Designing Camshafts

In reply to mke :

Please don't waste time on the HE head. It's terrible. 

•     I think the Pre HE numbers you posted from Mobeck sound about right for the Pre HE ( the good head.) also called the Flathead 
•       The numbers Mobeck posted reflecting their port work are higher than what I remember flowing. But like I said I removed the throat and I know that's a mistake now.
       Before I make the final cam plan I'll properly port one cylinder and see what those numbers wind up at.  
  
  I thought I saw the HE numbers someplace. I'll go back and look  but off the top of my head I think they are like 121 for the intake  and actually worse than that.  
  I'll be right back 

frenchyd said:

In reply to mke :

Please don't waste time on the HE head. It's terrible. 

•     I think the Pre HE numbers you posted from Mobeck sound about right for the Pre HE ( the good head.) also called the Flathead 
• 
   

The Mobeck graph is the only data I have, I just realized it Pre HE...I only saw the HE part

So whatever model I make will be wrong if you opt for the HE high compression but I can probably estimate those heads flow pretty close it you can tall me what cams it has and valve sizes when we get to that point.  I can throw different turbos on as the software has most of the common flow curves for them...gas vs E85 vs Methonol all very easy once the model is built

mke said:

frenchyd said:

Paul_VR6 (Forum Supporter) said:

I have a marketplace notification setup for v12, I kinda want one now 

 Too bad,  I coulda brought you one during the Christmas break. I went through PA to pick up my fender flairs. 
   Should I be looking around for you?  Any preference, Pre HE, HE?  Running, turns over? Parts?   Budget?  Looking for a car with it?  

I wasn't paying any attention to locations and had it in my head Paul was in England until I saw just PA .....30 miles away.  I may have just found my new dyno shop 

Edit: wait....is there a dyno at the shop or do you have a place you go to?

We don't have one we usually use NGP in Aberdeen they have a dynojet and we get good access. 

For the v12 I'd like a car around it, figure it won't run as there is a book called Jags that Run to fix that part.

mke said:

frenchyd said:

In reply to mke :

Please don't waste time on the HE head. It's terrible. 

•     I think the Pre HE numbers you posted from Mobeck sound about right for the Pre HE ( the good head.) also called the Flathead 
• 
   

The Mobeck graph is the only data I have, I just realized it Pre HE...I only saw the HE part

So whatever model I make will be wrong if you opt for the HE high compression but I can probably estimate those heads flow pretty close it you can tall me what cams it has and valve sizes when we get to that point.  I can throw different turbos on as the software has most of the common flow curves for them...gas vs E85 vs Methonol all very easy once the model is built

mke. 
 I will be using the Pre HE  Flathead non smog heads.  
   But they are actually better than what they flow. Here's why. 
    They don't have a combustion chamber. !  
     When the valve opens the charge can go all the way to the cylinder wall and the port is aimed to hit the wall at an angle. The combustion chamber is in the piston which is moving away  from the valve. 
   
A normal valve opens and the charge has to go over the edge of the combustion chamber  then back down again before it fills in the cylinder.  2 almost 90 degree turns. As the piston goes down. 
  
 We know that every change in direction  the charge takes reduces flow.  But a flow bench won't measure that. In fact  almost all flow bench testing  is done in the open air. 

See, no combustion chamber. 

My best guess as to intake and exhaust flow. Once I redo the port work is around 160 CFM intake and 130 CFM exhaust. 
      At this point unless I can dig up some more cash I'll probably have to settle for regrinds. 

The only time huron beats wedge is with a small bore.

frenchyd said:

    They don't have a combustion chamber. !  
 

Infact  almost all flow bench testing  is done in the open air. 

As you said the Chamber is in the piston which is very common.  Dished piston the dish is at least part of the CC if not most of the CC.  Normally the issue is the valves are shrouded because they are sunk into the head but you don't have that so nothing to fix there.  Bolt the head to a cylinder, bolt it to the flow bench,  get numbers,  and they will be fine.

I don't know what you mean about flow testing in open air.  For sure there are lots of ways to collect bad data but normally everyone understands the head goes on cylinder with a bore as close as possible to the real bore.  The other piece most people understand is a velocity stack is requires on the intake at a minimum, the actual intake is preferred.  

The mobeck numbers for the jag head look a lot like the ferrari head numbers from the same time period so I'd assume they are probably about right.

When I get the DM6 key, I'll plug it all in and see what happens.

Paul_VR6 (Forum Supporter) said:

The only time huron beats wedge is with a small bore.

I think it was Climax who proved you wrong. Well maybe that's what you're saying?  I'm pretty sure it was formula 2 in the 1960's   
   I'll read Jaguar history because the Irony is the two engineers who helped design theJaguar 6 cylinder during WW2   With Lyons went to Coventry Climax following the factory fire. Because of the success of the XKE  William Lyons  went shopping and bought Coventry Climax and got those two engineers back.  
   When Lyons wanted his V12 they built it and used the heron head.  They actually made as much power as the Hemi did by going 300 cc bigger. 

Is there any relevance to the huron vs wedge discussion when huron (or huron like) is the only option? 

If switching to the 4V 6 cly heads is an option do that, but otherwise???

True I went from huron to pent roof 4 valve, but that does feel like cheating.

mke said:

Is there any relevance to the huron vs wedge discussion when huron (or huron like) is the only option? 

If switching to the 4V 6 cly heads is an option do that, but otherwise???

If we're talking about the Jag V12 as a 4 valve engine, one side will practically bolt right on.  The other side you have to cut the drive off reverse it plus  change the timing cover to fit. . It's been done several times.   The problem is the compression winds up being something like 5-1  even with pop up pistons it's hard to get decent compression.

    When the factory did it properly the increase in power you'd expect wasn't  there and the added weight and increased fuel thirst made it not worth it for competition. 
   There is a guy in Australian who's been working on one for a very long time.   

In reply to frenchyd :

When did the last 2 valve F1 car run?

A 4V engine will make about 20% more hp for a given displacement of boost level.  On street cars  or race classes where you can up the displacement or boost it probably makes no differnce but same engine just swap the head and the parts that go with to match andf you will gain 20%.

mke said:

In reply to frenchyd :

When did the last 2 valve F1 car run?

A 4V engine will make about 20% more hp for a given displacement of boost level.  On street cars  or race classes where you can up the displacement or boost it probably makes no differnce but same engine just swap the head and the parts that go with to match andf you will gain 20%.

 Yes a 4 valve head will beat a 2 valve head on making power.  And nowdays all F1 cars are 4 valve.  
   I wonder why Jaguar stopped making 4 valve heads for their V12 after just those couple of heads they tried out in the race car.  The reason they gave is the added weight up high like that  ruined the handling and used too much fuel.  
What do you think the reason was?  

frenchyd said:

What do you think the reason was?  

Cost.  They came up with a really cheap head top produce and it delivered acceptable performance.  That makes car companies very happy, if not their race teams.

Today, for roadracing I'd be looking spin an engine with a 70mm stroke to 10-12k and from 5.3L expect to make around 1000hp or maybe a bit more.  

In 1970 I'm pretty sure there were no valve springs that would survive what I just describe.  They were WAY better than the 50s springs but still a problem.  Over at ferrari the street engines were 2 cam with rockers while the race engines 4 cam without...so they could spin them faster. 

You are working on a budget so anything out of budget means no race car on the starting line which is worse than a last place finish in my view.  So IMHO the goal for you're 2nd build (the 1st build is any running engine you find + 2 turbos you have) is what off the shelf parts can be put together with things you can make in your shop to get you out on the track in budget.

Wikipedia tells me there is an 84mm stroke crank...can you get one?  there is no replacement for displacement.  When you bump the displacement at a fixed head flow the max rpm drops and the torque goes up about proportionally, so about 17% less rpm and 17% more torque...about the same HP.  But, Lower RPM likes lower duration cams....cam problem solved or at least reduced.  If you can port the heads, build a set of headers, maybe build an intake you might touch 500hp....we'll see what the software says.  I think the budget path is something like this but I don't know if any of the rods or pistons work with what cranks as custom pistons is about $1500-$2000 so not budget friendly.

If you can't swap the crank then porting, bigger valves is possible, headers, intake and its a 400-450hp engine I'd guess. 

Can you cut the desk of the block to up compression if pistons are out of budget? This is part of what I was thinking on the crank change...that would bump the CR by 17% to if the 5.3L pistons will work with the 84mm crank..so 9.3, if you can deck the block maybe 9.5 or so and that is not too bad and you haven't spent much money.

In reply to mke :

I wouldnt say lower rpm likes lower duration, especially in the context of adding displacement. Id say bigger cubes like bigger duration, because it tames them a bit. So a big motor could run a big cam and actually have a usable power band.

In reply to mke :

The 84 mm crank is rare. First made in 1993 but 2nd 1/2 of 94 Ford went from Forged EN 40 steel that's hardened post machining.  To Sintered Iron.  Roughly 3400 84 mm cranks are made with the forgings. 1700  came here to America.  Plus by then Ford had cured the unreliability so they are highly prized.  Going price for 6.0 liter  engines is $3-5000.  Compared to $300-500 for the 5.3
  The stock valve spring don't float until 8300RPM. ( due to light spring assemblies  and mild profile).  Isky has inexpensive springs that raise that to 9700 rpm.  Then you can buy. formula 1 spring to raise valve float limits to silly. 
       There is a way to get  13-1 compression  by using the early 7.8-1 compression pistons and milling some of the top of the piston off. The trouble is then you have to relieve  room for the valves  and instead of a Hemi chamber you wind up with  a horrible mess. 
       

We tried something like that but only was milling 060 off the deck and gaining 2pt compression. Messed up the chamber enough that it didn't make any more power vs stock comp. We had another hypo that the quench area step height wasn't large enough, but never proved it. 

Opti said:

In reply to mke :

I wouldnt say lower rpm likes lower duration, especially in the context of adding displacement. Id say bigger cubes like bigger duration, because it tames them a bit. So a big motor could run a big cam and actually have a usable power band.

 A useable power band isn't important on a race car.   1500 rpm is plenty especially if you have the type of gearbox where gearsets  can be quickly changed to ratios more suitable to the track.      
     I had a Halibrand quick change rear end and the Seinz quick change gearbox. 
 With 3 different sets of gears for the Seinz  and 12 sets of gears for the Halibrand. The permutations seemed almost infinite.  Plus Halibrand offered something like 54 different sets, while others offered many more. Seinz had so many I could shift gears every few hundred rpm. 
I still have the gearbox and the gear sets.  Plus a quick change rear end would be legal in Vintage because the Group 44 3rd car had one. 

In reply to frenchyd :

A useable power band is everything in an autocross car where you often stay in one gear most of the run.

Paul_VR6 (Forum Supporter) said:

We tried something like that but only was milling 060 off the deck and gaining 2pt compression. Messed up the chamber enough that it didn't make any more power vs stock comp. We had another hypo that the quench area step height wasn't large enough, but never proved it. 

That's the flaw with combustion chambers. Even with wedge part of the valve is shrouded,  forcing flow to go up and over the chamber. 
    Another part of the flow has to go in the valve relief pocket  making the flame shape less than ideal. 
     In England the pre HE pistons were 9.00-1  except for part of 1980 when it was 10-1  that engine had 314 horsepower compared to America's 262. 
  Those are net HP. So as installed on a race car it would be around 350+ horsepower. 
      Cosworth made pistons for Jaguar in the 1980's through about 2000 thier pistons were very light, strong, and had a heart shaped combustion chamber in them.  Said to be worth more than 28 horsepower over the stock Hemi combustion chamber piston. 

In reply to Stampie :

Absolutely.  I probably should have clarified Wheel to Wheel  race car.  

Paul_VR6 (Forum Supporter) said:

We tried something like that but only was milling 060 off the deck and gaining 2pt compression. Messed up the chamber enough that it didn't make any more power vs stock comp. We had another hypo that the quench area step height wasn't large enough, but never proved it. 

I watched an Italian company testing combustion chambers on a one cylinder test engine.  Each little change made noteworthy power changes.  From squish area, shape, and depth through swirl,  flow,  shape, compression etc etc.  the one little cylinder had more than 4000 test hours. 
   I think it was Ducati 

mke said:

frenchyd said:

What do you think the reason was?  

Cost.  They came up with a really cheap head top produce and it delivered acceptable performance.  That makes car companies very happy, if not their race teams.

Today, for roadracing I'd be looking spin an engine with a 70mm stroke to 10-12k and from 5.3L expect to make around 1000hp or maybe a bit more.  

In 1970 I'm pretty sure there were no valve springs that would survive what I just describe.  They were WAY better than the 50s springs but still a problem.  Over at ferrari the street engines were 2 cam with rockers while the race engines 4 cam without...so they could spin them faster. 

You are working on a budget so anything out of budget means no race car on the starting line which is worse than a last place finish in my view.  So IMHO the goal for you're 2nd build (the 1st build is any running engine you find + 2 turbos you have) is what off the shelf parts can be put together with things you can make in your shop to get you out on the track in budget.

Wikipedia tells me there is an 84mm stroke crank...can you get one?  there is no replacement for displacement.  When you bump the displacement at a fixed head flow the max rpm drops and the torque goes up about proportionally, so about 17% less rpm and 17% more torque...about the same HP.  But, Lower RPM likes lower duration cams....cam problem solved or at least reduced.  If you can port the heads, build a set of headers, maybe build an intake you might touch 500hp....we'll see what the software says.  I think the budget path is something like this but I don't know if any of the rods or pistons work with what cranks as custom pistons is about $1500-$2000 so not budget friendly.

If you can't swap the crank then porting, bigger valves is possible, headers, intake and its a 400-450hp engine I'd guess. 

Can you cut the desk of the block to up compression if pistons are out of budget? This is part of what I was thinking on the crank change...that would bump the CR by 17% to if the 5.3L pistons will work with the 84mm crank..so 9.3, if you can deck the block maybe 9.5 or so and that is not too bad and you haven't spent much money.

 

 
  Any idea how thin stock pistons can be milled to before they will fail?  I've got to assume the factory put some extra aluminum  in them . The HE piston is flat topped and even with the top of the cylinders/ deck. 

  You are absolutely right. The 2nd engine is definitely budget limited. And I agree not racing is much worse than coming in dead last. 

My challenge engine    I have 3 good engines right now. 1 pre HE and 2 HE's  I might have to do some parts shuffling  but I have plenty of gaskets sets and odd gaskets. So that's no problem. 
 
     Since the block is open decked, milling the block would be straight forward. But dealing with the timing chain  would be a serious problem.  Removing links  could only be done  at certain spots without messing up The distributor,  which his driven by that.  And removing  deck would require milling the top of cylinder liners. 

In reply to frenchyd :

I was just making sure you were aware.  I want to beat the best Jaguar V12 you can send to the Challenge.