Also I read that wrong oops. I though he ment I lose cc's as in lowering compression. makes sense now.
Here is a custom cam I made that is very similar to the Scott Brown custom cam suggested. You can have him tweak it as he sees fit, but the numbers will be very similar. Cam specs are: lobe symmetry: symmetric lift@1.55: .484/.488 duration @.050: 220/236 @ 4* overlap duration @.006: 280/292 @ 62* overlap lobe intensities: 60/56 LSA/ICL: 112/108 Cam would idle very similar to the TA 212 (about 750 RPM idle with nice lope) with similar vacuum @idle (about 13-14" if memory serves--been a while) which is plenty for power brakes. Not quite as much exhaust emphasis as Scott Brown cam, so would be a good hybrid N/A cam with or without nitrous. 10:1 compression (7.75:1 with 68* IVC point), for use with premium pump gas, heads are Stage 1 valved (1.92/1.55) flowing at 230/150 peak, high flow dual plane and large tube (1 3/4" primary) headers with open exhaust. This reflects the optimal output and will vary depending on a myriad of factors, including tune, actual specs in real world, quality of fuel, atmospheric conditions, exhaust used, etc. etc. Average peaks: Torque: 406.5 ft. lbs. @4250 RPM with 388 HP @5500 RPM Screenshots forthcoming: http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_01_zpsmud8xbg2.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_02_zpsme99m8pb.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_03_zpslakvcqlf.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_04_zpsgiwu8v5a.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_05_zps3rhkfb4m.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_06_zpsnqqyjkwc.jpg.html http://s482.photobucket.com/user/garyfarmer1968/media/Custom Buick 350 cam_07_zpsrb3dgat9.jpg.html Enjoy! P.S.--images came up kinda small so difficult to read. Is there a better way of inserting an image file? I had to use the 'basic uploader' because the default one would not function correctly. P.S.S.--going to use photobucket. Sorry for the trouble viewing the screenshots at a proper resolution. Click the link next to the image and you can see a better image that you can actually read. I spent over an hour of my time doing all this only for it to end up having problems uploading decent images to this website. Gary
Hey thats awesome thank you! Could I ask a favor real quick? Could you possibly put this on a 110 lsa and a 106 center as well? Id like to compare.
I took another look at 110/106 LSA/ICL and it tightens the powerband by 100 or so RPM and adds about 1-3 ft. lbs./hp. Overlaps increase from 62/4 to 66/8. Rougher idle and less vacuum for power brakes, for a pretty insignificant power gain. I'm not going to post 7 (14) more screenshots for that lol. A note about camshaft design: keeping exhaust lobe more intense adds power, but makes the exhaust lobe wear out faster. I kept it at 56* intensity for this reason, which is about borderline for a fair tradeoff in performance/longevity, with emphasis on performance of course. You can squeeze more power out of it by tweaking, but the numbers will be relatively small for a tradeoff of much greater wear. See, all that stock cam stuff paid off didn't it. p Anyway, thar she blows. This cam could also be ground as a roller profile. Gary
To make the pics show full sized copy and past the "IMG" code on the upper right of each picture and they will show like this:
Sean to the rescue! Thanks bro. On another note, this camshaft (the one I created), I'd recommend as a roller profile because of the lift, and it fits nicely within the roller cam blank parameters TA offers, and is symmetric so would be easier to grind. It behaves very similar to the TA 212 cam, but with more spunk and a bit of an extended RPM band. If one were to grind it as a flat tappet, I'd recommend the 212's lifts (.454/.456@1.55). With more exhaust emphasis than the 212, would make for a good nitrous cam, or for use with the stock exhaust manifolds, as long as they're polished and an "X" pipe is used for scavenging. The extra exhaust duration will help things flow better with a somewhat restricted exhaust, and the cam is mild enough for every day street use, but hot enough to have a nice lope and increased power over the TA 212. You can aim for a simple "10:1" compression for ideal use with premium pump gas. Just say that Gary Farmer designed it. OR, tweak the numbers a bit and have someone else's name on it. Doesn't matter really. You're welcome. lol Gary
Gary, how much does it change power to use standard valves. According to images you have very good flowing heads.
I appreciate you doing that for me! sorry I didn't get a chance to reply over the weekend. I am shooting for 10:1 and im using headers and a x pipe. Ill make sure and say you designed or based it off of your design.
My time is limited throughout the week, so I'll get back with you later as time permits. Standard untouched Buick 350 heads flow at 198 CFM @400 lift, where it tops out. Mild cleanup yields another 5-10 CFM with same lift peak. What I call 'moderate' porting will give another 20-25 CFM over that, including the larger valves. It's not difficult to get 210-220 CFM from the heads with light porting and standard valves. You'll see about 10-15 hp loss without those larger valves. This is from memory. I'll do some more runs later to verify. Here's an image file of untouched heads vs a set of heads ported using standard sized valves: Notice from .400-.500 there isn't much gained, but then it jumps a bit from .500-.550 and plateau's off from there. I suspect there were some contouring issues that caused this, but the heads CAN flow up to .550 lift with some major work (and skill). Note: the vast majority of improvement was from .200-.400 lift. Keep this in mind when laughing at stock cam performance with ported heads... For the most part, best not to expect much past .400 or .450 with your standard port job. The new aluminum heads will be the game changer in terms of higher lift and all-out racing applications, where this head is better suited for street/strip stock-moderate applications. Cam lift on these heads doesn't need to be as high as most people seem to think. A lift of .450/.450 is about all anyone really needs in terms of lift; duration can be whatever though. The stock cam's asymmetric design keeps the lift in a good zone for longer periods of time, and while does not maximize power, does manage to squeeze more out of a shorter lift and does very well considering its size. It was never designed for maximum power output anyway, more for longevity. Anyway, we all know that story by now. Symmetric cam design needs to overshoot its lift a bit, and .450 seems to be the sweet spot. Anything more than that and you're adding unnecessary strain/wear to the cam/lifters, unless you go roller. Gary
Would it be wise to reiterate that putting larger valves in without porting work would be a backwards move?
Absolutely. Larger valves need to be contoured to the runners/throat/bowl and if they're not, will cause turbulence and actually decrease power. Or so that's my thoughts. At the very least, one needs to contour/smooth the transitional areas over to accommodate the larger valves. Also worth mentioning, the exhaust valve is essentially unchanged since later heads used those sized valves; it's the intake valve that needs the most attention. Gary
On the 2 pics with the graphed curves, is there a difference in the engines modeled or is it from using seat to seat specs vs. .050" #'s? I'm seeing one engine with 25 more tq from 2000-4000, and the other is 25hp stronger at a slightly higher rpm with a corresponding loss of tq down low. Basically they are trading 25 tq and hp or so. Am I missing something? There's a lot of tiny print to look over The 2 different tq curves would have very different characteristics on the street with the usual variables in drivetrain. Also, I'm curious which intake are you assuming and will it slightly outflow the heads? (Observed, not assumed) I use the same program when I want to play with cam specs, after I decide what the heads and intake are going to do. It's quick and easy to see changes in torque curves. As far as the loss perceived from larger valves in unported heads, that's how I usually see it on my flow bench. It usually screws up the velocity profile some and causes other problems, as the valve throat is not always the Minimum CSA. [Note; this isn't something really checked that often as it's usually an exercise in futility when the reason they are on the bench is to have porting work verified. I'll check a few valve sizes to determine shrouding issues or to help decide the actions needed to get the head steered where you want it.] Thanks Gary, just looking for clarity... not to be a pain in the rear! [edited to eschew obfuscation]
Yes I have heard from a pro head porter that after adding larger valves to 350 heads there was a lot of work needed to de shroud them.
Are you talking about the chamber side? Nonetheless, just pointing out that larger valves usually need a bit of work to see any benefits.
Its pretty simple As has been stated, the same tall narrow runners that make the heads have good velocity,are the downfall to its success as well Adding larger valves doesn't help in itself as they are in most cases not the restriction in a OEM port Now open up the pushrod area with raised roof,along with a ported bowl with no guide intrusion, and a wider, laid back short turn,to manage air speed, and a large valve head will cream a std valve example everywhere .
My point exactly. There isn't much on the chamber side to "shroud" the valve, the work is in the runner and bowl. Maybe the term was being used differently?
