Thanks 112 vs 114 lobe centers You cannot tell the differance in the two . That doesn’t make sense. I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. My lift will be about .580" intake and exhaust, with about 230/236 duration with a 1.7 rocker ratio, utilizing a Jesel shaft rocker system. On a naturally aspirated engine, the lobe separation angle has an effect on whether the engine reaches peak torque a little earlier or later in the rpm range. The lobe separation angle of a camshaft is often determined by the engine’s purpose, its displacement and its compression ratio. Hi, Clarence. This can … the specific numbers (durations, lobe separation angles, etc) are not where the trends lie. Come join the discussion about restoration, modifications, NOS parts, troubleshooting, VIN codes, and more! "It's not having what you want, it's wanting what you've got!" FWIW. LOBE SEPARATION ANGLE EXPOSED Valve Test 2 114 Cam (PN 11HR00239) For the second test we skipped to the opposite side of the spectrum. CHOOSING LOBE SEPARATION ANGLE Lobe separation angles (the angle in cam degrees between the intake and exhaust lobe are also referred to as "lobe centers") are very engine combi-a "peakier" torque curve more suited to stick-shift cars with multiple gear ratios to change between. Anything with a 112, 113 or 114 degree lobe separation is great for blowers and nitrous. We would like to let you know that your feedback has been forwarded to the proper department; your comments are important to us and help with the development of our online video streaming community. The size of the cam lobes does not affect the degrees of cam lobe separation though, although it can factor into the amount of overlap. hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. Looking at 108vs. This means when you install the camshaft with a set of stock gears, its timing will be advanced by four degrees, assuming everything else is perfect. 3. i have a 4 bolt 351C, stock bore, 10.5 cr with 351C Boss heads ,boss crank and rods. It can give you a lopey idle, allow the motor to rev up quicker, and change the amount of air used, changing the exhaust note, among other things. Most cam grinders will use a middle of the range 110/112 degrees for street motors. And these babies were getting run in the very late 80's and early 90's. It is the number of degrees separating the peak lift point of the exhaust lobe and the peak point of the intake lobe. Generally, smaller lobe separation angles cause an engine to produce more midrange torque and high rpm power, and be more responsive, while larger lobe separation angles result in broader torque, improved idle characteristics, and more peak horsepower. Overlap hurts bottom end (bleads off dynamic pressure) and … Alternatively, if you are running a bigger camshaft to gain maximum top-end power, cam makers often suggest reducing the lobe separation angle to recover power lost in the lower rev range.”, “If you changed the lobe separation of a street engine from 112 degrees to 106 and didn’t do anything else,” says Jon Kaase, “the engine would idle a lot rougher and generate worse exhaust emissions largely because of unburned fuel.”. Five-hundred cubic inch NHRA Pro Stock engines that rev to 11,000rpm operate on 116 degrees and 800-plus cu in Pro Stock Mountain Motors 120 to 122. My point was GM had a lot of red tape to work around to get emissions and mpgs demands. It can change just about every aspcet of the motors running. Looking at 108vs. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.” This paragraph is incorrect. ( just a wild ass … 196 Posts . If you are running a blower or nitrous the 114 LSA will benefit also. Frankly cams with a 108-114 lca unless in the perfect combo you won't usually see more than 15hp and you won't really feel the difference except for either a peaky or broad power band. Supercharged or nitrous engines should benefit from a wider lobe separation angle because they don’t need much overlap for exhaust scavenging. Mark-Classic Car Restoration Club. Some engine specialists refer to it as that 106 sound—the NASCAR Cup and short track oval sound where lobe separation is set at 106 degrees. Crane Cam 274' int/274' exh/ 106' lobe separation. indeed, expect low vacuum with anything lower than 110-ish. Is this true? Anybody here run a 108 LSA? Keep in mind that anything over .500 or less than 114 LSA you should measure clearances to be sure. This cam was ground on a much wider, 114 LSA. In conclusion, lobe separation angles change the amount of valve overlap, which affects many performance factors particularly idle quality, peak torque that can be moved from a lower rev range to a higher range and power bands that can be narrowed or broadened. A tighter lobe-separation angle (106 to 110 degrees) will produce a lopy … If a cam is ground “straight up,” both centerlines are the same and the LSA is one half of their sum. “Lobe separation angles,” he continues, “are influenced by the camshaft grind. To say that lobe size and shape dictates lobe separation angle doesn't make sense. Lobe Separation Angle (LSA) Jump to Latest Follow ... a 110 LSA cam vs a 114 LSA cam or vice versa? Alternatively, if you are running a bigger camshaft to gain maximum top-end power, cam makers often suggest reducing the lobe separation angle to recover power lost in the lower rev range.” For instance the old PS truck motors. 110 + 4 means that the Lobe Separation Angle is 110* and the cam shaft has 4 degrees of advance built into it. A wider lobe separation angle such as 112/114 degrees will give up power at the bottom of the range for power higher up in the rpm. Specify your cam with the wide lobe separation angle to ensure the lowest possible overlap. This can … It's wet flow tested at 690cfm. Either a misspeak or a typo. 3. As I said, “I’m so confused!”, Hi Doug. To find intake lobe advance/retard, simply subtract the Intake Lobe Centerline from the Lobe Separation Angle (i.e. A 350cu in oval track racing engine, for example, often runs on a narrow lobe separation angle of 106 degrees. “Lobe separation angle affects the valve overlap area, and in most cases forced-induction cams are designed with a 112-to-118-degree lobe separation angle. what is the differenc between lsa and lcl my comp cam is based on 110 lcl dur. If the scissors are nearly closed, you can cut well as long as what you are cutting is thin. : LSA 114 – IC 112 = 2-degree advance). Why? Simply put, tighter lobe separation angles (LSA) create greater low end torque, rougher idle and less engine vacuum. OK, what is hydraboost, and how do you like how the cam performs??? Generally a rough, loping idle is considered tough sounding, this type of idle is normally atributed to a high duration camshaft. Assuming all else being equal you would have more overlap (where the exhaust valve is closing and the intake valve is opening) with the 110 + 4 than the 114. Anybody here … Enter in your email and password to create a FREE account. Also, the article mentioned cam degrees, I can’t get my head around that term as the shaft makes a complete turn of 360 degrees therefore the lobe must also travel 360 degrees. Lobe Separation Angle. “Lobe separation angle affects the valve overlap area, and in most cases forced-induction cams are designed with a 112-to-118-degree lobe separation angle. the specific numbers (durations, lobe separation angles, etc) are not where the trends lie. The Lobe Separation Angle (LSA) is the distance between the centerlines of the intake and exhaust lobes on the camshaft. Wider lobe separation (ex. Naturally-aspirated cams are typically in the 106-to-114-degree lobe separation range.” mc1713 hyd 3 222 222 290 290 .447 .447 110 118 2000-4000 fair 817 comment: oem #3863151, 350hp, l-79, 327 mc5840 hyd 3 224 224 291 287 .450 .461 114 114 2000-4500 fair 817 comment: oem #3896962, 350hp, l-82, lt-1 mc1991 hyd 3 224 224 298 298 .465 .465 107 117 2000-5500 fair 817 comment: good low to mid torque. yet … This is sometimes referred to as the "lobe center" of the cam, but we prefer to call it the lobe separation angle. Sorry I am not a marine expert, but there is no engine vacuum on the exhaust side of the of the engine. 114 vs 110 lobe sep. on cam Discussion in 'High Performance Modifications' started by HULKZ28, Aug 20, 2006. Ok, I can see that but why do we hardly ever see a 383 or 400 that has a lobe seperation of 104-108. JavaScript is disabled. Lobe Separation Angle = (intake centerline + exhaust centerline) ÷ 2 LSA = (106 degrees + 114 degrees) ÷ 2 = 110 degrees. For instance the old PS truck motors. .050 int. Lobe-Separation Angle Tested and Explained. Supercharged engines typically benefit from a wider LSA because they don’t require as much overlap for exhaust scavenging as does the naturally aspirated engine. This particular Crane cam uses a recommended intake centerline of 108 degrees while the lobe separation angle (LSA) is 110 degrees. I am trying to pick a nice cam for my 454, as some of you know the one I had went flat and trying to pick a new cam. Lobe Separation or Lobe Center is simply the distance between the peak opening points on the Intake and Exhaust lobes. Compression willl be 9.75:1. Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. In contrast, a smooth-running high-performance street engine might use a lobe separation angle of 112 to 114 degrees. 108 is very tight producing lower vacuum and more of a 2 stroke "punch" powerband. Effect Of Changes In Cam Timing And Lobe Separation Angle The following tables illustrate how variations in lobe separation angle and cam timing will effect the behavior of the engine in which the camshaft is installed. I am sure that the writer or/and the speaker realized that. Widening their separation angle helps increase upper rpm power output. Summit Cam 282"/282" 114' lobe separation. 110 for sure. ALWAYS CHECK SEVERAL TIMES FOR ACCURACY. I am trying to pick out a hydraulic roller cam for my 351W with AFR 185s. ‬ So if I hear this correctly a cam with a larger degree of sepertion has more lope or sounds like a old Harley at slow idle? 4-Link72, do you run racing gas or pump with 10.5:1 CR? Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.” This paragraph is incorrect.To correct my first post: Narrow lobe separation doesn’t make for more low end torque at a lower engine speed. For timing 25-65-65-25, the lobe separation is 110 cam degrees (220 crank degrees). But I think they were fighting the same battle but Pontiac, who new hiw to build engines with horsepower, just didn’t have the technology in 1974. 238/248 duration, 300/310 adv. Flat Tappet vs. Roller. If the cylinder heads are the lungs of an engine, the camshaft is the brain. How is it measured? Sorry for all of the confusion, A narrower LSA will produce more torque at lower/mid RPMs, As it relates to this article, Cam degrees are the number of degrees of lobe separation between the intake and exhaust maximum opening. The vacuum is created on the intake side only. 110°-112°) results in Is it a hydraulic roller as well? A wider LSA, on the other hand, reduces valve overlap, offering better idle and cruising qualities. Its all relative. 104.5° + 10° = 114.5° Lobe Center If you have adjustable gears move them at this time and redo above procedure. Can someone tell me definitively which of the two differing comments on the effect of lobe seperation (overlap) on engine torque and idle is absolutely correct. Thanks dur. He simply asked what the difference would be if the same cam was ground with a 110 or a 112 degree lobe seperation. of 169 on a sport model. Wider lobe separation (ex. I wouldn't assume 4 links fuel requirements will mirror yours at all. Most cam grinders will use a middle of the range 110/112 degrees for street motors. (This information should be listed on your Cam Card. That doesn’t sound like much but with a manual transmission the actually ran pretty decent. 230 exh. The only reason the advance or retard a camshaft profile is … With this in mind, lobe separation angle is said to be in cam degrees, while duration is quoted as crank degrees. Overlap is the amount of time in degrees that the intake and exhaust valves are open at the same time, and excess amounts of it can work against your supercharger by allowing exhaust backpressure to negate supercharger pressure while the valves are open. Classic Car Restoration Club Video membership. 110 wider, 112 widest (of what you used for examples. A fixed angle on a single cam that contains both inlet and exhaust lobes. Your best bet would be to talk to one of the experts at a cam company to get a custom grind if you're that into the specs. Crane Cam 272' int/272' exh/ 110' lobe separation. ... (114-degree) lobe separation angle lost torque in the midrange compared to the tighter 106-degree LSA but made up ground with top-end power. It is measured in degrees of camshaft rotation. The LSA for that cam is 132 degrees – it produces very little low end torque but it is also notorious for virtually zero vacuum below 900 rpm and a very rough idle. In contrast, a smooth-running performance street engine might use a lobe separation angle of 112 to 114 degrees. Effect Of Changes In Cam Timing And Lobe Separation Angle The following tables illustrate how variations in lobe separation angle and cam timing will effect the behavior of the engine in which the camshaft is installed. Page 3 ... (112-114 or wider) are good for just about everything but a N/A carbed engine. Intake Lobe: #HF275/328 (CRA, designed for Ford 0.875 tappets) Intake lobe mathematic centerline = 112° ATDC Exhaust Lobe: #H287/3283 (CRA) Exhaust lobe mathematic centerline = 116° BTDC 114° lobe separation angle (camshaft degrees)-----Exhaust valve opening = 79.5° BBDC Intake valve opening = 25.5° BTDC 53° overlap ( 108° + 110° ) / 2 = 109° ADJUSTING LOBE CENTER SEPARATION A wider lobe separation angle such as 112/114 degrees will give up power at the bottom of the range for power higher up in the rpm. The mother of all “lumpy” cams is the Duntov 30 – 30 that was in 64 & 65 365 and 375 HP engines. Ground with a 114° LSA = 58° overlap. camshaft is a Cranecams F238. This is sometimes referred to as the "lobe center" of the cam, but we prefer to call it the lobe separation angle. What happens when you change ONLY the LSA of the cam and keep the lift and duration the same? Comp Cam 268' int/268' exh/ 110' lobe separation. Again we yanked the intake manifold, valve-train, and front of the engine to swap in the new bump-stick. I realize a lifter riding the lobe travels a greater distance but how does that affect cam degrees, and wouldn’t that change with the design of the lobe? Lobe separation, or lobe separation angle, is the distance (in camshaft degrees) that the intake and exhaust lobe centerlines are spread apart. FULL RESULTS-CHANGE ONLY LSA-LS CAM TEST. 1966 Toyota Landcruiser...under construction, VerticalScope Inc., 111 Peter Street, Suite 901, Toronto, Ontario, M5V 2H1, Canada. If a street car has smaller lift and duration numbers, they might run 112 or 114. A 110-degree lobe separation means that the peak opening points of the Intake and Exhaust lobes is 110 degrees apart. "The LSA, or lobe separation angle, is ground into the cam and cannot be changed. Of course, but you won’t get as much of the benefit from the power adder as you would with a wider separation angle. 104.5° + 10° = 114.5° Lobe Center If you have adjustable gears move them at this time and redo above procedure. Its primary influence is to impel urgent acceleration off the turns when the throttle is opened. I was just discussing with my son the reason why Pontiac used a VERY conservative cam in the 350 it put in the 74 GTO option. The problem is the engine sucks water in from the exhaust into the cylinders and ends up with water in the oil. This cam was ground on a much wider, 114 LSA. Lobe Separation Angle, or LSA, ... Again, much depends on the overall engine combination and intended use, but as a general rule, cams with a 110-to 112- degree LSA offer good power and decent street manners. Paul, Hello. The grunt work went quickly as we were eager to Cars. It is the number of degrees separating the peak lift point of the exhaust lobe and the peak point of the intake lobe. Thanks I suspect because it raised the working compression and with its four barrel carburetor gave the car 200+ hp. Lobe separation affects valve overlap, which affects the nature of the power curve, idle quality, idle vacuum, etc. Narrow lobe separation makes for more low end torque at a lower engine speed. .3010 exh .3070 lobe separation 114. 110 degrees on the lobe separation angles. I’ve done a lot of experimentation to prove this is what’s happening. A 350cu in oval track racing engine, for example, often runs on a narrow lobe separation angle of 106 degrees. I think the average lobe separation of the ones I dug through was 116.5. Please advise. "If two cams are identical with the exception of lobe separation angle (we'll say 108 and 114) the cam with 114LSA will make more low end power than the 108LSA cam?"
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