slant cam guessing game...428 lift?

Slant 6 Engines

  1. pishta

    pishta I know I'm right....

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    I bought a aftermarket cam off this board years ago and totally forgot the part number. I installed it (a year ago) and now am wondering WTF I installed! I know it was a mechanical as I got 11 solid lifters with it, but I dont know the grind. My only clues are the installed valve lift (mic'd off the spring retainer in the head) as .428/.428 WITHOUT any lash but I cant determine duration as my cam wheel is UA. These are taken with a dial indicator off a mag base with the dial as straight with the valves as I can get it. that seemed more precise than measuring the lifter side. Any clues? Or if you sold it to me, refresh my memory so I can set the prescribed lash. Im thinking it had to be a longer duration as the lift is nothing spectacular according to some .440 lift examples. Thats about a .285 lobe lift if the rockers are a true 1.5:1.
     
  2. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    You may or may not know about this: Cam Doctor


    But, it would answer your questions and is interesting, I think.

    I had an "unknown" cam once and took it to my local (Fremont, CA) speed shop, and he happened to have a "Cam Doctor" in his possession. It answered all my questions about lift/duration/overlap/ lobe centers. etc...
     
  3. pishta

    pishta I know I'm right....

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    Ill have to print out another Tavia degree wheel Tavia Performance Products Downloadable Degree Wheel, I had my old one mounted to an old 12" 78 record I found at a yard sale and the center was hogged out to mount it with a cam bolt. EZ enough to use, its just a pain that installed it already and that pan is a bear to get off when the motor is in the car. Besides that, the cam has to be pulled out the lower fascia hole and the bumper has to be removed!
     
  4. RustyRatRod

    RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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    Damn man. Are you that cheap? Degree wheels can be had really cheap. Tightwad.
     
  5. nm9stheham

    nm9stheham Well-Known Member

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    I got a pretty similar lift cam from Doug Dutra a year back. .290/.290 at the lobe. Duration is 244/244 with LSA 112, and is a torque grind for a 1 BBL setup. Clearances are .018-.022 IN and .020-.024 EX. I assume it is an Oregon grind; grind # is MFT-6112-17.

    I just printed out a degree wheel from Machinery Cleanery and mounted it on a circular piece of foam cored poster board; pretty sturdy that way.
     
  6. pishta

    pishta I know I'm right....

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    Hell yes! And they can be had cheap...for like free! :) I had a Moroso metal one and the printing on that was terrible. The silk screener was drunk and the lines were double printed and fuzzy to boot. Pdf print is razor sharp and can be scaled to whatever round backing you want to use. How about that old Bee Gee's 12" you are holding onto? I'll do this tonight and post up the specs I can gather but without proper lash will they be correct?
     
  7. pishta

    pishta I know I'm right....

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    2 days of after work activities so I'll check it tonight. Do I measure duration at .050 with correct lash ( unknown?) That's going to be tough.
     
  8. nm9stheham

    nm9stheham Well-Known Member

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    The published duration numbers are without lash.
     
  9. pishta

    pishta I know I'm right....

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    Thanks, I think I read that as I was researching it. Measure at .050, does away with entry ramp up and gives a baseline across cam makers, Exept crazy .020 MP cams. Cool
     
  10. nm9stheham

    nm9stheham Well-Known Member

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    Well, if you can, measure at about .005" lift to get 'advertised'. It is tricky to do and get consistent results.

    And of course the cam makers measure advertised differently. Lunati measures advertised at .006"; Crane mostly does it at .004". That makes the Lunanit VooDoo's look more aggressive, and the Cranes look bigger.

    I'm looking forward to see what you come up with.
     
  11. pishta

    pishta I know I'm right....

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    Ok, here are a few specs as far as I can tell. The method they use to get lobe lift must be measured off a foot long lifter on a slant as there is no easy way to mic off the pushrod unless you take the valvetrain off. So I tried a few times and looks like it may be a
    .286 lobe lift (.429 at valve) intake and
    .282 (.423) ex with a
    Intake Duration is 217.00 degrees @.050
    Exhaust Duration is 215.00 degrees. @ .050
    Installed Intake Centerline is 116.50 degrees ATDC.
    Installed Exhaust Centerline is 107.50 degrees BTDC.
    LSA is 112.0 degrees
    Overlap is -8.00 degrees.

    intake centerline looks wrong , I thought it would be 108?

    dunno, does this look close to anything? Its hard to get the dial indicator to stay on the rocker as there is no flat mounting surface on the head and the pushrods are pretty far from the mag base so its a balancing act. Made a slick degree wheel for nothing: printed out on photo paper, mounted it to a piece of cardboard and hot glued it to a P/S pulley so
    I could bolt it up to the balancer. Turned crank with bolt and 30" breaker bar, smooth and easy. Whatever it is, Im running it. Ill use 10/20 lash.
     
  12. nm9stheham

    nm9stheham Well-Known Member

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    ICL would be 108 only if there was 4 degrees of ground in advance or was installed with 4 degrees of advance. Yours looks to be installed 4.5 degrees retarded..... perhaps you are using an old, stretched timing chain?? You sure need to fix that and get 4 degrees of advance.

    Your cam is like one step below the Dutra torque cam I installed:
    208/208 @ .050
    .290/.290 cam lift.
    LSA 112.
    -16 degrees overlap at .050, or 20 degrees advertised overlap
    Grind # MFT6112-17 (Oregon?).
    Lash specified is .020/.022.
     
    Last edited: Jun 10, 2016
  13. pishta

    pishta I know I'm right....

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    timing is brand new with the cam install. Matter of fact, there is no chain slop at all when I go back and forth on the rotation. Installed it with a straight edge because I didnt want to do it again....[​IMG]

    I could have the TDC off a few degrees because I dont have a proper piston stop. more like a drum stick wedged in there and me running up the piston until it stopped against it in both directions then bisecting the degrees.
     
  14. pishta

    pishta I know I'm right....

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    Yeah, I got a piston stop on order. I cant get consistant results until I find a way to stabilize my mag base to something flat.
     
  15. nm9stheham

    nm9stheham Well-Known Member

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    Hey, order up an offset crank key or 2 while you are at it! You can use offset buttons on the cam pin but that is more work. IIRC, I used SB Chevy buttons drilled a hole at the cam pin, tapered it back to front, and tapered the button to match. The taper retains it from coming out, but a big washer would probably be smarter.
     
  16. Killer6

    Killer6 Well-Known Member

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    What? Your printing out degree wheels, but can't cobble
    up your own piston stop? Your tite-wad bona fidas are in
    question now.........:D. Mr gasket part#85, SB Chebby&
    BB Mopar cam bushing kit. The T-set I got at the time had
    a freakin' slot instead of a drilled hole for the cam pin, it
    made the mod a challenge..... bush.OD is 13/32" press.
     
  17. pishta

    pishta I know I'm right....

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    I had a spark plug that I bent the electrode out on but I can find it, but I think 10 bucks for an adjustable stop is worth my time. Too bad auto zone didn't stick it. They had the best price beating ebay. I'm going to make a bar that my dial indicator will mount to that goes over the entire lifter bank so all I'll have to do is loosen, swing up and slide it over to the next position. Also a clamp on pad that will go on the pushrod that will give me a point to measure it's lift as the swing of the rocker tip moves it off the dial indicator probe if you measure off the rocker. I'll bolt bar on using valve cover holes. Pics to follow. All this to ID a cam, you bet! Plus it'll be fun making it on a Sunday afternoon.
     
  18. pishta

    pishta I know I'm right....

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    9.99 through autozone

    [​IMG]
     
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