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cam size vs cid

Discussion in 'The Hokey Ass Message Board' started by young olds, Jan 1, 2014.

  1. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    Ive read that a cam acts different in different size engines ie, a 224 duration at .050 .500 lift will seem/act like a bigger cam in a 350 vs seeming/acting like more of a mild cam in a 455 or stock in a 502. Im wondering if this is true? Im thinking of doing a cam and intake on one of my 215's and im also looking at cams for my 455 so I have those type of specs in mind. I dont want to put a cam in it that is small for a 455 but will act big in the 215, its in front of an auto will stock stall. I have a 212 duration .490 lift cam in my 181ci 4 cylinder nova but idk if it idles/sounds built because the cam is big for the cid or because its not running perfect.
     
  2. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    Frrom a Mike Drew post:

    The following are LCA's that are commonly associated with high performance engines in regards to carbureted SBC CID. These are only guidelines and should not be a primary bases for cam selection. They get me "in the ballpark" only and should be used with discretion.

    112-114 302
    110-112 327
    108-110 350
    106-108 383
    104-106 406
    102-104 420

    The following are duration at .050" numbers that I have been using when looking for grinds. They are for 350 CID. When building larger engines, I will add 5-10 for 383 CID and 10-15 for 406 CID. When building a smaller engine, I subtract 5-10 for 327 CID and 10-15 for 302 CID. These again are only my "ballpark numbers" and should be use with discretion. Have you noticed I keep saying that?

    205-210 truck/RV
    210-215 mild performance
    215-220 high performance street
    220-225 street/strip
    225-230 emphasis on strip, stall converter
    230-235 poor street manners, high rpm use
    235+ race only
     
  3. 73RR
    Joined: Jan 29, 2007
    Posts: 6,624

    73RR
    Member

    Your basic understanding is correct. You can look through the various cam mfgr catalogues and see the same pattern. If you look at the oem cam specs for the 455 and compare to the 350 (Buick, Pontiac or Olds?) you will also see a pattern if the intended service is similar. The cam specs for the same brand 400 will likely be in between.

    .
     
  4. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    Thanks, the cams im looking at are spec'd for 300-340 buicks, though im working on an olds 215. I just want some street performance without going to big for a stock stall. The cam in particular has 210 duration int 218 exh
     

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 49,794

    squirrel
    Member

    A smaller engine usually wants a smaller cam, so it will not loose too much low end torque...which it doesn't have as much of just because it has less displacement.

    With more cubes, you can "afford" to lose some bottom end, so a bigger cam will work fine.
     
  6. 73RR
    Joined: Jan 29, 2007
    Posts: 6,624

    73RR
    Member


    For comparison, I sell a lot of cams for the 241 Dodge Hemi and your 210/218 is about as big as I would ever normally recommend. I think that in a 215 it might be a tad bit big. I would probably look at something closer to the 195-200 mark if all else is stock.

    .
     
  7. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    I was figuring that would be about the biggest I could go without being to big. It is stock now but if I do a cam ill go with an edelbrock performer and may pull the heads and do some bowl work. It is rated as 10.25:1 comp.
     
  8. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    I reread the OP and noticed a reference to a 4cyl 182. The recommendations you get are generally made for V8's. A 182 4 is equal to a 364 V8.

    For your 215 there is a large market for the Rover performance parts. Just google Rover aluminum V8.

    The 210-218 should be ok, it might help to advance the cam 2 - 4 degrees to help low end.
     
  9. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    I was using my 181ci nova as an example, It has a 212 duration at .050 .490 lift single pattern. Idk if being a four cylinder makes it a little different but if not I think that the 210/218 cam in the 215 would be just fine.
     
  10. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    To the camshaft it's CID per cylinder;

    181/4= 45.25
    215/8 = 26.875

    But the can should be ok, as I said you may want to advance it 2 - 4 degrees to help the bottom end.
     
  11. jimbousman
    Joined: Jul 24, 2008
    Posts: 547

    jimbousman
    Member

    I'm running a vintage Kenny Bell cam in my 215. I'l look up the specs tonight.
     
  12. jimbousman
    Joined: Jul 24, 2008
    Posts: 547

    jimbousman
    Member

    The cam in my 215 is a KENNE BELL C-114A hydraulic flat camshaft. The C-114-A number is stamped on the rear of the cam. Advertized in KENNE BELL'S BUICK 1984 catalog as the first cam that obtained 100 mph in the 1/4 mile in his Buick 300. The Applications are; BUICK 215, 300, 340, OLDSMOBILE 215, Rover all 3.5, 3.9, 4.2, or any 4.0, 4.6 V8 using a DISTRIBUTOR. The 114 degree lobe separation angle makes this cam good for moderate street performance with good torque with a wide power band. It has been discontinued for 27 years. The specs are: LIFT ( with stock 1.6 rocker arm ratio).. INTAKE (I) .488. EXHAUST (E) .494. DURATION.. (I) 284 (E) 294.... DURATION AT .050, (I) 218...(E) 228...CAM LIFT...(I) .304 (E). .309. INSTALLED INTAKE CENTER LINE (I) 109. LASH 0. LOBE SEPERATION ANGLE 114.
     
  13. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    anyone know what the early 60's isky e-2 cam specs are for the 215? I found an old article where they made good power with one.
     
  14. BobMcD
    Joined: Jan 25, 2013
    Posts: 322

    BobMcD
    Member

    I love those early F-85's. Have any photos?
     
  15. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    These numbers are R/S ratio related not CI, they are generally too wide, especially at the small ci end of the scale, and theres WAAAAY more to it than that. For instance, 283 chevy SS motors run LCA's in the area of 102-104.
    As general rules, the "right" LCA will narrow as the duration goes up, R/S ratio goes down, engine becomes more intake port restricted relative to bore size, or mech. compression ratio goes down.
    Also, if the combination is octane limited, which almost all HAMB motors are, the intake closing point (Which is governed by LCA+duration)is pretty much dictated by the mech. compression ratio that you are going to run.
    This info is worse than vague and oversimplified, its downright misleading.
     
    Last edited: Jan 12, 2014
  16. 73RR
    Joined: Jan 29, 2007
    Posts: 6,624

    73RR
    Member

    ...yeah...ain't the internet great...?
     
  17. fab32
    Joined: May 14, 2002
    Posts: 13,985

    fab32
    Member Emeritus

    Generally speaking the bigger the cubic inches the cam will act tamer. Example:
    When I built my first 502 I put in a cam that was quite nasty in a 396. The engine ran almost as mild as a stocker. Called Comp Cams and their recommendation was light years wilder.

    Frank
     
  18. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    will be running 455 olds with manual trans
    [​IMG]
    215 2bbl 3 on the tree
    [​IMG]
    215 4bbl auto floor shift
    [​IMG]
    the wagon is the one i want to put a cam in
     
  19. icsamerica
    Joined: May 23, 2012
    Posts: 62

    icsamerica
    Member

    The relationship is really on stroke, just so happens larger CID engines usually have longer strokes. The piston tends to dwell at TDC and BDC for longer times on engines with longer strokes so you can have more cam overlap and reversion becomes less apparent.

    If you were to plot a sign wave of the cam vs the pistons speed you would see engines with longer strokes would have less piston speed during the over lap and thus less reversion. So engine with longer stroke are less cam sensitive or can tolerate more cam timing.
     
  20. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Well, you know, I still think it is, in spite of the of the huge volume of complete BS that seems to gain credibility just by being out in print on some website.
    At the same time as crap like the above gets spread around, theres also tons of really worthwhile stuff. But the trick is, like you said on the thread about the hemi book, you have to look at it and think carefully about what is being said, and learn to discriminate.
    Like I said on that cam thread with the bs about "overlap bleeding off compression" the more you learn about the basic fundamental physics and geometry of how the 4 stroke engine actually works, like understanding the four strokes, and the relationship of the crank/valve motion through those events, and understanding how changes to rod/stroke ratio change the motion/accelleration of the piston through the stroke, the more you can at least start to weed out the complete bs.
    Asking people to hand you fish is a waste of time, the best thing to do is learn how to fish.
     
    Last edited: Jan 13, 2014
  21. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Two critical questions to be answered before anyone even starts thinking about a cam recommendation for this deal, unless they are pretty much just pulling numbers out of thier ass .
    What casting number are your heads? According to what I have read, theres three different head castings for these motors, all with different sized chambers, #829 at 43 cc nom, #534 at 38cc nom, and #746 at 51cc nom. This is going to govern LCA...
    next IMPORTANT question here, are you actually building a motor, or looking for a cam to bolt into a stock, running engine?

    FWIW, if my memory serves, there was a guy named Phil Baker in the Seattle area that used to build a lot of these motors. Whether he is still around or not, I dont know.
     
  22. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    its a running engine that I want to do a cam and intake swap on.
     
  23. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    ok, what heads are on it? Theres a difference of two full points of compression (8.3/1, 9.4/1 and 10.3/1) across the three heads. Is it a factory 4bbl motor?

    I assume you are keeping the original trans and 3.07 rear?
     
  24. young olds
    Joined: Oct 9, 2009
    Posts: 142

    young olds
    Member

    Its a factory 4bbl, I dont know what heads are on it. yes stock trans, stock rear but I dont know what gears.
     
  25. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    One more thing, the reason i asked if this was a bolt-it-in deal, or if the OP was building the engine?
    If he were building an engine, I would have suggested getting a set of the 43cc chamber #829 heads, and cutting .020 off the decks, so he could build a 10/1 motor with tighter squish. This would have been the ideal situation.
     
  26. tjet
    Joined: Mar 16, 2009
    Posts: 1,277

    tjet
    Member
    1. Early Hemi Tech

    You will like having a 455.

    Here's a nice example of a cam, compression, & gear upgrade.

    I'm building a w-30 spec 455 right now with the factory cam

    https://www.youtube.com/watch?v=10i1y2ZFFT4

    Here's my w-30 motivation

    https://www.youtube.com/watch?v=qzBOsbcvOxk

    On your 455, it will take up to 230* @ 050 & .500 lift max. Beyond that, you will need to plan for aftermarket adjustable rockers.

    Here's a nice sounder

    https://www.youtube.com/watch?v=mfC0icZ-FQs
     
    Last edited: Jan 14, 2014
  27. 66tintop
    Joined: Nov 7, 2012
    Posts: 450

    66tintop
    Member
    from Canada

    Well written , because I run chevy 302 , in ot car and I wouldn't want to run a 114 lca in it, I would have to wait till next week to make any power ! Lca depends on how tight you want to rev your engine ,cruiser needs lower rpm drivability ( 114-116 Lca) performance street ( 110-112 Lca) and high performance ( 102-108 ) just a suggestion !
     
  28. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    FG, I think applying empirical 4 inch bore SBC knowledge to a 3.5 bore engine with a spark plug located almost dead center of the bore may be skewing the results.

    We have a smaller bore, shallow chamber, and great plug location. I believe it's going to be very knock resistant.

    Thoughts?
     
  29. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    In order for the DCR to mean much you have to charge the cylinder. I think the tiny ports flowing 130 cfm will throttle the intake charge enough to make it work at 8.11 or higher. Of course instead of guessing we can draw on a wealth of Rover enthusiast experience.

    just my 2c
     

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