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- เผยแพร่เมื่อ 16 ส.ค. 2024
- This video goes over how to port a small engine cylinder head, step by step, including the tools, methods, areas to grind, and what gains to expect with your newfound flow.↓↓↓Tools Needed:↓↓↓
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On my heads, I tend to remove a lot more material blending the short side radius. I also remove material from the walls of the runner to try and blend and smooth the transition from the bowl to the runner.
Still educating to this day, i used your video as a guide to do my yx160 head and it worked out great! thanks
Simple explanation of a stage one porting well done sir thanks for sharing
"stage" lol. Engine work isn't rated in "stages" except video games and marketing gimmicks.
@@VeritasEtAequitaswell clearly there are stage 1,2,3, and 4 kits for predator 212, are those kits fake?
@@throwawaypt2throwawaypt2-xp8nx Congratulations, you've discovered that people will market things simplistically to consumers. Who ever could have imagined such a thing? No, stages are not a standard anywhere. They're arbitrary. You port for the balance of volume and velocity for your particular application, which depends on where you want to shift the powerband and what type of induction you're using, and its flow characteristics as well
@@VeritasEtAequitas obviously it's arbitrary but it has to be categorized somehow, what about for cars? audis have stage 1 ecu mapping, what u say to that. lol the phone u typed this out on for example the iPhone 13, number 13 is a "marketing ploy" arbitrary number too
@@throwawaypt2throwawaypt2-xp8nx Like I said, marketing. No, it doesn't have to be "classified somehow" lol. Just quit. It was funny, but now it's just disappointing that you're serious.
I appreciate your time. I'm gonna give it a go! Very well explained...best I've seen!
Great video! One the best I’ve seen regarding porting! Very clearly captured and explained! Thank you!
On my riding mower with a 13.5HP Briggs, I opened up where the air comes into the filter and made the path to the head as streamline as I could. Smoothed (just broke) the sharp edges where the ports transition into the bowl on both the intake and exhaust side. Also done a half shaft mod to the throttle and choke shafts in the carb.
On the intake side. The intake itself has a gasket, lip, then the port. The lip made a dark ring and the gasket made a slightly shinny mark on the head. So I opened up the intake port of the head till there was only 1/4th left of the dark colored ring. Going no more than 50% into the port towards the bowl and blended it to the OEM sized port.
I didn't do a whole lot on the exhaust side. The exhaust manifold port was much smaller than the port on the head and I wanted to open the exhaust manifold up till it was slightly bigger than the port on the head. Unfortunately, there wasn't enough metal. But I was able to get the exhaust port and manifold port to the same size.
I originally had a 1.2 ratio rocker on the exhaust and a 1.88 ratio rocker on the intake. Measured and remeasured to confirm the ratios. They are correct. I swap them around.
With all that was done and a spark plug opened up to.042in with the ground strap cut back, I've noticed the following. More power in the mid range to upper RPM's with no ill effect in the low RPM's. Throttle response is also much better now too. It needs a rejet since it runs rich at any RPM above idle. But I'm happy with the gains made with the governor still on. I'd be lying if I said it didn't feel like I got 3 or 4HP gain.
It's been my experimental engine. I've tried out several combination's so far and this has been my favorite one so far. Now I'm wondering how would it respond with a slight increase of lift on both the exhaust and intake valve and add a little more duration to the intake and a small bit to the exhaust side. Keeping the valves opening and closing events as OEM.
Plan to swap the 1.2 ratio rocker for a 1.5 when I find one.
There's a reason your exhaust manifold is smaller than the exhaust port on the head...there's a reason for every design detail on your engine. Porting is a massive waste of time and a big risk on a tiny 4 stroke engine.
@@A_Stereotypical_Heretic You just stay away from them then. Folks have been porting small 4 stroke (L and OHV) engines for YEARS and winning races with such engines and proven time and time again that it works.
And having an exhaust manifold smaller than the exhaust ports of the head is NEVER a good thing on ANY 4 strokes no matter how small or large the engine is.
It causes turbulence and makes for a non smooth path for the exhaust gases to freely exit causing improper cylinder clearing.
You actually want the manifold primary pipe the be about .150 thousandths larger than the exhaust ports of the head.
This will give the exhaust gases a smoother path to exit quicker clearing the cylinder more effectively plus the lip created helps reduce some of the reversion that happen to give the engine cleaner fresh charges in the cylinder.
@@jamesstoy8967 actually no, no one has ever won a race due to porting. Matter of fact they almost always cast with the port sizes they require for what they're looking for. The so called gains from doing this are so negligible that the risk of ruining your engine far outweighs the tiny fraction of performance increase you MAY see...but likely won't.
@@A_Stereotypical_Heretic believe what you will. You wouldn't see the truth for nothing.
Good stuff.
You did a nice port job, that looked really good.
Yes, be very careful to not knick the seats or you will need to get them cut again at a machine shop.
Sometimes if I feel nervous about that happening , I’ll put some thin strips of tape over them.
It can be fussy to apply though.
It doesn’t add a lot of protection from causing a knick, but it makes you aware of them.
If you’ve got your head off for work, clean up that casting flash in the ports.
it’s not much more work.
Yeah I really like the smaller flexible attachment on my dremel so I can even rest my fingers on the seat while working on the portwork. Once you knock the seat it could be game over for the head!
KartFab
Yup steady is the game. I got a dremel with the “speedo cable” and it’s so handy for this work.
I usually hang it from the ceiling over the bench so it’s easier to manage.
Set up a comfortable work area and go to town.
Hey i know it’s usually kids and inexperienced folks attempting this, with limited money but if you can try to round up a junk broken head.
practice on that and knick all the seats you want until practice makes perfect 👌🏻
what a simple and exactly accurate what and why porting the head.
Great video. Thank you for explaining it properly for use .
The only thing i might add is port matching the intake manifold /head connection and head / exhaust pipe connection.
this is the best video about the subject on YT. THanks
Great video! Awesome fundamentals
On thing you can do to increase power is to port and polish your oil return galleries as well as pressure galleries because those casting imperfections will decrease the oil flow with ultimately translates to power loss.
Ehh nope. Not on these small engines. Galleries eh? 👀
KartFab oil return ports on the cylinder head
I see no benefit to that. What we are talking about is a simple splash lubricated small engine. These engines have two holes in the head that communicate with the short-block. The hole between the lifters and the hole on the intake side. These holes allow oil to splash up into the head and drain from the head, as well as allow air (blowby) to pass into the valvespace, and ultimately through the valve cover vent. The only thing that matters here in the engine oil wise, is that you have enough of it in the engine. There is no power loss or gain to be found by what you are stating. In some higher HP applications, you can see an RPM increase by tapping the crankcase cover or block and routing some hose to the valve cover, allowing more airflow (from blowby and the movement of the rotating assembly) between the short-block and the valve-cover.
If you wanted to speed up oil flow around the top end, you could use a thinner (lower viscosity) oil which would have less trouble making its way around the engine. It'd also reduce drag on internal moving parts (ie, the bits that have to push through oil to do their job) which = more gains.
I don't recommend doing either on a small engine like this lol
Another awesome vid. Thanks!
No problem. Glad to help!
You need to do a better job on the intake's short turn radius.
I have a Cam in my mini bike now with 265 lift and 236 duration. It's an aggressive cam and i just paid like $125 bucks on Ebay for a Ported head that comes with the valve assembly and 22 lb springs and it's supposed to go very well with an aggressive cam that has 265 lift or more. I also ordered a bored out carb to go with them as well. I'm really hoping when i get all this put in my bike i notice a nice difference in power and performance but we shall see. It's only a 196cc engine so i dunno how much more power it can possibly produce but should be somewhat better. I've done all the usual mods to it already and as of now it goes around 45 mph. I'm hoping that after the stuff i ordered is installed it will go over 50 atleast. 🤞🚲
You can easily triple your horsepower with cam head and carb
How was your 196 build? I’m currently building a 196
@@litnlarry apparently not what he was hoping...
thank you, informative !
You're welcome!
You look high lol, nice video
IM HIGH ON LIFE MAYUNNN!!!!
Totally baked
can you reuse the head gasket if the engine has never been ran before and no heat has ever been built up?
if it is a steel ring style gasket, you can probably reuse. It is best practice to use a new one as you torque the head down the gasket will have a certain amount of "crush" to it when it forms to the head.
@@KartFab okay thank you
You can reuse any gasket if does not stick and tear, all you do when torquing is remove crush height and I did go to mechanicing school.
Do I have to get a larger carburetor and less restrictive exhaust to get perf. gains?
You get gains with different combinations. Carburetor is very restrictive, so you will see good gains with that.
What are the name of tools that u are use in porting?
1/8 inch shank carbide burr bits.
I got a few lawn mowers, ready to do some port work on them and see how it goes...
Did some port work to my weed wacker, things rips
@@ford200555 ?-? But two strokes don't have valves.
@@austindeems5406 mine does
@@austindeems5406 hahaahahahahaha
wrong
Thanks for another informative video,still waiting for parts on my baja heat so i can put together a torque converter/jackshaft set up, did you have any trouble with the back wheel moving with the tensioner, mine was stripped on the brake side... I had it all tight so i thought, i will get new one if they will hold up ok
You need to torque the rear axle to spec. Chinese bikes are of questionable quality but it shouldn’t strip if you had it all torqued properly.
Thanks
That area your porting would be the mca. It should be at least .85 of the throat😎
Polishing the exhaust is a good idea, but polishing your intake is not, keep it rough.
Yup, nice and rough to induce swirling, and reduce the chances of fuel vapour condensing back into liquid fuel on the smooth surfaces. Glad someone put it, I came down to the comment section to say the same :P (even though both of us are ignoring the fact that this is porting, not port polishing.
Another place I found needed serious work on one of my engines was the inlet 'manifold' where it met the intake and the carb - it was massively misaligned and needed a fair amount of material taking away.
Don't smooth it but don't keep it really rough. Leave it medium
@@brianciszewski6417 So when porting only smoothen the sharp edges and that's it? Or does it need to be roughend after with sandpaper?
@@JustKevinnn just don't polish it. After your last sandpaper weight let it be.
@@A_Stereotypical_Heretic your message came a bit to late, i did port it, and didn't polish it, the engine worked perfectly is was very fast sonit definitely worked, but after half a year it got tired, so now i have a yx160
I read that grinding the intake side reduces low end torque
Nah, grinding it WRONG will do that.
Do u need to upgrade your valve springs wene you port and /or polish ?
No. Unless you are putting a bigger camshaft with higher lift or duration.
Very helpful, me thanks you
Good day kart fab where can I buy racing heads for 18hp block, thank you.
You’ll have to be more specific
wait has anyone done this to a 142f for a bike
Great
I think I asked you already but can you do CG 250 engine
ya i had a cg150 i ported it the 30mm carb and an exaust ran a lot better. but the cam is small but i did find a upgrade cam a while back on ebay
@@redneckasmr-xd1gg what is your port diameter in intake and exhaust?
its wonderful. i port every small motor i get for even miniscule gains from the losses cuz of high altitude/less O2 in the air= less power. 3.5% loss of power for each 1000' in elevation? 1% loss in power for each 10*F over 60*F so i am already behind at 3000'... 13%? runs RICH with stock jet= BLACK spark plugs from soot of too much gas. they make BIGGER jets, generally NOT smaller jets for high altitudes/less O2
Insert a copper wire, that will reduce the area of the jet. Calculate the area of the jet and of the size you want it to be and find a copper wire that equals the difference in area. Or you can solder up the jet and drill it out to the desired size. Amazon has metric and Imperial mini drills that are great for this. I hope this helps.
Opposite is true. Smaller jets for higher elevation.
Terimakasih master enjin
Good info Grant!
Thanks. I stole it from Jody at ARC haha! Just a mild port job.
informative
love it
I’ve seen some idiots hogging out the exhaust ports 😳 don’t! They don’t seal to the exhaust gasket
why is there no throat? now i want to remove mine
Very good video, but...
That only covers OHV.
I am in the process of doing a "Stage 1" (Homemade Exhaust Headers) on my 1991? Kohler Magnum MV18 (Vertical Shaft) Engine. Model#MV18S Spec#58560 .
Is this engine even "Port-able"?
There are no casting "reminents" or intrusions in either the Intake, or Exhaust Ports...
I have been "suggested" to Upgrade to a Larger Intake Valve (1.500"), but the Stock one is 1.373", and I really don't know what to do, or what expensive Tools I need to aquire (for a One-Time job)...
I hope I'm not "overwhelming" you with questions, but I can't get a Straight Answer from anyone.
Feel free to Message/PM me if that would be more efficient. Or pass me to someone who KNOWS Kohler Magnum Opposed Twin Engines if you can.
Thanks for the Awesome Education!,
-Thomas (12)
Port Orchard, Washington
The three things that make power on an engine are the camshaft carburetor and cylinder head. Call of the folks over at performance 670.com. Even though this is a different business they can connect you with the people that work on the Kohler engines to make insane horsepower. In my experience multi angle valve job porting milling cylinder heads camshaft jetting etc. should all be done by professionals,
@@KartFab Thank you, will contact them tomorrow!
Sou ds grt ,,but u missed .ost important part 2 do most of all
Interesting...
You’re alive!
You thought I died? Ha ya DIY hates me...
Soooo...no gains?
27% increase with intake/exhaust
@@KartFab 27% increase in what?
I start hacking at my ports with a die grinder until the ports are as big as possible = 30 hp
Is it naturally aspirated ?
High percentage of ignorant comments here. Lol!
I have bob Ross vibes~
Ok..them lil shite engines....they got sum pep in they step...so....lets say...we do this to a ....Ughhh...250cc with 17lbs torque and 12hp....what's the % in Gains?
About 7% gain if you do nothing else. Porting is usually done in combination with a better cam and carb for the best performance. For example I have an engine that went from 10 ft lbs of torque to ~14 and 6.5hp to 17.5hp with ported head, 12.1:1 compression, slide carb, cam, and rebore from 212cc to 220cc
@@KartFab that's were I'm aiming...the only part that's hard to mod is the cam...since its a 250 and its a China import its hard to find and replace with performance parts
cubic feet XD
Don't need u porting nothing of mine,,o,, boy find flow bench,u,ll learn quick ,what a difference, u need 2 do!!!!
Bro don did it
bro why? take it to a machine shop
so what he gonna do with his all of the rotating bit and kit if he just sent it to machine shop ?.... the tungsten bit its not cheap to buy bro,
@@harisyoung4110 he said the bits were 12 bucks
Run what ya brung, build it, love it.
Rip and replace and pay to play are all too common bro, as my old man always says, get amongst it.
@@Louis-op4zj yea exactly man...im also all built it my self... i feel more perfection on doing it myself rather than asking machine shop do it... it not about money at all, it about pleasure... cheer mates
@@harisyoung4110 love ya work bro. Ever in oz send me a msg