twostroker1955
- twostroker1955
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Hi from the UK from a first time user. I have recently purchased a 200amp TIG welder from RTech in the UK. I have experience with gas (oxy acetylene) and arc from an apprenticeship many years ago. The TIG is new to me but I seem to be having some success thanks to Jody's excellent online video's. The reason for the TIG welder is I am building a project motorcycle based around Polaris two stroke engines and I will need to weld the crank pin to the crank web. This seems to be quite common on the web for various pressed-up cranks but I am struggling to find any real information regarding hints and tips to do so other than E308L stainless rods appear a favourite, even though none of the components are stainless. I was just wondering....hoping that someone on this forum may have some experience they would share. Cheers Dave
- MosquitoMoto
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Location:The Land Down Under
Welcome!
While I can't help you with your specific welding question, the Polaris engine in a bike made me think of this...
http://thekneeslider.com/tul-aris-two-stroke-racer/
...no doubt you are aware of it. I too would like an answer on the crank pin question as I am a lover of all things 2-stroke and will need to face this challenge myself eventually. One of the wise ones will show up soon enough with an answer.
Kym
While I can't help you with your specific welding question, the Polaris engine in a bike made me think of this...
http://thekneeslider.com/tul-aris-two-stroke-racer/
...no doubt you are aware of it. I too would like an answer on the crank pin question as I am a lover of all things 2-stroke and will need to face this challenge myself eventually. One of the wise ones will show up soon enough with an answer.
Kym
I am going to date myself a bit, but when I was racing MX I had my NEW crank trued , and welded, and when I got it back I was almost positive that there was no filler used. This was on a 250 Tecate 4.
If you can true the crank, weld it, then check it for true again after it cools. I wouldn't expect it to move , but you never know.
If you can true the crank, weld it, then check it for true again after it cools. I wouldn't expect it to move , but you never know.
Thespian is just an old username I have used forever , my name is Bill
twostroker1955
- twostroker1955
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Gents. Thanks for the response and interest.
Kym. It is always good to hear from a fellow two-stroke enthusiast. I have indeed seen the Tularis motorcycle. It was ridden some years ago at Mallory park in the UK. Very impressive with a lot of interesting engineering in there. I took voluntary redundancy from Lotus engineering last year after 29 years service with them as I was getting older faster than things were happening if you are old enough to appreciate that. I was the two-stroke bloke at Lotus (a rare breed it would seem) so OMNIVORE and ELEVATE were my babies so to speak!
In this instance I am using two of the 700cc twins but back to back (180 deg V) as you see in the photo. I am using two upper crankcase halves, off-set by 28mm and a single crank made up of standard polaris crank webs plus some of my own as you can see in the drawing. With this arrangement, the opposing cylinders move in the same direction so all primary and secondary forces are cancelled (vibration was a big issue on the Tularis). There will be a small secondary couple due to the 28mm off-set but this should be minimal. The cylinders will have trapping valves fitted and I am intending to use a DI system as used on the Toyota lexus V8 engine. The engine unit will drive through a Hayabusa transmission.
Josh. Thanks for mentioning the 309 rod. I noticed on the web that it is recommended for joining stainless to carbon steel. I am in two minds on this and was hoping to find someone with some experience of welding crankpins to confirm. I guess the stainless option is chosen as the steels used have a higher chromium content than normal and I am not sure if there is a metallurgical advantage regarding embrittlement etc. I do intend to use pre heat before welding but the last weld will be done as an assembly so I have to be aware of the roller big end bearings etc. I am also unsure how much heat will get transmitted to the bearings (only being welded on the outside away from the rod) and its effect on pin hardness from the TIG welding. I am looking (guessing!) to have a 3mm chamfer to be filled flush. The maximum web thicknesses are 20mm and 14mm. I have some old pins and webs so I can practice on these and see how much heat transfer there is and gauge at that point if there is an issue or not!
Bill. I have heard previously that some cranks are welded without filler rod. I guess this is more to stop axial movement rather than torsional. In my case, because of the layout and torque transfer across the engine, I am borderline on torque capacity at the final crankpin. I cannot increase the interference as it is close to yield anyway so welding is my only real option. I will be truing the crank afterwards as a matter of course.
As you have probably gathered by now, there will be some considerable aluminium welding to do on the crankcases and cylinders so please don't be surprised to see some more posts in the future. Thanks again for taking the time to reply. Cheers Dave.
PS. Struggling to add images / photos so apologies on that one. Will do it later after I have consulted the grandchildren who live in Australia!
Kym. It is always good to hear from a fellow two-stroke enthusiast. I have indeed seen the Tularis motorcycle. It was ridden some years ago at Mallory park in the UK. Very impressive with a lot of interesting engineering in there. I took voluntary redundancy from Lotus engineering last year after 29 years service with them as I was getting older faster than things were happening if you are old enough to appreciate that. I was the two-stroke bloke at Lotus (a rare breed it would seem) so OMNIVORE and ELEVATE were my babies so to speak!
In this instance I am using two of the 700cc twins but back to back (180 deg V) as you see in the photo. I am using two upper crankcase halves, off-set by 28mm and a single crank made up of standard polaris crank webs plus some of my own as you can see in the drawing. With this arrangement, the opposing cylinders move in the same direction so all primary and secondary forces are cancelled (vibration was a big issue on the Tularis). There will be a small secondary couple due to the 28mm off-set but this should be minimal. The cylinders will have trapping valves fitted and I am intending to use a DI system as used on the Toyota lexus V8 engine. The engine unit will drive through a Hayabusa transmission.
Josh. Thanks for mentioning the 309 rod. I noticed on the web that it is recommended for joining stainless to carbon steel. I am in two minds on this and was hoping to find someone with some experience of welding crankpins to confirm. I guess the stainless option is chosen as the steels used have a higher chromium content than normal and I am not sure if there is a metallurgical advantage regarding embrittlement etc. I do intend to use pre heat before welding but the last weld will be done as an assembly so I have to be aware of the roller big end bearings etc. I am also unsure how much heat will get transmitted to the bearings (only being welded on the outside away from the rod) and its effect on pin hardness from the TIG welding. I am looking (guessing!) to have a 3mm chamfer to be filled flush. The maximum web thicknesses are 20mm and 14mm. I have some old pins and webs so I can practice on these and see how much heat transfer there is and gauge at that point if there is an issue or not!
Bill. I have heard previously that some cranks are welded without filler rod. I guess this is more to stop axial movement rather than torsional. In my case, because of the layout and torque transfer across the engine, I am borderline on torque capacity at the final crankpin. I cannot increase the interference as it is close to yield anyway so welding is my only real option. I will be truing the crank afterwards as a matter of course.
As you have probably gathered by now, there will be some considerable aluminium welding to do on the crankcases and cylinders so please don't be surprised to see some more posts in the future. Thanks again for taking the time to reply. Cheers Dave.
PS. Struggling to add images / photos so apologies on that one. Will do it later after I have consulted the grandchildren who live in Australia!
crown 220 300 preheat quick welds
http://www.crownalloys.com/TechSheet/R220.pdf
is this a high compression engine?
craig
http://www.crownalloys.com/TechSheet/R220.pdf
is this a high compression engine?
craig
htp invertig 221
syncrowave 250
miller 140 mig
hypertherm plasma
morse 14 metal devil
syncrowave 250
miller 140 mig
hypertherm plasma
morse 14 metal devil
twostroker1955
- twostroker1955
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- General crank layout.jpg (27.14 KiB) Viewed 2296 times
- DSCF4546.JPG (71.4 KiB) Viewed 2296 times
Have you welded a crankpin like this previously? The other question I will have is what amperage should I be using to do the quickest weld?
Regarding the compression ratio, I am looking to run around 8:1 at exhaust closure which equates to 12.7:1 from BDC as a starting point. I will be limiting the rpm to around 7000. The use of DI allows typically higher CR's by 1 to 1.5 compared to port fuel so hopefully, I should be safe from knock / detonation.
I am attempting to attach a photo of the general engine layout as well as the revised crank for those that may be interested.
Thanks again. Cheers Dave
kiwi2wheels
- kiwi2wheels
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Call some of the UK guys who used to build the parallel twin TZ 250/350 cranks. This was fairly standard practice as the standard cranks ( pin interference ) were junk after one or two rebuilds.
They may have some rod suggestions. Inconel 82 may be worth considering.
In the ancient history dept, " Cycle " had a " TZ Papers " series that included photos / info, of their shop TZ's welded crank.
http://www.tz350.net/tz_carburetors.htm
" Setup of TZ250E is expertly covered in the article “The TZ Papers” by Phil Schilling in his article “The TZ Papers” Cycle magazine February1979. "
http://www.dadsvintageads.com/catalog.p ... ue__Suzuki
They may have some rod suggestions. Inconel 82 may be worth considering.
In the ancient history dept, " Cycle " had a " TZ Papers " series that included photos / info, of their shop TZ's welded crank.
http://www.tz350.net/tz_carburetors.htm
" Setup of TZ250E is expertly covered in the article “The TZ Papers” by Phil Schilling in his article “The TZ Papers” Cycle magazine February1979. "
http://www.dadsvintageads.com/catalog.p ... ue__Suzuki
2 stroke
since i always weld with a pedal i almost never
now exactly where its set. it seems to leave it around
80 0r a 100 and use the pedal to get a nice wet puddle.
i have never welded twins, only moto engine and not for
a few years.i looked in my garage to see if i still had any
rod i could send you but didn't find any. i think i used .045 or1/16
and only welded short welds on the outside edges of the
flywheels to not over heat the pin . sorry i can't be more specific.
senior moment....
hope this is some help.
craig
since i always weld with a pedal i almost never
now exactly where its set. it seems to leave it around
80 0r a 100 and use the pedal to get a nice wet puddle.
i have never welded twins, only moto engine and not for
a few years.i looked in my garage to see if i still had any
rod i could send you but didn't find any. i think i used .045 or1/16
and only welded short welds on the outside edges of the
flywheels to not over heat the pin . sorry i can't be more specific.
senior moment....
hope this is some help.
craig
htp invertig 221
syncrowave 250
miller 140 mig
hypertherm plasma
morse 14 metal devil
syncrowave 250
miller 140 mig
hypertherm plasma
morse 14 metal devil
- MosquitoMoto
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Joined:Sat Aug 01, 2015 8:38 am
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Location:The Land Down Under
Dave -
This all reminds me of Chris Howe, another man I'm sure you're aware of, who is (was?) building a 1000cc V-twin two stroke with 2X CR500 barrels grafted onto cases of his own making, wedged into an Aprilia RSV4 frame. (Line-by-line machining using an ancient manual mill!)
Gracious.
Also conjures up thoughts of big bore Banshee conversions, although it seems what you are doing is far more ambitious than any of this. Meanwhile I'm afraid the best I can manage is to create a pair of spannies for my GT250X7! But my love of the stinky runs deep, having owned and raced many and various noisy, smelly bikes.
I'll be watching your project with eager eyes. Love where you are headed with this.
Kym
This all reminds me of Chris Howe, another man I'm sure you're aware of, who is (was?) building a 1000cc V-twin two stroke with 2X CR500 barrels grafted onto cases of his own making, wedged into an Aprilia RSV4 frame. (Line-by-line machining using an ancient manual mill!)
Gracious.
Also conjures up thoughts of big bore Banshee conversions, although it seems what you are doing is far more ambitious than any of this. Meanwhile I'm afraid the best I can manage is to create a pair of spannies for my GT250X7! But my love of the stinky runs deep, having owned and raced many and various noisy, smelly bikes.
I'll be watching your project with eager eyes. Love where you are headed with this.
Kym
twostroker1955
- twostroker1955
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Thanks again for the helpful responses gents.
Kiwi2wheels. I will contact some of the current TZ users to see what is being done. I used to have a TZ350 back in the late 70's and I don't recall anyone welding the cranks then but that is not to say they weren't. The Inconel 82 rod may be an option....at least it is available in the UK. The crown 220 is difficult to find but I have emailed crown to see if there are any suppliers in Europe.
Craig. Thanks for giving me some direction there. I will try out on some old pins and see what seems to be best. I appreciate you looking to see if you had any rods. I have contacted crown to see what they can do for me in the UK. I will also contact some of the UK suppliers to see if there is an equivalent to the crown 220....you never know.
Kym. There was an article in a UK bike mag (performance bikes) last year which included Chris Howes endevours....it was nice to see that I am not the only 'optimist' around when it comes to such things. My machines are manual so I have the same laborious issues that no doubt Craig has. I believe that your interest in this is probably outside of the specifics of Jodys forum but if you want to stay in touch, you can email me daveblundell@mail.com
Thanks again to all. Dave
Kiwi2wheels. I will contact some of the current TZ users to see what is being done. I used to have a TZ350 back in the late 70's and I don't recall anyone welding the cranks then but that is not to say they weren't. The Inconel 82 rod may be an option....at least it is available in the UK. The crown 220 is difficult to find but I have emailed crown to see if there are any suppliers in Europe.
Craig. Thanks for giving me some direction there. I will try out on some old pins and see what seems to be best. I appreciate you looking to see if you had any rods. I have contacted crown to see what they can do for me in the UK. I will also contact some of the UK suppliers to see if there is an equivalent to the crown 220....you never know.
Kym. There was an article in a UK bike mag (performance bikes) last year which included Chris Howes endevours....it was nice to see that I am not the only 'optimist' around when it comes to such things. My machines are manual so I have the same laborious issues that no doubt Craig has. I believe that your interest in this is probably outside of the specifics of Jodys forum but if you want to stay in touch, you can email me daveblundell@mail.com
Thanks again to all. Dave