Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
4 l-bodies
Asa,
What I have found is running aftermarket camshafts is there is a definite loss of low end torque in lower RPM band, then of course "hopefully" there will always be a crossover point (RPM) where larger cam will be overtake the smaller camshaft and make it worthwhile.
For example it was found that Taft S2 gives up like 20 lb/ft down low (below 3500 RPM), approaches stock cam torque by 4000-4500 RPM and adds another 20 HP and 10 lb/ft above 4700. The larger S3 lost 30+ lb/ft below 4000 RPM. Then above 4700 RPM, it crushes the stock cam!
Many times what happens in not well thought out powertrains is powerband becomes tighter or more narrow because rest of powertrain isn't up the the task of increased RPM with the larger duration camshaft. Could be rod ratio, could be valvetrain limitations, turbo, gearing, converter, Say for example running a large duration camshaft in an engine that doesn't want to run much RPM, or tiny duration camshaft in a high RPM engine. Probably not a good combo, either way.
A perfect example of a not very well thought out powertrain was an old friends 351 4bbl (4V) Cleveland Mach 1 Mustang 25-30 years ago. Put in much bigger camshaft, and slightly higher stall converter, single plane manifold, along with not very deep gear. The vehicle was real dog until 4800 RPM. Way too big of ports for that size motor, not enough gear, and probably needed a looser converter. Very narrow powerband. From 4600 to 6400 it pulled pretty good, but then it was over. Made for a boring and lazy car to drive on the street. His buddies 351 Cleveland 2BBL headed Grande Mustang would eat it alive on the street. At the track, the 4V headed 351 would prevail, because he was always in that very narrow powerband. My 69 Z-28 was also another low torque dog. Huge duration factory solid lifter camshaft. At least that had a much larger powerband. Not much below 4000 RPM, then WOW! The factory knew it was going to need deep gearing, so they came with 3.73 gears from factory. It needed an even deeper gear. That 302 needed 4.56/4.88 gears to really wake it up. Needed RPM to keep in correct powerband. Same deal with the Ford Boss 302 and the Boss 429 Mustangs.
IMO, when selecting a camshaft, there are definite compromises to be considered, just like turbo selection. Bigger isn't always better. It will almost always effect something like low RPM torque, ecomomy, driveability, emissions, powerband, valvetrain life, etc. It also obviously has many positives too. That is one reason why turbo and NA used a different camshaft profile. Compromises...
Todd
interesting..is there any explanation as to why torque is lost with by opening the valve longer or further? or is it that the location of the valve event relative to the crankshaft was changed and thats what impacted the low rpm performance?
Re: TU and F4 Camshaft Follow-on Discussion
I had a somewhat negative experience with aftermarket cams in a Spirit R/T. Major loss of low end torque. But also had serious top end. All the power was shifted up higher in the RPM band that the car became no fun on the street. Adding insult to injury, I had also went with a 3.50 final drive gear rather than the stock 3.85. It was a pure dog on the street and was practically useless at stop light races unless you wound it way up and "drive it like you stole it". Interestingly it got wonderful gas mileage and was quite stout on the highway. But not fun 90% of the time.
That Spirit R/T has now been redone with stock cams, stock A568, T3/T4 hybrid, big intercooler etc.....the car is worlds better in every way now. That experience has definitely made me a skeptic as far as camshafts go, and also wiser to building a combo that works together overall. The previous setup was a failure but it taught me a lot.
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
Shadow
Nothing else was said AFAIK, i'm going off what info we have on the table Now, and that would be for Both.
In a Nutshell, and from what I understand, when you Increase lift, without any other change to cam profile, you allow for more power without changing the rpm (powerband). So More power Potential without moving powerband to the right. This will only work (actually make more power) IF all of the other components in the build can Support the added lift of the cam. Usually, when lift is Increased, Duration is Increased as well.
Increasing Duration, on the other hand, Directly effects the rpm that the motor operates in and moves the curve to the right (higher in rpm range) by allowing the motor to Breath More from the valve event (time) being increased.
So Increasing Duration, increases the time the valve stays open. Increasing lift, Does Not increase time the valve stays open, it just opens the valve More in that same time frame.
This is exactly correct. Two cams with identical specs, but one has more lift. The one with the higher lift will make more power over the same rpm range. Provided the top end (head, intake, exhaust) will keep up with the increased air flow.
Re: TU and F4 Camshaft Follow-on Discussion
Just a side track question Mechanically how radical of a cam profile can are roller valve train survive ( ie egg shape to almost digital or square shape ramps) ????
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
bakes
Just a side track question Mechanically how radical of a cam profile can are roller valve train survive ( ie egg shape to almost digital or square shape ramps) ????
Great Q, and also another reason that a lot of us kept to milder cam profiles, because it was thought that the factory rollers (or stated outright even, IMS) could Not hold up to higher lift cams. It was stated that we would need a Higher quality roller before we could even Think about high lift cams.
Actually quite Incredible when you think about it, that pure Speculation, without Any Proof, has been the number 1 reason it has taken this long to get to this point on these mtrs.
So, how good are the factory rollers (or at least the replacement rollers available to us) Ask Warren, he runs them with his Mechanical cam and no issues to date. AFAIK :nod:
Re: TU and F4 Camshaft Follow-on Discussion
Ha Ha i remember when people use to say you spit followers out at 8,000 +RPm Yet My Red Glh (2.2l carbed ) track car would shift at 8200 rpm and on one race day my driver and 5.ol Mustang got into 3 lap pissing match where we final pulled him on the straight away with shift lamp glowing visible from pit wall the whole straight away. when i got the car back in the pits i hit the TACH recall it read 9300RPm I didn't now if was to scold my driver (good friend ) of hug him . Hmmm blew that myth out the window.
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
iTurbo
I had a somewhat negative experience with aftermarket cams in a Spirit R/T. Major loss of low end torque. But also had serious top end. All the power was shifted up higher in the RPM band that the car became no fun on the street. Adding insult to injury, I had also went with a 3.50 final drive gear rather than the stock 3.85. It was a pure dog on the street and was practically useless at stop light races unless you wound it way up and "drive it like you stole it". Interestingly it got wonderful gas mileage and was quite stout on the highway. But not fun 90% of the time.
That Spirit R/T has now been redone with stock cams, stock A568, T3/T4 hybrid, big intercooler etc.....the car is worlds better in every way now. That experience has definitely made me a skeptic as far as camshafts go, and also wiser to building a combo that works together overall. The previous setup was a failure but it taught me a lot.
A friend had Delta cams in his R/T, was a total dog also, I had to put stockers back in, fixed. On the other hand, I ran my grind of cams in my TIII, a stage 1 and stage 2, both with triflow and they were friggin awesome, the Stage 2 were insane, would put like a mother to 7500 and had decent bottom end with the cams slightly advanced, even with an auto and a .82 GT35R.
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
bakes
Ha Ha i remember when people use to say you spit followers out at 8,000 +RPm Yet My Red Glh (2.2l carbed ) track car would shift at 8200 rpm and on one race day my driver and 5.ol Mustang got into 3 lap pissing match where we final pulled him on the straight away with shift lamp glowing visible from pit wall the whole straight away. when i got the car back in the pits i hit the TACH recall it read 9300RPm I didn't now if was to scold my driver (good friend ) of hug him . Hmmm blew that myth out the window.
You had to have a properly matched and set up valvetrain combo to pull those kind of R's. And depending on how close to the edge you were,you may not get away with it for very long!
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
acannell
interesting..is there any explanation as to why torque is lost with by opening the valve longer or further? or is it that the location of the valve event relative to the crankshaft was changed and thats what impacted the low rpm performance?
You mentioned rod ratio effecting a cam/head flow. I agree! A lower numerically rod ratio tends to like and even need larger port volume and a longer duration camshaft with a later (ABDC) closing point on the intake valve. It is due to the change in piston speed at different points relative to crankshaft degrees.
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
acannell
interesting..is there any explanation as to why torque is lost with by opening the valve longer or further? or is it that the location of the valve event relative to the crankshaft was changed and thats what impacted the low rpm performance?
Every motor has a "Fixed" operating parameter associated with it. This will be determined by a # of variables, depending of which cam, stroke, head ect ect ect you choose to select in the build.
When you open the valves longer and allow the motor to "Breath" it will naturally move higher in rpm. (because it Can) So don't think about it like you're Losing something, just see it for what it is, you are Moving the operating Range of the motor to a different spot. (hopefully one that will serve the build Better)
When you do it Right, the Benefits Greatly outweigh the cons. When you do it Wrong, well, that's when you hear of nothing but the Loss of low end vs very little gained up top. (and this is why people compare it like this)
So, put the Wrong cam into your build and you Will be Very disappointed. This is where Cam info and Real World results beat out sheet music, and why I have been so adamant about the Taft S3 and FWD F4!
In a nutshell; A decent grind will lose about as much in the lower rpm as it gains up top. A Bad grind will Lose More down low than it gains up top. A Good grind will lose a little down low, but the gains in the "operating" powerband will destroy any perceived loses!
So, a cam like the F4 or Taft S3 will make More TQ And HP than the motor made before (nothing lost/ everything gained) but the operating powerband will be higher in the RPM range, so the Beginning TQ will be lower than before because you Can't make HP higher in RPM without moving the TQ higher as well.
Hope that made some sense.
Re: TU and F4 Camshaft Follow-on Discussion
so, to start getting familiar with the reality of synchronizing and measuring the cam in-car on our engines, since I'll probably have to do this at some point, I decided to see if I could make some measurements
I have a scrap swirl head and a scrap stock roller shaft cam, along with the usual stock valve train
First task was to figure out where a dial indicator could actually be placed to measure valve displacement.
Assuming the goal is to do this with the head on the engine, we're left with pretty much just the valve retainer as a reference.
Is the valve retainer top surface flat? Unknown.
Is it perpendicular to the valve axis? Unknown.
That pretty much puts it in the realm of non-precision measurement right off the bat.
But anyways, in order to calibrate the dial indicator so that it is parallel with the valve axis, I used a precision ground washer. The important thing is that the washer is flat on both sides. Its not important what its thickness is as long as you can measure it, and it will fit on top of the retainer and not get in the way, etc..etc..
First I measured the washer using Horrible Fate dial crapilers. I dont think accuracy beyond about 0.001" is required for this so that should be good enough.
Looks like its 0.165" thick.
Then I set up the dial indicator to measure the retainer surface, and eye-balled it to as parallel with the valve axis as possible.
I then zeroed the indicator, and put the ground washer between it and the retainer.
I could usually get within 3 thou on the first try. After making small minor adjustments to the angle of the indicator, I eventually got it to 0.165". I think getting it within 0.001" is good enough.
And the reason I think that precision is not the king here is these two gems from Lunati and Crane:
Crane:
"it is important to make sure the angle of the dial indicator plunger is the same angle as the lifter or pushrod travel. We want to read "straight line" (linear) movement of these parts, so the plunger must be aligned properly. With the indicator in position, set the dial indicator to zero."
Lunati
"The stem from the dial indicator should be aligned with the lifter as close as possible. Misalignment will cause an improper reading."
Yeah well, HOW?
The retainers job is not to provide a flat and square to axis surface on its top , so therefore we can't assume it has one. Plus its sitting on top of a spring with plenty of air between its underside on the spring for quite a bit of its circumference.
Yes I just made all this up so if theres a better way lets discuss.
Or if its good enough, so be it.
NEXT:
I need a way to bolt the head down to something so I can measure valve displacement. And also some kind of degree wheel on the cam to measure rotation. Stock cam specs coming our way!! Sorry its not an F4 or R5 lol
http://i242.photobucket.com/albums/f...psjlzl5tux.jpg
http://i242.photobucket.com/albums/f...psnlhpjulg.jpg
http://i242.photobucket.com/albums/f...ps0k5lew68.jpg
Re: TU and F4 Camshaft Follow-on Discussion
Asa,
What I usually do when degreeing in cams in our 8V engines is I remove end of dial indicator and replace it with a #'d drill bit. In my case a #40 fits perfect. This will extend the range of the dial indicator and get it above the cam towers so it be be positioned parallel on valve axis and perpendicular to camshaft. I then have opposite end of drill bit (the part you chuck into drill) sharpened to a fairly sharp point. I then make a couple of dimples in retainers so dial indicator cannot walk or skate on retainer. If you find it walking around a bit, you can bet your not quite parallel or not quite perpendicular to cam. You certainly don't need to do this step, but for me it has helped indicator stay in relatively the same spot and maintain accuracy. I am also using a much softer spring on intake and exhaust for checking so I can quickly disassemble as needed. It also makes turning over engine much easier as you are not fighting spring pressure. As you've noted, some retainers are flat while others are not. Our stock retainers are much flater than most of the others out there. If you decide to do this, I think you will find you can then do away with your flat washer. In the last pic, you are close to perpendicular to camshaft but off just a few degrees. This certainly could cause the indicator to do a small pirouette, instead of remaining in one place atop of the retainer.
What are you using for a lash adjuster? Can't use a stock hydraulic one. You will need to come up with something that will have a bit of adjustability so the lash can be taken out. I can post a pic of mine if it will help.
Todd
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
bakes
Just a side track question Mechanically how radical of a cam profile can are roller valve train survive ( ie egg shape to almost digital or square shape ramps) ????
Yes that is THE million dollar question. Comp Cams talks about that a bit, saying they know just how far they can safely push it as far as accelerating and decelerating the valve. I do know your fellow Canadian Geoff at Colt has NA regrind roller cams with much bigger lift that he has sold to the circle track guys in the past. We certainly don't want a repeat performance of the slider S-60 camshaft durability. The good news is the roller cams have much harder and deeper surface hardening, and so they should tolerate a pretty stiff spring if needed. I have seen a couple of our roller cams that have had lobes that just start to crumble. I brought one camshaft to two different high end engine builders and both thought camshaft core was over hardened when manufactured. They both said yeah that just happens once in a while. I have some pics of failure but can't seem to find them at the moment. So I failed too (lol)! The size of roller in follower can also come into question as camshafts get more aggressive. There was a thread about that and the difference in slider follower a while back on this forum. The pivoting point is much greater in a slider over the rollers .700 diameter.
There is (probably more than one) reason Warren went away from a hydraulic roller camshaft.
Todd
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
4 l-bodies
Asa,
What I usually do when degreeing in cams in our 8V engines is I remove end of dial indicator and replace it with a #'d drill bit. In my case a #40 fits perfect. This will extend the range of the dial indicator and get it above the cam towers so it be be positioned parallel on valve axis and perpendicular to camshaft. I then have opposite end of drill bit (the part you chuck into drill) sharpened to a fairly sharp point. I then make a couple of dimples in retainers so dial indicator cannot walk or skate on retainer. If you find it walking around a bit, you can bet your not quite parallel or not quite perpendicular to cam. You certainly don't need to do this step, but for me it has helped indicator stay in relatively the same spot and maintain accuracy. I am also using a much softer spring on intake and exhaust for checking so I can quickly disassemble as needed. It also makes turning over engine much easier as you are not fighting spring pressure. As you've noted, some retainers are flat while others are not. Our stock retainers are much flater than most of the others out there. If you decide to do this, I think you will find you can then do away with your flat washer. In the last pic, you are close to perpendicular to camshaft but off just a few degrees. This certainly could cause the indicator to do a small pirouette, instead of remaining in one place atop of the retainer.
What are you using for a lash adjuster? Can't use a stock hydraulic one. You will need to come up with something that will have a bit of adjustability so the lash can be taken out. I can post a pic of mine if it will help.
Todd
Yes Id definitely like to see your adjustable lifters. I think we should all be posting pics of how we do this so as many people as possible can get comfortable with the idea and attempt it themselves. Its a very inexpensive and simple procedure and everyone should be doing it.
I think an extension to the indicator is a good idea. Its not a spacious area to put an indicator up close like I did. I'm not even sure the cam lobe would clear it. Extended indicator tips can be bought for most indicators including the chinese ones at mcmaster or flee bay: http://www.mcmaster.com/#indicator-tips/=ut662w
I dont see the purpose of putting a dimple to help hold the indicator there. If the tip changes location relative to the retainer surface then the indicator isn't parallel to the valve axis or the retainer surface is changing is relation to the valve axis. From the indicators perspective, the retainer surface should appear to be moving in one axis only and thats directly along the indicator plunger axis. Am I understanding you correctly? Why do you think its increasing accuracy?
I can see the purpose of the lighter springs so less notchiness is experienced. I like the idea of having a tool that will let me precisely manipulate the cam at will without relying on the engine at all. For analysis on the bench or if I need to do something in-car but I dont want to involve the crankshaft. I think a worm gear transmission would be perfect as it wouldn't let the cam self-rotate under spring pressure but would allow precision control of the cam rotation. A super cheap chinese 3" rotary table with a way to attach it to the cam sprocket would accomplish both eliminating the cam self-rotating and also providing a precise degree wheel for precision rotation. Something like this perhaps with a custom machined mount to bolt to the valve cover threads or something else: http://www.ebay.com/itm/New-Mini-Rot...item2ed917a5f1
The flat washer is to calibrate the dial indicator alignment, which, even if the retainer is perfectly flat and perpendicular to the valve axis, is still required because the indicator needs to be aligned to that. So the flat washer provides a reference displacement to a known value. But hey if crane and lunati seem to indicate that you can just eyeball it maybe its overkill. Actually it is (see below). Its only used temporarily and removed for actual measurement.
The last picture shows the indicator aligned very well actually, its indicating the displacement of the ground washer to within 0.001". But you are correct it is not perfectly aligned with the valve axis, although the picture exaggerates this. To figure out why this was I drew up what was going on in SW and answered my own question as to why eyeballing the indicator is probably good enough, although I would still calibrate mine.
Lets say the retainer/valve moves 0.165", how much of an angle can the indicator have from perfectly square to the retainer and still be accurate to say 0.001"? Turns out about 6 degrees. Thats easily seen visually. In the picture the center of the dial indicator face is about 3" above the contact point on the retainer surface. For 0.500" lift with the same 0.001" accuracy, the angle is just about cut in half.
So, to be clear, using a precision flat object lets you calibrate your indicator setup with a known displacement so you can be sure its measuring correctly and/or adjust it until it is. However it may be overkill depending on how accurate you really need the measurements to be and how well you can visually align it, which is probably within a few degrees. Still, I would calibrate mine. Especially if you cant get a clear parallax free view of the indicator to confirm its alignment visually.
http://i242.photobucket.com/albums/f...pse6953cb4.jpg
http://i242.photobucket.com/albums/f...ps359f32cf.jpg
Re: TU and F4 Camshaft Follow-on Discussion
I would also like to see an 8v solid adjustable 'checking' lifter and also a TIII version. I think the factory FSM had directions on how to make one for a TIII, but I have never seen an actual picture of one that anybody has built.
I only have experience dialing in cams for the TIII, but I can see how a dimple would help keep the tip of the dial indicator absolutely stable.
Re: TU and F4 Camshaft Follow-on Discussion
http://www.turbo-mopar.com/forums/at...=27377&thumb=1
i thought warren was running roller cam mechanical lifter
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
4 l-bodies
Yes that is THE million dollar question. Comp Cams talks about that a bit, saying they know just how far they can safely push it as far as accelerating and decelerating the valve. I do know your fellow Canadian Geoff at Colt has NA regrind roller cams with much bigger lift that he has sold to the circle track guys in the past. We certainly don't want a repeat performance of the slider S-60 camshaft durability. The good news is the roller cams have much harder and deeper surface hardening, and so they should tolerate a pretty stiff spring if needed. I have seen a couple of our roller cams that have had lobes that just start to crumble. I brought one camshaft to two different high end engine builders and both thought camshaft core was over hardened when manufactured. They both said yeah that just happens once in a while. I have some pics of failure but can't seem to find them at the moment. So I failed too (lol)! The size of roller in follower can also come into question as camshafts get more aggressive. There was a thread about that and the difference in slider follower a while back on this forum. The pivoting point is much greater in a slider over the rollers .700 diameter.
There is (probably more than one) reason Warren went away from a hydraulic roller camshaft.
Todd
If you have a friend at Colt, can you ask them the specs on the F4 "billet" cam? They are who make it. At least that is what I was told while I waited 1 milliondy months for mine to come in.
Quote:
Originally Posted by
bakes
Love that picture.
1 Attachment(s)
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
bakes
Just a side track question Mechanically how radical of a cam profile can are roller valve train survive ( ie egg shape to almost digital or square shape ramps) ????
The answer to this question depends on the lobe base circle diameter, max lobe lift, duration, and how aggressive the ramps are.
Often you can design a "max effort" lobe that will make it easier for the roller follower. As you increase duration the lobe profile becomes more circular and less "pointy" over the nose. As you increase the base circle diameter, the lobe profile over the nose becomes even less of a deviation above the base circle diam. Imagine a lobe with, say, .500 lift ground on a 12inch base circle, It would barely be a hiccup for the follower to traverse.
Compare the two cams in the attached photo. The cams are a S3 hyd. roller, and my SCX605 Mechanical. The rear cam has much less duration and less lift, and is ground on a smaller base circle. You can clearly see how much more pointed the nose is on the S3 than the 605 cam in the foreground. Which lobe do you think is easier on the valve train?
Also, as an aside; you can clearly see the asymmetry of the lobes.
On the 605 cam, the most aggressive area on the lobe, and most punishing to the follower, is the opening ramp, in the Major intensity area. It is as close to square as we could get.
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
Warren Stramer
The answer to this question depends on the lobe base circle diameter, max lobe lift, duration, and how aggressive the ramps are.
Often you can design a "max effort" lobe that will make it easier for the roller follower. As you increase duration the lobe profile becomes more circular and less "pointy" over the nose. As you increase the base circle diameter, the lobe profile over the nose becomes even less of a deviation above the base circle diam. Imagine a lobe with, say, .500 lift ground on a 12inch base circle, It would barely be a hiccup for the follower to traverse.
Compare the two cams in the attached photo. The cams are a S3 hyd. roller, and my SCX605 Mechanical. The rear cam has much less duration and less lift, and is ground on a smaller base circle. You can clearly see how much more pointed the nose is on the S3 than the 605 cam in the foreground. Which lobe do you think is easier on the valve train?
Also, as an aside; you can clearly see the asymmetry of the lobes.
On the 605 cam, the most aggressive area on the lobe, and most punishing to the follower, is the opening ramp, in the Major intensity area. It is as close to square as we could get.
Although it increased HP, the Taft S3 being a regrind with a smaller base circle is one thing I didn't like about it. I would much rather have a new billet over a regrind! Warren will you pass along some specs of your SCX605 cam, and would this cam be available to someone if they wanted one?
Re: TU and F4 Camshaft Follow-on Discussion
Quote:
Originally Posted by
bakes
He is, what made you think otherwise?
Quote:
Originally Posted by
chilort
If you have a friend at Colt, can you ask them the specs on the F4 "billet" cam? They are who make it. At least that is what I was told while I waited 1 milliondy months for mine to come in.
The specs are already posted as far as what we are going to get from the cam grinder. So until someone actually takes the time to degree/ instal one, we won't have anything more.
