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What sort of information do cam grinders ask for when you want a custom grind?


josh817

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I have a cam I want reground but I haven't been able to find any sort of form or document from a grinder.I would like to avoid a regrind only because it will require taking the base circle down, not to mention I don't know if they will be able to change the lobe centers, make it asymmetrical, change duration, etc. I want to avoid taking down the base circles due to superstition my dad has been feeding me. He does Triumph race motors and they will break camshafts if they attack the base circle. I don't know if its a problem on the Z cams however I did find one broken cam picture...

 

Anyway. I have a cam card thing here. Basically I just took my scanned copy of a Schneider cam card, reworked the font so its more legible and I entered in my own values. Only problem is, I have the values at 1mm of lift (kind of like how we get @.050" measurements)... Will a cam grinder be able to grind something for me if I give him the at 1mm of lift measurements or does he need the raw figures? :( I hope they can do 1mm lift measurements otherwise I'm out of luck. Here is the cam card I made up:

2vcu5ur.jpg

 

Central angle and lobe center is obviously not at 1mm of lift, however the duration and opening/closing points on the picture ARE at 1mm of lift. :unsure:

 

Anybody have a cam grinder in mind I could use? I prefer someone who has GOOD billets. I heard some rumor that Web Cams uses good billets possibly from Nissan, but I didn't think they made those anymore. Whatever it may be, I think I need a totally fresh cam, not a regrind. I think the picture I have, was a billet grind...

14yae6v.jpg

 

And here is someone who did an obvious regrind. To me that's a big no no. Looks like a break waiting to happen, but you guys tell me because I honestly don't know the integrity of our cams.

692a1g.jpg

 

One final question! On the cam card, I have Central Angle down, does anyone know what that might mean? As you can probably guess, I didn't make up this grind, I got it from a Japanese website and had to finagle the crappy Japanese english. The only thing I can think of is maybe central angle is like... lobe center? The central angle figures I have are roughly 100-101º, if that helps any. Because these lobes are asymmetrical in design, I'm curious how one figure out where the peak of the lobe is... Essentially I'm asking once again, is the information I have on the cam card shown, enough for a grinder to do his thing, or do I need more?

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A competent cam regrinder should be able to convert mm to inches without much of a problem. All that I have heard of, when it comes to cams breaking, is when you either go to far with the regrind, or the cam itself is a poor batch with casting and material flaws. there are three cam companies that I would trust with a regrind or new cam. isky, crower and comp. those three have been around a LONG time.

 

(I've seen and heard alot about newer comp cam, cams going flat recently though)

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A competent cam regrinder should be able to convert mm to inches without much of a problem. All that I have heard of, when it comes to cams breaking, is when you either go to far with the regrind, or the cam itself is a poor batch with casting and material flaws. there are three cam companies that I would trust with a regrind or new cam. isky, crower and comp. those three have been around a LONG time.

 

(I've seen and heard a lot about newer comp cam, cams going flat recently though)

Not concerned about them converting. What I am worried about is say for example on this cam card:

30jp4ef.jpg

 

How will a cam grinder know at what degree will the lobe start to rise, I mean, when lift is less then 1mm. You can see on that cam card, there was 61º of duration on the intake lobe before it hit .050". I don't have the "Duration Adv" figure I guess you could call it as its shown on the example. I only have duration and opening/closing time at 1mm of lift. To make it easier to consider, I could reword my question. Can a cam grinder, grind me a cam, if I give him only @ .050" of lift measurements? I'm not worried about it being metric, I'm worried about not having raw duration figures.

 

 

Yes, I am worried about the cam going flat problem too. The grind I have is radical, in the sense that its opening ramp is like... instant. Do you think it would be wise to have the cam nitrided (or some other form of hardening) after I receive it, or should it be hardened enough right out of the box? Same thing with rockers, should I have them hardened too? I'm going to need someone to refinish them since they're old used ones. If the wipe pads are only shell hardened, then I will need to address it.

Edited by josh817
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I think I will call him. I need to order springs and Ti retainers. I tried emailing them on what sort of springs are necessary for my application but I didn't get a reply, as usual. I find that most business website emails never work out, probably because they receive so many. It would be nice however to have them do the cam, springs, and retainers for me so I don't have shipments from different sources.

 

Web Camshafts does have a custom grind form however it doesn't ask for measurements, it says whats your application, how to you intend to use it, etc which I find EXTREMELY annoying because I don't want someone to advise me on what grind to use. I have my own grind, I just need you to grind it.

Edited by josh817
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From Isky $300-$500 complete with everything depending on the grind. I spent an hour on the phone with Ron, great guy wouldn't deal with anyone else.

Everything as in whatever it takes to do the cam, or everything as in cam, springs, and retainers.

 

If its the second option, I am very pleased with that.

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Also remember, you will need new rocker arms with a new cam. The best price I have seen on rockers are at AZC. I am about to do an Isky regrind here within the week and my total costs including rockers comes right at around $600, thats cam, springs, retainers, lash pads and rockers.

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I think what you are going to find Josh is that each cam company has its own established tried and true master profiles that they use and they will do their best to meet your needs. It may be a matter of calling multiple cam companies to find a profile close to what you want. If you can not live with that then what it comes down to is paying for a machine shop to create your master profiles for both the intake and exhaust. Those two custom profiles could run you up to $500 to build for a one-off cam so it comes down to a matter of how much do you want to pay for your custom cam.

Edited by Scott_M67
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I think what you are going to find Josh is that each cam company has its own established tried and true master profiles that they use and they will do their best to meet your needs. It may be a matter of calling multiple cam companies to find a profile close to what you want. If you can not live with that then what it comes down to is paying for a machine shop to create your master profiles for both the intake and exhaust. Those two custom profiles could run you up to $500 to build for a one-off cam so it comes down to a matter of how much do you want to pay for your custom cam.

I'll just be straight with you, its a Kameari cam grind. Kameari... charges $1100 for their cam, and theirs is proven, which is why I won't make an exception for the grind. This is the exact grind I want, nothing different... :o

Edited by josh817
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I'll just be straight with you, its a Kameari cam grind. Kameari... charges $1100 for their cam, and theirs is proven, which is why I won't make an exception for the grind. This is the exact grind I want, nothing different... :o

 

Do you have more information on that cam than what you've shown on the cam card in your first post? Those numbers are just specs to give you an idea about commonly understood cam characteristics - they are not everything you need to replicate an "exact grind". For instance, they really tell you nothing about the opening and closing ramp rates. If that's all you've got then you might as well ask for something close, or spend the $1100.

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Do you have more information on that cam than what you've shown on the cam card in your first post? Those numbers are just specs to give you an idea about commonly understood cam characteristics - they are not everything you need to replicate an "exact grind". For instance, they really tell you nothing about the opening and closing ramp rates. If that's all you've got then you might as well ask for something close, or spend the $1100.

I would think that if you have a duration, and a lobe center, you can see that the lobe center is closer to the opening than to the closing, which shows that its asymmetrical in design. Then you figure, lets just say you have 60º to get to .400" of lift, then you can figure out a rate by that. Correct? I know I don't have everything exactly on the card, however, I think there is enough information there to plug numbers in and find the rest of the unknowns. Correct?

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Personally IMHO I don't see anything special about that cam but all the specs aren't shown either. Let me say that typically a split duration cam like this 241/251 is used to make up for poor exhaust flow or use in a stock head. IMHO you would be farther ahead spending money on port work to achieve the best I/E ratio and utilize an exhaust system with as little back pressure as possible and run a single duration cam like a Racer Brown 325R with 254 degrees duration @.050". You could try calling Rebello Racing and see if they have a cam similar to it or at least get another opinion.

 

The best way to duplicate that cam is to shell out the ridiculous $1,100 and make master profiles from it.

 

 

I would think that if you have a duration, and a lobe center, you can see that the lobe center is closer to the opening than to the closing, which shows that its asymmetrical in design. Then you figure, lets just say you have 60º to get to .400" of lift, then you can figure out a rate by that. Correct? I know I don't have everything exactly on the card, however, I think there is enough information there to plug numbers in and find the rest of the unknowns. Correct?

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I would think that if you have a duration, and a lobe center, you can see that the lobe center is closer to the opening than to the closing, which shows that its asymmetrical in design. Then you figure, lets just say you have 60º to get to .400" of lift, then you can figure out a rate by that. Correct? I know I don't have everything exactly on the card, however, I think there is enough information there to plug numbers in and find the rest of the unknowns. Correct?

 

Sure, you can figure out that it is asymmetrical, but not 'how' asymmetrical it is.

 

For instance, not all 240° .500 lift cam lobes have the same shape, one could have a .200" lift duration of 190° and the other have a .200 lift duration of 230°, resulting in two radically different cams that have the same .05" duration.

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Also remember, you will need new rocker arms with a new cam. The best price I have seen on rockers are at AZC. I am about to do an Isky regrind here within the week and my total costs including rockers comes right at around $600, thats cam, springs, retainers, lash pads and rockers.

 

 

Dalta cams aswell as a few otheres can resurface your rocker arms. I think delta told me $3 or $6 each.

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