner who had an engine dyno. I learned so much from him and the things I saw in his shop. When the Speed Shop closed, I worked for the engine builder for a while and soaked up everything I could.

Throughout all this time, I raced. Mostly bracket racing as that is what was in vogue in this area at the time. But, I was also known to stop by the street scene in the wee hours of the morning. If you were savvy, it could be a lucrative place to hang out.

I had been out of racing completely for over 10 years. Now that the rust is knocked off, I am enjoying it more than ever. But, being a salty dog, does give you some perspective as a consumer. So, it is fun to share how I see it.

 

AWSOME THREAD. I noticed none of the BIG 3 cam know it all, thats not a proper combo and you should do this guys have comented but im shure you guys know who they are and bet they will be here to express there opinion lmao. Great job agian and i agree this should be stickey'd so new members will be warned in advance.

 

To add to what Darin said, I had a customer the other day contact me about a cam. He had been using engine dyno software to calculate valve events, different cylinder head flow, intake manifolds, cross section etc.

He even showed me a screen shot of what he came up with from his simulation.

This was a N/A engine mind you, and the VE% was in the low 120's. Of course this isn't correct as there are only a very select few N/A engines that can hit 100% VE let alone go over 100%.

If anyone in this thread has had their had in an engine like that it's Darin himself.

I guess I should extrapolate on what I feel I am in regards to Steve's descriptions lol.

I became a nut hugger of my father a long time ago. He had race cars for years and always taught me everything he knew about them. I was always interested in the camshaft and what it's purpose served. This was mainly because he told me the cam is what makes it sound so good at idle and that was always my favorite part. As I got older he taught me more and more, and I learned the basic cam timing events. What they did and what purpose they served. My dad was just a racer himself and worked on his own cars so he only knew what he put in his own cars. He also hand ported his own heads and I got to see him do this several times. It wasn't like I got information on how to spec a cam from him, I just learned what purpose they served and how they served that purpose.

His main saying to me when talking about building engines was, "Air, Fuel and Spark". Without one of these three you have nothing.

After that I became a catalog junkie. Endlessly searching lobe catalogs online or in a catalog itself. I bought every article of Car Craft, Hot Rod or GMHTP when they did a camshaft test. I taught myself what different intervals between lift points meant in terms of intensity, and how velocity, acceleration and valve lift helped to fill the cylinder in regards to the induction system in place.

You can say during this time I also became a nut hugger again, but this time of Brian Tooley. I always admired Brian's work and how he started his own business from nothing by teaching himself.

You could now say I am the speed shop owner. We have many many customers that I spec camshafts for in our local area and that come through our shop. Not to mention the camshafts I spec for people that aren't local to our shop. I get to see trends in real time every day when I spec a camshaft for one of my customers. I'm even so lucky to get to test things with certain customers that are just as interested in learning and making their car or truck as fast as it can possibly be.

Now that I'm building my own heads up 275 radial car that I've specified every last part down to the nuts and bolts on, I might have a shot at calling myself the famous racer one day! Haha!

I've got a long ways to go before I reach salty dog status like Brian and Darin though!

 

Definitely a good thread.

 

Great write up

 

I thought for sure that 'engineer' would be in that list somewhere. Checked again...nope. Guess they don't get their due respect. Just the shadetree crew. LOL

 

Awesome thread that should definitely be a sticky as there are some very knowledgeable guys who've posted in it, thanks for the laugh!

 

Another vote for the sticky hall of fame seven years later

 

X2!! I just read thru it AGAIN. Giants in the LS world meeting their minds!

 

You can literally walk through the categories and write down names of members on this site for each

 

Thanx for the resurrection guys. This was fun to write.

 

It certainly was a good write up.
I especially liked the thread you did comparing a hydraulic, low lash solid, and traditional solid camshafts.

 

I miss the tech posts for sure

 

There's a reason they went away...

 

LOL this thread is ( was? ) soooo true. Theres another class of cam spec'r though, the BS spec'r who only wants to fool his competition with crappy cam grinds and keep winning races with "the same cam" his slow buddy runs


I've been some of those cam titles too, back in my drinking days after a bottle o scotch or three I was an expert on everything, literally

 

Somehow I missed that one back in the day, great post though, thanks!