Custom vs Catalog Cams

[PRH]

And then there’s those situations where the heads are done, short block is done...... preferred cam has been installed and degreed....... v/p clearance is checked....... no room.
And no one wants to take stuff apart for additional machining to try and get it to fit...... so a new cam is ordered with the main criteria being creating more v/p clearance....... knowing full well it’s going to make less power.

It’s pretty rare for me to be involved with a build where making the absolute most power possible is at the top of the list of things most important for determining which cam to use.

[CamKing]

And then there’s those situations where the heads are done, short block is done...... preferred cam has been installed and degreed....... v/p clearance is checked....... no room.

We have to work around P2V, for many applications.
What I normally do, is figure out what would be the best cam, and then figure out how to change it the least, to make it fit.
I use a combination of reducing the duration, and widening the centerlines, to keep the Intake closing point, and exhaust opening point the same as the optimum cam. This effects the power less, then just decreasing the duration, or widening the heck out of the centerlines.

[PRH]

That’s essentially what I did.
The ex clearance was basically zero...... so unfortunately it’s likely going to end up being advanced more than we’d like, in addition to it being smaller/wider.

And it’s going in a puller, and those guys get a little unruly with the rpm..... so we want to make sure it has plenty of clearance.

I used slightly slower lobes as well.
It should be able to physically fit with adequate clearance.......but probably not exactly where I’d prefer it to be.

[Stan Weiss]

I am curious how / what software others are using to do this.

Stan

[4vpc]

A big factor is if it's a mainstream engine or not.

You could spend days looking through sbc and Ford cam choices online till you get dizzy.

Other stuff,, not so much

For engines without much selection available that makes sense.

I'm curious what makes a person stop looking at the catalogs and order a custom cam.

A simulation program.

[Krooser]

I've always been a low buck, or no buck, racer.

Back in the 80's I had a speed shop sponsor so I got free Engle cams to run in my dirt car. My pit guy blew one of our 351-c's while packing the track one night. Broke the cam. I was out of cash and out of free camshafts.

So I called Chet Herbert (late at night...he never answered his phones when he was working). I told him what I was running... good performance but I was getting beat off the corners. He said "no wonder... you're running a Chevy grind!"... So he sent me one of his $50.00 regrinds. Best cam I ever had in those motors and there were few cars I couldn't beat to the flagstand.

That was my first "custom cam"...

[GARY C]

I've always been a low buck, or no buck, racer.

Back in the 80's I had a speed shop sponsor so I got free Engle cams to run in my dirt car. My pit guy blew one of our 351-c's while packing the track one night. Broke the cam. I was out of cash and out of free camshafts.

So I called Chet Herbert (late at night...he never answered his phones when he was working). I told him what I was running... good performance but I was getting beat off the corners. He said "no wonder... you're running a Chevy grind!"... So he sent me one of his $50.00 regrinds. Best cam I ever had in those motors and there were few cars I couldn't beat to the flagstand.

That was my first "custom cam"...

All of my solid roller stuff has been Herbert as has some of my friends... 0 complaints or issues.

[PRH]

I had one Herbert roller for a SBC.
It worked well enough, but it was way off from what the specs were.
Was supposed to be 275/285-108, measured as 280/284-106.
Lift came up about .010” shy too.

One of my customers had one in a 440 Mopar....... I had him plot it out....... it was farther off from the specs than my Chevy one was.

[SchmidtMotorWorks]

Speaking of Herbert, I wonder if Ruben is still grinding cams.

All of those cams were ground with 1940's methods, tracing, offsetting and blending.

No computation involved, not even pencil and paper.

[Krooser]

Talk about old school Herbert sent me a cam without prepaying....I needed it for a Saturday so he just sent along an invoice.

Nick Arias sent me an extra piston (gratis) after I broke twice in one season. Got a note (said "you might need another") with the spare I had ordered.

Now that kind of service builds loyalty...

[GARY C]

Speaking of Herbert, I wonder if Ruben is still grinding cams.

All of those cams were ground with 1940's methods, tracing, offsetting and blending.

No computation involved, not even pencil and paper.

1940's .440+ cam lobes?
Don was the grinder I dealt with in the late 90's/2000's, lobe vs rocker ratio was exact, not sure if 7700+ rpm was 40's tec?

How many of Herbert's cams have you actually tested Jon? do you have any dyno or track data to back your claims?

[GARY C]

Talk about old school Herbert sent me a cam without prepaying....I needed it for a Saturday so he just sent along an invoice.

Nick Arias sent me an extra piston (gratis) after I broke twice in one season. Got a note (said "you might need another") with the spare I had ordered.

Now that kind of service builds loyalty...

Yes, not many trust worthy men left in the interweb of exspirts these days.

[n2xlr8n]

Not custom, but prior to running one of Jone's cams early on, I ran a Herbert CC6H in a 406 with track 1s that absolutely flew (6.40s in 2900 lbs)...for 1992.

[CamKing]

Speaking of Herbert, I wonder if Ruben is still grinding cams.

All of those cams were ground with 1940's methods, tracing, offsetting and blending.

No computation involved, not even pencil and paper.

1940's .440+ cam lobes?
Don was the grinder I dealt with in the late 90's/2000's, lobe vs rocker ratio was exact, not sure if 7700+ rpm was 40's tec?

How many of Herbert's cams have you actually tested Jon? do you have any dyno or track data to back your claims?

Ruben has been grinding all of Herbert's cams, since the 90's.
It's common knowledge.

[David Vizard]

Schmit motor works wrote:-

I'm curious what makes a person stop looking at the catalogs and order a custom cam.
A simulation program.

I stop looking at catalog cams when I find that there is not one that is on the right LCA. If Torque Master calls for say a 280/288 cam with 0.420 lobe lift on 109 LCA and I find one in the catalog then that would be what I get. If, for a BBC cam, it calls for say a 106 LCA (as is so often the case) then the best of luck trying to find a catalog that is right. Those 110-112 cams so often listed are, in a 498, down by over 40 hp and 40 lbs-ft of torque.

For my original COS cam program the data base had just about every catalog grind there was from all the reputable cam companies. Using this data bank the user could select the nearest catalog cam to the required spec.

If you feel the need to ask someones advice then make sure they have a lot of cam testing experience as the subject of gas dynamics in a high output engine are, to say the least, complex.

And by the way knowing what a successful NASCAR engine has for valve events will be little more use than satisfying your curiosity.

DV