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  • Camshafts 101

    updated more colt cam information

    guide made by me and my brother, 95PGTTech, the PT asshole.

    2.5L Camshaft 101

    This is mostly for you newbies out there to put all the camshaft information on this board in one place, but also to answer a few questions of my own. Mike Seli, Rob (CZT), and any other cam gurus, if you would like to add please feel free. Members, if they choose to add in here, keep it on topic. I don’t give a shit about your CZT IM, keep it out of my thread.

    First, some camshaft basics (but not too basic…if you don’t know these next sections pretty well, stick to bolt-ons and read more books). Let’s say I have the stock KL03 camshafts (I/E 0.338" lift, 196-198@ 0.050"). I left those numbers at that because there is some debate as to what they actually are (if anyone has a supporting source, please post). So what do those specifications mean?

    As a side note, you will commonly see I/E. This means intake/exhaust, which implies that the intake and exhaust cams are the same specification. Although common, this is not the most effective way to squeeze ever horsepower out of a motor, especially ours, if you really get into cylinder head flow considerations. If the intake and exhaust are of different specs, the two will usually be listed separately.

    First, lift. .338” means that the maximum the intake or exhaust valve will lift off the seat (open). What it really means is the amount the cam lobe will lift the tappet (lifter), but since we don’t have a pushrod engine, we can simplify the situation. If you ever look at a pushrod motor’s cam specs, you’re going to notice a significantly smaller lift number (multiply that number by the rocker arm ratio to get the actual distance the valve is lifted). The higher the lift, the wider the passage between the intake manifold runner and the combustion chamber - and as we all know, larger and less restrictive is usually better on the intake side. Obviously, maximum lift occurs at the nose of the camshaft lobe, its highest point (the sides up to the lobe’s nose are called the ramps). The ramps determine how quickly the valve goes from being totally closed to max open. Thus a camshaft can have a high lift and take a long time to get there, or it can have a high lift and take only a short time to get there; the ramps are just as important as the nose. Back to lift - increasing lift has the obvious problem of piston clearance (which becomes a real problem when wanting to increase compression ratio), but renders good power gains by stuffing more air into the cylinders at high rpm (loss of any low end torque is debatable). Lift is also limited to a certain degree by the diameter of the journals that the cam rides on - a camshaft with too “nosey” lobes will not be able to be installed. Lift also becomes an issue due to higher amounts of lift and greater spring pressures tending to slam the valve onto the valve seat upon the closing side of the lobe; although this is a problem, it can be dealt with by utilizing asymmetrical lobes (which I won’t get into, read more…basically, cough up a little more money to be able to run high lift and save your valve train at the same time).
    Last edited by 95PGTTech; October 19, 2005, 07:29 PM. Reason: cause I damn well feel like it :lol:

  • #2
    Now on to the second and third numbers - duration. In the example, this is listed as 196-198 @ 0.050”. The 0.050” measurement is lift, but not max lift, called the “advertised duration.” Every manufacturer picks a number that they find to be appropriate, but the industry had to settle on a standard number, and picked 0.050.” So just because you hear of a “crazy” 272/272 setup on a Mitsu Evo VIII, when the numbers are converted to the 0.050” standard, its duration is only 221 degrees. So the manufacturer of the KL03 camshaft is saying that with this cam, it keeps the valve open at least 1/20 of an inch for 196-198 (depending on your source) degrees of camshaft rotation. OEM cams like to have short durations to promote good part throttle response and good idle quality. Aftermarket usually have much longer durations; more duration tends to kill idle vacuum and quality, reduce low-end power, and produce massive amounts of high-rpm horsepower. Long duration also tends to absolutely annihilate gas mileage, so if you really know what you’re doing you may want to play around and try to retard the exhaust lobe center (which would mean still decent intake duration but less overlap)..

    To jump quickly back to dual-pattern cams, duration on the exhaust camshaft is where we see the desire for dual patterns. If you look closely at some of the cam specs listed later, there really is no difference between the intake and exhaust side other than the exhaust side’s slightly longer duration. As Mike Seli once pointed out, he makes huge gains in horsepower on the intake side (over the KLZE cores you send him) but he rarely touches the exhaust side; for those seeking an extra 2-3 horsepower, he can regrind the ZE exhaust side with a little more duration than his intake regrinds.

    And lastly, overlap. Overlap is the amount of time that the intake valve and exhaust valve are open at the same time. Increasing valve overlap has very common symptoms to increasing intake valve duration - poor idle, loss of low-rpm torque, good improvements in high-rpm horsepower. High-duration can help improve the scavenging of the cylinders and increase volumetric efficiency, but it could also be argued that overlap can have negative effects on compression ratio, however this argument differs from cam to cam - more specifics are needed for such a debate. Overlap is particularly of interest in turbo grinds (see the advancement note on the colt turbo regrind exhaust cam) due to desire to spool the turbo faster.

    I won’t get into lobe centerlines, asymmetrical lobes, camshaft phasing, VTEC, variable valve timing, infinite (solenoid) valve timing, etc. at this time. That’ll be in the 200 level class.
    Last edited by 95PGTTech; October 19, 2005, 07:27 PM.

    Comment


    • #3
      Camshafts available for the 2.5L Mazda KL03/KLZE head:

      **as far as I know, no one offers a brand new cam for our cars. This may change if someone goes to crower and wants something extremely aggressive, but all listed here are regrinds. Also, all cams here are for hydraulic lifters, except the millennia S cams, which are solid lifter cams. You could use a hydraulic lifter cam with solid lifters, but it would be advisable to have the cam modified to improve driveability.**

      (please feel free to chime in here)

      Cam…………………………Specs………………………….............Additiona l Information
      KL03.……………………....….I/E 0.338" lift, 196-198@0.050"

      KLZE………………………......I/E 0.350" lift, 200@0.050”

      Millenia S………..…………..KLG4 (I/E unknown, supposedly much tamer than ZE)

      Interprep Colt regrinds.................ZE cams...03's reground to ZE specs
      ...............................................rac e grind...I/E 0.363 lift, 218@0.050
      .................................................. .alleged 1100 idle, geoff reccommends megasquirt
      ...............................................tur bo grind...intake 0.355" lift, 210@0.050
      .................................................. ..............exhaust 0.350" lift, 200@0.050
      .................................................. ..............same as ZE exhaust, but 2 degrees advanced

      Mike Seli Regrinds………….I/E 0.353" lift, 208@0.050"
      ……………………….......………0.363" lift, 208@0.050" intake option
      ……………………………….......0.353" lift, 209@0.050" intake option
      …………………………….......…0.352" lift, 202@0.050" exhaust option

      Original colt grinds…………I/E 0.338" lift, 211@0.050"

      Colt super street .....…..I/E 0.355", and 210 deg @ 0.050

      Colt wild street........……I/E 0.365" lift and 218deg. @ 0.050"…..1100 rpm idle

      Colt race trim?

      Comp cams?

      Crower cams?

      CZT regrind………………..I/E 245 @ .37.………………….......no standard advertised
      ………………………………...................................... ........................CZT issues?

      Now that’s what I’ve provided y’all with, now my selfish part. Let’s say I have the following car: 95 Probe GT MTX, ZE block, heads, eagle forged h-beam rods, wiseco forged 12+:1 pistons (don‘t give me any shit about this, 14:1 is the max the motor can go without interfering, and with the Millennia solid lifters I can run any goddamn cam I want, this has been discussed a million times and I don‘t want to hear any more about it), MSnS, 550 injectors, fuel pump, dual feed fpr, headers, test pipe, exhaust, intake, 67mm TB, ported ZE manifold, phenos, Millennia mechanical lifters, dual valve springs, titanium retainers, yaddah yaddah. Basically a built mofo high compression N/A motor capable of setting its redline at 9000 rpm. From the stats above, what cams would you recommend for a daily driver (I don’t give a shit about comfort) that wants to retain a decent fuel economy (I’d settle for 17-20) but will used on a weekly basis at the track (mostly drag)?

      As far as I can tell now, the Colt Wild Street regrinds are going to be pretty aggressive, yet at 1100 rpm retain some drivability (when my car was CEL-abound for awhile I was running approx. 18mpg and idle was 1200, wasn’t undriveable but annoying…with the standalone I think I can improve fuel economy). I am also disusing the options with Crower about how expensive it would be to get a set of their lightweight roller mechanical lifters (I told them I own a Millenia not a Probe).
      Last edited by 95PGTTech; October 19, 2005, 07:26 PM.

      Comment


      • #4
        you forgot the KF-ZE Cams...which are supposedly more agressive than KL31 cams.

        Not sure the specs myself...i'd like to know tho
        Wil (admin iMazda.com) 93' MX-ZE
        Mods: ZE w/31 cams & curved-neck mani, 67mm t/b, obx headers w/2.5" straight-thru, 3" custom CAI,
        Mazdaspeed mounts, Tochigi Fuji Sangyo 2-way LSD, ACT clutch, Noble Green Metallic paint, E-spec headlights,
        OEM skirts, 16" SubZeros on Azenis, Tokico w/Eibach's, Mazdaspeed TTL & Bushing Kit, New OEM Leather seats & SE interior

        READ THE HEADER FAQ OR DO A SEARCH

        Comment


        • #5
          thread updated with Interprep Cams specs, from the makers themselves.

          what are these KF-ZE cams you speak of, neither of us have ever heard of them before.

          ****, forgot about the aussie cars. however, an hour of searching turned up diddly squat. people think they're more aggressive than the ZE cams, but exact specs are nowhere to be found.
          Last edited by 95PGTTech; May 11, 2005, 12:51 PM.

          Comment


          • #6
            40 degrees of overlap? All the specs I've seen show about 12-14 degrees of overlap at SAE open/close.

            Comment


            • #7
              Originally posted by lakersfan1
              40 degrees of overlap? All the specs I've seen show about 12-14 degrees of overlap at SAE open/close.
              the duration portion of the FAQ has been edited due to a lack of clarity, we regret the error.

              it is now edited, thank you pin spelling police.
              Last edited by 95PGTTech; May 11, 2005, 12:52 PM.

              Comment


              • #8
                Interprep
                Barry
                01 Saturn SL2 5-speed
                Easy Way Electronics

                Comment


                • #9
                  Id like to know what the KFZE's are as well! IIRC that motor was a mx3 and millenia engine which was a KL style block but only had a 2.0L V6. And the intake ports were kinda dinky looking. If you wanted to build a high revving smooth sounding engine a KF would be the ticket! But I would be curious how much more agressive these are over the KL31's, it cant be a huge difference.
                  Dan Brown - 1995 Turbo PGT ~ SOLD ~
                  287whp & 307lb-ft. @ 10.5psi & 12* Timing

                  Comment


                  • #10
                    some guy said the KF-ZE uses the same cams as the KL-ZE (p/n kl31) but I'd like to see that proven or disproven!

                    Comment


                    • #11
                      Originally posted by veltpak6
                      some guy said the KF-ZE uses the same cams as the KL-ZE (p/n kl31) but I'd like to see that proven or disproven!
                      I've been reading KF-ZE threads for a couple hours now, there are pictures showing KF-31 badged camshafts. Although no one has taken measurements off them, they're obviously different from KL31 cams - Ford and Mazda, being the cheapasses they are, would not spend the money to differently badge the same part, they'd use leftover KL31 stock.

                      Comment


                      • #12
                        dan sac just got a kfze moter. he would be the one to ask.
                        94Gt Ze Rio red,afpr,borla, sts,EIBACHS
                        ,gray->black int, mx6 leather,
                        need rio red sideskirts yesterday
                        Ze isnt rice its from JAP its a rice eater
                        My car is finally in the garage again

                        Comment


                        • #13
                          kf-ze is 2.0 K-series v6 rated at 170hp 140ish torque.

                          came in the 323f and lantis and the base model MS8 and probably a few others. I'm not even sure the overseas cronos had a FS engine. It might have had the KFZE in the lower-trim models
                          Wil (admin iMazda.com) 93' MX-ZE
                          Mods: ZE w/31 cams & curved-neck mani, 67mm t/b, obx headers w/2.5" straight-thru, 3" custom CAI,
                          Mazdaspeed mounts, Tochigi Fuji Sangyo 2-way LSD, ACT clutch, Noble Green Metallic paint, E-spec headlights,
                          OEM skirts, 16" SubZeros on Azenis, Tokico w/Eibach's, Mazdaspeed TTL & Bushing Kit, New OEM Leather seats & SE interior

                          READ THE HEADER FAQ OR DO A SEARCH

                          Comment


                          • #14
                            I've only seen KF cams with KF01 on them.

                            http://members.cox.net/jasonplastow/kfze%20cams.jpg

                            Comment


                            • #15
                              that puts that issue to rest!!!

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