Help cam advise 292 or 320 = 330ft

Rp236

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Working with 236cc 72 bore 58 stroke 3.465 rod at 0 deck 27/25 SS dul spring mill 60' 27 head gasket going to 43 nicely ported 1.3 roller tips 28 carb issue is I've tried both 292/260 square lobe tip an 320/260 both NR cams seems the 292 is mch harder pulling seat an tach says so but guy told me the 320 would do better that's why I got it so is there anything I'm missing or that could hender the output of cam not performing as I think anyway any advice on this or do I just put 292 back in cause just plain better
I'm fairly new to building for performance of these engines but not to building small engines,
 

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Mercado

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Hi i have the almost the same set up 72x58 14cc head with 32 ans 27 valve 28mm carb cam i have 290lift246 duration with 1.2 ratio rocker i just order a 310 lift and 260 duration for more top end becuase the 290/246 cam was top at 7900rpm becuase it hase 104lsa so the new cam is 260 duration but at 104lsa too see if it holds up to 8500
 

Rp236

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Far as ur rpm limit compression can play a part in it I also have a 212 that would top out at 8200 with a cam close to urs I put 36dual springs an it turns 9270 an power feels better,both cams I trying makes strong power I never topped either cam out I only go as fast as it takes when racing the 320 is super strong from 6500 up at 8200 front wheel is coming up I have to lean forward tach said 8864 an was still pulling hard on last race the 236 is very strong
My compression is 13-3-1 my 212 made better power when I also took the high compression head down to 12-1(unshrouded valves
Are ur valves shrouded this kills flow
But all this is my experiences an works for me final on the cams 292 is stronger for 300 ft but after that the 320 is honestly I'll probably stick with 320 as I loose taking off but last 50/75 ft Its all me but mph doesn't always beat time
 
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Have you guys paid any attention to the valve seat area? It's the most restrictive area in the engine and a tiny improvement in flow at the valve curtain can greatly enhance performance. If your working with just a run-of-the-mill straight 45° valve job it's likely the biggest improvement in efficiency you can gain from. A proper valve job and thoat design aimed towards your goals can produce a very solid bump in hp in your targeted rpm range when done correctly.

When the big timers get the parts they need figured out they turn the focus to the valve seat area. Also, be sure that your exhaust is properly tuned to your rpm range to provide the best scavenging. I take it you guys are mostely focused on mid and high rpm so I would go with a well designed 2 or 3 step header. You have to design it for the cam and rpm range. A certain diameter primary at a certain length to a certain diameter at a certain length type of header also can make a huge difference when dialing in an engine. Just swapping cams isn't the best solution. A smaller cam with proper exhaust might work better for your specific situation. And a bigger cam might feel like it looses power if you keep the exhaust on that works better with a smaller cam. If you have the proper exhaust for the bigger cam then you might see a much better result from the bigger cam.

If you are looking for peak efficiency and performance then you have to realize that all of the components have to harmonize and the valve seat areas are critical. It's a whole engine thing, not just a cam thing. Since the cams have different LCA, lifts, overlap, durations, etc they need different timing and supporting systems that support the characteristics of the cam. A shorter, larger diameter primary tube to a longer, but only slightly larger diameter secondary tube on a header will support one cam while a longer, smaller diameter primary tube to a long, large diameter secondary plus a 3rd stage header might be best for a different cam but if you swap them with the other cams neither would perform as well.

Just something to keep in mind I guess. Maybe you already know this. I'm just trying to help. I read all the time about people swapping parts but rarely do I read that they altered the header, intake runner or valve seat profile to take better advantage of all of the parts they have spent so much money on.
 

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On the valve seat area we isntall aa bigger seat for valve then ported all the edge and conners and on both sides and on the header im using a F&b custom header its a high center header but with the bigblock size
 
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On the valve seat area we isntall aa bigger seat for valve then ported all the edge and conners and on both sides and on the header im using a F&b custom header its a high center header but with the bigblock size
Other than the larger seat needed for the valve you can add angles and work on the throat width, angle and depth to improve flow with not only improved peak numbers but also flow and atomization characteristics to improve overall efficiency.
 
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The ready made headers are usually pretty good for general purposes but there are usually improvements that can be made to tune it better for your specific engine. Also engine timing is very important. If you just swapping cams out without providing suitable changes elsewhere you are not getting the most benefits from the cam change. You might see an improvement but in order to get the most out of your engine you have to be certain that the whole system is optimized to the specific engine events. It's the small supporting changes that make the difference between 2 engines with the same components. If everyone just had to slap the same components together they would all run the same and there wouldn't be anyone who built exceptional engines. It is in those supporting modifications that changes a great engine into an exceptional engine.

Knowing what you want, the understanding of the relationships between the different components and systems of the engine and understanding the compromises are the keys to making the right choices for getting the absolute most out of your engine. If everyone uses general off-the-shelf parts then everyone ends up with general performance. The end goal is always efficiency. The more attention paid to the intricacies of eeking out more efficiency the more you will thand out from the "off-the-shelf" part gatherers. The only thing that the parts do is try to make pumping air in and out more efficient. If you focus on the systems that support and control the characteristics you increase the efficiency. Efficiency=Power.

The parts combinations can be very good but when you are in a competitive situation it's usually better to invest time and money on dialing in supporting systems to match your cam and get your valve seat areas efficient rather than trying to find a cam to fit the exhaust and current air flow. Pick your goals, figure out the exact cam for your needs and then dial in your supporting systems to your cam. Remember that the intake velocity, quality airflow and atomization are the most crucial for efficiency no matter what cam you have. Pay attention to reversion, build in good scavenging of the head and take advantage of overlap... the exhaust is the beginning of the intake cycle and can be very beneficial if you design your exhaust system properly.

The guy kicking everyone's butt at the track incorporates these things but will never tell you about them. If you haven't heard any of these things listed above as being so important then there are 2 possibilities why... either they actually don't matter, or they are crucial and they don't want you to find out about them so they don't have stronger competition.

Parts can only get you so far. Some guys put together easy puzzles, some take the time to put together jigsaw puzzles... But the true stand-out guys are hand sculpting 3-D masterpieces. The challenge is the most efficient engine, not putting together puzzles.

Sorry, I got carried away thinking back to when my dad built competitive engines and was trying to make me realize just what to focus on, teach me the physics involved and how to get the most efficiency possible.
 
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What I'm trying to get at is that simply swapping cams out and leaving everything the same can only gain you so much and may even show a net loss. You could have to improve spark, adjust timing, adjust intake, exhaust, carb settings (ofcorse), valve springs, etc. Plus you have to be ready to make compromises. A cam that is best for high rpm might loose time in a run/lap because you loose bottom or mid range. To compensate you might use a header that has a longer or small diameter primary and with 2 shorter 2nd and 3rd stage to better scavenge the head in the midrange and provide a stronger precharge pull to the intake during overlap. This might result in a tap less pull on the top side but improve the low and mid-range more resulting in overall better E.T. or lap times.

There are so many combinations that just pulling parts from the shelf will only get you so far. Taking the time to experiment with header design can be very beneficial. It's not expensive or difficult if you do it yourself. A proper valve job is often underrated. Much of these things are over-looked because the companies are there to sell you products and can't stock every single combination that works. Focus on the things that can gain you the most efficiency and get that right and then all the other changes are even that much more improved.
 

Rp236

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It's ok yes figur
The ready made headers are usually pretty good for general purposes but there are usually improvements that can be made to tune it better for your specific engine. Also engine timing is very important. If you just swapping cams out without providing suitable changes elsewhere you are not getting the most benefits from the cam change. You might see an improvement but in order to get the most out of your engine you have to be certain that the whole system is optimized to the specific engine events. It's the small supporting changes that make the difference between 2 engines with the same components. If everyone just had to slap the same components together they would all run the same and there wouldn't be anyone who built exceptional engines. It is in those supporting modifications that changes a great engine into an exceptional engine.

Knowing what you want, the understanding of the relationships between the different components and systems of the engine and understanding the compromises are the keys to making the right choices for getting the absolute most out of your engine. If everyone uses general off-the-shelf parts then everyone ends up with general performance. The end goal is always efficiency. The more attention paid to the intricacies of eeking out more efficiency the more you will thand out from the "off-the-shelf" part gatherers. The only thing that the parts do is try to make pumping air in and out more efficient. If you focus on the systems that support and control the characteristics you increase the efficiency. Efficiency=Power.

The parts combinations can be very good but when you are in a competitive situation it's usually better to invest time and money on dialing in supporting systems to match your cam and get your valve seat areas efficient rather than trying to find a cam to fit the exhaust and current air flow. Pick your goals, figure out the exact cam for your needs and then dial in your supporting systems to your cam. Remember that the intake velocity, quality airflow and atomization are the most crucial for efficiency no matter what cam you have. Pay attention to reversion, build in good scavenging of the head and take advantage of overlap... the exhaust is the beginning of the intake cycle and can be very beneficial if you design your exhaust system properly.

The guy kicking everyone's butt at the track incorporates these things but will never tell you about them. If you haven't heard any of these things listed above as being so important then there are 2 possibilities why... either they actually don't matter, or they are crucial and they don't want you to find out about them so they don't have stronger competition.

Parts can only get you so far. Some guys put together easy puzzles, some take the time to put together jigsaw puzzles... But the true stand-out guys are hand sculpting 3-D masterpieces. The challenge is the most efficient engine, not putting together puzzles.

Sorry, I got carried away thinking back to when my dad built competitive engines and was trying to make me realize just what to focus on, teach me the physics involved and how to get the most efficiency possible.
The ready made headers are usually pretty good for general purposes but there are usually improvements that can be made to tune it better for your specific engine. Also engine timing is very important. If you just swapping cams out without providing suitable changes elsewhere you are not getting the most benefits from the cam change. You might see an improvement but in order to get the most out of your engine you have to be certain that the whole system is optimized to the specific engine events. It's the small supporting changes that make the difference between 2 engines with the same components. If everyone just had to slap the same components together they would all run the same and there wouldn't be anyone who built exceptional engines. It is in those supporting modifications that changes a great engine into an exceptional engine.

Knowing what you want, the understanding of the relationships between the different components and systems of the engine and understanding the compromises are the keys to making the right choices for getting the absolute most out of your engine. If everyone uses general off-the-shelf parts then everyone ends up with general performance. The end goal is always efficiency. The more attention paid to the intricacies of eeking out more efficiency the more you will thand out from the "off-the-shelf" part gatherers. The only thing that the parts do is try to make pumping air in and out more efficient. If you focus on the systems that support and control the characteristics you increase the efficiency. Efficiency=Power.

The parts combinations can be very good but when you are in a competitive situation it's usually better to invest time and money on dialing in supporting systems to match your cam and get your valve seat areas efficient rather than trying to find a cam to fit the exhaust and current air flow. Pick your goals, figure out the exact cam for your needs and then dial in your supporting systems to your cam. Remember that the intake velocity, quality airflow and atomization are the most crucial for efficiency no matter what cam you have. Pay attention to reversion, build in good scavenging of the head and take advantage of overlap... the exhaust is the beginning of the intake cycle and can be very beneficial if you design your exhaust system properly.

The guy kicking everyone's butt at the track incorporates these things but will never tell you about them. If you haven't heard any of these things listed above as being so important then there are 2 possibilities why... either they actually don't matter, or they are crucial and they don't want you to find out about them so they don't have stronger competition.

Parts can only get you so far. Some guys put together easy puzzles, some take the time to put together jigsaw puzzles... But the true stand-out guys are hand sculpting 3-D masterpieces. The challenge is the most efficient engine, not putting together puzzles.

Sorry, I got carried away thinking back to when my dad built competitive engines and was trying to make me realize just what to focus on, teach me the physics involved and how to get the most efficiency possible.

Yes it's ok to get carried away if enjoyed lol,
Have no doubt IV thought through every sanario putting this together in my understanding of thsez engines from my performance automotive view which is different but basic 101 an I'm getting how an what tbses things like this is my 4th 236 but using methenol this time ,each one better than last for what I use them for but right not just bolt n go some these little builder tricks to say that some builders have shared if can be applied has greatly improved me,not being in the circuit to say so they don't mind, instead of having to choose from what's offered we came up with a cam grind that's scientific to what I need but till it gets tested will tell,I live 2miles from presicion cam so good not to have to Wait ,all is the same on this build internally wise except the cam an head which is genuine Honda no billit the thing that gets me is the $ one can sink in a head no more than it really is but the cast head porting done by another but assimbled at home component wise is costly itself by testing n selling the others gave me alot of info an which way I needed to go for the one to keep, another thing is do they have a rehab for people messing with these little things an the gambling part as how much can b lost or gained in a few seconds it has become very addictive,
 
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If they don't have a rehab, they should start one! Lol I looked into a few upgrades and thought it was a little ridiculous what the cost was they were asking so I have not ever tried to build one of these up. I have always fitted a better engine from something else like a quad, dirt bike or street bike and ended up with way more HP for WAY less than it would cost to build one of these up.

I'm glad you understand the basics and how to go about making the right decisions. It's hard to tell on a forum if a person is a teen just trying to build a more fun kart or a guy trying to get the last 1/4hp for his competitive kart. Grabbing parts off the shelf is great for non-competitive use and even great for competitive use until you are maxed out with performance from the parts that you are using. You have so many guys that only focus on parts that they don't ever realize that seat work, throat design and proper harmonizing is the key to peak performance. Good job.
 

Rp236

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If they don't have a rehab, they should start one! Lol I looked into a few upgrades and thought it was a little ridiculous what the cost was they were asking so I have not ever tried to build one of these up. I have always fitted a better engine from something else like a quad, dirt bike or street bike and ended up with way more HP for WAY less than it would cost to build one of these up.

I'm glad you understand the basics and how to go about making the right decisions. It's hard to tell on a forum if a person is a teen just trying to build a more fun kart or a guy trying to get the last 1/4hp for his competitive kart. Grabbing parts off the shelf is great for non-competitive use and even great for competitive use until you are maxed out with performance from the parts that you are using. You have so many guys that only focus on parts that they don't ever realize that seat work, throat design and proper harmonizing is the key to peak performance. Good job.
I
If wasn't for me building n selling motorized bicycles at times I'd never had the$ to put in these engines an when I did sell the last 3 it was mostly to cover parts which is ok I enjoy building small engines 2 or 4t when u throw 1500 r so into one for me it's for keeps
Ik what u mean by maxed out with what u have or a dam I could had did this or that instead of but we learn ,we got done yesterday building my brothers 212 it's the 3.707 rod n piston setup basic head wrk except we tryed a biased port work this time 292)260 1.2's 24miku
Feels like gonna run good
We'll see how this plays out between the two of us btw right I'd love to out a 125 2stroke on a kart
Wilmington NC has no kart tracks a homemade little play one but muddy minibikes is all it's good for that's only reason I'm not into it here
Ok enough blab said
 
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