CAM SELECTION ,HOWTO CHOSE/ BUILD YOUR EXACT CAM -best cam gx390 gx200 ,preditor 420,212
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- Опубликовано: 11 окт 2024
- how to translate the measurement of your intake valve width for "lift" ,also how to calculate your "duration" based on rpm and compression ratio & a (calculation with chart to chose your ("LSA"))
The amount of knowledge in this man's head he shares for the love of the topic is humbling. Thank you.
This man is a legend. He's answering all of the questions I have had about building 212cc clones. He has proven that bigger isn't always bigger and there really is a science behind making power on these motors.
💕❤️❤️💕❤️💕❤️💕 I love a comment from someone that can take info from these videos and put it to use. ✊
Thank you for sharing the key components of compression, duration, lift, and lobe separation angle for proper cam choice. The graphs and formulas are very helpful! I also appreciate what you shared about spring pressure for a cast cam as well as drilling a hole in a stamped rocker. Those are two valuable things a budget conscious builder like myself can take to the bank. Thanks Paul for such an informative video.
Glad it was helpful!
I'm a new player to this game and I must say that this is the most informative video I've ever seen on this topic. Thank you for sharing.
Your welcome
most informative video i have seen on cams for these small engines. thanks for the solid info!
@@Charliegsand thanks .. lots of info given back in the day. Check out all those videos
This has helped me a lot! Im build my 212 for drag racing and finding the right cam is a pain in the ass! I will take a longer look at cams now to get more power and optimize the power!
Good stuff .. you got a good head ? I know it’s almost done but my Cadillac heads are half off this month
Ryan...go to Isky Cams - tell them to grind your Cam to grind you the V8 Flathead grind 3/4 race 404 grind on 108' LCA & about .250" lift with 1:1 std rocker arms. There's No genius in it...@ 112' degree LCA you'll have a wider power and but will wait forever for the power to kick in & it will sound milder than tighter LCA, I've known the lobe centres to be run down to 100' LCA there's more torque with tighter LCA's 112' is bordering on pedestrian.Theres a few holes in your theories.No offence intended.for example lifting the valve higher than a 1/4 of the diameter will give you more flow.That 1/4" inch is called the flow window & not necessarily lifting the valve higher will do you good, in fact that max flow window is used to decide the max lift required of your new Cam, Some engines loose flow if you fit bigger valves.Theres a few other things that are debatable in practice but I'm watching the Olympics.Goodonya Trev New Zealand
Ryan....would a home built and affordable small engine Flowbench to confirm your porting efforts interest you ? I've had a massive Stroke @ 57 & I'm looking for ways to make some small pocket money - I've lost 250K so far from a repeated empty home break-in.I would be a copy of one I built in my early teens & throws a few theories out the window: you could learn as you port etc.Cheers Trev New Zealand home of World's fastest old Indian.
Here’s a quick number to remember when converting mm to inch. 25.4.
If you divide your millimeter number by 25.4 you will get a fairly accurate inch corresponding number. If you need a precise conversion then multiply your millimeters by .03937= inch.
E.g.
.Quick method
36mm divided by 25.4 = 1.417
.Precise method
36mm x .03937=1.417
The precise method is usually best when it’s super critical for that third decimal to be close as possible. But just remember 25.4. It’s easy
Why does this guy only have 5K subs?! Thank you so much! This was the video I needed
🤣🤣🤣🥷💯🚀
Kyle... RUclips algorithms.Cheers T
@@trevinskiking2165 🥷🥷🥷🤫🤫🤫
@@trevinskiking2165 we like small groups, people that are actually seeking knowledge can find this easy 🤗
@@paulskartslifan4206 Autocratic sensorship hint ? Want can you find easil,y on the net, sorry , you've lost me.Thanks T
Definitely gonna share you answered questions for my future builds thank you
Wow! I'm thinking that engine will be able to go to the moon when you get done !
This guy will tell you that he does it all when in fact the machine shop does all the work.
You'll never see this guy working or welding he is all talk and is only selling on ebay . I have no problem with him selling and I wish his great wealth.
I do have a problem with him telling people how he does all the work , porting heads welding, and putting in bigger valves. If you listen to his video he does it all.
HE'S A GREAT READER AND REMEMBERS WHAT THE EXPERTS TELL HIM.
Calling on all people for that info ....this is a section for us to share facts and findings ...if you have info on a big block that I have not yet gone over ...POST IT HERE !!!! I will read , research and reply to ALL comments !!!! Thanks for watching ...hope you like the content ! Paul , from Paul's karts
Paul's karts Lifan 420 you need to talk to Tim Isky at small engine cams. You guys both know camshafts
Lol...I like how you think ...I tried , I have his cell number ..it's his small engine line phone number ..I left voice mails and texts to no response ..I got a number to a guy from a old timer in the game ...if you know who I'm talking about ..wink wink ..he gave me a mans name that has recently been grinding cams in his garage..no one knows him so I like i like that ..I am calling him tomorrow to see what we can put together !!! Sooooooo yea ...if we get something made that works I'll def post all the info HERE on you tube....for all to see ...no secrets here !!! Facts for all !!!
@@paulskartslifan4206
What happened?
What do you mean ?
@@paulskartslifan4206 Hi..Probably other people posting info etc...? Trev NZ
Great video paul . My supercharged 4.0l v6 mustang has 116.5 lsa and 234°dur @.050" and .500" lift and only 2° of overlap.. 18 psi boost and pulls to 6800 rpm and makes 450rwhp about 570 at the crank. Wide lsa makes more topend and shortens overlap. 106 lsa is more torque and overlap. I like your vids. You look like you are sweating to death or nervice lol. As far as exhaust size goes i would start at the same size as your exhaust port which should be about the same size as your exhaust valve and step it up twice to 1.5 id and then 1.75 id if you have the room for the length even go to 2" id! I like the first stage of the header pipe to be slightly bigger than the exhaust port so the head acts like a dam to prevent reversion when the piston goes back down the hole. A wide lsa with little overlap helps with reversion also. I been drag racing 40 years and have friends who does heads and builds motors for racers. He taught me a few things. He is 83 now. Im 58 and still playing! Keep up the good work.
Trying to figure my 223 wild at got 10.8
Not on chart
Hi all very nice video
the better running of the engine where I think that changing the lob distance is mainly due to the displacement of the moment that the inlet valve closes so with a smaller lob distance the inlet valve closes later try an adjustable cams shaft sprocket and you will notice the difference
generally it has to do with closing the inlet valve sooner or later
it has the biggest influence on the performance of the engine
greetings Bert
Good video! Wish I saw it before ordering the predator 212 cam 😐 but luckily they're cheap! Thanks for the info Paul!
Yeaaaa buddy !!!
It might still be ok if it's not super wild.Cheers,Trev NZ
Thank you so much. Pure genius!!!
Bam what !
@@paulskartslifan4206 ... Right, I wish I could read like this guy , wow! He is a reading genius !
i was just looking at your heads online and cant wait to get my hands on it
👊😎
Expansion chamber is a must smooths out the pressure wave . Double the volume for half the length of the exhaust. I use a portion of a 2 stroke system. Put your hand in front of the opening at two feet and it thumps you hand
Yea , all the top engine manufacturers figured this out long ago. Most Cars, trucks, motorcycles and off road vehicles use these, it’s just math and science ! Gotta love it !
With those calculations a predator 212 with one of your heads having a 32mm intake valve would come out to a value of 10.34 which estimating on your chart would be over 114 degree lsa. Probably in the neighborhood of 117 degrees
John...it's not an injected LS small block Chevy.Cheers Trev NZ
So for the new guy to the channel. This is 5 years old. Have we found a manufacturer to grind these cams and how do we reach them? Looking to build a engine with the torque on the low end of the rpm range.
@@NWTejas I have cams made and ready to ship on the website Paulskarts.com
Paul you are da man loved cam selection video
BOOM thanks
Really awesome video, thanks a lot! Is there a way to apply the formulas for 4 valve engines? Especially the LSA formula would be interesting.
A good 450 pro mx or kart motor easily makes over 60 hp on race gas. 4 lightweight valves, overhead cams , liquid cooling all make a difference
wow lots of good info thanks for sharing
Awesome videos great explanation and detail 👌
This info is awesome. Thanks for putting it out
Thank you for all the info. How would a person get started in building small engines
Go too night school shop classes or the at home mail order classes your see in the the back of magazines like popular mechanics or the like.Goodluck Trev NZ
Or buy a cheap $99 harbour freight Predator 212cc Engine on Special for a new one you can add perf parts too later or Sqroung around for an old L head Flathead B & S or Techumseh engine,you can usually pick one up for about $10 or less & basically foolproof, but get one that is running or near running.Try your local small engine shop man,he might have an old spare he'll give you if you ask him nicely & tell him what you're doing.Goodluck.Trev NZ
@@trevinskiking2165 thanks for the advice man
@@ranger6779 No worries 😎
At one time you could take a home based course & It was based around then current L head or Flathead engines Briggs etc ..I think they were called ICE or Something Similar....another reader might remember more if they are USA based (I'm away from my library) It'll teach you old hot rodding technics like " porting & relieving " ,milling the head & other things & if you stuff up you haven't got a lot of money invested & find a helpful small engines man or woman who's happy to show you the way to putting it right..could also pickup some 1960's & 70's karting,Minibike & small engine books.Buy a W/shop manual for the engine you end up with.T
There is a jump starter at harbor freight there cheap like 80 bucks and it's small u could take it with ur electric start go kart lol
I'm building a gx390 I have a completely stock motor and want to know the first things I should do for power I'm used to the usual cam carb and head but idk if I'll blow this thing up haha
Saw some guy here at youtube trying to use gx390 stock cam into gx270 probably stock head. What do you think about that ? I feel a little shame to ask dumb ass question like this because what you do and showing us is realy good professional high level stuff. Thank you for that all.
Think the cams are the same fit ? Not to sure ,I have done a few but don’t do to many 270’s .. so I think knit might fit but why he was using a stock cam I don’t know .. you would have to check the stock cam specs between the two
@@paulskartslifan4206 As lobe separation or duration I dont know but whats noticable was the lift. Cams looks same but 390 had bigger lift. Thank you for the answer.
Glad to be of assistance
got a question for u my brother....i got 1990 k5 blazer 5.7 just got the enging rebuild still have the swirl port heads on it and its pretty mush stock i have high perfomace intake im eliminating the computing trying to make my mine up if im going to go with a carb or some efi sniper..i have 700r4 trans and 4.10 gears and up graded my torque convert to a 2000 to 2400 stall ..it has a up grade cam in it howard cams ratter 188005-09 lift .525/530 and duration .050 ; 227/235 centerline 103 i want to no is that a good cam to go with them swirl port heads and would i be able to hear the cam..i dont no to mush about cams..i no the vortec or aluminum heads would have been better but the engine was already build already..i do have headers 3 inche pipes all the way back
The Cams that you sell on your website are they gauranteed to fit in a 196cc engine no matter what the set up is ? Or will i need to do clearancing for sure ? I understand you don't wanna drop the specs for competition reasons but at the same time i wanna know that it will slide right into place with a max stroke crank and billet lifters no problem and have strong pull from 0 - 50 mph or higher.
They need to be clearanced , same as any actual performance cam. Easy stuff to do as far as jobs go
Great video . Thanks for sharing
This helps build peak cylinder pressure :-D
What does ?...
This sounds like some classified shit.
hi paul i calculate my engine is 165cc =10.1 cubic inch valve is 28mm=1.1 inch so i calculate is 10.1/1.1=9.18 is nearly 10 so my LSA IS 117?
Hey Paul. Do you anyone if makes longer valves for a tecumseh ohh60 engine? I have a stock cam with some homemade 1.3 rocker arms and some 12hp lawnmower valve springs that I shortened. I plan to run alot more cam in the future but I'm gonna need some longer valves. If you know any website let me no. Thanks
I know where you can get custom valves made .. yes .. but the price for custom valves is high .. over $100 .. what size is the stem .. and what’s the length you need .. that might help more than the application ...
@@paulskartslifan4206 not sure the dimensions yet. I just wanted to know for future reference
What cam would you guys suggest for a tillotson 212r with a flat top piston, jt-207 head with 27in 25 ex, 9.1 compression, billet rod, Real PE24mm carb. Want power to pull from 25 2700rpm to what ever 26lb valve springs can handle. Cm super x grind cam sound like a good choice or bad?
The PKRPM3 for that setup will be best
Paulskarts.com
@@paulskartslifan4206 Thanks for the reply really appreciate it. Not looking for crazy motor, but should do alright. The stuff you build man incredible. You should have gone to that HP battle you would have cleaned house.
How do you determine where the exhaust centerline should be when you sing this method
This video helps with cam selection .. it does not go over cam centerline ..it’s talking about LSA or lobe separation angle ..which is difrent ... I think Jody from arc has a video on cam centerline
ehhh im pretty close so ill just keep the cam i got, 330 246 110 cam with 1.3 roller rockers for a 401cc 11.7:1 big block
If you like the videos send me the likes .. but that button on every one .. tha is for watching and let me know if you need a built head .. I’m out here !!! Till next time , keep speeding !! Lol
Now make a chart for 212
Awsesome
Have you dyno tested the two cams yet? what where your findings?
I went with a 112 lsa and worked for what I was doing on the dyno .. now that I’m putting it on the mini bike I switched cams .. a lower lsa for that
What is the big block?
What is a good Cam for these GX390 to 460 Engines for making Max hp around 5000-5500rpm?
If you want power send me your head for work .. I will consult you on a cam based on head work and engine size
Watch videos in my playlist “ how to optimize your engine”
@@paulskartslifan4206 do you have an email address I can contact you at?
Text me ..781-492-7358
maybe the flannel shirt wasn't the correct choice for that day
Yea I had a cold and was sweating it out ..lol
@@paulskartslifan4206 very good videos. I'm guessing your from the east coast?
106...108 rough idle
I use my valve cover as a catch can. I vent it with a line that has a oneway valve (venting out)
Valves get oiled
😎🤙
No info what you cost
Exactly. The phrase “no news is good news” definitely does not apply to engine building 🤙
But what if it has multiple valves like 4 or 5 for some Yamaha's?
Can you rephrase the question ? But what if , what ?
What if instead of 1 intake/exhaust valves it has 2 or 3 like some dirtbike engine. Then how does the calculation work?
Multi valve heads are difrent, if you have a multi valve head the cfm flow numbers need will be higher .. in that case velocity within the ports is extremely important .. kinda a rule of thumb is bigger is better .. especially in multi heads,, the ports feeding the valves are smaller and will be if it from bigger valves and proper sized ports ..
hi sir i want to ask if the duration correlate with compression then valve lift correlate with vavle size or any else that relate?
I don’t understand the question.. please re fraze
Paul's karts Lifan 420 sir i mean how to choose camshaft lift if my valve is 33/28 size and compression ratio about 13.1
I’m posting another video now that might help you
Paul's karts Lifan 420 nice really appreciate that thanks lot sir for helping me 😊 👍👍
What cam did you go with
Do you sell cams if I provide info?
Hope I'm getting my math right...to get .375 lift with 1.5:1 roller rockers, I'd need .250 lift on the cam with 109 degrees of duration right? Love all this info.
If you like them , then like them , HA !
Yes it seems your math is right
I'm sorry boys but there's a lot of equations mathematical and evaluation to get you a miscalculated technicality I have it's what I painted on the side of the tank
It’s true. All it takes is one thing to be off and throws out the balance. Great observation to take from this video. James 💕
Paul do you have a website?
No but I leave my number on the videos
@@paulskartslifan4206 on face book at all ...would love to have a chat (text) about some of the points raised here want to turn a gx270 in to a flying machine ...literally
I would never leave the ground with an engine not built for planes or small air craft. But super cool concept .. love the idea. Be CAREFULL tho
You crazy 😂
Let me tell you something big boy I got the awesomest head in the world 32/28 when it licks it Breeze So well,,, Ps. 23+ is what the dinos been saying damn my Luck I'M being very selfish right now love you all have fun keep good brakes
Bro you must be hot
You talk to me much get to the point man got damn