Designing Camshafts

mke said:

I'm goin to repart the @050? 

Had to go back to my notes and it was 1mm so closer to .040", and I may have found an error in the rocker ratio calculation now as well. Will update once I fix the math (it's a floating roller rocker so its weird from cam to valve motion). Advert duration on my big ones is well over 300deg. Reminder that I'm drag race on methanol trying to rev a high compression boat anchor to the moon. 

Frenchy those heads look a lot like our 12v vr6 heads and we can make 600whp on 2.8L on E85 on a completely stock engine at 30psi and we only eat pistons sometimes 

In reply to Rigante :

I thought it was 9L and that was pushing it. 

Paul_VR6 (Forum Supporter) said:

mke said:

I'm goin to repart the @050? 

Had to go back to my notes and it was 1mm so closer to .040", and I may have found an error in the rocker ratio calculation now as well. Will update once I fix the math (it's a floating roller rocker so its weird from cam to valve motion). Advert duration on my big ones is well over 300deg. Reminder that I'm drag race on methanol trying to rev a high compression boat anchor to the moon. 

Frenchy those heads look a lot like our 12v vr6 heads and we can make 600whp on 2.8L on E85 on a completely stock engine at 30psi and we only eat pistons sometimes 

Heron heads flow remarkably. When the combustion chamber is in the head shortly after the charge leaves the valve seat it has to take a 90 degree turn followed by another 90 degree turn in order to get out of the combustion chamber and into the cylinder. 
  Each 90 degree turn costs energy and slows up flow. 
   Without the combustion chamber to dodge in a heron head the charge can flow all the way to the cylinder walls  before starting to swirl. Not only do Heron heads flow more they also swirl which does a wonderful job of mixing fuel and air. Helping to more completely burn the charge. 

frenchyd said:

mke 

Pump E85 can be 53-86 % ethanol and 15% gasoline. Or you can buy It by the 5 gallon can or 55 gallon drum.  
 Then it's 85 % ethanol  ( 114 octane compared to methanol's  116 octane ) and 15% 100 octane racing gasoline. 
No I mean ignition timing.  To prevent preignition  on America's 91 octane it's only 8 degrees. 
     

Alcohols contain oxygen (liquid air) and have much high heat of vaporization so Gas to 100% ethanol adds something like 7-10% and gas to 100% methanol added something like 15-20% kind of depending on the cooling.  Result may vary, blah, blah.

Octane is a whole different thing....you have enough for the application or you don't.  If you are adjusting timing based on knock rather than hp, you have the wrong fuel for the setup or wrong setup for the fuel.  Again, there are exceptions, mostly in boost land where most booth but less timing is a higher net. 

In reply to yupididit :

10.058 litres! according to AJ6 engineering

frenchyd said:

Heron heads flow remarkably. 

Our Heron style heads don't, it's a 90 in and some very goofy ports for packaging. Still they can make some power.

Rigante said:

Does this the engine have the E type heads 

 

Or the later May Fireball heads?

on the later heads the exhaust valve is up high and really shrouded. they did this for emissions /MPG but it limits flow hugely. Lots of chat on the Jag forums about what  to do with them.

 

I think having a really good look at the flow is the first port of call rather than potentially pricey cam builds. Jag tuners tend to add capacity as these have huge potential and you can get 10L if you really try 

 

 

The early " Flat heads" were in production from 1971- until 1981 ( last produced in 1980). So 6 years after the XKE 
 The HE heads from 1981- 1995 ( V12's built in 1996&97 were made from stores) 

 I have 3 sets of the flatheads and 2 of the HE. 
    I started building V12 race motors in the 1980's  yes a great amount of attention was spent on gaining flow. But to get even flow in all 12 cylinders took me over 200 hours. ( and that was after I found out there were 2 different casting cores and casting companies). 2 cores for the Flathead and 2 cores for the HE  for a total of 4 cores. To be fair I've never wasted time on the HE. 
     Hand porting is slow work especially given the long ports Jaguar uses. Too often I'd carefully measured with go-no go gauges I made only to break through.  
     The Forum gave me the solution when I was told what casting marks to use. 
     I eventually used my verticals mill and went from 200+ hours per set of heads to 12.  
 I used my own homemade flow bench to measure flow.  As long as it was improved and all 12 cylinders were equal  I didn't care what the numbers were. 
     We can have a long discussion about flow benches if you'd like.   I digress 

      What I found out was with stock cams  there was very little difference  in power between ported and stock.  
    Think about that. The stock cams run out of steam at about 5500 rpm and less than that  flow volume is more than adequate.   AJ6 made actual  mid range gains by simply cleaning up the entry flow by sliding Bell mouthed tubes  into the runners.  

      Once you have cams that can work at 7000 or greater  the demand won't be met  by material you can remove on the intake or ports. 
     To be sure TWR was able to get 500 hp using stock intake manifolds and stock iron exhaust manifolds. However I kept hearing rumors that the foundry's were pretty busy doing special projects.  

In reply to frenchyd :

Thanks for the comprehensive answer

Paul_VR6 (Forum Supporter) said:

frenchyd said:

Heron heads flow remarkably. 

Our Heron style heads don't, it's a 90 in and some very goofy ports for packaging. Still they can make some power.

Yeh , I should have identified Jaguar heads.  Didn't Coventry Climax work on Fords Heron heads for their formula 2 engines?

  But I'm sure your heads would have flowed a lot worse  if it had a combustion  chamber in the head

mke said:

frenchyd said:

mke 

Pump E85 can be 53-86 % ethanol and 15% gasoline. Or you can buy It by the 5 gallon can or 55 gallon drum.  
 Then it's 85 % ethanol  ( 114 octane compared to methanol's  116 octane ) and 15% 100 octane racing gasoline. 
No I mean ignition timing.  To prevent preignition  on America's 91 octane it's only 8 degrees. 
     

Alcohols contain oxygen (liquid air) and have much high heat of vaporization so Gas to 100% ethanol adds something like 7-10% and gas to 100% methanol added something like 15-20% kind of depending on the cooling.  Result may vary, blah, blah.

Octane is a whole different thing....you have enough for the application or you don't.  If you are adjusting timing based on knock rather than hp, you have the wrong fuel for the setup or wrong setup for the fuel.  Again, there are exceptions, mostly in boost land where most booth but less timing is a higher net. 

When working with boost priorities change a bit. From Octane to cooling. 
      I learned that back in the 1990's.   Back then racing gas wasn't so silly expensive.   The guy Who helped me get my Champ car running on a pair of used Saab turbo's  used to squirt windshield washer fluid  into the intake manifold  to cover up where we couldn't richen  the ECM enough to meet cooling  needs. 
    We never used knock sensors. Just exhaust gas temps. 
  Here in Minnesota winters where air temps get down to 40 below our WW fluid can be bought with 10-20 -40% methanol.   The Bosch system we used could be richened some with a knob on the back of the ECU  

It also would trigger a cold start injector when  boost went over 3 psi.  And he had a sensor that triggered the WW fluid system when exhaust temps rose too much. 
  It was a real kludged job.  Too rich, too lean, too rich and too lean again.  We got away with it by using Gold palladium spark plugs and Windshield washer fluid.  

Paul_VR6 (Forum Supporter) said:

mke said:

Even then....yes can shift things a bit by changing the lobe centers, but not a ton

I have some data that says otherwise, but only IRL. We have done things like backed the intake cam one tooth to give more clearance with full vvt, and seen gains in the top end that didn't make sense. Exhaust seems to do less, usually we leave that locked.

Also, turbo, most of the time just the stock grinds are fine because you make more power easily by just turning the boost up. I have one customer with a 2.8, huron style head, making over 600whp on e85 stock low lift, low duration camshafts. Just a cam swap is worth ~100whp but why bother 

The difficulty with the internet is one person says one thing another agrees or disagrees  etc the original questions get lost. 
  Let me see If I can straighten this out. 
  What increasing the lobe center does is it softens the rate of acceleration of the lifter. So instead of the spring being shocked it's gradually moving up. 
      Cam timing with regrinding SOHC   is a tough trade off.  Yes you can move cam timing a bit at the cost of less duration. ( there is only so much metal )  Computer simulation gives me that answer.  Lift vs Duration is also another question for computer simulation. 
 

   What I haven't heard a single word about is long rod. Or short stroke.  Effect of alcohol and Boost. With regard  to lift or  duration.  
      Well, yes I know too much is a bad thing. And too little you underperform. 

 .  
    

Do you have  reliable flow numbers for the heads?

Its been danced around a bit but without flow numbers you really can't pick a cam....other than just do what others have done.    Several of us have thrown out this duration or that, but if you need 20% more air you can get it with 20% more duration or 20% more head flow so its not really possible to know if its a lot of cam or a little without head flow.

frenchyd said:

When working with boost priorities change a bit. From Octane to cooling. 

You my point.  Properly setup and tun ed

Gas makes x hp

Ethnol 1.08x

methonol 1.15x. 

That its it. 

In reply to frenchyd :

Just watch the video that Jerry posted, and your questions on rod length vs stroke will be answered.
A little bit simplistic, but everything is explained with pictures and animations and examples.
Just watch it.

mke said:

Do you have  reliable flow numbers for the heads?

Its been danced around a bit but without flow numbers you really can't pick a cam....other than just do what others have done.    Several of us have thrown out this duration or that, but if you need 20% more air you can get it with 20% more duration or 20% more head flow so its not really possible to know if its a lot of cam or a little without head flow.

What I really remember was how improving the flow didn't yield much increase until I replaced the cam. 
 AJ6 Engineering spoke indirectly about that.   And sold a modified intake manifold that subtly  reduced flow while improving mid range power.  Owners loved it because it filled in a hole on the street.  
     I recall how even stock flow numbers responded positively to methanol. I started out with stock numbers making 262 horsepower and with no change except 50% more fuel  I gained 55 horsepower. 
   It wouldn't have done that if the ports weren't big enough to allow all that extra mass 

 I worked it backwards on the computer and "ported"  the intake and heads to my maximum flow leaving the stock cam specs.  And lost 7-8 horsepower. 
 
Edit; I'm looking for the flow numbers. Not having any luck so far. It was in the attic but we've hauled all of the stuff in the attic downstairs. We are making the attic into an art studio.  It's big 30' x 30' with 8 foot ceiling at the peak and 4 walk in dormers  to provide natural light. The lakeside has a radiused  front where we will put windows to view the lake.  
     All those boxes of car books, magazines, etc have the numbers but I've only been through about 10% so far. The good news is that more than 1/2 of the original boxes     were tossed out ( after I checked them all carefully last year )   Probably less than 70-80 boxes to go. 

clshore said:

In reply to frenchyd :

Just watch the video that Jerry posted, and your questions on rod length vs stroke will be answered.
A little bit simplistic, but everything is explained with pictures and animations and examples.
Just watch it.

I did watch it several times. I now clearly understand what I thought was crazy. But I'm having trouble grasping how that affects flow.  It seems to me that the faster the piston moves the less efficient  it will fill the space.  But the slower it moves the less "vacuum" is created to fill the space.  In other words I know I can't have my cake and eat it too.  

frenchyd said:

What I really remember was how improving the flow didn't yield much increase until I replaced the cam. 

That is telling you the head was not the flow restriction and you need to look at the intake or exhaust...remember its a system and its very common to find the factory parts match meaning you get very little by replacing/modifying a single part.

The cam adds more flow time so you get more through all components, at least to a point.

Head porting add more flow to the head but its only helpful if the intake and exhasut can also flow the increased amounts.....remember the conversation we had about headers?  Apply it now as its unlikely the factrory exhaust has much extra capacity.  Headers and tail pipes are very well understood and its pretty straight forward to get them close.

Intakes are more a challenge so I do all my intake flow work with the intake system bolted to the head until I have data that tells me its ok to do it anyother way.

In reply to mke :

My home made flow bench is not calibrated   I just looked for universal flow improvement. The same amount on each cylinder.  I got numbers by working backwards  

I did my port  work on the intake and then the head  To measure I hooked both up. 

In reply to frenchyd :

so its the exhaust ;)

My flow bench is homemade as well, I calibrate it with oriface plates.

Paul_VR6 (Forum Supporter) said:

Had to go back to my notes and it was 1mm so closer to .040", and I may have found an error in the rocker ratio calculation now as well. Will update once I fix the math (it's a floating roller rocker so its weird from cam to valve motion). Advert duration on my big ones is well over 300deg. Reminder that I'm drag race on methanol trying to rev a high compression boat anchor to the moon. 

I was forgetting both drag racing and 2 valve.

I'll sat this too the graph for my engine are probably a specail case.  WAY back I did some quick required  flow math and headed to the flow bench and worked like a dog to make it so, then realized I'd plugged in a RWHP number and treated it as a crank number....meaning I had about 20% more flow than I meant to have. 

So now, tuned for max output it wants to peak at 10500-11000 rpm when I ment 8500.  I think it will end up around 9k with the headers I built, but for sure there is another 5-10% hp to be had if I replace the tri-y headers with step-headers.  Kind of an odd place to be.....

mke said:

frenchyd said:

What I really remember was how improving the flow didn't yield much increase until I replaced the cam. 

That is telling you the head was not the flow restriction and you need to look at the intake or exhaust...remember its a system and its very common to find the factory parts match meaning you get very little by replacing/modifying a single part.

The cam adds more flow time so you get more through all components, at least to a point.

Head porting add more flow to the head but its only helpful if the intake and exhasut can also flow the increased amounts.....remember the conversation we had about headers?  Apply it now as its unlikely the factrory exhaust has much extra capacity.  Headers and tail pipes are very well understood and its pretty straight forward to get them close.

Intakes are more a challenge so I do all my intake flow work with the intake system bolted to the head until I have data that tells me its ok to do it anyother way.

 

The one constant professional head porters have told me is exhaust flow should be 80% of  intake flow. With the Flathead it's  at 94% and the HE it's  87%. ( both stock).  
     

frenchyd said:

The one constant professional head porters have told me is exhaust flow should be 80% of  intake flow. With the Flathead it's  at 94% and the HE it's  87%. ( both stock).  

Head flow and exhaust system are not at all the same thing.  Exhaust is everything after the head on the way out....and your to use some help.

The heads you don't have are irrelevant....so what are your heads at?

I like to be at 80-85% on the head on sports cars type applications for whatever that is worth.....but the answer changes with rpm and a few other factors so as always, results may vary.

In reply to mke :

mke 

 I have 3 flatheads and 2 HE's   ( sets)   Plus 3 complete engines.    I'm working very hard not to acquire any more.  I've probably got enough parts to build another.   That's down from my previous peak of 50. 
      I also have  5 different transmissions three sets of rear ends 

frenchyd said:

In reply to mke :

mke 

 I have 3 flatheads and 2 HE's   ( sets)   Plus 3 complete engines.    I'm working very hard not to acquire any more.  I've probably got enough parts to build another.   That's down from my previous peak of 50. 
      I also have  5 different transmissions three sets of rear ends 

Lets try another way...what engine are you asking for help designing cams for?

Its time to  make a list of the parts you are using so we can figure out what cam design makes sense for that specific engine combination.  I don't need any expiation about the parts at this time, just a list.  I filled in what I know, which is very little.  If the item is undecided and will be purchased later to match the cam just say "match".  Then I will get my software key back give you a couple graphs and this thread can end  rather than continue in circles.

Bore = 

Stroke =

Connecting rod length=

Compression ratio=

Head flow=

Combustion chamber design (picture please)

Intake setup (please picture)=

Turbo make and model=

Exhaust = log manifolds, no mufflers

Tailpipes  =

Fuel  = E85

Intended use = 

desired use rpm RANGE = ??? to ????

In reply to mke :

Good luck