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Z.hb71

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Can someone tell me what crankcase cr is ? How you measure it? And also, how in the hell do I measure port open durations???? I'm asking because I think I want to design my own custom exhuast rather than buying one, becuase rcmax is 400+, and Alx is 300+, and those are overseas and I don't know if those would perform the best in my application cuz I use a different cyl and stroke. This is for future reference btw.
 
If you and I where gonna walk to the store you would not be happy with just using your feet like the rest of us...... ( Zed) "hey heres an idea let's cut my feet off ? we can reattach them when we get there and while we there blind fold me as well" ???? don't like the easy way do y???
?????????? No mate, their prices are very expensive ($300-400 for rcmax and Alx), I understand why they are that price, I just don't want to spend that much, plus, I like making my own poop (not actually Gunna weld it and such, not that cool). Now if I some how end up with $300-400, well hell, then why go and make one, I'll just go with a rccmax or alx pipe.
 
port timing is measured from TDC, then you rotate the crank while using a protractor (TDC being at 0 deg) to determine how many degrees it takes from TDC to reach port(s) open, (you can use a flashlight and as soon as you see a hint of light coming through, its open.) then you keep spinning the crank until ports are closing, (flashlight method works for this as well.) take note of the degree, then subtract the one from the other to get your duration.
 
port timing is measured from TDC, then you rotate the crank while using a protractor (TDC being at 0 deg) to determine how many degrees it takes from TDC to reach port(s) open, (you can use a flashlight and as soon as you see a hint of light coming through, its open.) then you keep spinning the crank until ports are closing, (flashlight method works for this as well.) take note of the degree, then subtract the one from the other to get your duration.
so i would need to take the head off correct? not the cyl, the head. that definitely helps D3MON!!!!
 
http://www.rcuniverse.com/forum/car-nitro-gas-engines-269/5995115-induction-timing.html
i know its on a different forum sorry lol, but definitely some good information on there, pertains more to nitro because the crank timing, but concepts are the same.
so i would need to take the head off correct? not the cyl, the head. that definitely helps D3MON!!!!
to do it right yes, you pull the head off the top. you can pull the plug shine a light down there and watch through the exhaust side of the engine with the pipe off, (this is not exact and hard to gauge, if you are looking for ballpark, this might be ok. for anything specific, do it right lol.

i actually re-created that excel spreadsheet because the one in their links don't work anymore lol cant remember where i saved it to though.
 
to do it right yes, you pull the head off the top. you can pull the plug shine a light down there and watch through the exhaust side of the engine with the pipe off, (this is not exact and hard to gauge, if you are looking for ballpark, this might be ok. for anything specific, do it right lol.

i actually re-created that excel spreadsheet because the one in their links don't work anymore lol cant remember where i saved it to though.
alright thats not a problem, in winter ill be pulling the intire cylinder off because when the final assembly took place i didnt have a proper set of digital calipers, so i went for 1mm of squish when it should me 0.7mm, so ill be fixing that, and while im at it just do this. and by do it right, how do i do this? measure the distance from tdc to port open ?
 
alright thats not a problem, in winter ill be pulling the intire cylinder off because when the final assembly took place i didnt have a proper set of digital calipers, so i went for 1mm of squish when it should me 0.7mm, so ill be fixing that, and while im at it just do this. and by do it right, how do i do this? measure the distance from tdc to port open ?
i was meaning do it right by removing the head lol. ive seen instances that when a person doesn't want to tear down, and just shines a light through the spark plug hole didnt work correctly. got different readings doing it that way and by removing the head and doing it that way.
 
i was meaning do it right by removing the head lol. ive seen instances that when a person doesn't want to tear down, and just shines a light through the spark plug hole didnt work correctly. got different readings doing it that way and by removing the head and doing it that way.
oh right. yeah cant imagine it working well by just shining a light without the head off lol. trying to get a exhuast that is actually meant for my specific engine with my specific stroke with my specific cyl and that actually fits my truck properly (the existing one fits ok but it is in the way of quite a few things)
also, i wont be doing the welding or anything like that. i am just going to design it and buy the meterial (either stainless steel or titanium), if i could tig weld and have all the tools then i would be doing everything myself.
 
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oh right. yeah cant imagine it working well by just shining a light without the head off lol. trying to get a exhuast that is actually meant for my specific engine with my specific stroke with my specific cyl and that actually fits my truck properly (the existing one fits ok but it is in the way of quite a few things)
definitely! guess i don't exactly know what you mean by "Crankcase cr", haven't heard that term before. i definitely am interested to see your progress if you do decide to design your own pipe.
 
definitely! guess i don't exactly know what you mean by "Crankcase cr", haven't heard that term before. i definitely am interested to see your progress if you do decide to design your own pipe.
i think its crankcase compression. no idea what it means and how to measure it but i actually don't need it now. was going off of some weird online exhaust builder but im gunna use this $20 app thats mentioned in this post
https://www.instructables.com/id/Build-a-Tuned-pipe-for-a-2-stroke/
im going to go off of this thing. doesn't seem that hard when you figure out port timing and such, plus the app makes it pretty easy
 
so, btw im just planning everything out at this point, this is all gunna happen next spring i believe, if i decide to do this that is (looking like a very good option), so 2mm ss or titanium would be fine right? or too thin? so far its $40 for the exhuast simulator, then around possible $60 for steel or ti, then fabrication costs which i don't know. maybe i could rent a tig for cheaper and learn and then just get all the meterial bent and rolled by someone else. i don't know yet, me welding depends if my parents want to let me loose with a 11000 deg torch LOL
edit: renting a tig is gunna be a solid no, way to expensive, nearly $130, so ill get that done aswell.
 
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so, btw im just planning everything out at this point, this is all gunna happen next spring i believe, if i decide to do this that is (looking like a very good option), so 2mm ss or titanium would be fine right? or too thin? so far its $40 for the exhuast simulator, then around possible $60 for steel or ti, then fabrication costs which i don't know. maybe i could rent a tig for cheaper and learn and then just get all the meterial bent and rolled by someone else. i don't know yet, me welding depends if my parents want to let me loose with a 11000 deg torch LOL
If anything I would almost think 2mm would be on the thick side, my snow machine pipe was even thinner than that and it was aluminum though iirc. If you can I'd try measuring your existing pipe and going similar to that. Going to tell you now TI is a process to weld, I definitely say go steel. Tig welding is my favorite type of welding, just take it slow and clean the TIG tip as soon as you get contamination, (dip it in the puddle etc.) or the welds look really bad, practice alot before starting on the final piece. It is not really recommended to grind tig welds, the joints should be close to flush with the materials. Imo tig welding is very relaxing.
Hopefully any of that makes sense and is helpful lol
 
If anything I would almost think 2mm would be on the thick side, my snow machine pipe was even thinner than that and it was aluminum though iirc. If you can I'd try measuring your existing pipe and going similar to that. Going to tell you now TI is a process to weld, I definitely say go steel. Tig welding is my favorite type of welding, just take it slow and clean the TIG tip as soon as you get contamination, (dip it in the puddle etc.) or the welds look really bad, practice alot before starting on the final piece. It is not really recommended to grind tig welds, the joints should be close to flush with the materials. Imo tig welding is very relaxing.
Hopefully any of that makes sense and is helpful lol
definitely helpful but in my edit, renting a tig isnt worth it, as much as id like to learn. il measure my pipe, i think its carbon steel, but it is pretty thick and heavy, want it lightweight that's why ti is an option (ti also depends on were i go to weld, seams like steel more people can weld for cheaper) but thinner ss is probably the best option, again depends on the total cost of ti and the welding costs.
edit my pipe is 3mm thick steel. so in that tutorial, the guy used 18 gauge steel which is 1mm, what do you think about that?
 
definitely helpful but in my edit, renting a tig isnt worth it, as much as id like to learn. il measure my pipe, i think its carbon steel, but it is pretty thick and heavy, want it lightweight that's why ti is an option (ti also depends on were i go to weld, seams like steel more people can weld for cheaper) but thinner ss is probably the best option, again depends on the total cost of ti and the welding costs.
edit my pipe is 3mm thick steel. so in that tutorial, the guy used 18 gauge steel which is 1mm, what do you think about that?
Dirtbike pipes are exposed, and sit in front of the frame pliable to be impacted, probably why it is so thick. I would think 16g or maybe even 14g or somewhere around 1.5mm would be plenty thick for your application. The dirtbike pipe is also odd shaped and not as structural as straight tube. Too thick won't really hurt anything but add extra weight. Might look into oxy-acetaline welding? Close to TIG but very controllable with thin materials as compared to mig.
 
Dirtbike pipes are exposed, and sit in front of the frame pliable to be impacted, probably why it is so thick. I would think 16g or maybe even 14g or somewhere around 1.5mm would be plenty thick for your application. The dirtbike pipe is also odd shaped and not as structural as straight tube. Too thick won't really hurt anything but add extra weight. Might look into oxy-acetaline welding? Close to TIG but very controllable with thin materials as compared to mig.
ok that makes sense, didnt think of that, so ill do 1.5mm. ill look into that type of welding, what type of machine is needed for that? cuase it might still be just as expensive in which case ill go to someone, but i do definitely want to learn if possible.
EDIIITTTT googled oxy-acetaline welding and it looks similar to brazing?
 
ok that makes sense, didnt think of that, so ill do 1.5mm. ill look into that type of welding, what type of machine is needed for that? cuase it might still be just as expensive in which case ill go to someone, but i do definitely want to learn if possible.
It's not really a machine per-se, you know those green and red gas cutting torches? It's a specific tip for one of those, then you buy filler rods like you would with tig.
 
It's not really a machine per-se, you know those green and red gas cutting torches? It's a specific tip for one of those, then you buy filler rods like you would with tig.
yeah, looked into that just now. so would just get a cutting torch and change the tip to the proper one and get filler rod? ill check rental prices , should be cheaper than a welding machine rental. one place was $62 for 3 hours. which isnt bad, then $10 for the tip, and then whatever for filler rod, so probs$90 or around there. still not sure if its really worth it. will continue to look tho for a better deal.
 
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yeah, looked into that just now. so would just get a cutting torch and change the tip to the proper one and get filler rod? ill check rental prices , should be cheaper than a welding machine rental. one place was $62 for 3 hours. which isnt bad, then $10 for the tip, and then whatever for filler rod, so probs$90 or around there. still not sure if its really worth it. will continue to look tho for a better deal.
when i had one, it was already fitted with the tip and stuff, so not really sure exactly what set up it had, sadly didnt have it very long before life got in the way.
should be able to talk to a local welding supply house and they would be able to give you information on what you need exactly and to get what they recommend for filler rod. buy extra filler rod though. if you think its going to take 6 sticks, buy 8 or 10 lol. if memory serves me right, you should get half the length of stick in weld length. so if the stick is 12", should get you 6" weld. been awhile though but i think thats what i remember.
 
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