Comp Cams offering Nailhead Thumpr

Discussion in ''Da Nailhead' started by CameoInvicta, Nov 30, 2009.

  1. wkillgs

    wkillgs Gold Level Contributor

    Right....sort of. The dyno 2003 program allows you to change the ramp from mild to wild. The stock cam spec'd out at a 2.3 which is between 'OEM' and 'mild".
    It doesn't take into consideration the rocker ratio, which could change the open/close rate.
    Adding roller rockers is a way to effectively increase the valves 'rate of rise', which can turn a mild cam into one that works like it has fast opening/closing ramps!:grin:

    The 2003 manual describes some of the math is uses in the calculations. I'm still reading it tho.
    But it uses the valve size as a start to calculate MAXIMUM possible flow, then takes the type of head (stock, or ported) to determine the amount of restriction there is.....and subtracts that from the maximum.
    The alternate method is to directly enter known flow numbers...
    But I haven't yet grasped what it actually does with those flow numbers.
    Anybody get to that page yet?
  2. kitabel

    kitabel Well-Known Member

    Adding roller rockers is a way to effectively increase the valves 'rate of rise', which can turn a mild cam into one that works like it has fast opening/closing ramps.

    I assume you're talking about a specific roller rocker which also has higher ratio?
    It's the ratio change that increases the rate, the roller tip has no effect.
  3. wkillgs

    wkillgs Gold Level Contributor

    With Tom's roller rockers, the ratio is increased, which gives more lift and faster valve opening/closing rates.
    With the stock rockers at max lift, I calculated a ratio of 1.63 on the exhaust, and 1.697 on the intake.
    Tom's rr gave me 1.91/1.92 ratio!
    Ratio WILL vary depending on stuff like valve height, pushrod length, and in the case of the rr, where the adjuster screw is (how far in/out).

    Now, we've all seen various stock rocker ratios reported.... But this is what I got on my build, carefully measured (several times) using an adjustable solid lifter for testing purposes.
    Your results may vary!
  4. wkillgs

    wkillgs Gold Level Contributor

    BTW, anyone else out there using the Dnyo2003 program to test different cams???
    It's been quite an eye-opener for me! The most important thing I learned is that the Isky 310 cam I installed in my blue GS around 1978 was a real bad choice... It only makes more power than stock when revs get over 4000. Below that, it's a dog. Both the dyno2003 and my butt dyno can confirm that!
    (but it runs 13.40's so I can't complain too much:laugh: )
    Now I can test some other cams before buying.:grin:
  5. CameoInvicta

    CameoInvicta Well-Known Member

    I've been playing around with Dyno 2003 quite a bit. Thanks for that link Walt!

    Also, regarding rocker ratios, I'm quite surprised at what you measured for the stock ratio. They were factory rated at 1.6, however I thought they were only effective to 1.4 at best.
  6. wkillgs

    wkillgs Gold Level Contributor

    Andy, you mentioned the Accelerated motion cam.... I call it the A-motion 224-243-115.
    Numbers are: intake duration- exhaust duration- lobe spacing . Easy to remember that way!

    Anyway, I've been comparing similar cams and am surprised to see the results are near identical. Take a look:
    Accelerated Motion: 224-243-115; lift= 0.463/0.460
    Schneider 298-96H: 232-238-110; lift= 0.516/0.524
    Carmen Faso: 230-238-112; lift= 0.512/0.517
    TA-30: 228-228-112; lift= 0.488/0.488
    EDIT: TA-413-401 is better for comparison than the TA-30: 234-244-113.
    the TA-413 has almost the same output as the Schneider 298-96H.

    -Cams specs are derived from published duration@ 0.050 and lobe spacing.
    -Lift is either published or calculated with 1.6 rocker ratio.
    -Lobe ramp speed is kept constant at 2.5 for consistency.
    -Cam advance/retard (intake centerline) is adjusted for best results.
    -Short black and heads are near-stock for this sim. On a higher flow setup, the cams were again very close!

    I'm seeing the Schneider edging out the others in most cases. but not by much. Interested to see if you get what I did.

    Attached Files:

    Last edited: Dec 13, 2009
  7. wkillgs

    wkillgs Gold Level Contributor

    BTW, on the Dyno2003 version, I had a hard time entering the intake centerline into the data file, and having it stay there.
    Entering it in the 'Cam Manager' pop-up box didn't work....:confused:
    You have to go to the toolbar at the top and select 'Cam Math' and enter it there. :Comp:
    You can either advance/retard the cam by changing that cl, or the 'advance/retard' function below on the main page.
  8. CameoInvicta

    CameoInvicta Well-Known Member

    Yes, I'm also having a few issues with the Cam Manager. It's an awesome tool, however, it's a bit picky.

    As far as comparing cams go, yes I'm getting what you get. I'd love to run that Schneider grind, however I'd be a little worried about VP clearence issues. Hudrod had mentioned that his TA 413-401 cam fit, barely, and the Schneider has a little more lift and a little additional overlap. It would be tight - it might have to be retarded a bit to get proper clearences.

    Hudrod, did you advance or retard your cam at all? Also, are you using stock steel shim head gaskets or Fel-Pro composites?
    Last edited: Dec 13, 2009
  9. wkillgs

    wkillgs Gold Level Contributor

    Yes, more duration and more overlap will cause vp clearance issues. The stock (and replacement) pistons are a PITA for us!

    I used a milder Poston NH400 in my red GS build. It just barely fit with 0.065" to 0.095" vp clearance. heads milled 0.007", stock 0.015" head gasket.
    Toms rr only took away about 0.020" vp clearance, if that.

    Poston NH400 Specs:
    218-218 duration
    0.486-0.495 lift (measured)
    Intake: opens -1, closes 39
    Exhaust: opens 52, closes -4

    It's an awesome street cam!.... LOTS of torque below 4000 rpm, but lacks the top-end power of the bigger cams.
  10. Babeola

    Babeola Well-Known Member


    I got this program up and running with Carmen's cam and the Magnotti heads sitting here with a 10:1 compression, but I can not seem to print the page to jpeg like you did. It want to print to XSP Document Writer. XSP DW does not convert to JPEG and it is not valid extension for upload. I have Photo Suite, but can not seem to capture the screen with it? I will post if I can get it to work.

    Cheryl :)
  11. wkillgs

    wkillgs Gold Level Contributor

    Cheryl, glad to see you are giving Dyno2003 a try. It's a great tool to compare cams. Have fun!
    I just used the 'print screen' key and pasted it into MS Paint....was able to save it as a jpeg there. But for some reason, it is decreasing the size from 1300 pixels to 800 when I upload it.:Do No:

    Some day I'm just gonna buy a MAC!
  12. CameoInvicta

    CameoInvicta Well-Known Member

    Yep, that should work.

    I think the board decreases the size because the file is to big, so it shrinks it a little bit.
  13. Babeola

    Babeola Well-Known Member

    Success: Here for a good capture or not so good as below.

    Cheryl :)

    Attached Files:

    Last edited: Dec 17, 2009
  14. Babeola

    Babeola Well-Known Member

    I looked at cams for my friend's new SC Cobra combination here while I was at it. Do not open it if you have an aversion to Fords. One plotting was with stock cams at stock compression (8.5:1) with the new (rebuilt, CNC ported and oversized valves x 32) heads at 21 pounds of boost, One was with the new compression (9.6:1) with the new heads and Ford GT (Supercar) cams at 21 pounds and the last is with the new heads and the actual custom cams (Comp) being used with the new 9.6:1 compression ratio at 21 pounds. Cams make a huge dfference in this case!

    Cheryl :)
  15. CameoInvicta

    CameoInvicta Well-Known Member

    Cheryl, one thing you might need to address is the "lifter acceleration rate". The program has 3.9 plugged in, and most of the aftermarket cams I've come across are only in the neighborhood of 2.6 or less. Just wanted to let you know so your data is as accurate as possible.
  16. Babeola

    Babeola Well-Known Member

    I did this with a known 455 engine combination that was dynoed. I added the particulars including head flow to Dyno 2003 here, and graphed the difference here. They are a little off, but you can tell they are basicly the same curves -20 HP/TQ on the Dyno 2003 curves here or there.

    Cheryl :)
  17. Mr62Buick

    Mr62Buick Guest

    Ok, I have a stock 1962 Wildcat with the original, unrebuilt 401. This is what I have for mod's.

    Stock 401
    factory 2x4 manifold with correct numbers matching twin carters (from a 65')
    Stock distributor with pertronix installed
    Factory cast manifolds (to keep the originality for the Buick shows, I do have my own 4 into 1 or tri-y headers I make, but would like to stay stock.
    T-400 3 speed auto with stage 2 shift kit
    3:42 posi rear end

    When starting from a stop, the car grabs so much, I can barely spin the wheels. I want something with a lope, but not too agressive, something that people will notice. I have the switch pitch set-up in my car, so changing the stall speed is no problem. I Built this trans and sell them on ebay once in awhile. i currently had about 10 of these units. :) Anyways, who and what cam grind would be the best to spin the wheels easily and have a nice slightly aggressive lope from the engine bay. The only thing I know about nailhead cams is anything bigger than .500 lift means engine disassemble and anything lower than .012 lobe separation means more lopeyness.

    Last edited by a moderator: Jan 12, 2010
  18. CameoInvicta

    CameoInvicta Well-Known Member

    Hey Steve! Long time no see.

    If your looking for a good lumpy off the shelf grind, you might want to look at the TA-413-401. You'll give up a little low end, but it'll have pretty good top end, and will sound awesome. Plus with the 113* lobe seperation angle, it will still run power brakes. Plus, it should fit w/o any VP clearence issues. I've been looking at this cam for some time - it'll probably end up in my '62 come spring :3gears: .
  19. wkillgs

    wkillgs Gold Level Contributor

    It may be difficult to find a cam that has a lopey idle AND makes good low-end torque....
    In general, a stock or mild cam will make more power up to approx 4000 rpm. At that point the bigger cams take over and make more power. The big downside to the larger cams is you lose a lot of low rpm (2000-4000) torque.

    To get a lopey idle a closer lobe separation is required in the range of 107-110 degrees. A stock or torque cam is closer to 114 degrees.
    I'll take a look thru my files and see if there are cams to do as you desire.
  20. CameoInvicta

    CameoInvicta Well-Known Member

    Technically you don't need a really tight lobe seperation angle to get a lopey idle, just a big cam. The tighter LSA doesn't hurt, but you could easily toss something like the TA-413-401 in w/a 113* LSA and still get a good rumble.

    However getting something custom ground opens up a whole new realm of possibilities. Something like 224*/236* @.050 w/a 110* LSA should perform well and sound at least semi lopey. Plus I would think it would still produce enough vacuum for power brakes.

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