quote Originally posted by Will: That only works on modern engines like LS1's that have extremely good head flow at very high lift. If the 4.9's port flow peaks at .450 lift, then lifting higher than .450 just stresses the vavletrain unecessarily. LS1's can show flow increases up to .600 and beyond with good port work. You're better off camming the 4.9 like an old '60's small block because of its head flow. Don't follow the LS1 cam example.

if you get the valvetrain work that Rick Stewart did to his, i.e P&P, larger intake valves, LS1 springs, .480 cam, that doesnt seem to be the case, judging from his dyno numbers.

IVO means "intake valve open"; IVC means "intake valve close". These numbers are where the valves opens and closes... these are NOT the .050 lift points.

What's the rocker ratio of the 4.9? Anybody wondered if the duration at .040 is at the valve or at the lobe?

What the IVO, etc, numbers give you is whether the cam is installed "straight up", in which case the intake lobe center angle ATDC equals the exhaust lobe center angle BTDC; or if the cam is advanced or retarded.

However, everything done with desktop dyno is GIGO without solid head flow numbers... a *curve*, not just peak flow. This information will also be valuable for other reasons. For instance, if the port flow levels off at .400 lift (and it might, considering that stock lift was .380ish), then lifting over .400 just costs you more money in terms of machine work to the heads, valve springs and other valvetrain mods.

While lift and duration go hand in hand with normal cams, when regrinding a cam, the new lobe must fit entirely within the confines of the existing lobe, which means that lift and duration trade in different and sometimes strange ways.

quote Originally posted by Will: IVO means "intake valve open"; IVC means "intake valve close". These numbers are where the valves opens and closes... these are NOT the .050 lift points. What's the rocker ratio of the 4.9? Anybody wondered if the duration at .040 is at the valve or at the lobe? What the IVO, etc, numbers give you is whether the cam is installed "straight up", in which case the intake lobe center angle ATDC equals the exhaust lobe center angle BTDC; or if the cam is advanced or retarded. However, everything done with desktop dyno is GIGO without solid head flow numbers... a *curve*, not just peak flow. This information will also be valuable for other reasons. For instance, if the port flow levels off at .400 lift (and it might, considering that stock lift was .380ish), then lifting over .400 just costs you more money in terms of machine work to the heads, valve springs and other valvetrain mods. While lift and duration go hand in hand with normal cams, when regrinding a cam, the new lobe must fit entirely within the confines of the existing lobe, which means that lift and duration trade in different and sometimes strange ways.

so basically what you are saying is that because the new lobe has to fit inside the old lobe on reground cams, it is almost pointless to get the cam reground for TRUE additonal lift without longer pushrods, lowered spring seats, new valve guides, etc? i guess that would make sense since the end of the lobe, where the valve will have maximum lift, doesnt change... so perhaps all these cam regrinds are pointless without the extra pushrod length, because the valve isnt opening any greater distance without it?

now my next question: assuming you do a thorough P&P job on the 4.9L heads, and you have the larger 1.94 intake valves that rick stewart used, can the ideal lift/duration be calculated so that everyone knows the maximum cam grind needed to open the valves enough to take advantage of those valvetrain mods?? rick just guessed by using the .480 /205 duration cam from delta, but that might not yield maximum results?

Unless your heads actually flow less at say .500" than they do at some lesser lift point, the extra lift is fine. If your heads flow equal at both .400" and .500", then running a .500" lift cam will give better results than a .400" lift cam, asuming both have the same duration at .006", .050" and .200", Because the valve is spending more time flowing as much as it can. And it's doing so just as the intake charge is up to full velocity, as the piston is in the middle to bottom portion of it's downward travel. Lift has little effect on driveability, but really affects cylinder filling, so run all you can.

quote Originally posted by Will: IVO means "intake valve open"; IVC means "intake valve close". These numbers are where the valves opens and closes... these are NOT the .050 lift points. What's the rocker ratio of the 4.9? Anybody wondered if the duration at .040 is at the valve or at the lobe? <snip>

The rockers are 1.6:1

I think I have to argue about those measurements not being made at .050" If the advertised duration of a cam is measured at .050", then those numbers are going to also be @.050" If you take those numbers and do the math you'll find that the result exactly matches the advertised duration.

Take my Delta cam:

IVO: -3.5 BTDC (which is actually 3.5 ATDC)
IVC: 38.9 ABDC (which is actually 218.9) (180=BDC+38.9 degrees=218.9)

So the easy math with these numbers is 218.9-3.5=215.4

215.4 is the advertised duration of this cam at .050.

To the rest of the hot rodding world, IVO means "intake valve open". If Delta wants IVO to mean "Intake valve's been open for 30+ degrees", that's their ballgame.

quote Originally posted by Isolde: Unless your heads actually flow less at say .500" than they do at some lesser lift point, the extra lift is fine. If your heads flow equal at both .400" and .500", then running a .500" lift cam will give better results than a .400" lift cam, asuming both have the same duration at .006", .050" and .200", Because the valve is spending more time flowing as much as it can. And it's doing so just as the intake charge is up to full velocity, as the piston is in the middle to bottom portion of it's downward travel. Lift has little effect on driveability, but really affects cylinder filling, so run all you can.

Yes, from the standpoint of duration at a given flow point, the higher lift helps, BUT the extra lift DOES hurt the wallet. For heads that irreparably stall at low lift, the ideal lobe would be one that ramps rapidly up, holds at .400 forever and then ramps rapidly down. A cam MFG might be able to grind you a custom one like that, but that would probably negate the cost savings of not doing the valvetrain mods to support the higher lift.

quote Originally posted by Will: To the rest of the hot rodding world, IVO means "intake valve open". If Delta wants IVO to mean "Intake valve's been open for 30+ degrees", that's their ballgame. <snip>

And what do you think the duration represents? Wouldn't happen to be from the point where the VALVE OPENS to the point where the VALVE CLOSES would it? Exactly what do you think is the point at which the valve is considered "open"? That very question is the reason "the rest of the hot rodding world" uses .050" as the standard reference. And Delta doesn't "pick" .050" as their valve open reference, they have it listed at a number of different positions, starting with .003" up to .250" and they have the associated durations listed alongside.




I assume that we're both interested in the facts here, not assumptions or perceptions. If you have some evidence that I'm mistaken then please show me. I'm not infallible, and frankly, I've learned more in the last 3 days or so since this thread started than I ever knew about cams before. So if I'm wrong, don't just tell me, show me how and explain it to me.

This delta cam was ground with a very old grinder. And while it specs as having a 110 degree lobe separation, from studying the numbers, the actual result here is just over 111 degrees. Now, some companies who offer their own cams actually have COMP or some such do the grinding for them, but that's obviously not the case here. Far too much imprecision. This is more typical of cams ground pre '85. As for holding the valve at .400", this is easy if you have non-roller lifters, they're called "lift rule" cams, very common in the world of entry level circle track racing, and very cheap for the SBC. But for any grinder to create such a low lift "lift rule" hydraulic roller would be more $, except for one thing. Stock Eliminator rules being what they are, it's easy to find cams for the 5.0L Mustang that give 0.444" lift at the valve with 1.6:1 rockers, same as stock 5.0 cams, but have more duration. How much more, that's very secret. But if you want to pursue it, call Comp and ask to speak with Billy Godbold. You would have to send them a virgin 4.9 cam.

quote Originally posted by Isolde: This delta cam was ground with a very old grinder. And while it specs as having a 110 degree lobe separation, from studying the numbers, the actual result here is just over 111 degrees. <snip>

I think you're looking at the intake centerline. It says to the far right that lobe separation is 111.4

quote Originally posted by Taijiguy: And what do you think the duration represents? Wouldn't happen to be from the point where the VALVE OPENS to the point where the VALVE CLOSES would it? Exactly what do you think is the point at which the valve is considered "open"? That very question is the reason "the rest of the hot rodding world" uses .050" as the standard reference. And Delta doesn't "pick" .050" as their valve open reference, they have it listed at a number of different positions, starting with .003" up to .250" and they have the associated durations listed alongside. http://img.photobucket.com/...aijiguy/Untitled.jpg

The numbers are in the "open" and "close" columns because that's the most convenient place to put them. How can a valve open 6 or 7 times in a row without closing?

IVO is when air starts to get into the cylinder and happens when the valve comes off its seat. IVC is when the cylinder stops exchanging air with the manifold and happens when the valve is back on the seat. The duration between these two is the *seat* (aka "advertised") duration (typically this is at .005 lift). When the valve is at .050 lift, it did not just open... it's been open for 30+ degrees. IVO, etc, are never marked from anything but seat duration.

What are you using for head flow numbers in your DD sim?

[This message has been edited by Will (edited 06-19-2009).]

quote Originally posted by Will: The numbers are in the "open" and "close" columns because that's the most convenient place to put them. How can a valve open 6 or 7 times in a row without closing? IVO is when air starts to get into the cylinder and happens when the valve comes off its seat. IVC is when the cylinder stops exchanging air with the manifold and happens when the valve is back on the seat. The duration between these two is the *seat* (aka "advertised") duration (typically this is at .005 lift). When the valve is at .050 lift, it did not just open... it's been open for 30+ degrees. IVO, etc, are never marked from anything but seat duration. What are you using for head flow numbers in your DD sim?

I'm using default settings that come with the program, they have various choices- single plane stock low flow manifold up to IR and more.

I'm still not clear on what the actual reference for what "open" is. I know there's seat-to-seat measurements, but that's not the same as the *VO/*VC measurements we're discussing. If I understand your explanation, that it would be as soon as the valve starts to flow air, would that be at .001, or .0001", or.....? Don't you have to have some specific reference point at which the valve is considered open? Or is it just left to individual interpretation?

quote Originally posted by Will: Sounds like an interesting possibility is someone wanted to order a batch and then resell them as drop-ins. I'm not convinced that Delta's is a drop-in, from what's posted on Jon Lagler's site (Fiero Addiction).

John has already been proven wrong though, many people have bought the .480 lift cam from delta cams, and it works with no valvetrain mods, save longer pushrods on certain engines

quote Originally posted by stickpony: ...many people have bought the .480 lift cam from delta cams, and it works with no valvetrain mods, save longer pushrods on certain engines

Maybe I'm overlooking something here, but because that cam is a regrind, wouldn't one need longer pushrods to realize an actual improvement in maximum lift with that cam on all (as opposed to just "certain") 4.9L engines?

I suppose that cam would physically "work" without longer pushrods, but then its maximum lift would be no different than a stocker's, wouldn't it?

quote Originally posted by Will: Not that it won't "work"... it just won't give the results that the same mod would give on a high flow engine like an LS1.

doesnt an LS1 already come with a bigger cam stock? and doesnt it have 0.8L more displacement? and doesnt it have higher compression, DIS, better manifolds, etc...??

theres more than just the heads that limit the 4.9L.

quote Originally posted by project34: I suppose that cam would physically "work" without longer pushrods, but then its maximum lift would be no different than a stocker's, wouldn't it?

The distance the lifter moves from base circle to nose of the lobe is lift. It doesn't matter whether the base circle is 1.500" or 60" in diameter. The longer pushrods are necessary to get the rocker/valve combo back into the proper point in the rocker's travel.

quote Originally posted by stickpony: doesnt an LS1 already come with a bigger cam stock? and doesnt it have 0.8L more displacement? and doesnt it have higher compression, DIS, better manifolds, etc...?? theres more than just the heads that limit the 4.9L.

Nah, it's pretty much just the heads. If there were significant power to be had in the engine, the aftermarket would have picked up on that and most of the necessary parts would be available by now.

I was talking about built LS1's, in which most head porters go for every last CFM they can get at a billion inches of valve lift.

[This message has been edited by Will (edited 06-21-2009).]

quote Originally posted by Will: Nah, it's pretty much just the heads. If there were significant power to be had in the engine, the aftermarket would have picked up on that and most of the necessary parts would be available by now. I was talking about built LS1's, in which most head porters go for every last CFM they can get at a billion inches of valve lift.

so would it be safe to say that the way to calculate the extra pushrod length would be to take the difference in lift of the stock cam vs the performance cam installed, and then divide it by 1.6, sine the 4.9L has 1.6 ratio rockers arms, and that number will be the extra length you need out of a replacement pushrod?

Not quite.
To get valvetraing geometry excruciatingly correct, the rocker tip needs to cover ground equally on both sides of the centerline of the valve. If it starts in the stock location, but has more lift than stock, then it will move further across the top of the valve at peak lift than it used to. This means that the closed position has to be "backed up" a little bit to compensate. That assumes, of course, that the valvetrain was excruciatingly correct stock.

quote Originally posted by Will: The distance the lifter moves from base circle to nose of the lobe is lift. It doesn't matter whether the base circle is 1.500" or 60" in diameter.

I find this an interesting thread, and I thought yours to be a colorful example, perhaps because it purposefully was so exaggerated ("...doesn't matter whether the base circle is 1.500" or 60" in diameter").

But then it hit me that if the diameter of the cam's base circle doesn't matter, and the cam's regrinder presumably isn't adding material to the cam's nose to make it --- and the cam's resultant maximum lift --- any higher, then where is the increased maximum lift of the reground cam coming from?

quote Originally posted by project34: But then it hit me that if the diameter of the cam's base circle doesn't matter, and the cam's regrinder presumably isn't adding material to the cam's nose to make it --- and the cam's resultant maximum lift --- any higher, then where is the increased maximum lift of the reground cam coming from?

If the peak stays the same and the base circle is made smaller, then the delta between the base circle and the peak will be increased, which is an increase in overall lift. Typically, they remove material from the base circle to increase lift and recontour the peak to change duration.

Depending on how much is removed on an application with fixed rocker pivot height (like the 4.9), the hydraulic lifters can self adjust to accomodate some reduction in base circle, but they can only do so much. Past a point, longer pushrods will be required.

quote Originally posted by fieroguru: If the peak stays the same and the base circle is made smaller, then the delta between the base circle and the peak will be increased, which is an increase in overall lift. Typically, they remove material from the base circle to increase lift and recontour the peak to change duration.

Ahah! So if I understand you correctly, you're saying base circle diameter does matter, and that a cam reground to a smaller base circle can generate greater maximum lift (not just a greater rate of lift), even if the height of the cam's nose is unchanged. That would help a great deal to explain how the Delta Cams regrinder for these 4.9L cams can increase their maximum lift without adding material to the cam's nose.

quote Originally posted by fieroguru: If the peak stays the same and the base circle is made smaller, then the delta between the base circle and the peak will be increased, which is an increase in overall lift. Typically, they remove material from the base circle to increase lift and recontour the peak to change duration. Depending on how much is removed on an application with fixed rocker pivot height (like the 4.9), the hydraulic lifters can self adjust to accomodate some reduction in base circle, but they can only do so much. Past a point, longer pushrods will be required.

so thats why a standard length pushrod can be used on some 4.9L engines with the "drop-in" delta cam, because the hydraulic lifters are compensating for the difference?

There's also the aspect of essentially moving the rockers closer to the cam by shaving the heads. I'll be taking .050" off the face of my heads, which effectively reduces the distance between the cam and the rockers by that same amount. It seems that those who need longer rods need them longer by about .060". That's probably not a coincidence and likely indicates who needs longer rods and who doesn't.

quote Originally posted by project34: I find this an interesting thread, and I thought yours to be a colorful example, perhaps because it purposefully was so exaggerated ("...doesn't matter whether the base circle is 1.500" or 60" in diameter"). But then it hit me that if the diameter of the cam's base circle doesn't matter, and the cam's regrinder presumably isn't adding material to the cam's nose to make it --- and the cam's resultant maximum lift --- any higher, then where is the increased maximum lift of the reground cam coming from?

Lift is always the difference between the base circle and the lobe, as noted above.

Old radial aricraft engines can have 60" base circles (and maybe even larger). I've seen a cutaway of a Pratt & Whitney 36 cylinder radial (4 banks of 9) in which each bank's "cam" was a ring around the crankshaft, driven by a thin, large diameter planetary gearset (the ID of the cam ring was the ring gear in this gearset). Those rings were probably pushing 60" in diameter, yet valve lift was probably about 1".

OT-----

just saw Transformers: Revenge of The Fallen, and christ almighty, it dogged the 1st movie....

Go see it people. do it now.

Do we actually get full-body shots of Transformers for more than three frames at a time?

I hate Michael Bay's editing in the first movie. Has he overcome that problem?

quote Originally posted by Will: Do we actually get full-body shots of Transformers for more than three frames at a time? I hate Michael Bay's editing in the first movie. Has he overcome that problem?

Yes, there's more robot sequences in this movie than i know what to do with

quote Originally posted by Taijiguy:

I did'nt think delta would sell someone's cam profile,It's kinda wrong!There Is not a problem here,because I try to help anyone that has interest in this engine.The flow research did'nt cost me much,as it was done for me,at a tech school, as a favor to me.

I hate to think,What if, I was part of a competative race team with thousands of dollars invested in flow research.makes me think differently about Delta.

I don't quite get your post..who's cam profile is it? It's not theirs?

As a side note, I ordered 1.73 SBF roller rockers today. So the valve lift will be a bit greater than advertised. I'll have the shop doing my heads machine the steel rocker mounts to accept the pedestals.

quote Originally posted by Taijiguy: I don't quite get your post..who's cam profile is it? It's not theirs? As a side note, I ordered 1.73 SBF roller rockers today. So the valve lift will be a bit greater than advertised. I'll have the shop doing my heads machine the steel rocker mounts to accept the pedestals.

I guess It's theirs to sell now,still kinda wrong though.

I'm also confussed about what they have done,if that is the "cam card" that came with your cam.they must have "jacked up" That is the report for my cam, they tested on 02-04-08.How can it be what they sold you? do they not test the actual cam they ship to the customer?

quote Originally posted by ChadTanner: I did'nt think delta would sell someone's cam profile,It's kinda wrong!

quote Originally posted by Taijiguy: I don't quite get your post..who's cam profile is it? It's not theirs?

I didn't understand your point either. The cam each of you have is just a standard regrind of Delta's, is it not? Why would Taijiguy or you have the "rights" to its design? Taijiguy isn't claiming he designed this cam. Are you claiming you designed this cam?

quote Originally posted by ChadTanner: I guess It's theirs to sell now,still kinda wrong though. I'm also confussed about what they have done,if that is the "cam card" that came with your cam.they must have "jacked up" That is the report for my cam, they tested on 02-04-08.How can it be what they sold you? do they not test the actual cam they ship to the customer?

I don't understand why you apparently feel Delta did something wrong. You and Taijiguy were each provided a "cam card" containing the specs for a cam that is just a standard regrind of Delta's. Not surprisingly, the cam spec numbers on the cam card accompanying each standard regrind are the same. However, you apparently feel they should be different.

Why?

I wouldn't be surprised if Delta doesn't have a cam grinding machine of their own, either, but so what? You have a more agressive cam than what GM installed, and you're not getting sued for using it. That's all that really matters.

quote Originally posted by project34: I don't understand why you apparently feel Delta did something wrong. You and Taijiguy were each provided a "cam card" containing the specs for a cam that is just a standard regrind of Delta's. Not surprisingly, the cam spec numbers on the cam card accompanying each standard regrind are the same. However, you apparently feel they should be different. Why?

I "Chad Tanner" had flow research done on the 4.9 heads and intake.the cam card I posted,Is the cam(designed by a third party) delta grinded and tested for me on 02-04-08. The specs were given to delta by me.

I realize I don't own anything,I give away any information,I have about this engine,because I hope to help Anyone interested in the caddy engines,It's a hobby.

I think delta did something wrong,because If I were I a competitive racer and had spent thousands on R&D (which I did not) I would be very mad if they sold my cam profile to another race team.Thats why I now think differently about Delta.

When Delta or anyone else regrinds a used cam,no two cams are the same,due to differences in the cores, some cores may have 50'000 miles,some may have 200,000 miles.I have seen great variances in the same profile,especially in the middle of the ramp.Thats why I think they should test each cam they grind (I thought they did) and not just send a copy of the report from the first cam they grind with that profile.

Thanks....
Chad

[This message has been edited by ChadTanner (edited 07-10-2009).]

Hmmm...that's interesting. i don't know about the legalities, but I guess I'll say "thanks" for your efforts. I wonder how it'll run with the 1.7 rockers.

As for the sheet I posted, I think that's intended more as a grind card rather than a test per se. I asked for a grind card and that's what they sent. And yes, they do have their own equipment, they grind their cams on site as far as I know.

what they done was legal,It just says something about a companies character.If I wanted to be a competive race team,I don't need to spend anything on R&D,just find a winning team,then ask Delta to grind me a cam like theirs and while were on the phone,ask "what else do you about their engine".(lol)


I did do some research on 1.7 ford rockers for this engine with that cam.I'll dig up some stuff that might be a help to you.

Thanks.....
Chad

quote Originally posted by ChadTanner: I did do some research on 1.7 ford rockers for this engine with that cam.I'll dig up some stuff that might be a help to you.

Wow, you really are into these 4.9L engines if you've data on them with 1.7 Ford rockers!

In contrast, my question theoretically should be comparatively easy.

Might you know the duration at 0.050" lift of the stock 4.9L cam? Early on in the first page of this thread, stickpony posted its lift at 0.384" with 1.6 rockers, but no one apparently knows the stock 4.9L cam's duration at 0.050" lift.

quote Originally posted by project34: Might you know the duration at 0.050" lift of the stock 4.9L cam?

Not exactly,as in,new from the factory with no wear(never seen one of those).

However a stock 4.9 camshaft with 100'000 miles give or take 20'000.

First understand that at that miliage,there is hardly any difference in the intake and exhaust,not enough to worry about two measurements to call it a duel patteren,but a short answer would be about 298 degrees @ .050 ramp.

Thanks...
Chad

quote Originally posted by project34: Might you know the duration at 0.050" lift of the stock 4.9L cam?

quote Originally posted by ChadTanner: Not exactly,as in,new from the factory with no wear(never seen one of those). ...but a short answer would be about 298 degrees @ .050 ramp.

I was hoping you might have had an answer to this mystery by having seen somewhere a published figure for a then-new, stock 4.9L cam.

The 298^o at 0.050" lift that you'd guessed at seems very high, so much so that I'd think it would render a Caddy engine unstreetable, which probably wouldn't be a good plan to appeal to a Caddy sedan's typical customers.


Maybe that 298^o refers to the stock 4.9L cam's advertised duration, rather than to its duration at 0.050" lift?

Even Taijiguy's reground, aftermarket cam has only 215^o degrees duration at 0.50" lift. My guess is that a new 4.9L cam at 0.050" lift would have been more in the neighborhood of 200^o or somewhat less --- not at 298^o.