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Author Topic: Why the lack of published cam specs  (Read 4379 times)

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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #30 on: June 23, 2018, 10:46:34 PM »

GRC: The severity of the opening/closing ramps in TCs relates more to Hydraulic Roller tappet limitations than cams. Oil aeration and lifter bleed down cause power loss and valvetrain noise. This is a big deal with larger Hyd. RLR cams in Big Block Chevies, as a heavy valve train and the required heavier spring pressures required cause lifter bleed down and noticeable power loss. This is why the popular 5.0 Ford engines respond well Horsepower wise with Hyd.Rlrs. and BBChevies don't. These issues are also why a drag car engine works better with a HYD. RLR. than a boat or other endurance engine. A drag car that runs only 10 second passes and then sits for a while does not heat or aerate the oil nearly as much as a Harley with hot aerated oil from miles of use. The other thing that I don't understand is why similar cams in HDs use 50 to 80 lbs. more seat pressure than a BBChevy engine. I have experimented with lighter than recommended spring pressure in HD engines with good results, but no explanations as to why from the cam companies. I expected Comp cams to explain their recommendations to me since they grind both auto and HD cams, but no info so far.
A BBC has a higher rocker ratio, bigger diameter and longer spring, heavier spring retainer, a similar length pushrod, bigger diameter and longer valve, and heavier locks than an HD, but less recommended spring pressure than the HDs for the same RPM range.

When I bought my 565" 14-71 blown and intercooled BBChevy powered boat, it came with a 260 degree @.050 and .670 lift Hydraulic Roller Comp. cam with 160 lbs. seat pressure as recommended from Comp Cams. RPM was 5300 and the boat ran high 90 MPHs. It had valve train noise above 4400 rpm (the lifters were bleeding down). I changed nothing but the lifters to solid rollers (different pushrod lengths were needed) and gained 450 rpm and 9 mph. I lashed the lifters at .004 intake and .005 exhaust. The valve train was a lot quieter too.

Bottom line: I run either short travel lifters or standard low bleed lifters and lash them up a half turn from the bottom with good results in my HDs, and never any signs of pump up. P.S lifter "pump up" (actually brought upon by valve float) was an old phenomenon from the old days when they didn't have computer designed and Spintron tested cam lobes and valve springs. Just some observations for comment from the TIMINATOR
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MCE

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We should publish
« Reply #31 on: June 23, 2018, 11:35:01 PM »

I wonder if we would get in any trouble for publishing the lobe profile data for HD cams...
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Nocvo

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Re: We should publish
« Reply #32 on: June 23, 2018, 11:36:11 PM »

I wonder if we would get in any trouble for publishing the lobe profile data for HD cams...
I'm guessing you would get a legal eagle phone call lol
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HD Street Performance

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Re: Why the lack of published cam specs
« Reply #33 on: June 24, 2018, 10:06:11 AM »

Why would there be any issue? And what significance and value would it bring to an average builder? I have stated what horsepower levels are currently. Over 20 years ago nightrider published horsepower expectations for modified street riden Harley bikes and what it would take to get there. The twin cam was nearly new and the prevalent engine was the EVO. They actually haven't changed a whole lot in all those years. We et al builders are building higher quality engines that last longer between overhauls however. We can give credit where due to the aftermarket and some to Harley as well as ingenuity. We now are at about 1.2 hp/cu in with 1.1 being more common and affordable. Will publishing the cams specifications help us move higher in horsepower levels normally aspirated on pump gas? Is the valve train, including the hydraulic roller lifters, the achilles heel that is holding horsepower back? On a similar but side note when testing a few of the cams you will find some tricks done that were done when I was a kid to win in stock class racing with cam profiles.
Quote from one of the manufacturers'
These cams get from .004" to .053" in only 32 degrees as our competitors cams get only from .020" to .053" in 36 degrees the result is better manifold vacuum, do to less non-advertised overlap also referred to By HARVEY J. CRANE as the cross over area so better engine acceleration thru the range.
This is in reference to opening, the closing is another story.
Makes power and is hell on parts.
Then you have S&S that designs and grinds their own cams. Industrial engine lobes by comparison.

So what are we going to do to bring these motors up while still remaining something you can put the wife on the back and ride cross country? That would help the OP and all Harley performance enthusiasts and more importantly the average guy, the ham and eggers, that just want to pass a truck on the freeway headed up a hill.
« Last Edit: June 24, 2018, 10:08:02 AM by HD Street Performance »
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MCE

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Re: Why the lack of published cam specs
« Reply #34 on: June 24, 2018, 11:08:55 AM »

I was thinking more about the serious performance engine guys. Jon Q Public wouldn't know what to do with any of it,
neither would allot of others. And why would they? (We already talked about that)

Quote
So what are we going to do to bring these motors up while still remaining something you can put the wife on the back and ride cross country?

Good question. Continuous R&D is what makes it possible. (Spending tons of time on the dyno, flow bench, (and simulators)).
The never ending pursuit of continuous improvement, It's just what some people do.
 
I'd like to have a database shared by like minded people so we could exchange/share data files. I have quite a collection
of them, but not as many as I'd like.
« Last Edit: June 24, 2018, 11:43:15 AM by MCE Performance »
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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #35 on: June 24, 2018, 11:50:17 AM »

I don't see any legal issues with publishing raw data. We just wouldn't want to publish any of our conclusions as to the relative merits of certain designs. As per data only, would publishing the actual screen size of a laptop be any different?
In my experience looking at the shape of the lobes graph and digesting the quirk and jerk and acceleration rates is the more meaningful data to have. Its just not anything that Joe Average could do anything with. I feel that those that can use the data meaningfully probably have already spent the coin and have a cam analyzer, or are saving up for one...
As an alternative, graphing a lobe on a lathe between centers every 10 degrees or so will give a newbie the ability to at least get an idea as to what the differences are in the way a cam different cams act in their engine.
I started regrinding mini bike cams on my grandfathers lathe with a tool post grinder and a home made degree wheel when I was 14 or so, and that experience came in handy when I was running my street/ strip Chevelle years later. It ran high 10s at 124 mph with a Comp Cams street roller cam, and I wanted more. Long story short, I bought 5 "larger" cams from other manufacturers, all with 4 to 9 degrees longer duration at .050 and up to .075" more lift. All went slower, in ET and MPH. So I went back to the degree wheel/lathe for several evenings (it did take that long to get meaningful info) and discovered that every "larger" cam had less area under the curve. I called Comp. and bought another cam and went faster. Sold the other cams, destroyed a credit card and bought a Cam Dr. at the next PRI show. I still have it and use it regularly.
There are more than a few cam companies that produce laughable cams in area under the curve and quality, that are big sellers, because most cams are bought for "the sound," or the idea that "any power gain is more than I had." This is true of automotive and bike cams. Some people you just can't help.  Just more ramblings from the TIMINATOR
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MCE

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Re: Why the lack of published cam specs
« Reply #36 on: June 24, 2018, 12:10:26 PM »

Ha! Good points Tim. (I started out on single cylinder flat heads too, in the 60's).

I forgot to mention the track as a testing tool. That's the one that really counts.
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MCE

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Re: Why the lack of published cam specs
« Reply #37 on: June 24, 2018, 01:09:55 PM »

We had an engine shop class in high school. They had a small engine dyno that we tested the
Briggs, Kohlers and Tecumseh on. Blew up a bunch of them!
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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #38 on: June 25, 2018, 11:14:24 AM »

I still play with mini bikes when time permits. Currently doing an 8HP OHV B&S motored Heald Super Bronc. Torq-a-verter drive, custom header (played with the formulas and re did it length and diameter 7 times), bored, flowed, and rejetted the carb, longer runner intake manifold, completely filled/reshaped intake runner, reshaped/filled exhaust runner, unshrouded combustion chamber, milled head, Cadillac NorthStar intake valve, V-6 Nissan exhaust valve,both the same stem size but cut down in length, 5+ angle valve job, advanced timing(made an offset crank key), indexed and side gapped spark plug, and whatever I forgot. Nothing at all done to the short block, never dissembled it, only top end. Original HP=7.8, new HP=15.9. STOCK CAM WITH STOCK PHASING (so far). Old top speed=34, new top speed=63+. I have a cop RADAR gun.
Sometimes its easier to try things on a single cylinder, or a 4 cyl. 2000 Pinto engine. You can learn something on anything...  I taught myself porting with a 2300 Pinto engine, Dykem layout fluid and spray paint. Where the air goes, so does the fuel, fuel removes Dykem, Exhaust burns paint, where the exhaust goes, no paint. I figured that out when I was very young and couldn't afford a flow bench. Paint/Dykem the ports, make a full throttle blast down the street, remove head grind/reshape the clean spots. By the time I made an industrial shop vac flow bench, I had a reasonable idea how air worked. The Superflow 600 came later...
Study steam engines if you want to understand compression(expansion) ratio effects. Study Boyle, Hooke, Gay-Lussac and Hilsch if you want to learn about air. The Super Flow tells you what happened, studying the pioneers tells you why.  TIMINATOR     P.S. later I'll clue y'all in on my other mini bike project.
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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #39 on: June 25, 2018, 11:51:25 AM »

Sorry about the long winded post, but in conclusion: If you don't publish cam specs, maybe you aren't grinding your own cams, or are just copying someone elses lobes, and mebbie using different intake lobes form one guys cam and an exhaust lobe from someone else's cam. Maybe you don't really understand what it is you are doing, so you can't really have a good discussion about it. Or perhaps you really think that you have re-invented the wheel and have discovered a "secret" grind that works perfectly in everything. The proof is on the street and on the dyno. Not in the advertising. A while back a company advertised: "The Worlds Most Powerful XXX Cam." It did make a bit more power than the other XXX cams, but for those of us with a way to analyze cams, we knew that it was actually a longer duration than an XXX cam, and also had more lift than advertised, and that's why you needed their "Special" valve springs.
I AM NOT POINTING A FINGER AT ANY COMPANIES HERE NEW OR OLD!!!!!  Just relating what went on in the automotive Cam Wars of the 1970s.
"Those who do not study History are doomed to repeat it." I don't remember who said that, but I know its true.   

Boy, I probably started something here!         TIMINATOR

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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #40 on: June 25, 2018, 11:56:27 AM »

P.S. My Grandma said: "If the truth hurts, it probably should."     TIMINATOR
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MCE

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Re: Why the lack of published cam specs
« Reply #41 on: June 25, 2018, 12:03:12 PM »

I had to take allot of those M.E. classes, (even though I majored in Electronics).

I've forgotten most of the math formulas (it's been 40 years) but the concepts
are still up there. And I read allot too.
« Last Edit: June 25, 2018, 12:23:29 PM by MCE Performance »
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MCE

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Re: Why the lack of published cam specs
« Reply #42 on: June 25, 2018, 04:06:29 PM »

We didn't have access to computers like we have now, when I went to school. (If you needed a computer for an assignment,
you had to schedule it and fight over time slots.)
 
Now days, with the computing power that's available and the simulator programs, just about anyone can attempt to design
whatever they want. It's so damn amazing how far things have come. It just blows my mind to think what will be available
in another 20-30 years.

Advances in metallurgy and computing power are what's driving the advances and the power we're able to get out of these
engines.
« Last Edit: June 25, 2018, 04:16:56 PM by MCE Performance »
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TIMINATOR

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Re: Why the lack of published cam specs
« Reply #43 on: June 26, 2018, 11:29:41 AM »

Another reason for no cam specs: The company just signed up with a large supplier of cams that are all the same as a lot of other "Private name" cams. If they published the specs then all would know that they sell the same generic stuff as others. In the automotive industry, Elgin grinds the house brand cams for many distributors. I believe that at least one company still advertises on their own web site that they will grind, box, and label your "house brand " cams. Google 204/214, 222/222, 214/224 duration automotive cams for instance and see how many brands you come up with. Some companies actually mis label the cams by a degree or two and a few thousandths lift to mislead you. Those generic cams have been sold since the 1970s and are of ancient designs, but they are useful to some because they will still make more power than a stock cam, and are cheap. Not to say that nobody else actually grinds their own cams to that spec. but if it looks like a duck, walks and quacks like a duck, mebbie it just might be a duck. Especially if most of the ducks look the same and are cheep (pun intended).
Then there are a few automotive companies that buy the old "master" lobes that were used on old manual cam grinding machines when the original companies sell them off cheap (because the "master" is worn and no longer grinds what was originally intended.) Some of them Cam Dr. the resulting lobes and then advertise the cam as what it actually grinds to now, problem is that the ramps are no longer the shape that was originally intended (valve float? or just less area under the curve?)
Another company comes to mind. This guy Cam Drs, the lobes to compute the area under the curve, then sells the cams as a shorter advertised duration like a modern cam so his old cams seem to make as much top end power as newer fast ramp designs. Idle quality is worse and they come up on the power band later, but can make the same power up top. I became aware of that practice in about 1990 when I built a set of BBChevy competition heads for a customer. I supplied Comp Cams springs, retainers and locks, and set them up for the cam as indicated on the cam card he had. I tried to talk him into a Comp Cam too, but he "went to school in California with this guy and he bought the cam really cheap because they had History." The heads sat until about 6 months later when he had the cash for the short block, he assenbled it, drove it on the street for a few weeks and took it to the dragstrip and bent every exhaust pushrod. After listenening him scream about my incompetance for about an hour, he brought over the heads. I pulled out a copy of his cam card and checked the clearances as stated on the card, they were fine. More screaming. I went with him to his garage and removed the cam myself, came back and Cam Doctored it. Intake and exhaust durations were 5 to 7 degrees longer and exhaust lift was almost .05 something higher. The cam was marked the same as the cam card. No apology. He did make excuses and the guy sent him another cam, it measured the same. He blamed my Cam Dr. We checked about a half dozen of other cams I had laying around, and all the others were fine. No apology still. I never did any more work for him again. But after hearing stories from others, I posted a large blown up copy of the cam card and the Cam Dr. results along with his name and date. He sued me for slander. I won. I left that info on the wall for about 15 years, along with a copy of the the court judgement!
I Cam Dr. every cam I install since, and refuse to install one every once in a while.
Sorry for the long rant, but it might save someone a bit of grief.  TIMINATOR   :soapbox:
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remington007

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Re: Why the lack of published cam specs
« Reply #44 on: June 28, 2018, 02:22:49 PM »

I had a interesting thing happen on my shovelhead last winter. I have been running a Andrews #2 in my 87 inch stroker and i had a starting issue from compression. So in the general world i thought to just add a cam that the intake closes later, problem solved. So i went from a #2 that closed a 35* to a V-Thunder 4010 that closed at 42*, 7 degrees later should help right?  Instead it raised the compression 10 lbs. So i would guess something below 53* advertised timing does affect things. 
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