Open chat thread for Buick 350 Camshafts

Discussion in 'Small Block Tech' started by sean Buick 76, Oct 16, 2013.

  1. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Custom GC
    GS-Street

    .451/.453
    212/224
    280/295
    114* (112* int) (116* exh) @.050
    2000-5000 (5600)
    -10.00 @.050
    10.5
    Smooth




    This cam came from an idea on how to modify the popular TA 212 350 cam (even TA has modified their cams over the years...many of the cams you see in their catalog aren't the same today as they were).

    The idea was to make it a bit milder. Reduced the duration @.050, left the duration gap between I/E the same at 12*, left the seat duration on intake the same, but increased the seat duration for exhaust and increased the LSA for a similiar power band. This cam would turn on around the same time as the TA 212 since it has less duration but a wider LSA, and pull to about the same RPM.

    This idea was created some time back, and I would modify it even further by adjusting the centerlines on I/E making them split pattern, but keeping in a similar spirit of this cam. Probably 112* int centerline and 116* exh centerline for a 114* LSA. This would improve bottom end and lower the RPM where peak torque occured, but still maintain the higher RPM power range.

    This would also somewhat alter the static compression @ 8:1 dynamic because the centerlines @.050 aren't the same as they would be at seat, increasing it a little to run a little bit higher compression. Overlap would also be affected a little from the original.

    This cam could be used in lieu of the TA 212 cam in any application the TA 212 cam would be suitable for, with increased compression, smooth idle, better vacuum, and better valvetrain stability/longevity.

    It would be difficult to discern whether it would give more power or less power, though I'm sure the differences would be negligible in this regard....though with more benefits (only thing you'd miss was the lopey idle, which some people want).

    Some could point out that a wider LSA would net less power, but the increased compression would help compensate this (even though both would be at 8:1 dynamic, the increased static will benefit top end). It may have a few less ponies, but would have a wider power band and the other aforementioned qualities.



    Things like this in general would make a good street cam. Some may call it splitting hairs, and yeah I guess it is, but if everyone always just left well enough alone, there would never be any improvements or alternative options.

    ---------- Post added at 09:49 PM ---------- Previous post was at 08:49 PM ----------

    I think I would prefer, however, one that looked more like this:


    .434/.449 .015 exh emphasis fr mild head work @ 66%-69% I/E ratio
    208/224 16* exh emphasis @.050
    278/299 21* exh emphasis @seat 70*/75* I/E hydraulic variance & 5* gap increase from .050 to seat
    112.75* LSA 109.5* int centerline, 116* exh centerline @.050; 116* int centerline, 112* exh centerline @seat
    10.56:1 SCR @ 8:1 DCR
    -9.50* Overlap @ .050

    Duration @.050, overlap and LSA indicates smooth idle (close to Crower level 3, but ever so slightly smoother) at ~650 RPM with ~17-18" vacuum.

    Power band: 1800-4800, best shift point @ ~5300, will rev to 5800

    The cam specs stay in the spirit of the stock cam, with larger lift and duration numbers. Centerlines and LSA are identical to stock Buick 350 cam.

    ---------- Post added at 11:33 PM ---------- Previous post was at 09:49 PM ----------

    Here's a Buick 350 hydraulic roller cam for ya, Sean:


    .533/.556 .023 exh emphasis
    227/249 @.050 22* exh emphasis
    282/304 @seat 22* exh emphasis, 55*/55* straight pattern hydraulic variance for a faster ramp profile, but not too extreme
    114* LSA straight pattern centerline
    10.00* overlap @.050 (about as high as you want to go for a 'streetable' cam)
    10.56:1 SCR @ 8:1 DCR


    Wider LSA and lower int. duration @.050 will give smoother idle and better vacuum than normally expected from a 10* overlap cam: should idle around a lopey 800-900 RPM with ~12-13" vacuum guestimation.

    Power probably won't turn on til around 2600-2800 RPM (3000 stall or Jim's 1800/3200 VP converter needed) and pull hard to ~6100-6300 RPM with some heavily ported heads, big valves, 1 3/4" full length headers and TA's intake topped off with a nice combo spacer and 800 CFM Qjet (or one of those 890 CFM monsters (ported Qjet) I'm hearing about).

    :TU:
     
  2. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Thanks Gary,

    Yes Jim's car (that is using this cam) has all of those things including 10.5:1, high stall converter, ported heads, ported TA intake, 950 CFM carb etc.
     
  3. GS Jim

    GS Jim Platinum Level Contributor

    Hi Gary, Obviously You know your Cams! Obviously I Don't. I saw on their web Site that they make 8 Cams for the Buick 350. A few for some performance levels. I picked the milder performance level 3 Cam. I wanted to give it a try. If I don't like it I'll put my Poston 114 back in.

    Ponch
     
  4. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    To my knowledge this cam doesn't exist--I just pulled it out of thin air last night while thinking. :p

    Yeah if he's using the one you showed, he's gonna need all the good stuff. :)

    I can make any cam for any application. It's simply a matter of bringing some numbers together for a goal. Making a custom cam that suits the vehicle is key I think. Whatever your heads flow @ particular lift, that's where you should start, then just put durations and centerlines to it and juggle them around to match whatever you want.

    I use a couple calculators online, mainly the ones that determine dynamic compression and configure overlap. The rest I just make up based on some knowledge and a little bit of guessing (with no engine to test them in), but it's an educated guess.

    I like tossing some ideas out there, and this is the thread for it. Maybe it'll give someone else some ideas or they can use the info as reference or whatever.

    I enjoy contributing to the community however I can.

    ---------- Post added at 12:20 PM ---------- Previous post was at 12:12 PM ----------

    This is the only hydraulic flat tappet cam Level 3 from Crower for the Buick 350 that I can see: http://www.crower.com/index.php/camshafts/buick-350-compu-pro-hydraulic-cam-276-hdp.html

    There are multiple Level 3's for other engines though. Be sure you didn't pick a cam for the wrong engine! That would suck.

    Poston 114 would be a good cam too. Wide LSA and 214*/241* @.050" for duration--a nice wide emphasis on exhaust.
     
  5. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I like the Poston 114, I have not found a cam I like better... Other than maybe a custom roller grind of course. I have two here stashed as they do nt make them anymore. I am going custom for the cam in my Skylark but at least at fist I am using a 114 cam for nostalgia reasons... Mark Burton who custom built my car for me also used the 114 cam in his Skylark. Here is a video with it before the turbos and one after:

    http://www.youtube.com/watch?v=jI3CtXSPq-A&feature=c4-overview-vl&list=PLD0EDD02380F8D301


    http://www.youtube.com/watch?v=XLRfK6l-aRc
     
  6. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Wider LSA and heavy emphasis on exhaust is the ticket to a better camshaft. It's probably why you like it so much, even more than the TA 212. The TA 212 has extra emphasis (but not as much as the Poston 114) on exhaust.

    Mainly it's the duration that needs the extra emphasis. I add more emphasis on the lift as well, though you could get away with a straight pattern lift (same lift on I/E), or maybe slightly more lift on exhaust. Both TA 212 and Poston 114 have slightly more lift on exhaust ( .002 and .005 more, respectively), while stock cam has .015 more on exhaust.

    Any time you foresee some restriction for the exhaust (manifolds, smaller primary headers, reducers, muffler shop bent pipes, etc), you're going to need more exhaust emphasis. If you were to open the exhaust runners up to closer to 75% ratio I/E (the 'magic' number), and use free-flowing exhaust, you could then use a camshaft that was closer to straight pattern.

    Much like how you can use straight(er) pattern cams for the Stage2 heads vs the Stage1 which benefit more from split pattern, because the exhaust on Stage2 heads are more 'ideal' (I disagree with the 'ideal' assessment, though others feel the closer you build a Buick engine to a Chevrolet engine, the better the Buick becomes, which isn't true).

    For balls out high RPM use, sure. But for street machines, no. You hurt your torque when you make the engine work against itself this way.

    TA 212 has 18* more duration on exhaust than intake while Poston 114 has 27* more duration on exhaust than intake...quite a bit more.

    The reasoning behind this is the exhaust runners don't flow as well as intake, so less lift is needed on intake. It's always a good idea to match the lift of the camshaft to the plateau where the flow planes off for the heads, and it generally ends up being a bit more for exhaust than intake. (intake side tends to flow more CFM at lower lift, while exhaust flows less CFM compared to intake, but will flow more at higher lifts--ever wonder why the intake valve is larger than the exhaust valve?) Adding duration to exhaust lets it stay open longer, allowing better evacuation and therefore less contamination (exhaust gasses still in combustion chamber) for intake stroke.

    Always remember that it can't get in if it can't get out. :TU:

    If you like, I could break down the details of the Poston 114, explain them a bit, and maybe tweak it a bit. You could use the info for a custom grind later on or something since you seem to prefer that style of cam.


    If you look at the ratios, the Crower level 2 cam is very close to the TA 284-88H cam, it just has less lift and duration and 2* more LSA.
    Crower level 3 is more like a hopped up version of TA's RV cam (which would be considered a performance cam for smaller cubes like the 350).


    (cool vids, thanks)

    Another reason for exhaust emphasis is forced induction. Mainly on turbos since the exhaust feeds the boost for intake. A wider LSA also works well with this, since it tends to reduce the overlap. Excessive overlap = power getting blown out the exhaust.

    I can see why you'd like the Poston 114 for a turbo application, because it only has .5* overlap @.050.
     
    Last edited: Oct 18, 2013
  7. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Gary,

    Do you ever sleep??????????????


    Thanks for all the good info.


    I see that Crower is discountinuing some mechanical cams. They allready dropped the hydraulic level 1.

    I think I'm going to buy a couple level 3's and 4's to have if they decide to stop making them.

    And no I do not work for Crower but love their 350 Buick cams.
     
  8. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    I can get a little obsessed sometimes I guess. :eek:

    I noticed the level 1 was gone.

    All you have to do is get the cam card with opening and closing events for your cam(s) of choice and have a good grinder make them.

    I tried getting their seat-seat info but all they had on their site was .050 numbers for timing events. You have a Level 3 now, do you have the cam card for it? If so, does it show the seat-seat numbers and are the intake and exhaust centerlines equal (straight pattern) or are they different (split pattern)?

    If you do, post that info up here in this thread, that would be awesome!
     
  9. ceas350

    ceas350 "THE BURNER"

    Its your obsession that teaches others... keep up the good work.I'm still learning :)
     
  10. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    I'm still learning too! :p

    Never stop learning. Ever.
     
  11. alec296

    alec296 i need another buick

    I would imagine Gary gets a lot of headaches too .lol.but anyways , you mentioned a little on cams for turbochargers so explain some more on that and the differences for superchargers. And make sure its understandable as I don't have an engineering degree yet
     
  12. jay3000

    jay3000 RIP 1-16-21

  13. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Yeah I dig Crower too. They put forth extra effort to match camshafts with the cubes.

    Keep in mind that static compression doesn't mean as much as dynamic compression, and that is determined by when the intake valve closes. Intake valve duration at seat, intake centerline, and where you degree the cam in at all play a role to where the valve closes, and this in relation to the stroke is where your compression stroke begins, and is what determines the dynamic compression.

    The goal for premium pump fuel (about 93 octane at sea level) is 8:1 dynamic. I've heard 8:1 - 8.25:1 with good quench, which the Buick 350 is exempt from because it has an open combustion chamber. Dished pistons are actually best for Buick 350 because it gives a more uniform burn volume. Smaller combustion chambers have less room for expansion so are less susceptible to detonation, which the Buick 350 has. There's no hot spots or sharp edges with this combustion design, which helps reduce detonation risk.

    So it doesn't need quench with a dish piston and open, small combustion chamber. Incidentally, this is also what makes it an ideal candidate for forced induction. It's not like a BBB. It doesn't matter where in the hole the piston sits. It's this way by design, not by flaw.

    Anyway, 8:1 for premium, 6.5:1 for regular. Doesn't matter which cam or pistons you use (though dish is best), or where your static compression ends up, what you pay attention to are those dynamic numbers--and the closer you can get those dynamic numbers to the ideal ratio, the more efficient your engine will be (best mileage and power).

    :TU:
     
  14. pmuller9

    pmuller9 Well-Known Member

    I still like the stepped dish that extends into the combustion chamber creating quench.

    [​IMG]
     
  15. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    No headaches believe it or not. I thrive on thinking about shtuff like this. What is work to others is play to me.

    Buick head design will benefit from exhaust emphasis no matter how you slice it, unless you can open up the exhaust more than the intake to bring the ratio closer to 75%, then you can run closer to straight pattern. Also, it's important to note that I'm referring mostly to mild-moderate performance cams. You start getting into top-end engines and you still want exhaust emphasis, but you want some overlap (which you'll get by nature of increasing durations) to aid in scavenging.

    There'd have to be a balance between finding where the ideal lift, duration, and centerline were for the head flow. I just do the numbers in my head, though you'd really need a computer to get exact numbers...though computers only do what they're told, and won't consider nuances and subtle variations unless its programmed to do so.

    Getting back to your supercharger question, you still want emphasis on exhaust and wider lobe center/LSA so you can minimize overlap so your power won't get blown out the exhaust.

    While the exhaust won't feed boost like in a turbo application, it still needs more exhaust because there's way more air/fuel going to intake and it has to get the F out of there when that exhaust stroke comes up. The piston's not going to wait around for the exhaust valve to empty the cylinder. :p
    Any exhaust left after the valve closes remains in the cylinder and takes up space (as an innert gas) that air/fuel could be using when intake stroke comes along. This reduces power and engine efficiency, and gives it what I like to call 'indigestion'. So while the engine would still run fine and make good power, it leaves power 'on the table' compared to using a camshaft that would be optimally suited.

    I'm no camshaft guru, I just explain things how I see them in my mind is all. I'm still learning too fellas.

    I would say you'd match the camshaft to the amount of boost you're going to want to run, so you'll know about how much extra exhaust emphasis you'll need.

    Valve timing events will be important in determining the compression you'll need and boost you'll use, and in the end your ultimate goal is 8:1 dynamic for premium fuel, even with boost.

    ---------- Post added at 11:36 PM ---------- Previous post was at 11:35 PM ----------

    Hey Paul! Haven't seen you in a while. You been doing ok?


    I've learned a thing or two since we last communicated. I seem to be doing ok with it.

    Where's that step go to create the quench? There's no flat quench pad in the head chamber like there is on a big block, and anything over around .065 or thereabouts (the number varies based on who you ask) pretty much nullifies any quench.
     
  16. pmuller9

    pmuller9 Well-Known Member

    Hey Gary

    Race season is finally over and we are planning our next set of changes based on what we learned this season.
    I've been watching the threads and haven't really wanted to add to what has been posted. It's all been good!

    The piston step goes above the block deck into the combustion chamber to within .040 of the chamber ceiling.
    AMP was offering this service at one time.
    The chambers would have to be machined so they the same depth/shape and match the contour of the piston step.

    Paul
     
  17. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Ah that makes sense! Thanks for that bit of info.

    But how's that make for clearance? You want a little bit for thermal expansion and such, right?

    Excellent way to tweak the combusion chamber even further.

    I imagine with that setup, you could push DCR to around 8.25:1 - 8.5:1 for pump gas on the Buick 350.
     
  18. pmuller9

    pmuller9 Well-Known Member

    Yep. .040" clearance all the way around between the piston Step and the combustion chamber at TDC. That becomes your quench distance.

    The step will have radius edges that match the radius of the sides of the combustion chamber.

    Way back when, Dick Landy did something similar with the Hemi. He made a domed piston that filled the hemi chamber and simply cut out the areas where the valves extended into.
     
  19. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Good stuff. Thanks Paul!
     
  20. alec296

    alec296 i need another buick

    I see mostly the same cams being discussed. But I found cams for buick350 made by Howard's cams , Schneider and risky all have some decent sounding can grinds. I'm no expert on if they work but their are choices other that the basic ones being used. Sh
    Schneider 270 H seems decent for mild street with I assume pretty good lower end power range.Howards has some decent n/a cams. Figure I will mention these so they can be discussed.
     

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