BLESS YOU TINMAN FOR GOING SLOW AND TAKING YOUR TIME WHILE SHARING YOU GOLDEN NOTEBOOK. THAT NOTEBOOK IS POUR GOLD TO ME. I AM TATALLY A VISUAL LEARNER. THE NOTEBOOK, GOING SLOW WITH YOUR CUTAWAY IS PURE GENIUSE WHEN IT COMES TO EDUCATING ME. PLEASE KEEP THE SLOW PACE AND ATTENTION TO DEATAILS. YOU HAVE CREATED AN AMAZING EDUCATIONAL SERIES ON PORTING TO HELP GENERATIONS TO COME!!! CHRISTMAS HAS COME EARLY FOR ME BECAUSE OF YOU TINMAN. I WANT TO GRADUATE FROM TINMAN'S UNIVERSITY OF POWERSAW PORTING!!!
My Dad has always said that when in search of horsepower you should remember an engine is little more than a glorified air pump...in that the more efficiently you can get air into and out of the engine and the fuel to match you will always make more power. Liking the content here big time...so glad Buckin sent me this way
Ok that's too good I posted my original comment while watching the video...and promptly heard you start talking about moving air and working in duct work lol 👍
Props to Ironhorse... he's the reason I found your channel. I'll be at the next Buckinstock as well, can't wait. We should use the lathe on a build in the near future, that would be cool to see how the numbers change.
I'm watching this as I get the port numbers for an almost unused 375K that my work was going to scrap while cleaning the yard. Going to put it back as a chainsaw instead of a concrete saw. Heard all sorts of stuff about how bad the timing numbers are because they are limited way down in rpm (a black coil will fix that😜) so far without a base gasket im at .023 squish 102 exhaust 156 duration 124 blowdown 75 intake 150 duration And its a 75 cc overbore. Think it will make a fine saw with a little massaging.
In my motorcicle ,50 cc, 30 years ago , i dont change the timing but made more larger the inlet and outlet hole to have more Power. Sorry for my English. Good Christmas
I was pretty confused by the degree math at first, but now I totally get it. Here's how I think about it: There are 360° in a circle. From TDC to BDC is one half of the circle, or 180°. If the exhaust opens at 102° after TDC, then it is open for 78° until it reaches BDC (180° - 102°). Because it is circular, it will close at the same position on the upstroke, which is 78° ABDC or 102° BTDC. This means that the exhaust port is open for 78° on the downstroke then 78° on the upstroke, for a total of 156°. The formula for exhaust duration is then (2 * (180° - X)) where X is the degree at which the exhaust opens ATDC. For intake it is the same, where X is the degree at which the intake opens ABDC. Hope this helps someone.
Hi Tinman. I'm a porter in NZ. I don't do it commercially just for myself and a few mates. I get where you are at with this video and you have done a great job helping guys out. Like you I would love to have a conversation with a group of guys and share info. I don't know anyone in NZ who does it I'm sure there must be few. I have a 372 Meteor that I killed some years ago with an 87 Exhaust. It was generally peaky but made no power and so it got put on the wall of shame. Recently I got it down and studied it and saw some glaring errors in my thinking, run some numbers and moved my intake down to 92 ATDC. I also did a small flow correction and changed my aux transfer shape. This cylinder is now on the saw and it works extremely well as a cookie cutter. It's not a work saw nor will it ever be but its a lot of fun. It runs a 390 carb and looks totally stock but sounds and runs like a race saw. I guess I have had about 3 or 4 goes at getting that cylinder to run over the years. As you say it takes time to understand what's going on and what's the best pick to make it run. The 372 is my pet saw. Frankly my 372's ported to 98 exhaust are seriously fast saws with strong torque. Faster than my stock 660 and 395 with a 24 bar and still faster than my 660 with a 30 inch bar. Its taken me 10 years off and on to work it all out and its nice to finally be porting at a level where I'm actually happy with the saws. The last piece of the puzzle for me is the combustion chamber and compression ratio. It maters more than we give credit. I recently got a CNC mill and I have been cutting perfect combustion chambers into stock cylinders. WOW! Huge difference! I now see why guys build there own heads for race saws.
Hey man. Where abouts in nz are ya? Just setting up my first timing wheel. Haven't known of anyone in nz porting saws until stumbling across this comment
I have some old tiny homelites that still start after sitting for years. Since they aren't worth much they will be my first projects to get a feel for porting. Excited to get started.
Hopefully CA will open the darn border. Missed my fishing trip to Silver Dollar, ON this year. Vancouver would be a heck of a trip and bucking stock would be great! Thanks for more porting info, I plan on staring my first port soon as you wrap this series.
Tinman your making me want to play around with some old blown up saws I have laying round. Most are small saws (30 cc) and some slightly larger home owner saws. I do have a back ground in engine building to include 2 stroke Detroits. Maybe one day I will be confident enough to play with the saws that make money. I tend to like fast saws. My favorite is a Husky 346xp. Just picked up an Echo 620p though. Thanks you for this in-depth look.
I blame bucking Billy then iron horse now your 3rd on the blame list, all started with a 038M last year coming across your channel keep up the great work and taking time to explain better then a text book 🤟 happy holidays bud
If timing numbers are a language then I'm illiterate! Good thing Professor Tinman is having these night classes at Tinman University. Thanks Tinman!!!!!!
Just a heads up on wet flow it flows different then dry or just air so what works good for a dry flow system will typically not work for a wet flow. Wet flow meaning fuel and oil or fuel. I have learned from my dads buddy on single cylinder engines for kart racing and him using a wet flow bench. I have learned that smooth surfaces is a no go in intake ports of any kind. some have gains from it me personally no the rougher the surface the better. The dimple porting for something like a cookie saw that'd constantly at its peak rpms. I have had good luck with it in saws I've built. also the spacing and size and depth of each dimple does affect flow with wet meaning fuel/oil. It helps with atomization the fuel to air mix for better combustion. The saw might load up on fuel at idle from it depending the application. If you pay attention to some stihl intake boots they have little spikes in them close together. Just a thought in things to try. it could speed up the air flow. To large of ports can slow the speed down.
Very good thoughts. I agree on everything you said. Why would stihl put ribbing in the intake boot unintentionally? And bigger is not always better. Flow is #1.
There are different ways to speed up airflow and slow it down certain turbulence is a + and certain turbulence is a -. I've gotten into the dimple porting and have had very very good luck with it with saw builds. My idea came somewhat from fishing. If you look back at some of the late 80's early 2000's spinner baits blades not the shape of the blade but the dimples on the blade. Bait companies started going this because it helped with vibrations and different shapes and sizes and how far apart each dimple is caused the blade to put off different vibrations in order to attract a large mouth or small or spot... etc it's the same concept when putting that same work into a intake port. Yes the flow speeds up as the port gets small but the air to fuel stays atomized from the demples or say a 80 grits rough surface or sandblasted surface or ribbed surface. I personally have gotten to like dimples and ribs lol makes for a better fuel burn
All the saws I've ported on the exhaust port 99 or 100 , those are good work saws , now I've ported saws that worked good by machining the piston instead of the cylider
“Woods port”=“3/4 race cam” 😂🤣. All kidding aside, great video bud. My first saw I accidentally pushed the intake almost out to 160* of duration and it’s wicked but I don’t know how practical it will be, but that’s what junk free saws are for I guess🤷♂️. Hey all it’s gotta do is start, idle, and murder wood!
I run a saw daily for a living and own 15 saws. I also watch a lot of porting videos and I enjoy your videos and personality more than any other tuber/porter ive seen! Awesome content and explanations. I never ported a saw until watching your videos now I have one pretty mean 1980 028 super. It cuts and runs much better than the other 2 028 supers and does better than the 29 super or 290!! Thanks for your enfo and videos
So thankful for you and what you are doing for the community. Not quite understanding all of it yet however, I didn't quite understand MOA when i first started shooting but one day, it just all clicked. I felt stupid for not gettin it sooner. I have an MS390 that's sitting in my garage just begging to get back to work. And believe you me . . . It needs it. Thank you again for sharing with the community
Once again, good stuff. Air pump: basic fact about all engines that most people forget. Numbers are "easy", but "what they mean" is the hard stuff, the learning. Good explanation on what they do (exhaust height, rpm, intake, throttle response). Just like everyone else, Thank you for sharing.
I have not gotten as far into the book as I'd like but I suspect that "ideal" timing numbers will change according to displacement but also how bore and stroke relate to each other, considering these are cross flow scavenging engines. I have a lot more studying to do on blow down.... it seems like there has to be a sweet spot where the exhaust exiting will create a suction effect helping to pull the charge into the cylinder, rather than relying on the charge to push exhaust out. Much to learn...
i don't know if you covered it in another video, but maybe people would benefit from what would change if you added in a gasket. What would change if you took the squish down to 0.020. Maybe if you drew it out, it would be interesting. I guess a delete will increase compression because it is sinking the piston deeper. Sinking the piston deeper increases blowdown i think? So then when you make the lower ports flow better it brings in more fuel? On a motorcycle, when you get the tailpipe less restricted you end up changing jets or fuel mapping. Buckin' was talking to a saw guy, I think Walker, and he said that most saws will run well around 150 degrees. Very interesting.
Great stuff Tinman. Really appreciate these vids. Getting a lot out of them. Myself and a few buddies are trying to do this, but more for milling saws with long bars, so torque is our goal. With that there is a bit of translation from your outlook with HP being primary. I did hear clearly though that we are looking to keep the exhaust roof lower. If you could touch on that a bit more as you go it would be appreciated. Even if it just to contrast high HP/RPM Vs. a slower torquier build. I almost think from your description that there may be a great balance for it all, maybe with a nod to torque in the build. Again thanks, you've more fans than you probably realize.
Hey Tinman. I’ve watched all your vids and I subscribe to other saw build channels and have listened to so much great advice and guidance. This vid leaves them all for dead. That’s not to say all those other educators aren’t awesome, you’ve just nailed it with this one. As a novice saw builder, sincerely thank you 👊
Tinman high quality stuff in this video I’m getting it more and more every time you post on this echo porting serious I love it. I greatly appreciate it!!
Tinman your videos are so awesome you explain everything in super detail to make things easy to understand. Been working on Small engine stuff for a very long time but never got into porting and timing saws. I wish I had but now trying to learn now.
Hi, interesting and instructional video. I'am a swed and the Husqvarna is a swedish company, but man you murder the Husqvarna pronansuation, it shuld be like [hus_kvarna] ;-)
Murder wood! I appreciate you taking the time to explain the numbers. You have all the numbers, so if you get the same saw, or you need to put a new top end on you can make it happen again easy. You've done the math already. I appreciate you going over this stuff again. Have an awesome Christmas sir!
Aren't there like tools where you insert your dimension, numbers, and could get an expected outcome of torque/rpm? Just like in SOLIDWORKS or something. Would like to begin porting for myself (probably just cleaning production castings and opening them a bit up) but I'd need to have numbers from a respected porter to begin with my saw (because I haven't found any numbers for my saw yet😅)
Thanks tin man you explain well got a 61 i fancy having a go at Electrolux ? but im going to really look at your vids your very clever keep showing us ,you and family have a nice Christmas thanks .
Started watching your series on saw porting. Freaking love it so far! Awesome information! I just got through the third video and can't wait for the next one. So glad I came over here when buckin suggested you!!!!!
I like your approach and your right it is a air pump I started out learning porting race car heads at my uncles machine shop he gave me some old heads and taught me what where and why after 2 years porting thinking about air flow he threw a wrench in my wisdom by teaching me what I couldn't see threw a flow tech flow bench after a couple years teaching my self what where and why I had stacks of cylinder heads waiting for me and a following...there is dynamics , fuid dynamics to be exact I like your videos and share the passion for the nasty saw that cuts .also you hit on the every saw is different with a purpose 👍
I have a grizzly g0602. Have not use it in 2 years to be honest. 1500 dollar for it and 500 in tooling to sit most of the time. Picking up a small stand mill tomorrow.
All good stuff Tinman, but you forgot to mention piston overhang in the intake port at TDC, if the piston skirt is lower than the intake roof it never fully opens effectively reducing the port size so if this is the situation it's sometimes better to trim the rear piston skirt to increase intake duration and also clear the top of the port. Lowering the port floor will increase the duration but the piston skirt will still be in the way at TDC making the port smaller than it could be.
Following on from my comment above, cutting the piston skirt is an easy way to experiment with intake duration, go too far with it and you've only wrecked a piston not your whole cylinder.
Thats an interesting point. I don't really worry about the skirt covering a but of the top of the port at TDC because most chainsaw pistons dwell anywhere from 3 to say 6 degrees at the top of the stroke. The piston really doesn't move at the Point just before or after TDC so there's really no flow up there. Most of the flow occurs just after the piston opens as the case vacuum should be at its highest upon opening. Just my oppinion. Thanks for the comment have a great day!!!
@@tinmanssaws As you've said in your videos different folk do it different ways and it's whatever works for you but I prefer to get every obstacle I can find out of the way. Bearing in mind that at 9000 rpm the air has to go through the ENTIRE ENGINE in 0.0066 of a second ( 60 seconds divided by 9000 ) my race bike engines used to go 120000. that's 0.005 of a second, from the carb inlet to the exhaust port exit.
Hi Tinman, I've watched these videos several times over now just to get my head around it while checking the numbers on my mo chine and I really appreciate and thank you for the time that you've put in, but I don't understand how you can drop your cylinder 0,014 and yet maintain the same Transfer, Intake and Exhaust opening numbers????? Am I missing some thing?🤥
Man this is awesome, I am two saws in, Started with small saws 3400 countervibe, Also a ms 270 both saws for the moment are screamers, thanks for the videos. 🤘 Have a good one
Gray videos. The old lady wants to watch movies but I like to watch this. I’m in Phoenix and don’t really even have a use for more than a once in awhile saw. But think I’m Going to look for one too mess with
LOVE THE WAY YOU BREAKDOWN EVERYTHING ,SO IT MAKES SENSE, VERY UNDERSTANDABLE HOW YOU EXPLAIN STUFF ,YOU WOULD HAVE BEEN AN EXCELLENT SMALL ENGINES TEACHER ,WISH YOU A MERRY CHRISTMAS AND BEST WISHES FOR 2021 HOPEFULLY THIS COVID CRAP LEVELS OUT BY SPRING BE SAFE TINMAN
Dear Tinman: I’m probably not alone, but even as a reasonably intelligent two stroke engine tinkerer, I still don’t understand what these numbers are being catalogued for? I do understand the various phases or stages where you note the dial gauge values, but I don’t see the whole picture from 30,000 feet. What is the overall purpose of recording timing numbers? Is there a reason to even do this if we are not doing any mods on the saw, such as porting etc.? What am I missing?
Great video Tinman!!!!Thanks for the great info and thanks for taking the time to explain everything in normal human terms. Keep it at and have a Merry Christmas.
AWSOME JOB 👍 again explaining porting you and Harv are the best out there in my opinion keep up the fun your having and I'll be trying my own porting, Have a GREAT HOLIDAY !!
Okay, so lemme get this right... Lowering the squish, Gains compression.. and compression increases cutting torque?!?! and exhaust port duration gains RPM's? So is there any noticeable difference in just base gasket deleting?!?! What does it achieve exactly?
Great series man I love it! I need a bit of knowledge as this is my first attempt. Is it ok to say go 1 deg on intake and 2 exhaust on a husky 120e mark ii 38cc "open port saw" or would you recommend something different I have only seen one of these done because no one does open ports saws and he only done the exhaust roof, cut the transfer port walls deeper and spark advance and ground the venturi on the carby, it ate after that. I got exhaust 109 ATDC 142 dur And intake 68 BTDC 136 dur Will that mess things up?
only now am i going through these videos, plenty of views i see, imagine a few years from now. for my stock stihls for now ive only widened exhaust ports a little , tapered the exhaust side of the piston and increased the angle in the intake like Harvey showed, and simple blending inside the aftermarket cylinder and a free flowing muffler, thats as far as i dare go for now, but once i get a degree wheel it will be time for a saw that is not a clamshell.
I have a Husqvarna 130 saw that won't run. After putting some oil in the cylinder, she starts and then stalls. Without going crazy would a new ring possibly save this?
Merry Xmas congratulations on the sub's. I just put together 661 made of a blown up one and one that had a large oak impact the e carb had me scratching my head but it works keep up the great work I feel like I know you
Hey thanks just subscribed like the info I’m new to portin myself n these are basically saw motors I’m playing with in fact it’s a super common mod to put a saw jug on these bottom ends.
Tinman, you say raising the exhaust roof and therefore increasing exhaust duration will result in more rpm. But in raising exhaust roof you increase blowdown too, which you say lowers rpm. This has me confused.
So if you did lower the squish down to .020 how much more would you have raised your exaust port? And would you have changed the intake more? Also shouldn’t your top ring be past your exaust roof right before the intake cracks open?
So,I'm looking to port a stihl ms250 for cutting firewood. I don't have the saw yet, but I'm thinking about how I want to build it. I've never ported a saw, but I have polished intake and exaust ports on a few saws. I think since I'm cutting firewood, not racing, I think I'd be better off to build for torque. I'm thinking about dropping my exaust port 2 degrees, and just polishing my intake port. How do you think this will work? Those saws are just high temperature silicone that seals the bottom end, so there isn't a way to delete the base gasket.
I do trimmers to finance my saw addiction! Seriously. The service and send em out trimmer game makes good play money. But the real knowledge is coming in now and coming in hot. From the tinman!!
@@tinmanssaws for now I've only Remove base gasket because it had over 0.9mm(I'm probably your only Italian subscriber) squish which is around 38 thousands I believe. Enlarged the ports , raised little bit the exhaust. Removed any restriction on both cylinder and crankcase , lower transfers were restricted with over 5mm excessive alluminium so made them match the crankcase
@@5150powder I've never thought about modify small engines but since I've found tinman , I've started looking for old stuff to do practice , reading books about 2 strokes and things like that. Hopefully in the next future I'll buy a kit saw , probably an MS361 clone and there will be some serious fun
Lots of good info in this one Tinman. ''I move air at work''(poot). Sorry needed a pre Christmas fart joke. Happy Christmas to you and your family big fella. It's going to be 21degrees C here in Tassie for Chrissy, stay warm.
When adding 2 degrees of intake timing, would you trim piston skirt or open the intake port. I’m afraid of loosing velocity by opening the intake port.
I found an old Stihl 017 I'm fixing to start messing with and I'm wondering if you have any "numbers" that would be a good starting point to go to. Thank you for these wonderful videos.
I have a question I don't know if you would be able to answer it brother I have an old McCulloch 510 pro mac it is a small saw 30 something CC's I can't remember right now I'm having a problem with the chain I would like to convert it over to a 6 or 72 sprocket and conventional organ chain I would like to keep the McCulloch bar is this a possibility or what I have to change everything out and possibly would you know what to change it out too I really appreciate it if you could help me if not I understand thank you.
