Frenchy call this number 1-707-545-6115
The man you will want to speak with is Dema Elgin Elgin Cams
Some of his best customers include:
Elgin Cams has the largest percentage of cams used at "Mid-Ohio" from GT-1 to Formula-V. In his spare time, Dema travels the country giving speeches on cams and camshafts as well as doing extensive traveling for fun. He also recently retired from teaching at DeAnza and Skyline Colleges, Automotive Technology Classes after several decades.
Tell him Larry Mertl(rip) says Hi.
frenchyd said:
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 ) ...
Hold the phone.
Valve acceleration is a result of cam lobe design. It has nothing to do with lobe centers.
Your engine has intake and exhaust lobes on the same camshaft. Lobe centers, or lobe separation angle, are effectively fixed. You cannot adjust that number unless you're grinding the lobes down, which seems somehow counterproductive. But your cam grinder should determine what that angle is so that he can take into consideration when selecting a grind.
Your statement, "there is only so much metal", suggests that you are regrinding the existing lobes and not welding them up. That's likely to impose a real limitation on the profile you can create by removing metal. You are going to reduce the base circle of the cam. Some valvetrains are more tolerant of this than others. This engine uses shim-under-bucket followers, correct? That's more forgiving than shim-over, but there are still limits.
One point here that I think you may be overlooking. Unless your local cam grinder actually is Bruce Crower or Dema Elgin, he's not going to sit down with you over tea and finger sandwiches and engineer a boutique profile just for you. He is going to ask about your lifter diameter and your valvetrain and your intended RPM range and a few other things, and then he's going to pick a master (probably very mild if you are not welding) that will probably work alright.
I am very certain that a cam meant for NA use will not do well under boost. And vicey versey.
You want a cam with no overlap, so you don't push raw fuel out the exhaust, and so the exhaust back pressure doesn't pollute the new charge.
Also I don't see boost fitting into the challenge financial restrictions. That barge is going to need the ponies.
I expect a V12 would turn a T-5 trans inside out, aren't those trans torque limited?
A Th400 can be built strong enough to twist off the driveshaft on a second gear shift..
In reply to bentwrench :
The Nelsons turn 20PSI + on reground camshafts. On one occasion 40 PSI totally stock bottom end 4200 cc. Six Cylinder. They ultimately made 824 rwh ( times 1.2 at the flywheel. )
Jaguar runs tiny lift (.375 at the valve) and practically no duration ( 210) a regrind won't generate much more than that. But will add 100 horsepower which probably will help
Check on E Bay and Amazon for best prices but I only paid $237 for a pair of T3/4's. With built in boost limit and free shipping. The car is a Southern California car so I can chop up the stock exhaust and make it work.
I may not be able to turn 9 sec quarter miles but hopefully be a little faster than they are in the auto cross. My best guess is at around 25-2600 pounds.
Please Note I won't be there. The car, my truck, and trailer will be with Erick and Jeff if they can make it.
Two of my transmissions are GM Turbo 400's which for autocrossing and drag racing should be good.
DarkMonohue said:
frenchyd said:
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 ) ...
Hold the phone.
Valve acceleration is a result of cam lobe design. It has nothing to do with lobe centers.
Your engine has intake and exhaust lobes on the same camshaft. Lobe centers, or lobe separation angle, are effectively fixed. You cannot adjust that number unless you're grinding the lobes down, which seems somehow counterproductive. But your cam grinder should determine what that angle is so that he can take into consideration when selecting a grind.
Your statement, "there is only so much metal", suggests that you are regrinding the existing lobes and not welding them up. That's likely to impose a real limitation on the profile you can create by removing metal. You are going to reduce the base circle of the cam. Some valvetrains are more tolerant of this than others. This engine uses shim-under-bucket followers, correct? That's more forgiving than shim-over, but there are still limits.
One point here that I think you may be overlooking. Unless your local cam grinder actually is Bruce Crower or Dema Elgin, he's not going to sit down with you over tea and finger sandwiches and engineer a boutique profile just for you. He is going to ask about your lifter diameter and your valvetrain and your intended RPM range and a few other things, and then he's going to pick a master (probably very mild if you are not welding) that will probably work alright.
If I'm using my own cores. I'll use as big a lob circle as I can fit in. The reason for that is it gives me more radius to work with. Thus less shock to the valve springs. Higher RPM. ( stock floats at 8300 ) So yes it does affect design. I can also spread or reduce lobe centers.
He's a small town machinist working with cars, trucks, Stationary engines, semi's and farm tractors. I can dig through his scrap cam piles and find cores that I can machine down to fit my engine. Yes I will have to pay scrap metal prices to him or whoever I get cam cores from. So what's today's scrap metal prices? 50 cents a pound or less? Do I add the 2 or 3 dollars before or after I machine off the excess?
Then there is trading. I think the cam followers are 1&1/2 inches. And other Jaguars are 1& 3/4 plus I can do the same with valves. Bigger valves, higher lift, more duration, different lobe centers? At a few dollars to the build.
There is an advantage to being 73. Oops 74 by the time of the challenge.
Several guys have written that they want to see how fast I can go with a low dollar Jag. Maybe I'll leave one engine pretty stock except for a couple hundred dollars worth of turbo's? Do all the trick stuff to run Vintage.
bentwrench said:
Frenchy call this number 1-707-545-6115
The man you will want to speak with is Dema Elgin Elgin Cams
Some of his best customers include:
Elgin Cams has the largest percentage of cams used at "Mid-Ohio" from GT-1 to Formula-V. In his spare time, Dema travels the country giving speeches on cams and camshafts as well as doing extensive traveling for fun. He also recently retired from teaching at DeAnza and Skyline Colleges, Automotive Technology Classes after several decades.
Tell him Larry Mertl(rip) says Hi.
Sounds like a great guy to talk about this stuff.
Thanks.
The cool thing is Mid Ohio is similar to Elkhart lake. A power track with longish straights and a few tight corners.
yupididit said:
In reply to Rigante :
I thought it was 9L and that was pushing it.
The limit is reached with the aide of a spacer plate. It worked because it's an open deck block.
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.
Page 1 Frenchy says don't compare LS to Jag V12.
Page 4 Frenchy compares LS to Jag V12.
I feel sorry for Dema Elgin on that phone call.
Stampie said:
Page 1 Frenchy says don't compare LS to Jag V12.
Page 4 Frenchy compares LS to Jag V12.
I feel sorry for Dema Elgin on that phone call.
I do understand the difference between rocker arms and overhead cams. I also understand the difference between a 90 degree V8 and a 60 degree V12.
frenchyd said:
I also understand the difference between a 90 degree V8 and a 60 degree V12.
The internal combustion process, however, does not.
mke
Dork
2/26/22 1:39 p.m.
DarkMonohue said:
frenchyd said:
I also understand the difference between a 90 degree V8 and a 60 degree V12.
The internal combustion process, however, does not.
I was going to say the same but held my tongue. ...I'm tapping out now
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.
Stampie said:
Page 1 Frenchy says don't compare LS to Jag V12.
Page 4 Frenchy compares LS to Jag V12.
I feel sorry for Dema Elgin on that phone call.
Where did I compare an LS on Page 4?
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.
DarkMonohue said:
frenchyd said:
I also understand the difference between a 90 degree V8 and a 60 degree V12.
The internal combustion process, however, does not.
Since we are talking about camshafts I fail to understand how a cam designed for a lifter, pushrod, & rocker arm. Reflects what a cam should do directly to a valve. Won't there be flex on the pushrod, mass on the lifter, resistance on the rocker that's not there when the lobe pushes directly down on the valve?
Also in a V8 adjacent cylinders will fire between 90 to 270 degrees apart. Air Mass is effected every time it starts and stops.
The Jaguar fires evenly 60 degrees apart so the air mass is sequential and adjacent
An engine is a series of compromises. Those for a V8 are different than those for a V12.
mke said:
I was going to say the same but held my tongue. ...I'm tapping out now
Good call. I'll join you on the sidelines.
Frenchy, best of luck and so on.
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?
In reply to frenchyd :
You can't just randomly machine whatever hunk of metal into a camshaft, even another camshaft. The vast majority of camshafts are not tool steel, so the heat treatment is only superficially on the lobes, as soon as you grind through that the camshaft is worthless. And no, you can't just randomly re-heat-treat something like that after grinding on it. You also can't just heat treat the whole cam because it makes the shaft too brittle and takes the elasticity out of it.
Seriously, do some reading.
Mr_Asa
PowerDork
2/26/22 3:04 p.m.
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.
Javelin said:
In reply to frenchyd :
You can't just randomly machine whatever hunk of metal into a camshaft, even another camshaft. The vast majority of camshafts are not tool steel, so the heat treatment is only superficially on the lobes, as soon as you grind through that the camshaft is worthless. And no, you can't just randomly re-heat-treat something like that after grinding on it. You also can't just heat treat the whole cam because it makes the shaft too brittle and takes the elasticity out of it.
Seriously, do some reading.
I've stood there and watched them grind and then treat several of my cams over the decades I've been racing.
So you are telling me the process has changed?
frenchyd said:
Javelin said:
In reply to frenchyd :
You can't just randomly machine whatever hunk of metal into a camshaft, even another camshaft. The vast majority of camshafts are not tool steel, so the heat treatment is only superficially on the lobes, as soon as you grind through that the camshaft is worthless. And no, you can't just randomly re-heat-treat something like that after grinding on it. You also can't just heat treat the whole cam because it makes the shaft too brittle and takes the elasticity out of it.
Seriously, do some reading.
I've stood there and watched them grind and then treat several of my cams over the decades I've been racing.
So you are telling me the process has changed?
There is a HUGE difference between regrinding a camshafts lobes and doing a literal surface treatment and machining a random diesel camshaft into a different lobe width and base circle diameter and trying to heat treatment it to survive in a gas engine. If you don't understand why that's different, then you shouldn't be messing with camshafts.
Javelin said:
frenchyd said:
Javelin said:
In reply to frenchyd :
You can't just randomly machine whatever hunk of metal into a camshaft, even another camshaft. The vast majority of camshafts are not tool steel, so the heat treatment is only superficially on the lobes, as soon as you grind through that the camshaft is worthless. And no, you can't just randomly re-heat-treat something like that after grinding on it. You also can't just heat treat the whole cam because it makes the shaft too brittle and takes the elasticity out of it.
Seriously, do some reading.
I've stood there and watched them grind and then treat several of my cams over the decades I've been racing.
So you are telling me the process has changed?
There is a HUGE difference between regrinding a camshafts lobes and doing a literal surface treatment and machining a random diesel camshaft into a different lobe width and base circle diameter and trying to heat treatment it to survive in a gas engine. If you don't understand why that's different, then you shouldn't be messing with camshafts.
Well some of the truck cams I've seen are big enough to carve down to fit in the Jaguar without even offsetting them. All I need is a 2" shaft and 28 inch length plus the flange. I think I can get .500 lift from that. Stock is .375 And by reducing the base circle over .400 is possible. 
