Camshaft And Valve Timing Event Articles

Mopar Racers Forum

  1. 12many

    12many Well-Known Member

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    • skrews

      skrews Well-Known Member

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      Pick the cam at the bottom of the page. :thumbsup:
       
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      • 12many

        12many Well-Known Member

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        Or just start a “what cam” thread. Likely your best bet if all you want is to know, without learning!:rolleyes: Me? I want to learn....because.....I want to know about these things. mondello.com - Camshaft Theory
         
      • PRH

        PRH Well-Known Member

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        Good info in that one from Mondellos site.

        After you’re armed with all that info...... you have to sort through it and figure out how it applies(or, to say it another way, how do you apply it) to what you’re doing?
         
        Last edited: Jan 11, 2020
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        • 12many

          12many Well-Known Member

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          At the moment I’m absorbing it all, getting a few reply’s on recommendations at the same time using what I know, am learning and coming up with my own initial specs, revising, questioning myself on some, comparing other setups, all the while searching as many lobe lists, as well as seeing what there is off the shelf that gets close or may actually hit the mark. For myself, I’m just not going to be content on just having someone spec a cam for me and call it good, without knowing why I get some of the specs I get. I’ve already accepted that I see and agree with others that I want some of that “area under the curve” action, shorter seat duration, and more lift. So onto timing, characteristics and how much
           
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          • PRH

            PRH Well-Known Member

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            Many years ago I tried a new at the time series of fast rate hyd cams in a motor I put together.
            “On paper” it seemed like this was going to be a slam dunk.

            Well, I was seriously underwhelmed by that cam in that motor.
            So, I swapped it out with a much older design, that again “on paper” looked like it was going to be worse in every way for that build.
            It did everything better.
            More TQ, more HP, more responsive, revved higher before float, and had a quieter valvetrain.

            Sometimes the theories don’t always play out like they’re supposed to.
             
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            • 12many

              12many Well-Known Member

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              It’s obvious there are many theories. I first contacted Jones with the specs shown in the other thread. He recommended a 316 adv, 260@.050” .378” lobe (.604” before lash) on a 110lsa with max power at 6700-6800? I got to thinking, asking here, thought it was too big, decided to lower my max power rpm a little, 6500. Got a revised recommendation from Jones. A 304 adv, 252@.050” .364” (.582” before lash) on a 110lsa with max power at 6300rpm. Both single pattern using .875” lobes. Ok, let’s try another source with same build etc. Howards came back with a 274 adv, 246@.050” .384” (.614” before lash) on a 108lsa, single pattern .904” lobe. The first one with 875 lobes with big seat duration, good lift, second one still big seat duration, with what I’d consider very mild lift 875 lobes. And then the last one with very aggressive 904 lobes but less advertised, @.050 and on a 108lsa and 58 degrees overlap. The first cam is an outlier, the second Jones and Howard’s are very different but of the two I’d pick the Howards for the area. But timing events I’m not sure on. And I’m not going with max aggressive lobes. Now eyeballing Bullet, and liking some of the older Ultradyne lobes. Still waiting on reply’s though.
               
              Last edited: Jan 11, 2020
            • PRH

              PRH Well-Known Member

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              One way to get an education on how timing events impact the power output and power curve on a motor is to try a bunch of different ones....... all in the same motor.
              Over the last 20+ years, the one motor I have tried the most cams in is my friends Stocker.
              At least 15 different ones.
              Lsa’s from 104-109, installed positions from straight up to +6, single patterns to cams with 14deg split.
               
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              • mbaird

                mbaird mbaird FABO Gold Member

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                I would love to see a dyno shootout with 4-5 different custom cams on same engine!
                Has anyone seen such a test ?
                 
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                • mbaird

                  mbaird mbaird FABO Gold Member

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                  AND. ????
                   
                • 12many

                  12many Well-Known Member

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                  Yeah, maybe I’ll just end up playing pin the tail on a camshaft, or stick the various recommendations on a dart board and just have at it.
                   
                • yellow rose

                  yellow rose Doctor of Thinkology.

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                  If this is the case and that's what you want...be prepared to lose your hair. And your mind!!

                  I posted a long reply in a different thread here in this forum a minute ago and I touched on this very thing!!

                  If I wasn't stupid and knew how to copy and paste with this iPad I'd just do that and add it here.
                   
                • yellow rose

                  yellow rose Doctor of Thinkology.

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                  It's done all the time. The issue becomes you found the cam for that application and it makes the other cams look like junk when they may not be.

                  I remember an interview with Larry Morgan years and years ago (got to meet him in 1998 and he is a funny dude...sorry for the name drop) and he said they spent the off season only testing cams.

                  They went through 200 different cams and a 55 gallon drum of fuel. Just testing cams!!! They didn't change the intake manifold, the headers, the ports or anything. Just the cams.

                  Obviously they do lash loops and moved the ICL all over the place, but like testing oils and fuels, any real testing is time consuming and very costly. If you want real results.
                   
                • 12many

                  12many Well-Known Member

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                  True. I have out of control OCD.....obsessive cam disorder!
                   
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                  • skrews

                    skrews Well-Known Member

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                    • 12many

                      12many Well-Known Member

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                    • mbaird

                      mbaird mbaird FABO Gold Member

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                      If they were all custom grinds for a specific build and application it would really highlite the individual talents of the grinders .

                      That test does highlite the range of outcomes but because it was a stroker it throws the shelf grinds off .
                      If it was a standard 360 or 340 it would have been a better test due to controls.
                       
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                      • yellow rose

                        yellow rose Doctor of Thinkology.

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                      • skrews

                        skrews Well-Known Member

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                        The Hughes cam mentioned in the article was ground by Bullet at that time. Hughes cams are now ground by Howards, a step back IMO.
                         
                      • PRH

                        PRH Well-Known Member

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                        That test highlighted one important aspect of buying a cam, if you’re not making the decision/choice on it yourself....... and that is...... who’s on the other end of the phone can really make a big difference.

                        The Comp selections for those tests were terrible.....as is pretty obvious from the results.
                        Comp has some really nice lobes that would have definitely competed head to head with the best cams of that test.
                        But, their catalog “Race” cams for Mopars are pretty off the mark imo.
                         
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                        • skrews

                          skrews Well-Known Member

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                          I agree, Comp actually has some very good profiles, but one needs to talk to somebody in the know when you get a cam from them. And yeah most of their Mopar shelf grinds suck.
                           
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                          • Mattax

                            Mattax Just the facts, ma'am FABO Gold Member

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                            To some degree engine dyno simulation programs are useful for doing a bunch of comparisons when the real thing is out of reach.
                            I bought Dynomation thinking I could also learn something about the relationships of various changes to outcome.
                            It still a struggle - because without the experience its harder to judge when you (I) have made poor inputs. Garbage in = garbage out.
                            One thing that threw me for years was that the stock engine simulations were not matching real life dyno curves.

                            What was interesting was we got pretty good match when we compared simulations of the Zebra-Dart's 318 to the actual dyno pulls.
                            Thanks to Wyrmrider this past year finally figured out what was wrong with the stock simulations - the chrysler cam specs.
                            I know the better simulation programs aren't cheap, but for some of us they are a cheaper or more reasonable way to see the effect of cam events than swapping cams in our engines.

                            Now if they would just simulate a part throttle pull....
                            ;)
                             
                          • yellow rose

                            yellow rose Doctor of Thinkology.

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                            I think that is what Brother YR has been preaching. For years and years.
                             
                            Last edited: Jan 11, 2020
                          • yellow rose

                            yellow rose Doctor of Thinkology.

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                            I read the article. Pretty interesting. One thing that bothered me (and I get it...it was testing for a magazine and they don't have a ton of time) was they didn't even move the cam timing at all to see what happened.

                            I'd have loved to seen what would have happened if they took the MP .620 and installed it at 101 or 100 instead of the 104 they stuck it at. Even 102 would have let you know if you were trending in the right direction.

                            I also noted as the cam timing was changed to make the overlap triangle steeper and more pointed the power curve changed. It took more timing to get the same RPM, but the bottom and middle numbers were better too.
                             
                          • skrews

                            skrews Well-Known Member

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                            I too found it interesting that the Hughes/Bullet cam performed as well as or better than all the other cams at any given RPM and out powered them all at peak. Bullet has always done well in my book, and they have the most extensive .904 lobe line of any cam manufacture by far.

                            I too would like to see the the .620 cam advanced 6 or so degrees just to see what it'd do.
                             
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