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David Neibert
07-27-2005, 01:38 PM
I'm curious if the other people using Stiegemeier's big cam (240/240 .539/.539) are getting the same kind of HP & TQ numbers I am.

Since installing this cam in the spring of 2004, I've made numerous changes to my car and dynoed it several times. It doesn't seem to matter what the outside temp is (47f-95f) or how much fuel (10.8-13.8 AF) or how much timing (26-31 degrees) or how much I overdrive the blower (15%-24%) or how much exhaust restriction I've got (w/cats vs. no cats).

The car still pulls between 325 and 335 rwhp. Considering I have an AOD with a fairly loose non locking converter that's not bad and is still enough to run high to mid 12s, but it's a far cry from the power it was making with my old cam (usually 350-370 rwhp).

I've been told by more than one person, that my problem is with the cam having too much duration....especially on the intake side. Simply stated the overlap is causing too much of the intake charge to bleed off which results in less air and fuel getting into the cylinder. BTW, I only get about 130 psi doing a cold motor compression test. I think I was getting about 155 psi before.

I've ordered a new cam made from a billet blank that has much less duration and more lift (very close to my old cam). But before installing it, I'd like to know if others are having similar results with the 240/240 cam.

David

sizemoremk
07-27-2005, 03:14 PM
What grind was your old cam, and what grind is the proposed cam?

I've never really understood what was the real difference in higher lift and higer duration???

joker12552
07-27-2005, 03:39 PM
What grind was your old cam, and what grind is the proposed cam?

I've never really understood what was the real difference in higher lift and higer duration???
Higher lift means the valve actually extends higher out of the head, duration is simply the amount of time it is extended. I dont know about supercoupes alot, but when it comes to mustangs, power adder cars (ie, nitrous, turbo, or supercharged) all tend to make more power with a cam that has a little higher lift and duration on the exhaust side (ie. a split duration cam)

David Neibert
07-27-2005, 04:15 PM
What grind was your old cam, and what grind is the proposed cam?

I've never really understood what was the real difference in higher lift and higer duration???

My last cam was a crane regrind with something like 226/239 intake/exhaust .600/.600 valve lift.

My new one is a comp cam billet with similar intake duration, less exhaust duration and about the same valve lift. Sorry the specs are at home.

David

sizemoremk
07-27-2005, 05:57 PM
Higher lift means the valve actually extends higher out of the head, duration is simply the amount of time it is extended. I dont know about supercoupes alot, but when it comes to mustangs, power adder cars (ie, nitrous, turbo, or supercharged) all tend to make more power with a cam that has a little higher lift and duration on the exhaust side (ie. a split duration cam)


The part I don't understand is what is the difference between having it open longer, or having it open further???

What is the flow difference of higher lift vs longer duration... Is there some kind of formula to determine flow based on valve size and duration at a particluar lift, or duration?? I don't mean flow numbers for the head, heck I don't really know how such a thing could be measured...

Basically what would be the difference in 230/230 .520/.520 vs say 220/220 .560/560

Does lift breath more, or does duration breath more???

I know both are usually increased, but is one more benificial than the other????

I know the cam I have going in the new motor is 212/220 .531/.539 114 LSA.

Since ordering it, I'm kinda worried that it won't be "big enough" after looking at some of ya'lls cam specs, but I figured forced induction rules of thumb say longer/higher exhaust than intake, and most street cams seem to be around 220 duration before having streetability issues... at least that seemed to be the deal when reading general camshaft selection...

I like this thread, and hope we get alot more responses, because all of the threads I've read here, don't seem to go into actual cam selection theory; rather folks just talk about what cam grinds they have and whats avaiable, at least that's all I ever seem to find. I'd like to understand cam selectio a little better than just going with a "known good combo" even if the one I have is best for my application...

XxSlowpokexX
07-27-2005, 06:29 PM
Dave what is the lobe seperation?

I'd get a new grind. You will get more power and better drivability due to less steep ramps on your lobes

fast Ed
07-27-2005, 06:46 PM
Dave, I have no direct experience with aftermarket cams in our SC engines, but generally speaking, 240 degrees of duration at .050" lift is going to be too much for a motor that's going to be under 6500 rpm most of the time, especially one with a blower. As you've seen, your cylinder pressure is down. The other specs you have sound better for sure.


cheers
Ed N.

Scott Long
07-27-2005, 08:23 PM
My friend put that cam into a stock valved SC w/ home ported heads, he had a hell of a rough idle, and it made less power than with the stock cam.

Basically the mods were .030" overbore, gasket matched heads, steigemeier cam, mac mustang headers w/ flange welded 180 degrees to clear steering shaft, no cats, flowmaster force II exhaust (resonator and mufflers). It had stock throttle body and maf, w/ an old SCP intake tube and a 9" K&N cone filter. It was faster before the cam and over bore.

sizemoremk
07-27-2005, 08:29 PM
My friend put that cam into a stock valved SC w/ home ported heads, he had a hell of a rough idle, and it made less power than with the stock cam.

Basically the mods were .030" overbore, gasket matched heads, steigemeier cam, mac mustang headers w/ flange welded 180 degrees to clear steering shaft, no cats, flowmaster force II exhaust (resonator and mufflers). It had stock throttle body and maf, w/ an old SCP intake tube and a 9" K&N cone filter. It was faster before the cam and over bore.


Which cam???

XxSlowpokexX
07-27-2005, 10:03 PM
BTW Dave I had that cam and got rid of it before I even used it

Mike8675309
07-27-2005, 10:20 PM
Lift influences how much air can enter the cylinder within a give amount of duration. Duration is a measure of the time the valve is opened as degrees of crankshaft revolution.

Here is a hot rod article on the mechanics of camshafts it:
http://www.hotrod.com/techarticles/43418/index2.html

It sounds like this cam on Dave's car has too much overlap. Most engines have some overlap to allow for getting the last bit of exhaust out, but on this cam it sounds like the overlap is too large. On a supercharged motor, too much overlap can bleed boost out the exhaust limiting cylinder filling. You only have so much time to get the exhaust in and out based on the rotation of the crankshaft and rod length.

XxSlowpokexX
07-27-2005, 11:20 PM
Lobe seperation plays a big part here...One thing you cannot change with a regrind....GET A NEW CAM DAVE!...I;d love to see you gain back your lost HP and then some

David Neibert
07-27-2005, 11:21 PM
Here are the cam cards for what I had in the car and what I've got now.

The good one was the same as Chris Wise had (I/E 226/238 .597/.631 lift @ 1.73 ratio), but it was very hard on the valvetrain and kept ripping rocker studs out, which caused a bent valve, and it also broke a lifter retainer (dogbone) which trashed the cam and several other things. See the thumbnail below for details.

The current cam is (I/E 240/240 .555/.555 lift @ 1.73 ratio) , w/114 lsa Here's a link to the cam card. Sorry it's hard to read.

http://www.sccoa.com/forums/attachment.php?attachmentid=12909

The new cam I just ordered yesterday isn't a regrind like the others and is made from a new Comp Cam billet blank. The specs are (I/E 224/228 .572/.580 lift @ 1.65 ratio) 114 lsa, 4 degree advance. I don't have a cam card yet.

David

PS: Intake valve closes at 42.0 degrees ABDC on the old cam
Intake valve closes at 50.0 degrees ABDC on what I have now

David Neibert
07-27-2005, 11:44 PM
It sounds like this cam on Dave's car has too much overlap. Most engines have some overlap to allow for getting the last bit of exhaust out, but on this cam it sounds like the overlap is too large. On a supercharged motor, too much overlap can bleed boost out the exhaust limiting cylinder filling. You only have so much time to get the exhaust in and out based on the rotation of the crankshaft and rod length.

Mike,

Yes, that's pretty much what I'm being told. On the plus side, I haven't broken any valvetrain parts in over a year. The old cam broke something every two months :mad: .

With the new cam the base circle will be bigger allowing the duration I want without the ramps being as steep as there were on the regrind. Which should be much easier on the valvetrain.

David

David Neibert
07-27-2005, 11:51 PM
I know the cam I have going in the new motor is 212/220 .531/.539 114 LSA.

That's pretty much the same cam Dave Dalke and a few other fast guys have in their motors. It's also very close to a Coy Miller stage I cam. I think you will be happy with it.

David

Dick Hughes
07-28-2005, 11:35 AM
That's pretty much the same cam Dave Dalke and a few other fast guys have in their motors. It's also very close to a Coy Miller stage I cam. I think you will be happy with it.

David

David or Anyone:
Would you happen to know the specs for the "Dr Fred" cam (which we are running). He was rather secretive about it.

SCrazy
07-28-2005, 11:37 AM
Dave:

I don't remember the exact numbers but I had cam profiles done on the big Steg cam and a Dr. Fred when I built my motor. What I found interesting was the even though the Steg cam had greater total lift and duration specs the Dr. Fred cam flowed more air because the curves were fatter and the area under the curves was greater.

It was very interesting to see how the absolute cam specs were far from the entire story as far as which cam flowed more air.

The other interesting thing we learned from the profiles is that our cams have massive spikes in the Jerk curve which indicated that the cams are designed the throw the followers out of contact with the cam. Somebody once referred to these types of cams as "lofters" and comp was grinding them this way intentionally.

pablon2
07-28-2005, 11:52 AM
That's pretty much the same cam Dave Dalke and a few other fast guys have in their motors. It's also very close to a Coy Miller stage I cam. I think you will be happy with it.

David


What size valves (and length) and springs will work best with this cam? I have the same one. Profile being:I/E 212/220 .531/.539 114 LSA.

Kurt K
07-28-2005, 11:58 AM
Just curious Dave, are you going to have to run a shorter pushrod since you won't have a regrind cam anymore? I know I would because my pushrods are longer than stock.

David Neibert
07-28-2005, 12:24 PM
Just curious Dave, are you going to have to run a shorter pushrod since you won't have a regrind cam anymore? I know I would because my pushrods are longer than stock.

Kurt,

With the stud mounted adjustable rockers I'm using, I don't really expect to have a problem with the pushrod length. Right now I'm about midway down onto the rocker stud and think I have plenty of room to raise the rocker enough to accomodate the larger base circle. If there is any concern, it's with how the tip of the valve stems and the roller on the rocker arm are going to line up.

The valve stem length, springs and the install height of the retainers are good for about .625 lift without binding the spring or contacting the valve stem seals. So I know that won't be a problem. The rockers I'm using are intended for an Olds motor (I think) and the fulcrum position allows for a little more adjustment than the Ford rockers.

Won't really now until I get the cam in and set the preload.

David

Scott Long
07-28-2005, 12:28 PM
Which cam???

Steigemeier's cam

David Neibert
07-28-2005, 12:45 PM
What size valves (and length) and springs will work best with this cam? I have the same one. Profile being:I/E 212/220 .531/.539 114 LSA.

Sorry, I don't know that answer.

David

Micahdogg
07-28-2005, 04:27 PM
Only other thing to keep in mind when raising the rockers is valve cover clearance. I can't remember what kind of room is under there though.

Before you get into the cam work too much, have you considered another tune? From how your car was acting a month ago I can't see a cam swap fixing that.

Micah

David Neibert
07-28-2005, 04:53 PM
Only other thing to keep in mind when raising the rockers is valve cover clearance. I can't remember what kind of room is under there though.

Before you get into the cam work too much, have you considered another tune? From how your car was acting a month ago I can't see a cam swap fixing that.

Micah

Yes, It's getting a new SCT chip and dyno tune as soon as Dave Dalke comes in town. Might be Saturday August 13th, but still trying to confirm the date with Dave. I expect to gain about 20-25 rwhp with a good tune and a cool motor.

I've made a few minor changes since the trip to Springfeild and the car has ran great ever since. Biggest change was an adjustable regulator to temporarly correct a very lean condition. BTW, Since the morning we left Springfeild, the car has ran fine other than a few CELs (181 & 189 lean condition at part throttle bank 1 & 2).

Since raising the fuel pressure it runs even better and there are no more CELs, but according to the dyno, it doesn't have the power it should.

David

Randy N Connie
07-28-2005, 05:04 PM
I dout that many cars ran well on the day of Micha's wedding.
Wasent it about 110 temp that day.

David Neibert
07-28-2005, 05:11 PM
I dout that many cars ran well on the day of Micha's wedding.
Wasent it about 110 temp that day.

Randy,

Yes it was extremly hot. I tried running the AC and the temp quickly rose to the "R". After shutting the AC off it wouldn't cool down and started stalling, backfiring and throwing CELs.

I thought it was the DIS module or the Chip freaking out, but it could have been overheated fuel and a mild case of vapor lock. I don't really know what happened that day.

David

Kurt K
07-28-2005, 11:06 PM
I dout that many cars ran well on the day of Micha's wedding.
Wasent it about 110 temp that day.
My car ran fine :D :rolleyes:

I even got to use my AC :D :D

Rich Thomson
07-29-2005, 08:15 AM
Here are the specs for the Dr Fred cam. I believe he had a few different grinds. 18in vacuum at idle on stock heads with 1.73 roller rockers.

http://www.mn12performance.com/images/520cam-specs.JPG

Micahdogg
07-29-2005, 12:33 PM
So Freds cam is a 212/218 at .520 lift with 112 degree separation. I don't know about the separation, but it looks like a relatively mild cam. That would be the next step up from the smallest Crane offered of 208/208 @ .509 lift.

Micah

Mike8675309
07-29-2005, 01:19 PM
It was my understanding that all other things being equal, a 114 LSA was pretty close to ideal for our engines.

Rich Thomson
07-29-2005, 03:15 PM
The cam specs would change depending on the heads.

68COUGAR
07-30-2005, 01:52 PM
power adder cars all tend to make more power with a cam that has a little higher lift and duration on the exhaust side (ie. a split duration cam)
Fords in general like a split duration cam, with more duration on the exhaust. I think that is due to the restritive design of most OEM Ford exhaust ports.

68COUGAR