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Custom vs Catalog Cams

General engine tech -- Drag Racing to Circle Track

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SchmidtMotorWorks
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Re: Custom vs Catalog Cams

Post by SchmidtMotorWorks » Sat Aug 17, 2019 4:24 pm

I talk to my guy at UD, he said that more than likely what happened was the wheel wasn’t removing any material off the base circle during the final finishing.
That could be if they started the process with a cam that was ground for a higher lift and just ground-off the lobe until it was the desired lift.
As you mentioned, it might have never ground down to the base circle and some distance above it.

That is a lot of trouble to sort out if you don't have an easy way to measure the cam.
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Re: Custom vs Catalog Cams

Post by PRH » Sat Aug 17, 2019 5:22 pm

These keep coming to me.......

This happened with a grinder who shall remain unnamed, but they are no longer in business......

We were doing some 305 sbc’s for this one oval track class. .390/.410 lift rule.
At this point I was already using a lot of Comp stuff, but they didn’t seem to have anything as short as I wanted.
I had a lobe master listing from this other grinder, they had something about like what I wanted, so I order it up.
These were pretty low buck entry level type builds, so not a lot of extra time went into plotting out the cam.
Degree it in, and off it goes.
Motor runs good, guy is competitive, and happy with it.

The next year we build another one.
Order up the same cam...... only for some reason, this one got a little more scrutiny when it was installed.
The ex lobes all have way less lift than they’re supposed to, although the timing events all appear correct.
A call is made to the grinder....... again it’s another “impossible” occurrence.
He has us measure this and that...... it keeps coming up short.

So, he says he’s going to call us back.

Calls us back........ the master was made wrong. The cam was what the master was.
No one ever checked it before !!

He says........ hey, that other one worked good for you...... it would have been the same way...... just run it.
While we couldn’t really argue with that, we kinda wanted it to be right.
He said he’d have to have the master redone....... and we couldn’t wait that long.
So, we sent it back...... and I ended up finding a little Isky cam that worked really well.
Somewhat handy with a die grinder.

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Re: Custom vs Catalog Cams

Post by swampbuggy » Sat Aug 17, 2019 5:35 pm

So PRH did you use any more Isky cams after that one that did really well ?? Mark H.

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Re: Custom vs Catalog Cams

Post by PRH » Sat Aug 17, 2019 6:19 pm

We built a few more of those 305’s, and we used that same Isky cam in them.
Somewhat handy with a die grinder.

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Re: Custom vs Catalog Cams

Post by Walter R. Malik » Sat Aug 17, 2019 8:29 pm

PRH wrote:
Sat Aug 17, 2019 6:19 pm
We built a few more of those 305’s, and we used that same Isky cam in them.

That's weird ...
back in the 90's we used an ISKY Z-25 cam in many 305 Chevrolet S.C.C.A "A Sedan" engines.
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Re: Custom vs Catalog Cams

Post by ssregal39 » Tue Aug 20, 2019 11:48 am

PRH wrote:
Sat Aug 17, 2019 6:19 pm
We built a few more of those 305’s, and we used that same Isky cam in them.
LR1?

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Re: Custom vs Catalog Cams

Post by PRH » Tue Aug 20, 2019 12:12 pm

.390/.410 lift rule....... SL1
Somewhat handy with a die grinder.

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Re: Custom vs Catalog Cams

Post by Elroy » Tue Aug 20, 2019 12:33 pm

PRH wrote:
Sat Aug 17, 2019 4:05 pm
Here’s another cam anomaly story........

Early 90’s, my friend decides he wants to go NHRA Stocker Racing.
Is tired of the straight up bracket racing.
So, we get another set of head castings, stock manifold and carb, put all that on his old street motor and see what it does.
At that time, it seemed like getting cheater cam lobe data was like pulling teeth.
I was primary using UD at the time, and they didn’t do any of that.
The guy I dealt with there gave me the name of someone at Lunati to talk to.
We had no idea where to even start, so we just left it up to him to set us up.
Put it all together, go to the dyno...... we don’t know what’s good or bad, tune what we have and put it in the car.
It’s a 68 GTO, and at the time it was an E car.
Go to the track...... won’t run the index.
Send the converter back, blah, blah....... no better...... need more power.
Well, the cam had what I thought was quite a lot of duration...... and I felt like if it was 6-8* less it would be better.
I get a copy of some Crane lift rule masters..... pick out a couple lobes, they grind it up.
Back to the dyno with the new cam...... power is up everywhere.
Put motor in car....... 3 tenths quicker!!
But...... keeps putting pushrods through rockers.
That wasn’t an issue with the Lunati.
So, we call Lunati ask if they have anything smaller than the first cam.
They do, so we order it.
My friend puts it in and plots it out.
Lift and .050 numbers on the intake are correct, but the .006 number is like 375*.
Ex lobe if fine...... maybe 300@.006.
Call them up..... phone tech asks us how that’s possible since there only 360* in a circle.
We remind him there’s 720* available, since the cam runs 1/2 speed.
They need to confer about it, then tell us to send it back and they’ll measure it.
Cam goes back, we get a call telling us that there’s nothing wrong with it, the duration @.050 is right on.
We tell them that’s not what we’re concerned with, it’s the 375@.006 we didn’t like.
Never any confirmation about that from them, but they’ll grind us another one.
I ask to have the lsa changed 1* to insure they don’t just resend the same one back to us.
New cam shows up....... same exact problem.
I talk to my guy at UD, he said that more than likely what happened was the wheel wasn’t removing any material off the base circle during the final finishing.

Mike can probably elaborate on that.

Needless to say we sent it back as well, and went on to try a few different offerenings from Comp and Lazer....... back to Lunati...... then back to Comp again.
Yeh...... we tried a few cams in that thing.
Very cool story. When I was young before I knew any better I just assumed that cam grinding was some space age extremely accurate deal done by crazy smart people on highly sophisticated equipment. It was later that I learned that it could very possibly be a worn out WWII era machine being operated by a nitwit. :lol:

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Re: Custom vs Catalog Cams

Post by PRH » Tue Aug 20, 2019 2:49 pm

We ended up going back to Lunati after a couple of tries with Comp that didn’t turn out well for us.
That next Lunati was the old “stock duration” profile which works pretty good on the dyno, but didn’t run all that well in the car.

After that we were advised by some Buick guys we knew that Lazer was pretty good with Pontiac’s.
We (well, “I”) had a philosophy I was trying to implement with this motor, and the guy at Lazer was adamant that what I was trying to do wouldn’t work, and that what Pontiacs like is “this”.
I told my friend, hey...... what I’m trying for doesn’t really seem to be getting us there...... so try what he says and see what happens.
It lasted one trip (test n tune) to the track........ it was a huge step backwards.
1/2 second slower than the rocker killing Crane(the fastest to date).

About that time Lunati has ads in the National Dragster about their cnc cam grinder, and how they can tweak existing lobe designs without having to make a new master.
So, we revisit the idea of tweaking that original Lunati cam that was too big.
I call and talk to them, discuss what I want to do, they say sure....... no problem...... and grind it up.
Well..... it’s not exactly what we discussed.
I told them to use the intake lobe from the original cam, and use that as the ex lobe....... and to make the new intake lobe 8 deg shorter.
Well, it was 8deg shorter at .050, but it was the same as the ex lobe at like .200.
So it’s faster....... which isn’t necessarily bad(the Crane was fast too), but we were trying to not have rocker/pushrod issues.
Well, we put it in and the car runs the best it ever had....... and no rocker issues.

We ran it for a few seasons and started working on other aspects of the car now that the speed had started to come around.
********************
The main thing I took away from dealing with all that is how important it can be to have a good working relationship with the person on the other end of the phone at your favorite cam shop.

And here is an example of why I say that........

One of the Comps we got, looking back on it now, is kind of funny.

This was after the failure to get what we were hoping for from Lunati with the two cams with the odd duration @.006 numbers.
I had my friend call Comp(I had no connection there at the time), and ask them if they had some stocker lobes with xxx lift and zzz duration.
They did....... so he orders it....... it arrives and he plots it out.
Again, at this time it seemed nearly impossible to get things like duration@.200 Numbers...... Stocker lobes were top secret.

Anyway, my friend calls me after plotting it out..... a couple times.
The numbers are odd, so I go over to check out.

Well, he had the numbers right....... the cam was ground using two lobes from very obviously different lobe families.
The intake lobe looked like a teepee....... the ex lobe was square.
So, yeh....... the .006 and .050 numbers made sense, but the ex was about 35* longer @.200 than the intake.
We ran it, but the motor had no “pop”. Ran about a tenth slower than the index.
Had we been able to get all the details of those lobes prior to ordering that cam...... we would have passed on it, and seen if there was something better they might have had.

After that, we got a hold of someone at Comp and relayed our experience, and got the point across that we’d prefer something where lobes are at least close to each other in terms of ramp speed and design.
The next one we got measured up “fine”, but it was a little smaller than we really wanted. It was the closest thing they had to what we were looking for.
It ran better than its slow/fast predecessor, but we felt there was still power left on the table.

This was a while before we tried the Lazer or had the cnc Lunati cam done.
Somewhat handy with a die grinder.

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Re: Custom vs Catalog Cams

Post by SchmidtMotorWorks » Wed Aug 21, 2019 12:59 am

Can we discuss cores?

How do you know what core you are getting?

Most product listings do not mention what the core is.
Just looking at flat hydraulic SBC cams for now.

Jegs lists a house brand SBC hydraulic flat cam for $69 (could this be made in China)?
Comp and Lunati are listed at about $120 - $130
But the "Thumper" is $149

My guess is these are re-boxed cams, not even made at Comp or Lunati.

Some mentioned that they got custom cams for about the same price as shelf cams.
From what I see, custom cams are about another $100 more (at least).
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Re: Custom vs Catalog Cams

Post by ClassAct » Wed Aug 21, 2019 2:00 am

SchmidtMotorWorks wrote:
Wed Aug 21, 2019 12:59 am
Can we discuss cores?

How do you know what core you are getting?

Most product listings do not mention what the core is.
Just looking at flat hydraulic SBC cams for now.

Jegs lists a house brand SBC hydraulic flat cam for $69 (could this be made in China)?
Comp and Lunati are listed at about $120 - $130
But the "Thumper" is $149

My guess is these are re-boxed cams, not even made at Comp or Lunati.

Some mentioned that they got custom cams for about the same price as shelf cams.
From what I see, custom cams are about another $100 more (at least).

I paid 185 bucks for my custom SFT cam. There is no way I'd ever consider a "house" cam. That's a crap shoot at best. The grinder will be the one who can do the most cams for the least money.

I'm talking about a cam with a line comparable to a Comp MM series lobe, not some rumor the mill .842 lobe.

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Re: Custom vs Catalog Cams

Post by paulzig » Wed Aug 21, 2019 7:04 am

SchmidtMotorWorks wrote:
Wed Aug 21, 2019 12:59 am
Can we discuss cores?

How do you know what core you are getting?

Most product listings do not mention what the core is.
Just looking at flat hydraulic SBC cams for now.

Jegs lists a house brand SBC hydraulic flat cam for $69 (could this be made in China)?
Comp and Lunati are listed at about $120 - $130
But the "Thumper" is $149

My guess is these are re-boxed cams, not even made at Comp or Lunati.

Some mentioned that they got custom cams for about the same price as shelf cams.
From what I see, custom cams are about another $100 more (at least).
If we look at roller cams, which is ALL I would buy these days comp has -8 for the SADI core and -9 for the billet, and the -9 is all I would ever get even if it costs 100 more, so the reason why I go to the custom is not about whether or not a certain duration number is there it is all about the core...

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Re: Custom vs Catalog Cams

Post by CamKing » Wed Aug 21, 2019 11:47 am

paulzig wrote:
Wed Aug 21, 2019 7:04 am
comp has -8 for the SADI core and -9 for the billet,
But Billet What ?
They buy billet steel cam cores, from multiple manufacturers, made from multiple materials, with multiple heat treat processes.

Material
8620 steel
8650 steel
8660 steel
1050 steel
1055 steel
1060 steel
5150 steel

Process
Carborized
Quench & Tempered
Induction Hardened

Just because it's a billet steel cam core, doesn't mean it's correct for your application
Mike Jones
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Re: Custom vs Catalog Cams

Post by swampbuggy » Wed Aug 21, 2019 11:59 am

Yes Jon i am feeling what you are saying. Whenever i purchase any engine parts i insist on knowing "ALL" of the details/specifications including such things as molecular make up, heat treat if applicable, hardness, among others information. If you do not ask, you may be disappointed ! Mark H.

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Re: Custom vs Catalog Cams

Post by CamKing » Wed Aug 21, 2019 12:14 pm

SchmidtMotorWorks wrote:
Wed Aug 21, 2019 12:59 am
Can we discuss cores?

How do you know what core you are getting?

Most product listings do not mention what the core is.
Just looking at flat hydraulic SBC cams for now.

Jegs lists a house brand SBC hydraulic flat cam for $69 (could this be made in China)?
Comp and Lunati are listed at about $120 - $130
But the "Thumper" is $149

My guess is these are re-boxed cams, not even made at Comp or Lunati.
That's a good guess.
Some buy from overseas, but I don't know what the costs or processes are.
There are 2 major cam core suppliers for cast iron cams. EPC and CMC. Both use the same foundry(CWC).
Both of these cam core companies produce finished cams, to be reboxed, and sold under multiple labels.
Many, are the exact same cam, just a different box. For example, you can buy the same cam for Edelbrock, and pay twice as much as you would have, if you bought it from Speed-Pro.
I had both EPC and CMC grind production cams for me, The cost for the finished cam was $6-8 more then what they charged for the unground cam core. These were my lobe designs, and they ground them, 100 at a time. If you used lobe designs from their library, it was cheaper.

As for the cores, I don't know what quality the offshore cores are.
EPC, and CMC have multiple grades of cores available, and are priced accordingly.
Mike Jones
Jones Cam Designs

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Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
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