How the Summit Racing Cam Timing Calculator Works 

Thank you for watching, Von!

Thank you for watching!

Exactly...

J

As long as it's an SBC with 10:1 compression.

​@@aldo6192 I'm looking forward to trying Vizard's 128 calculation on my current build. What you said about 108 can be said for 110 and that's about all comp offers. So why does comp speck most of there cams lsa for roughly a 305😂😂 I agree Vizard loves to ramble and get sidetracked with his stories now that he's in what his 80's now?

Thank you for watching!

please note from several sources that say any of it cant be calculated by DCR etc. there are many other factors that can affect pump gas compatibility. from your intake valve opening degrees is where you can get your dynamic compression ishoot for8.5to 1 its right in the pump fuel zone= 7.5 to 1 minimum to 9.5to1 max and that is hot.for instance GM's ZZ350 crate motor is 195PSI that is high but the fast burn chamber gets away with it. race engines that use race fuel or additives go beyond this of course. its really fun when you do also. it creates a supercharged affect. iuse a direct head port cooling, piston top coating, and smooth all the sharp edges this is the real reason for polishing because polishing does not create more flow. it evens the heat dissipation and heat is the power in a combustion chamber and cylinder, this creates the pressure. you want 195 psi in a fast burn or modern performance head chamber at max. if you go direct head cooling know what your doing. basically if you get a hot spot in the chamber or a sharp edge, this is what causes a ping. that is bad. do not operate an engine that pings under those detonation conditions. ican blueprint an engine for you. or spec your cam matching your dynamic compression to run the most on pump gas also varies with altitude and how good you fill the engine cylinders. Really its going to matter what cylinder pressure actually measured is. you want 175 PSI minimum, to 190ish PSI

@@7REDDRACO7 Excellent information. I learn a lot from RU-vid comments like yours. Thanks!

@@7REDDRACO7 very good info. I had a 6 liter LS with a fairly large cam at 238/242 duration and Trickflow heads with 10.9 compression ratio and I was very surprised to find 220 PSI with an accurate compression gage. I thought a cam timing of that size would produce much lower....... but it didn't. All was good tho. 93 pump gas only.

Stock

@@brandon_907 it has a stock one but I just want something a little bigger

Any cam change requires a retune. There are a few cams on the market that you can use stock springs with though, but it's a lot of work to put in that new camshaft only to gain like 5hp from that small cam

CCA-12-249-4 will work fine with your stock TBI and springs. www.summitracing.com/parts/cca-12-249-4

There is a multitude of reasons why an engine designer may use a longer or shorter duration on their design. Anything from expected power output to intake manifold design or even air intake components.

Go look up Port flow, watch lift numbers as soon as the ports start losing flow increase(ie at .300 lift it flowed 100cfm and .400it flowed 150cfm and .500 it flowed 159cfm) you have reached max flow and going past that drop off is waste of adding valve spring opening pressure etc. Then you have to decide WHERE you want it to make best torque(torque is what an engine makes, HP come from a formula that denotes how much work it does. Basically torque gets you off the line and gets you moving HP is representative how fast you will go at higher speeds. If your in a truck, you want a fat,flat torque spec and matching converter and gear to make use of the torque up to say 5500(HP and torque numbers meat at 5250). Now if you want a hard charging screamer car, you need MORE duration/overlap, more rpm capable parts and gears/converter and yes better heads. I put a 355 Chevy together used some old 991 heads that factory came with 1.74 intakes, I opened them up to 1.94 , throated (bowl work under valve) raised my port guide by 5/32" (ie spot faced guide boss so stuck out less) paired it with very small in numbers cam it was one designed by Lingenfelter for use with very old Accel SuperRam fuel injection kit that was so Old it had MS Dos software to tune it so it couldn't use a sloppy cam. That engine was a torque BEAST. AND I used TCI Saturday Nite Special converter and 3.42 gears in my Monza. It was like .456-. 465 lift 256-265 duration advertised and like 112 love sep. Tiny cam, more like split lift,split duration 325 HP 327 cam but in that combo I'm betting it made every bit of 450lb ft of torque. I even used Edelbrock Scorpion single plane air gap intake and 600 Carter carb(it really did love the 780 Holley I later installed. Still. GT 40 heads have a sweet spot in flow, use a truck intake and they can scream on street

Hi Brian, we would need some additional information from you. Can you give us a call? 1-800-230-3030

The Notes here: www.summitracing.com/newsandevents/calcsandtools/summit-cam-timing-calculator say: 1.) For accuracy in comparisons, always use figures measured @ .050 in. lift. 2.) If opening the intake Atdc or closing the exhaust Btdc, enter as a negative (-) number.

The old 10 to 1 l48 350 engine comes to mind. Try taking out the stock cam and putting in a comp xe250h or 252h. Usually results in a ping king, that you gotta recurve ignition advance, or run higher octane. Yet the .050 intake valve closing is very similiar...

i had to check...it should read 113.75* LSA and 2.25* advance.

Yea I had to Google summit cam calculator because I couldn't find it on mobile. I found it pretty useless myself. Would be a lot more useful if it would let you use different lobe profiles because not all lobe centerlines are dead center of the open and close.

We would recommend the TFS-K306-485-460 and it is $3,523.79. www.summitracing.com/parts/tfs-k306-485-460/make/chevrolet

You will have a hard time getting gains with stock LS1 intake, and smaller injectors.

depends on lobe ramp rate, a sloppy cam will lope with less duration, a modern tight efficient lobe with fast ramp rate will take longer duration to 'lope' since the cost of efficiency and more power everywhere is less lope versus duration. What engine do you have Morris, and any other details you can provide , what car, engine, compression,? etcetera then ican recommend you a cam that shall give you exactly what you want.

@@7REDDRACO7 I got a 225 MoPar /6.

A cam with 263-280 duration @ 0.050 would be a full race cam and have extremely lopey idle. A cam with 263-280 advertised duration would be a step above stock, or very mild. Barely audible, if at all.

@@7REDDRACO7 BAhahahahahaha....you have no frickin clue what you're talking about!!

Lower lift...wider LSA

Yes he is using the @.050" duration numbers. In his explanation of understanding cam lingo he failed to explain the Advertised vs @.050 durarion numbers. Funny, how the confusion between Advertised vs @.050 duration #'s has been going on since the 1970's.., some things will never change

Thanks

beans or soup

You could use the kb/ uem calculator @.050 +15° method I hear that 8.75 on that calculator is close to 8.25 using seat duration. That's like 170 psig /185 psia

@Joe Figueroa Smart guy. 💪

@Joe Figueroa Still a decent explanation brother.

@Joe Figueroa And to me that's okay because it creates job security and if someone wants to know more, they can ask questions. That's what I do. I'm quite sure I'm more informed than the average guy and I'm always happy to help others. But I totally get what you're saying. What I consider common knowledge is way over most people's heads but again, that's fine by me.

@Joe Figueroa I live with the philosophy of "live in collaboration not competition".

The LS7 cam will work fine in the 4.8 and will have a noticeable idle. Just remember to check your piston to valve clearance. I recommend upgrading your factory valve springs and the trunions in the rocker arm. We offer a kit that will take care of that for you and that part number is SME-K-14300: www.summitracing.com/parts/sme-k-14300/overview/

Hi!

them to hit our target valve events. Your timing chain could probably be returned, but if you have a Sloppy stage 2 - you could possibly tune the events a little bit depending on displacement, gear, converter, etc. The original sprockets are probably in good condition and I would recommend just replacing the chain with www.summitracing.com/parts/sme-143012

He's just making a basic comparison of valve events at 0.050" showing how that effects lobe seperation, overlap and advance, he already stated how each affects the motor, now why would he want to get into advertised duration numbers ?? Im curious what this mistake is ?

@@aldo6192 Sadly china makes the rules in EU and many states of the USA!