Designing Camshafts

Mr_Asa said:

frenchyd said:

Javelin said:

frenchyd said:

DarkMonohue said:

frenchyd said:

  If I'm using my own cores... <snip> I can dig through his scrap cam piles and find cores that I can machine down to fit my engine.

So you are planning to whittle Jaguar V12 camshafts out of camshafts from an unrelated engine?

Please document this endeavor. It sounds fascinating.

Diesel cams from Semi's tend to be a lot bigger than automotive cams.  Plus most are 6 cylinder which makes it more likely  the lobs will be where I can use them.  
    Finally. It's a straight forward machining process to reduce diameter and shorten things.  

Again. Camshafts do not work that way.

See, I thought a camshaft timed the valves when to open and close.   
   So if camshafts don't do that how do they work?  
 

No offense here, but I think you might need to re-read everything or work on your reading comprehension or something.  

No one said anything about camshafts not opening or closing valves.

You did.  You said "camshafts don't work that way".     
  The lobes open and close the valves based on where and how much lift and duration the masters have. The Masters guide the duplicators. 
     Have you ever watched cams being ground?   If not, they basically put the masters on a shaft at the right point and use that as the master in the duplicator.  Once they have duplicated the profile on  your camshaft they take them off and heat treat  the cam ( or cams in my case). 
    I'm sure most domestic engines have masters but low production engines start out with existing cams unless you provide the core. 

frenchyd said:

Mr_Asa said:

frenchyd said:

Javelin said:

frenchyd said:

DarkMonohue said:

frenchyd said:

  If I'm using my own cores... <snip> I can dig through his scrap cam piles and find cores that I can machine down to fit my engine.

So you are planning to whittle Jaguar V12 camshafts out of camshafts from an unrelated engine?

Please document this endeavor. It sounds fascinating.

Diesel cams from Semi's tend to be a lot bigger than automotive cams.  Plus most are 6 cylinder which makes it more likely  the lobs will be where I can use them.  
    Finally. It's a straight forward machining process to reduce diameter and shorten things.  

Again. Camshafts do not work that way.

See, I thought a camshaft timed the valves when to open and close.   
   So if camshafts don't do that how do they work?  
 

No offense here, but I think you might need to re-read everything or work on your reading comprehension or something.  

No one said anything about camshafts not opening or closing valves.

You did.  You said "camshafts don't work that way".     
  The lobes open and close the valves based on where and how much lift and duration the masters have. The Masters guide the duplicators. 
     Have you ever watched cams being ground?   If not, they basically put the masters on a shaft at the right point and use that as the master in the duplicator.  Once they have duplicated the profile on  your camshaft they take them off and heat treat  the cam ( or cams in my case). 
    I'm sure most domestic engines have masters but low production engines start out with existing cams unless you provide the core. 

Now this is a WONDERFUL example about how you don't read.

You are saying that I said "camshafts don't work that way."?  Would you like to reread the posts, who said them, and then maybe reconsider your comments?  All the relevant quotes are in this post.  You don't even have to scroll.

bentwrench said:

I am very certain that a cam meant for NA use will not do well under boost. And vicey versey.

Many think that until testing happens. A lot depends on turbo selection, not huge backpressure helps. Generally any cam that is streetable na can be used with pump gas limited boost levels. Ymmv. 
 

*also ignoring the last page other than its easier to start with a piece of round stock than a cam from a different engine 

In reply to Paul_VR6 (Forum Supporter) :

 With E85 if I tune for that only I don't need the sensor and input  from the sensor.   Since the challenge  limits what I can spend I can really " save" by not  doing as fancy of boost relief.  And put that stuff on after the event.   
    Now I'm thinking  I should use the early Flathead with the 7.8-1 compression  with its improved flow  for higher (11.5-1 compression) and lower flow. 
  You are absolutely right regarding round stock. However a $2000 budget limited car rewards work you do yourself.  Instead of spending a lot for the right round stock spend a buck or two and cut it down myself. 
    I'm deeply torn between those who are following me to see what a cheap Jag can do and showing what I can do on a tiny budget.  
    

In reply to frenchyd :

I hate to admit it but you draw me in just to watch the E36 M3 show.

Paul_VR6 (Forum Supporter) said:

bentwrench said:

I am very certain that a cam meant for NA use will not do well under boost. And vicey versey.

Many think that until testing happens. A lot depends on turbo selection, not huge backpressure helps. Generally any cam that is streetable na can be used with pump gas limited boost levels. Ymmv. 

Generally lift and duration for mild street n/a motors are just fine for boosted ones. The thing that makes all the difference is the lobe separation angle and amount of overlap. Generally good n/a cams will have a wide LSA with a decent amount of overlap between the closing of the exhaust valve and opening of the intake valve to promote cylinder scavenging (where the negative pressure of the escaping hot exhaust gasses help draw in the fresh air/fuel charge). This is anathema to turbochargers however, as it makes the turbo work against itself. Turbo cams tend to have tighter LSA's and much less overlap. (Superchargers are different since they have n/a style exhaust paths.)

Mr_Asa said:

frenchyd said:

Mr_Asa said:

frenchyd said:

Javelin said:

frenchyd said:

DarkMonohue said:

frenchyd said:

  If I'm using my own cores... <snip> I can dig through his scrap cam piles and find cores that I can machine down to fit my engine.

So you are planning to whittle Jaguar V12 camshafts out of camshafts from an unrelated engine?

Please document this endeavor. It sounds fascinating.

Diesel cams from Semi's tend to be a lot bigger than automotive cams.  Plus most are 6 cylinder which makes it more likely  the lobs will be where I can use them.  
    Finally. It's a straight forward machining process to reduce diameter and shorten things.  

Again. Camshafts do not work that way.

See, I thought a camshaft timed the valves when to open and close.   
   So if camshafts don't do that how do they work?  
 

No offense here, but I think you might need to re-read everything or work on your reading comprehension or something.  

No one said anything about camshafts not opening or closing valves.

You did.  You said "camshafts don't work that way".     
  The lobes open and close the valves based on where and how much lift and duration the masters have. The Masters guide the duplicators. 
     Have you ever watched cams being ground?   If not, they basically put the masters on a shaft at the right point and use that as the master in the duplicator.  Once they have duplicated the profile on  your camshaft they take them off and heat treat  the cam ( or cams in my case). 
    I'm sure most domestic engines have masters but low production engines start out with existing cams unless you provide the core. 

Now this is a WONDERFUL example about how you don't read.

You are saying that I said "camshafts don't work that way."?  Would you like to reread the posts, who said them, and then maybe reconsider your comments?  All the relevant quotes are in this post.  You don't even have to scroll.

What are you trying to say?  You keep on saying camshafts don't work that way. 
  Are you saying I don't know how a camshaft works?   
   Are you saying I don't know how to grind a camshaft ?  
  Are you saying it can't be done?  
 

   What are you saying?  Please explain yourself. 

In reply to frenchyd :

berkeley's sake you're dense.

Read what I said.  You can tell I said it because it is under my screen name.

Javelin said: Turbo cams tend to have tighter LSA's and much less overlap. (Superchargers are different since they have n/a style exhaust paths.)

All equal, tighter lsa is more overlap (assuming you are measuring it the way most do). Havent seen a downside in the 112-116 range that we use in the street cars na. 

Paul_VR6 (Forum Supporter) said:

Javelin said: Turbo cams tend to have tighter LSA's and much less overlap. (Superchargers are different since they have n/a style exhaust paths.)

All equal, tighter lsa is more overlap (assuming you are measuring it the way most do). Havent seen a downside in the 112-116 range that we use in the street cars na. 

Ah nuts, I got that backwards. It's been over 15 years since I was messing with cam profiles on turbo motors.

Granted I wasn't trying to make them out of lightposts or sawing V8 cams in half...

In reply to Mr_Asa : OK then tell me how you think camshafts work. 
   Oh by the way. How many racing engines have you built in your life from the ground up?  

  I'm guessing now,  60 years is a long time.  Probably around 20-30? or so. Let's see , straight 8 Buick, 55 Cad El Dorado , BMC A. Offy 270, Sunbeam 1750, MG TD, Ford Flathead, Buick 401  Chevy 327, Jaguar 3.8, Jaguar 2.4, Jaguar 4.2, Jaguar 3.4, Ford Kent, MGA1622, Buick 425, Datsun 1600(x4) Datsun 2000 (x3) for BRE.   Jaguar 3.8   Corvette 350, Offy 255, MGT series (x4)  Jaguar V12 Ford model A  Chevy 350, (x2) Chevy 430 small block. •••••• Jaguar V12 

In reply to frenchyd :

Dude! I'm the one that told you cams don't work that way! READ!!!

And the way I'm talking, since I'm sure you didn't READ my reply pages ago, is that you can't just grind random cams to fit or grind down an old cam to somehow get larger lift/longer duration without reduced base circles and all sorts of other things that have to be considered. You have no idea what you're doing and it shows with your lack of reading comprehension. 

Oh, and I've built dozens of engines, including this one:

Don't tell mke you can't grind your own cam. He's done it. 
 

 I don't know what happened to the picture I posted of the V12 camshaft.  But I said basically I need to start with a piece of 2" stock ( plus the flange, that's 28 inches long That would wind up giving me .500 lift over the stock .375. 
 I went on to talk about heat treating etc. 
     Is it easier if you start with a cam core, sure, but the challenge rules make it worth doing. Because the $2000 limit. So I trade a few hours (OK A lot of hours) making my own cam core.  
There is a lot more Engine work you can do if you're willing and have access to equipment. 
   So maybe you just want to order something. Not everyone is limited that way. 

frenchyd said:

In reply to Mr_Asa : OK then tell me how you think camshafts work. 
   Oh by the way. How many racing engines have you built in your life from the ground up?  

  I'm guessing now,  60 years is a long time.  Probably around 20-30? or so. Let's see , straight 8 Buick, 55 Cad El Dorado , BMC A. Offy 270, Sunbeam 1750, MG TD, Ford Flathead, Buick 401  Chevy 327, Jaguar 3.8, Jaguar 2.4, Jaguar 4.2, Jaguar 3.4, Ford Kent, MGA1622, Buick 425, Datsun 1600(x4) Datsun 2000 (x3) for BRE.   Jaguar 3.8   Corvette 350, Offy 255, MGT series (x4)  Jaguar V12 Ford model A •••••• Jaguar V12 

None.

Know how many times someone has advised me to reread something cause I'm being a damn fool and I go and reread it?  Every single time.

Considering your very very basic questions and misconceptions about motors, I would very much like to inspect your "racing engines" and look at your win:loss record.

In reply to frenchyd :

Wow you are not getting this. Unless you are a metal foundry, you are NOT making cam cores. Camshafts don't work that way. You are extrapolating from a very very limited knowledge base into something that is ludicrous, like the DEI Corvette guy.

But you know what, fine, prove me wrong. Find some Detroit Diesel cam and whittle it down until it fits in a Jag and fire that puppy up. I'll put $50 on it not lasting more than 30 minutes. Go ahead, I'll wait. 

In reply to Mr_Asa :

Sure. Just look up Black Jack Spl. These are the trophy's  that really mean something to me.   Most of the rest I didn't bother collecting or gave to corner workers. 
  If you look at my Name you'll see me on the pole at Navy North Island San Diego. Next to me is a Ferrari Testa Rossa. Behind him is the 1956 LeMans winning Jaguar D type behind him is another Ferrari Testa Rossa 

Behind me is the only 1957 Corvette SS made by Duntov.    Cars in that field were probably worth 200 million dollars  and the trophy on the top shelf.  The Crystal glass bowl says First in class. 
      There is a video of me Racing against Sir Sterling Moss  in the Bahama's  during speed week.   Watch it through to the end.  That's me getting up on the podium  to finish second to him.  That's the trophy on the second shelf. 
 

Have fun checking me out. I sure had fun racing. 
       

Javelin said:

In reply to frenchyd :

Wow you are not getting this. Unless you are a metal foundry, you are NOT making cam cores. Camshafts don't work that way. You are extrapolating from a very very limited knowledge base into something that is ludicrous, like the DEI Corvette guy.

But you know what, fine, prove me wrong. Find some Detroit Diesel cam and whittle it down until it fits in a Jag and fire that puppy up. I'll put $50 on it not lasting more than 30 minutes. Go ahead, I'll wait. 

Can't make your own camshafts? Without a foundry? 
  Please tell that to mke 

What a menace, certified goon and y'all have been going back and forth with him for 5 pages. LMAO

Some days I think frenchy must be some 13yo misreading his grandfather's journal. But kids these days have better things to do. 
 

that being said you (well not me, but one with the right tooling) can make a cam from a billet, without a core

Paul_VR6 (Forum Supporter) said:

that being said you (well not me, but one with the right tooling) can make a cam from a billet, without a core

sure, I designed and got a buddy to make me 48 lobes worth

But make a cam for 1 engine from a cam from another engine is a whole different thing.  Before heading down this path I tried to talk a couple cam grinders into re-timing my TR (testarossa) cams to match the 400i firing order and was told multiple times it can't be done....and that was just re-timing a few lobes, not taking a cam from 1 engine and putting it in a whole different engine.  I never want to say something is impossible but it is wat easier to scare from scratch than to do that.

Paul_VR6 (Forum Supporter) said:

All equal, tighter lsa is more overlap (assuming you are measuring it the way most do). Havent seen a downside in the 112-116 range that we use in the street cars na. 

When I think turbo or blower cam its got a LSA in that 112-116 range.  When I think NA its more like 106-108 so this post made me think a little. 

I'm pretty sure the longer duration the cam has the more LSA it wants and vice vera....but that 114-116 kind of represents the practical limit so at some point you have to just suck it up and live with the low to mid rpm reversion the overlap starts to cause and admitt its a dragrace cam 

Seems like a long shot but not impossible. If an old cam is the right length and generally bigger, why couldn't it be re-ground to a smaller physical shape? It's just a piece of metal, and getting something from a junk yard and whittling away on a mill or lathe using your own labor seems like the definition of Grassroots.  

I get kinda uncomfortable because  after all these years, in a place that is generally so welcoming - it's so predictable that a handful of people choose to be immediately dismissive and combative toward Frenchy. Instead of just skipping his stuff.

I might be in the category of "lots of posts that contributed very little" - but he certainly could win the award for "GRM most misunderstood". 

I really hope Tim and Margie will jump in the new red sports car and make a drive up to Minnesota and write a feature on Frenchy. There seem to be a lot of really cool stories that could be told. 

OHSCrifle said:

Seems like a long shot but not impossible. If an old cam is the right length and generally bigger, why couldn't it be re-ground to a smaller physical shape? It's just a piece of metal, and getting something from a junk yard and whittling away on a mill or lathe using your own labor seems like the definition of Grassroots.  

In theory sure, but the odds of having metal to cut everywhere you need the metal is pretty much 0%. You need 2.5-3" OD depending on the engine the cam is going into.  I used 8620 rods but if you had your heart set on iron you could by iron rods instead of steel and succeed.   Making functional engine parts is pretty hard......

mke said:

Paul_VR6 (Forum Supporter) said:

All equal, tighter lsa is more overlap (assuming you are measuring it the way most do). Havent seen a downside in the 112-116 range that we use in the street cars na. 

When I think turbo or blower cam its got a LSA in that 112-116 range.  When I think NA its more like 106-108 so this post made me think a little. 

I'm pretty sure the longer duration the cam has the more LSA it wants and vice vera....but that 114-116 kind of represents the practical limit so at some point you have to just suck it up and live with the low to mid rpm reversion the overlap starts to cause and admitt its a dragrace cam 

I think you've hit the nail on the head.  Turbo camshafts  do tend to fall in that LSA area of around 114-116  I hadn't noticed it before. I'd assumed individual needs would vary enough so that rules like that wouldn't apply. 
        I wonder how much of that is  cam grinders looking out for their customers best interest and leaving some bottom end  at the cost of some top end?  
      I know my Black Jack gave up everything below 3500 rpm in order to maximize  top end power.  I simply charged rear end gears to ensure    I never was below 4000 on the track.  You do that sort of trade off on race only cars. 
  The real answer I've been looking for  can only be found by work on the simulator, the dyno and then race track.  
     Because as much as I've learned to trust each I've  found enough variance to test and confirm. 
Numbers confirm  I can't afford that. Domestic engined people have millions of engines to sort out and find the optimum.  Jaguar made 121,000 V12 engines, only 1/2 of which came to America.  Of that 60,000    50+ years have whittled it down dramatically. Add  a complex and unique fuel system plus accidents,  rust, the nature of  collectors, very few were ever developed to their full potential.  And those by people older than myself. 
      So I guess I will never know.  It's a case of take my best option and go with it.