VALVE SHROUDING *explained* PRO’S and CON’S of installing BIG valves PREDATOR 212 gx200 gx390
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- Опубликовано: 26 авг 2024
- MUST WATCH !!! HOW VALVE size can HELP or HURT your FLOW , does BIGGER valves mean more POWER PRODUCTION ??? , how to CALCULATE the DIFFERENCE between big valves and SHROUDING LOSSES and the increase of SPRING RATE needed to move a bigger valve
Wow! This was the best explanation of valve shrouding I have ever seen!
Great video bro!!!! Knowledge is power and we all want more power lol.
So true! Great video !
I had to learn all this ,when my son blew his yz 450 head there’s 5 valves in that head so alotta work to rebuild it ! Let’s just say I had a headache and gray hair by the time I learned how to rebuild high compression/performance racing head !
Still wanna build a banshee before I die! Lol
That was some damn good Advertisement!! I think I'm going to have to do business with you one day soon.
Haha .. thanks and he’ll yea brother I’m here if needed 💪
That's Beautiful ❤️
Thanks man .. it’s appreciated .. I’m my own worst critic and I think my early work looks so bad lol. But check out some stuff from the last 2-3 years … it’s really beautiful when I found my inner Michelangelo and started doing art work on these heads
Also velocity & atomization suspension , Great video 💗
Hey Paul, i noticed the valves had a pronounced tulip on the combustion chamber side. How about using valves with a flat side on the combustion chamber side? That would raise the compression ratio a bit and then you could un shroud around them a bit and keep your target compression ratio?.
Yes it would , those valves are the common SI valves there mass produced that way and sold everywhere including on my site. I do make custom valves (flat faced) with options for multiple angle back cuts etc .. also have titanium valves (also flat faced) those come with back cuts the way we sell them and are the very best valves we offer. If you need valves check out my website Paulskarts.com
Bro...which fuel do you run on??
Great, whats the flow numbers
Don’t remember on this one was years ago.
good video great knowledge
Great vid 👍👍
If I want more power (top end) out of my tillotson 225 what valve head should I get? I been getting mixed answers.
Top end requires more cfm. Usually going to a bigger valve like the 32mm with proper porting will give you better top end. Just with proper clearance around the valve. We radius cut to unshrouding the chamber… this is a very old video. Lol … check out our website to see how the chamber will look .. link below
Paulskarts.com
18:1 is diesel compression jesus
That's what I was thinking until he said spark plug, I'm like, wait, what?
I really want to know how this thing ran. This head was all around a bad idea
I’ve seen this head on eBay did the guy back out?
I sell heads on e bay .. I doubt it was this exact head you saw .. the ones I sell now are not free hand cut chambers but done on a mill with a radius cutter .. I sell lots of variations on e bay .. check em out ..
hey Paul can you recommend a book about that?
I think the next video after that where there are 3 heads in the pic I go thru a few books I suggest . Try watching that video ... and make sure your liking all my videos if there helpful ... I need the help !! Thanks bro
ruclips.net/video/h6061enpuu8/видео.html
Engine math .. it’s a great book
How much Cfm is that head producing the way it is ?
No clue .. if the customer wants it flow tested it costs 85$ and I’ll take it and get it flow tested .. my guess is low 50s
If the proper clearances where made to unshroud ,and the intake valves seat was installed it could probably do 75cfm as is
Enlarging the intake port would further increase the flow ..
That my current beef with the customer .. for him to keep his goal compression ratio and not put a larger piston to increase the compression ratio that way .. the chamber needs to be 10cc .. for it to be this small with that size intake valve the shrouding will real havoc on the flow of the valve ... remember at high rpm cylinder filling or the lack of is the limiting factor in horse power production .. so limiting the downward flow of air by the valve being basically a wall in the way of air flow is huge kick in the nuts to power !!!
ahhhm...ahhhh....ahhhmmm...ahhhh...ahhmmm...did u watch ur vid and count how many times u say ahhhhmmm... ahhhh... ahhhhm??? apparently not. ahhhhmmm.... ahhhhh... ahhhhmmmm
If your customer goes with a 3in bore you will probably have enough space for properly unshroud those valves. But I honestly dont see that a high compression 3 in bore small block will be good for anything but drag racing in a mini bike. He should follow your advise in 1st place.
It’s geting a welded block , only oversizing piston enough to straighten bore after welding .. the welding worps the sleeve ...not 3” piston going in .. prob .010” over ...and a compression ratio of 18:1 has no chance of working ..it’s a horrible design engine for any style engine ... also if it was a drag mini bike engine it has way to much compression .. see if you can find out what the optimum compression ratio would be ??? Nothing needs 18:1 ... nothing !!
@@paulskartslifan4206 Ive seen some crazy small chambers with 3in bores for drag racing but the real challenge will be to seal the compression, thats why Drag Mini Bike ( Charles) use grooved heads that doesnt need head gaskets and John fear use 8 bolt custom made heads instead of 4 bolts. They go by the idea that "compression is the holy grail".
How do you feel ? Is compression the holy grail ?
Also sealing it up is just one thing ... there are so many better ways of making power ... high compression is detramantal to rpm .. and no rpm , no horse power ... if compression ratio is to high it takes to much power to compress .. this eventually becomes a force the engine needs to contend with .. why do you want to make a serious opposing force that’s working against your power potential ... I can’t say anything about John fear , never heard of him .. but mini d bike has actually been at competitions that I won ..I create power based on better design characteristics .. focusing on a single cycle of the engine like the compression cycle only gives a limit to your work ... I didn’t get to be the current record holder by just making compression.. any monkey with a half a brain can get compression .. I hope your learning this stuff here .. I hope these videos are opening your eyes ... this is the way of the future ... imagine the things I don’t tell !!!
Also I am just assembling this engine ... I’m just doing what I was asked to do !! There are tons of what ifs , and if I could have’s .. all over this build .. so he’s your right .. there are a lot of ways to improve on this !!! For sure man !!
Hi sir if engine built at higher compression etc 15:1 engine become knocking when high rpm what is the better way to slove engine knocking ?
I’d check piston to head clearance or valve clearance.. is it a billet piston .. sometimes they knock before reaching operating temp , they swell to size
Do you have a you tube page ? Make a video of the sound ... I am here to help you .. I’ll do my best !
Something is wrong there ... obviously lol... it’s hard to diagnose from here ....
Also lower the compression ratio just a bit ... that will help overall power production at higher rpm’s ... plus really check piston to head clearance ... what is the dimention at ? Give me a rundown of the build....
What fuel are you running? At 15:1 compression 93 octane gas is not enough. Racing fuel or ethanol id recomended for high compression engines
That porosity in the head isn’t going to cause problems??
Yea , it looks bad .. that’s about it .. porosity is almost always in fast aluminum welding .. but This Head was made a year ago and a few months ago I got a $4000 welder just for welding shit cast .. still has some porosity ( it’s very rare to weld one without it ) but it’s a lot better .. cast aluminum sucks .. also Tig welding needs to be suuuuuuper clean .. any even water will cause porosity .. a little oil and it’s like welding on black styrofoam
Paul's karts Lifan 420 yeah I’ve always heard that there’s too much sylica trapped in the metal to get a clean weld
How much would a ported and polished big valve head be that has basically stock compression, I’ve got a build in mind but I’m not sure what I want the cr to be because it’s going to be a build geared towards longevity
Text me
Man my head have come a long way since this video .. the newest head videos are crazy nice .. much less porosity now that I’m looking back and the milled out radius bowls I do now are a long way from the free hand stuff I used to do ... what a trip ... HA !
Paul's karts Lifan 420 is the number in the video your cell number?
Bottom line, tell your builder your goals, and let him design your powerplant.
As the bigger valve drag our weight
Every setup has its own set of obstacles. If you can run a big valve correctly they are a advantage. Really anything done correctly is an advantage.
No it doesn't work like that. A 32mm valve even shrouded will still outflow the smaller valve even at low lift. The SEAT I.D. is why it flows more. And yes even shrouded, test it then report back.
I feel as though you are wrong ... and I don’t appreciate you coming on my page and bluntly stating I’m wrong !! As if to satisfy some Alfa male complex .. but please explain how a SHROUDED valve can flow MORE than an unshrouded valve , the SEAT at this point is not the restriction and that’s the point Im making here .I’m talking about valve shrouding .. i would have thought that you would have known this ...it’s this kind of mis informed thinking I’m trying to help with here ..that’s like saying if you close the window in your car it will still flow the same amount...that’s just wrong ..there is a minimum amount of space of .200” that it takes to successfully pass air around the valve .. I spent a lot of my personal time and resources in development of a better cylinder head .. it was my RESEARCH that got me Here ... I can state this as a FACT .. this valve will definitely flow “LESS” shrouded ... that’s where the term “ SHROUDED “ came from .... unless the term shrouded means nothing and is just a made up term. But it’s not, it’s a widely used and well known term in the industry ... but I’m open to hear how you think the statement you made is correct ... please let me know
Barry Young just did this test on a stock size engine with zero porting on the Dyno. The engine was a stock class engine, so hardly any mods are allowed. I will send a link to it. It's in the PoBoys group.
A stock head is not shrouded .. it’s just an inverted bowl .. in this situation the bigger valve seat will surely perform better .. i even went into that in the video ....I’m talking about welded heads that have to little space between the chamber wall and the valve .. it’s like standing in a 3’ tube and opening a 3’ umbrella ... no air will pass ...
You not listening at all, try and understand. Read this twice, this is a whole stock class engine on the Dyno. Making only 12+hp and then he installed a 32mm intake valve only no porting, no bowl work. Meaning he left that huge step from where the old seat was at. He flow tested it stock, then with the bigger valve, then Dyno tested it. The 32mm valve is right next to the chamber wall, shrouded. The results are posted.
Ok I read it twice .. and it seems like your running in circles away from the original statement you made of how a shrouded valve will still flow Like an in shrouded valve .. the start your telling now does not depict the situation we where talking about .. I know for a fact your a long term builder and I have subscribed to you a long long time ago and I respect you a lot ... BUT lol .. I do believe you tried to flex a little muscle here and got busted lol ...the fact is ,a shrouded valve in the areas where the valve is closer to the wall than .200” will flow less ! Do we agree on this ?