108 vs 110 lobe separation

If you're an OEM automaker looking for a steady idle, good fuel economy, and passing tailpipe emissions, this is the cam of choice. The 108-degree cam offered both the most power and torque, but idle quality suffered compared to the wider LSAs. The standard bore block was then stuffed with a 4340 forged steel 4.0-inch crank and 6.125-inch rods, along with a set of flat-top, forged JE pistons. However, it is fixable. Hopefully It will do fine in my 2276 mostly drag bug. Split duration/lift only helps when your intake/exhaust ratio is low on the exhaust side. As a result, you can enjoy a pleasing engine outcome. I had a 110 cam in my beetle and I didn't like it-the bottom end was doggy. The 110 is probably a better choice for a performance street engine. by bigjoe1 Sat Dec 06, 2008 10:48 pm, Post The 114 cam will give more low end torque, good midrange, less power up high. 114LSA +4 puts the intake centerline at 110 degrees before top dead center. 13 The three power curves indicate that the wide (120-degree) LSA (green lines) lost considerable torque to the other two cams. One segment that truly benefits from a wider LSA is the marine marine market. More over-simplifications: If that were the only consideration, the 101 cam is the clear winner. Ultimately, it makes the 110 LSA an oil-consuming LSA. That was all, and we have already reached the concluding point. Hey guys, can anyone tell me how rough of a idle a cam would be with a 108 lobe separation? If you changed the lobe separation of a street engine from 112 degrees to 106 and didnt do anything else, adds Kaase. Lobe separation angle does. Its also critical that valve overlap is kept to a minimum as the induction system can create a suction that pulls water into the motor, adds Bolander. dur. All rights reserved. 2.1.2.4.2 Side-lobe suppression shall be provided in accordance with the provisions of 3.1.2.1.5.2.1 on all Mode S-only all-call interrogations. I have 108 for LSA and my headlights take awhile to go up when the car is idling. by Paul H Tue May 13, 2003 1:24 pm, Post FWIW. Although both wide (112-116) and narrow (102-110) lobe separation angles do have an effect on overlap, it's still possible to get a lot of overlap with very wide lobe separation angle cams. Walter Noah is a process engineer who has a knack for resolving even the toughest technical issue. To overcome this inherent problem in wide LSA camshafts, you simply need a higher-flowing intake port. It creates an unsteady manifold vacuum condition that, on a fuel-injected engine, confuses manifold air pressure (MAP) sensors, making it hard for them to regulate fueling. To further minimize any dyno variations, the engine's oil and water temperatures were kept the same for each pull. If you compared these two cams side by side in identical engines, the first cam would actually have a slightly better idle and would produce slightly more peak power at upper RPM's. Idle vacuum showed a considerable spike to 14.7 in-Hg, likely the difference between being able to run power brakes and a mandatory leg workout. But, you may wonder knowing that a higher valve clearance rate reduces the chance of damaging the valve by the piston. The final cam was tighter still, with a 108-degree LSA. I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. Howards Cam Vs Comp Cam: Which Is The Best Option For You? http://www.mustangworks.com/cgi-bin/moi-display.cgi?220, http://www.popularhotrodding.com/en6em_camshaft_specs/lobe_seperation_angle.html. If you take any of the . If the exhaust valve closes too early it will trap some of the spent gases in the combustion chamber, and if it closes too late it will over-scavenge the chamber and take out too much of the charge, again creating an artificially lean condition. A narrower lobe separation angle can provide less power but can also lead to less wear. A lower efficient compression rate leads to a higher fuel consumption rate by your engine to produce higher power. The intake air control valve (IAC), which regulates idle speed, also has to work overtime and often attempts to "catch" the idle, but usually shoots high or low. We promise not to use your email address for anything but exclusive updates from the Power Automedia Network. It really comes down to the application. As usual, Marc (aka Master) is correct. I had an XE 274 in it. Like choosing a cam in general, the key to eliminating separation anxiety is to find the proper balance of driveability and performance. Lobe Separation Angle "LSA "Jump to Latest Follow 1 - 17 of 17 Posts . You can research your heads to find out where yours are, but honestly I don't think it will be worth the effort on a tow vehicle. Retarding the camshaft (a higher intake lobe centerline number 108 vs. 104) will generally start the power band later in the RPM range and decrease the cylinder pressure. With a 108 degree lobe center, a cam will have a rougher idle and produce less vacuum due to more overlap. - Sheryl Crow. Tests have shown that, for a given cam profile, a tighter (smaller) lobe center will produce more average horsepower and a quicker revving engine. 05 To ensure our stroker combo had sufficient airflow, we installed a set of Chevrolet Performance CNC-ported LS3 heads from Gandrud Chevrolet. It depends on the combination of engine size, head flow and head flow balance, as well as a big one, exhaust flow capabilities. 110 LSA: But, contrarily, at 110 LSA, you dont have to face the problem of engine knocking. by Hoxviii Mon May 12, 2003 7:50 pm, Post The balance of midrange torque and top-end horsepower lends this LSA range to the majority of street/strip engines. A wide lobe seperation is not always better than a narrow one, or vise versa. The Idles increasing vacuum improves the idle quality and the engines overall performance. 09 All testing was run through a set of 1 3/4-inch long-tube headers and 3-inch exhaust. However, a cam with 108 will only pull 12-16", which is not enough for power assisted accessories. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. A 112 LSA would be better if I had an automatic, but the engine builder (who has built many, many drag racing engines)told me I would have much faster acceleration with the 108, at the expense of a broader power band of course, but that 108 would not unduly penalize me for the street. Good cam for a lower rpm street engine. The takeaway from this test is camshaft LSA is a double-edged sword. A cam with a 112 lobe center will pull approximately 16-20" of vacuum, which is good for power brakes. The lobe separation angle or LSA is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes. For Example: A 110-degree lobe separation means that the peak opening points of the Intake and Exhaust lobes is 110 degrees apart. from the intake to the exhaust and vise-versa.Thats why a performance cam will usually have a rougher idle than a stock one. The 120-degree cam minimized torque production through most of the curve, while the 112-degree cam offered more torque but slightly less peak power. Again, these are general bits of conventional wisdom. In my opinion, the rougher the idle the better! "When the low-pressure wave in the exhaust reflects into the intake, the pressure delta actually helps pull air and fuel into the cylinder. A 112-114 degree lobe center will have a better idle and produce more vacuum with less overlap. The 234o duration kind of eliminates the RV usage. Yearh, I have been reading a lot about this issue. = Tight Below 104 Deg. It is dangerous to be right in matters on which the established authorities are wrong. Post The result sounded wonderful, but it didnt rev as enthusiastically and it made 30 less horsepower than normal, says Lawrence. In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. Average power was also down, but the engine pulled ahead of the 101 cam at 5,400 rpm, picking up 6.5 hp at peak. Ed JTO learn to park Joined May 31, 2009 180 Posts Most street cams are ground 4 degrees advanced which boosts bottom end, throttle response, vacume, mpg driveability etc. Good luck. Thanks again. A cam card with its myriad numbers, acronyms, and abbreviations is one red-pen stroke away from a failed math test. The Fora platform includes forum software by XenForo. This has been my long time understanding! 110 LSA: The 110 LSA shows up mechanically advantageous in mechanical aspects like higher RPM, lower engine knock, moderate cylinder pressure, improved idle vacuum, and higher piston-to-valve clearance. JavaScript is disabled. 15,215. ohio. 110 LSA: However, if you look at the rate of cranking compression at 110 LSA, you will find a reduced compression rate from the standard cranking compression PSI level. A forum community dedicated to vintage Ford Mustang owners and enthusiasts. THis is a real generalization, but the weaker your heads, the more you will like the smaller centers ( 106-108) the better the heads, and the higher the compression, the more it will like the wider centers ( 112-114)everything else falls somewhere in the middle( 108-110) Once you get close with the cam centerlines, it wont make much differance if you change it up or down by 2 degrees. It also depends on what the vehicle will be used for and if economy and vacuum are important. Come join the discussion about popular models such as the Mustang, Galaxie, Falcon, Fairlane, Torino, Shelby and many more! We do not stock profiles with 109 or 114 lobe centers. by xstfudonniex Sat Dec 06, 2008 4:21 pm, Post by lazaris Fri Dec 12, 2008 2:18 pm, Post The SAME can be said. such as 290 @.050? The lower the lobe seperation,, ie. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Methods: We evaluated 30 individuals with PD (62.47.2 years) and 22 age-matched healthy controls (61.06.4 years). by mrsmythe Wed May 14, 2003 2:26 am, Post This comparison highlights that the 106 LSA is a good performer in a few mechanical aspects than the 110 LSA. It will also give you a smoother idle and probably even better gas mileage. But this is not the only reason. The valve covers, valvetrain, intake manifold, harmonic balancer, front cover, timing set, and cam were yanked. This process slows down the reaction rates of the air-fuel mixture, causing temperatures to drop and preventing the engine from overheating. It may not display this or other websites correctly. AquaTraction Vs SeaDek: Which One Is Better For you? The engine would idle a lot rougher and generate worse exhaust emissions largely because of unburned fuel.. The 30-30 Duntov is on the high end of the duration recommendation. The Fora platform includes forum software by XenForo. After the next three pulls, it was clear the 113 cam was way down on low-end torque. Has anybody experienced it/ tried it? As lobe seperation spreads does the powerband. Once more the engine came apart to install the third test cam, a 107 LSA. Really wide lobe separation angles are used in boosted applications. camshaft is a Cranecams F238. The same is true for intake valve closing. Copyright 2022, S&S Motorsports LLC, All Rights Reserved - Powered by, http://www.webcamshafts.com/cam_glossary.html, http://www.newcovenant.com/speedcrafter haft/3.htm, Webcam 86A 108LC w/1.5 vs 86B 112LC w/1.3s. On engines equipped with independent intake and exhaust cams, the LSA is adjustable. Save my name, email, and website in this browser for the next time I comment. 108 versus 110 will drive the power band down. Lobe sepsration is an advanced description for overlap.If you take a cam on a 112,and grind it on a 108,you add more overlap,the time the valves are both open.Narrower lobe centers mean more low end and midrange torque,along with a peakier powerband,and a slightly rougher idle.Tradeoffs are sensitivity to octane ratings,total timing, and air fuel ratio.A lot to swallow I know,hope this helps you. The tighter the lobe separation angle, the peakier the power curve will be, confirms Bolander. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know. hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. I've heard similar cams (only about 5*'s off) and they have a nice rumble to them. O onovakind67 Registered Joined Dec 14, 2001 6,242 Posts Cam and Lifters, Hydraulic Roller Tappet, Advertised Duration 282/288, Lift .589/.600, Chevy, Big Block, Kit. Due to the tightness and frequent overlapping of the intake and exhaust valves, the engine cant generate the high RPM as it is supposed to. Lower cylinder pressure is advantageous for your engine. 10 Tuning the timing curve and fuel from the 42-lb/hr FAST injectors was handled by this Holley HP management system. Everyone has a different idea of gentle.While its true that the duntov cam may seem rough in a 283 it is still a factory offering and they never go to radical on there profiles for street cars.If you want a rough idle, try a 283 with a .550'lift roller and 13.5 to 1 compression,THATS ROUGH. Higher overlapping lets less oil fall through the oil inlet. Let's just talk lobe sep angle. Wide LSA cams are also applicable in forced-induction applications where less exhaust overlap is required. The 114 LSA is good for a blower or nitros motor. i've heard of this being done something about the massive amounts of duration allowes gasses to disipate? too much for the street? We use 86b webcams with 1.25 rockers frequently in stroker motors.It's a nice way of getting close to .500" for hot street motors with average heads. Lobe separations on 383-406 cids.104-106-108-110? Realize what the engine is going in, however, as you may not be able to use the wildest cam out there. But, the narrow or broad powerband choice varies from person to person. The tighter the lobe center, the lower the RPM range; the wider the lobe center, the higher the RPM range. by bug1914 Tue May 13, 2003 2:56 am, Post The first cam featured a wide 120-degree LSA, while cam number two narrowed the angle to 112 degrees. 110 LSA: But here, quite surprisingly, you have to face the reduction of the EGR effect due to the 110 LSA. It idles very well at 650 rpm with a nice lope and runs strong. "When you've properly tuned a performance motor, you create high- and low-pressure waves in the intake and exhaust that help cylinder filling," said Comp Cams' Billy Godbold. What happens when you change ONLY. I will be running an Edelbrock Performer RPM, with a Quick Fuel 750cfm with a screw adjustable vacuum secondary; it's called the Pro-vac. Also know as Lobe Separation; Lobe Center is simply the distance between the peak opening points on the Intake and Exhaust lobes. I am trying to pick out a hydraulic roller cam for my 351W with AFR 185s. But i would nt go any wider than 110. by mrsmythe Mon May 12, 2003 11:15 am, Post Contrariwise, 106 LSA car engines are the best choice for people seeking energy-efficient cars with moderate engine power. It should still make close to 600hp and 600tq in my 512" stealth headed big block. Thats just the way the customer wants to roll, and engine builders find its easy to deliver such a powerplant. by Marc Mon May 12, 2003 11:38 am, Post I would say 114-117* would be a normal 1960's stock cam range and 117* to 120* is more what we see on modern engines. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. A cam with a 112lobe center will idle smoother than a cam with a 110lobe center. The only reason I . For any additional clarification or questions please contact our Tech Line at 714 523-0530. https://www.youtube.com/watch?v=57gfBu8uc6k&t=1s. The #1 intake lobe centerline is usually between 100 So, the 110 LSA engine is a suitable choice for people prone to be the fan of a powerful engine with mighty acceleration power. We will safeguard your e-mail and only send content you request. The Crane has a smoother idle, broader power band, and . I though my car would have a nice rough idle with the solid cam with a tight LSA I put in my car, its go a slight lope to it, but it pulls hard. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. any input is appreciated guys, thanks. The graph above compares intake valve closing points of the three cams used in the test. Professionally ported & polished iron 4V head with titanium intake valves, stainless exhaust, titanium retainers & keepers & dual springs. 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. ~These are just some of the drawbacks weas guys who like to go mach 10 with our hair on fire and these little motors screaming at rpms that make other guys cryhave to deal with.~. Despite no changes in lift or duration, this cam sounded much more aggressive than the other two with wider LSAs. Noah knows a lot about whats happening in the car industry with the latest piloting productions thanks to his professional experience. The engine has AFR heads, Crane rockers, a TCI balancer, a Scat Rotating assembly with Mahle pistons, an Edelbrock RPM Air-Gap intake, an MSD ignition, and an Aeromotive fuel system. (2002) et rappel sur une carte hors texte. The other thing is that you can make more power with a smaller aftermarket cam. Pretty much standard for an RV type cam. For a better experience, please enable JavaScript in your browser before proceeding. Performance Distributors Keeps The Spark Alive With SOS, A New Diesel Piston That Increases Power And Reduces, Shop Tour: Brian Tooley Racing Expands To Be A One-Stop, Melling Offers New Timing Kits for Ford 4.6L and 5.4L SOHC, Reborn Retro Blower Packs Positive-Displacement Power For Fox, EngineLabs Tool Of The Month: Summit Racing Lb-In Torque, Why You Should NOT Emissions Delete Your Diesel, Can A Cold Air Intake Really Help Your Trucks, Ask The Expert: We Want Your Questions For Canton Racing, The Answers: DeatschWerks Responses To Your Fuel System, SEMA 2022: GEARWRENCH Leveled Up With Distinct Quality Hand, EngineLabs Tool Of The Month: Summit Racing AN Wrench, HOLY SHIP! Every spec is a road map to what the valves are doing, the most common of which are lift, duration, and lobe-separation angle (LSA)the latter needing the most explanation. Torsion Beam Vs Multi Link: Who Wins the Battle? changing just the LSA on my cam wouldnt make a bit of difference on vacuum operated items E ericnova72 More for Less Racer Joined Jan 13, 2007 22,026 Posts i have a 4 bolt 351C, stock bore, 10.5 cr with 351C Boss heads ,boss crank and rods. The 110o will make more power overall. After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. However, these rules are not absolute. Thanks for the replies, particularly that link Marc, very informative. We will also custom grind any of the above profiles with a custom lobe center, for an additional $20 dollars. Test 1 was easy. The article was called "Separation of Power" and they tested 5 cams ranged from 106 to 114 LSA. 110 LSA: On the other hand, 110 LSA is a wider LSA with almost no overlap. I've seen a few comments in threads on here that have said things like "going to the 112LC from the 108LC gives 4lbft more torque at the bottom and 2bhp more at the top" yet this would seem to go against what webcam say on. The introduction of Lunati'snew Bootleggerhydraulic series - with its wicked 108-degree lobe-separation angle, fast opening profile and plenty of area under the lift curve - will serve only to fuel the flames on this heated bench-racing topic. General topics - 76 LA built, CA car with m20. But to choose the perfect cam, all of that information needs understanding. indeed, expect low vacuum with anything lower than 110-ish. That means your engine can produce more power with a minimum amount of fuel combustion. How To Properly Replace Ignition CoilsContinue. Tight lobe separations, such as 108 or shorter, will cause the peak torque to build earlier in the RPM range and peak-out in a short amount of . kinda off topic.. but while we're on the topic of cams, duration,lift,ect has anybody heard of using high compreshion (13:1) on pump gas, by useing alot of duration? It is the DESIGNED events that yield CENTERLINE. 110 LSA: On the contrary, if you look at the powerband at 110 LSA, the powerband is comparatively broader. 110 LSA: Oppositely, the cylinder pressure is comparatively lower at 110 LSA than at 106 LSA. Yeah but do the experiment on the dyno and tell me your intuition is correct. Now that we have a basic understanding of lobe separation angle, we can put together a test to illustrate just what happens when you make changes to it. Cam timing plays an important role not only in the power generated but also the overall character of the powerplant. The tightest LSA (101) was worth 21.5 lb-ft of torque and a much broader powerbandat the cost of much lower idle vacuum, which would make it more temperamental in a street car. 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. GRIND #: CRB3 3194 /3196 HR111. Looking at 108vs. A tighter LSA is always going to have more overlap, which allows the exhaust and intake systemif they're tuned wellto work together.". I would have to say that your cam choice sounds like a winner to me. Come here to talk with others who like to drive fast. Well, it is quite a natural event that you may not find the lope separation angle mentioned at the engine body. For example, an oval-track small-block that needs to motivate the car off the turns quickly might have a narrow LSA of around 106 degrees, resulting in more overlap. The extra cubic inches will smooth out a rough idle in a 327. It has been tried in the VW business earlier, but then they gave it up because of problems with too high temperatures around the exhaust valve, causing them them to break. Tight LSA cams make excellent low-end torque and have a beautiful power curve. 01 Choosing the right lobe separation angle for your LS cam shouldn't cause anxiety. BUT, 114 will have more vacuum at idle, which will work better with some fuelinjection. Hopefully it turns out great. I am pretty sure, right now, you find yourself in the middle of the rising debate of 106 vs 110 lobe separation angle. The 114o lobe will add a lot more vacuum at idle. 106 LSA: 106LSA results in a decrease in piston-to-valve clearance. probably just enough to get me in trouble.. So, this LSA is suitable for your engine and its components. This is one of the many reasons why Clay Smith Cams always recommends degreeing your camshaft in using the Lobe Center Method. This recommendation is only if you shift at no more than 7000. If the overlap phase occurs too early, it will create an overly rich condition in the exhaust port, severely decreasing the gas mileage. thanks. Well, I saw that Erson makes some nice hydraulic rollers with 108 LSAs, and I know that tighter LSAs have more midrange, so I thought they might be worth a try. Unfortunately, good street manners are often at odds with performance, as wilder cam timing usually decreases idle and (low-speed) driveability. 112-110 Deg. When boost or nitrous are introduced, and engine builders contemplate choices between single-, dual- or reverse-pattern camshafts then the discussion gets muchmore technical. 106 LSA: At 106 LSA, the cylinder pressure is a bit higher. Getting back to the sound of an engine, its no secret that a raucous, lumpy idle is often preferred by street cruisers, regardless of the ill manners and inefficiency of such an engine setup. (ICL + ECL) / 2 = LOBE SEPARATION ANGLE (LSA) LSA is a RESULT of the PROPER events. To demonstrate changes to lobe separation in action, we ordered three camshafts from Comp Cams, all ground with identical lift (0.541 intake and 0.537 exhaust) and duration (230 intake and 236 exhaust) but with three different LSAs: a 101, a 107, and a 113. Its the shifting problem again with your Chevy! somthing to that aspect. I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. A narrow, more specific power band is also a product of a narrow LSA, as is a lumpy idle qualityoften referred to as the 106 sound. Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. That is why 106 LSA consumes less oil. Mike Magda is a veteran automotive writer with credits in publications such as Racecar Engineering, Hot Rod, Engine Technology International, Motor Trend, Automobile, Automotive Testing Technology and Professional Motorsport World. Part Number: HRS-CL120325-08. Given that nitrous works best in the mid- to upper-rpm range, nitrous-powered engines need a wider lobe separation, like 112 . Read More Chevy 350 Ignition Coil Location And Everything About ThemContinue, What causes a car to bog down when accelerating? But, at 106 LSA, the cranking compression may increase above the standard PSI level. Consequently, decreased torque rate often leads to more energy consumption. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. Pick the cam with the valve timing events that fit the engine best, forget about LSA, it is only a result of the events. 110 LSA: On the contrary, it is pretty unpleasant to inform you that the efficient compression rate decreases at 110 LSA. In reality, a cam with 220 at 0.050" and a lobe center angle of 112 will have the exact same mechanical overlap as a cam with 217 at 0.050" and a lobe center angle of 109. You can modify the lobe center a little bit but not enough to change the actual overlap of the grind. A 232 deg duration cam with a 108 deg LCA will have the same valve overlap as a 236 deg cam with a 110 deg LCA and idle will probably be very similar. 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? Before we all start suffering from separation anxiety, we need to understand what lobe separation angle actually is and then how it affects your engine. The 112-degree cam offered nearly all the low-speed and mid-range torque of the 108 cam but the peak power suffered above 5,200 rpm. But, the internal processings are much more complicated. JavaScript is disabled. Good cam for a lower rpm street engine. Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). 110 LSA: On the contrary, at 110 LSA, the engine fails to reach the maximum torque, resulting in a decrease in torque rate. For a better experience, please enable JavaScript in your browser before proceeding. Knife edged & profiled 4MA Cleveland crank weighing 50lbs. Mechanical aspects like maximum torque, narrower powerband, higher cranking compression rate, efficient compression rate, effective EGR effect, and lower oil consumption rate increase the car engines efficiency and make it energy efficient. Either learn to fix it, or learn to write checks. On larger displacement units 116 to 118 degrees of separation are common. 108 Lobe Separation These are my motors specs 1979 - 347 Stroker 10:1 Compression Holley 670 Street Avenger or a Holley 650 (I have both) Roush 200 Cylinder Heads (minor head work) 1.6 Roller Rockers Shorty BBK Headers 373 Rear End 5 Speed Transmission Cross Gap Intake (Power Band 1500-6500) FlowMaster Dual Exhaust (of course no Cats) MSD 6Al The other thing is that you need to tune your ignition advance to maximize your performance. Lobe separations gives lots of overlap and lobe centers just happens when the grinder decides how the peak of the lobe will arrive on a specific grind by their tooling. That way you can discuss what you want from the engine and how changes in LSA or any of the other specs will affect how the engine performs.