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  • Cylinder head port welding help

    Hi all -

    I'm filling in the floor of the exhaust ports of some motorcycle heads for vintage racing. I've had some success, but it's sure hard and I could use some help getting "over the hump" so to speak.

    One issue is of course that the heads are 40 years old, and very contaminated. I've been bead blasting the ports, die grinding to clean and washing with carb cleaner or acetone (whichever I happen to have at the time). That seems to work ok, once I get going. Getting things clean enough to weld seems to take several iterations of weld/grind/weld/grind. They're of course way too small for a stainless brush, even a cut down one.

    Another issue is that I'm more than maxing out my machine - a Synchrowave 180 (and the breaker it's on). I could use more power. I am pre-heating before welding and it helps but not enough.

    The third issue is just a matter of size, the ports are very small and difficult to reach into far enough. I could use an arc bender... :-)

    It's very hard to reach in the ports at all, even with a way too small cup on the torch, especially as far in as I need to reach in and fill for best flow. I would usually be using a gas lens, but there'd be no way to see or put in filler with a gas lens setup - the cup would pretty much fill up the port. Also, the port forms a nice venturi to drag air into the weld no matter what you do with gas flow. I've tried using alum. foil stuffed into the valve seat with moderate success there. I've thought of using a gas lens and rediculous tungsten stick-out but haven't tried it.

    What I've been using so far that's worked as well as anything is a 1/8" pure tungsten, a #5 cup which is about as large as can fit in the port, and about 20-25 cfm of pure argon. To reach way in I have to stick the tungsten too far out and have a lot of problems with oxygen contamination and arc wander around to other parts of the port as it's almost impossible to get much of an angle at the floor of the port. The part of the port near the exit is a piece of cake by comparison.

    The first pic I've attached is an unmodified port - It's hard to see but you should be able to get relative size by the torch - it's a WP20 size with a #5 cup.

    The second and third pics show partially modified ports.

    The fourth pic shows a partially modified port on a later model head, with much more shrouding around the exhaust port exit making it even harder to reach in the port.

    I do have a weldcraft water cooled bendy torch that's straight, but it's no smaller around than the #20 with the gasket under the cup, so it won't help in this case. Would be the bomb probably in deeper slightly larger ports.

    So far my best success for getting weld far enough in to reach the "short side turn" and make an effective change is to put a blob of filler partway into the port, and use arc blow to shove some of it in farther. I'm definitely maxing out my maching trying that, and it takes a lot of weld/grind/weld/grind cycles to do anything remotely effective.

    I've been doing a lot of research both here and on weldingweb.com and it looks like some of you might really be able to help with some advice on gasses, etc. Also, if anyone has any ideas about arc redirection or how to weld in really tiny ports.

    Now - these don't have to be quality welds, inclusions are even okay I suppose though I like to do quality work always. What I'm doing is reshaping the ports for better flow and proper size. We've learned a lot about proper port size and shape since these heads were made.

    From what I've read, it looks like I want to experiment with helium mixes at least, possibly straight helium and DCSP. I do have an XMT300 with an HF-251 box in the shop as well (usually hooked up to a 22a wire feeder) - which would entirely solve the power problem if DCSP and helium is the answer.

    It also sounds like a helium/argon mix with the Syncrowave might be worth trying, either buying a bottle of mix or trying to mix my own from a separate helium bottle and a y fitting. I've been watching ebay for a smiths mixer for several months, and I'm sure I will eventually fine one, but right now they're not coming up.

    My inclination is to buy a bottle of helium and try both about a 50-60% mix of helium/argon with the syncrowave on AC and a y fitting, and straight helium and DCSP with either the syncrowave or the xmt.

    Any advice appreciated. If I can make this significantly easier and quicker than it is right now I think there'll be a market for modified ports. As it stands I'm doing this for my own racer and a couple of my sponsored "development riders."

    Thanks -

    Michael
    www.batemanracing.com
    Attached Files

  • #2
    I have afriend of mine that has about 5 torches hanging off his aero wave uses several torches with different configurations. the one has a clear cup on it so he can see through the cup abd the tungsten id inly about a 1/2".
    Its all about having the right torch for the job at hand,
    Be carefull with what your blasting with because it can empregnate itself into the aluminum, use a carbide with big flutes designed for aluminum and let the tig torch pull the contamination to the top and knock the suut of the top and keep cleaning untill theres no more suut, then you can try using filler metal after its clean.

    Comment


    • #3
      Glass

      Let me "ditto" Portable Welder.

      I'd be using a Pyrex cup - available at a good price from HTP America (1-800-USA-WELD). That will let you see exactly what you're laying down and where.

      Hope this helps. Please post the "afters" as well.


      Joe

      Comment


      • #4
        Are you familiar with the Titanium puddy, that alot of race engine builders use to shape and fix case porting and jugs. Most if not all use this especially if they are in the development stage of finding what porting style they will use. Is does hold up and even on exhaust ports with EGTS as high as 1350 degrees. I noticed you said its an exhaust port ...... so are you making it smaller ??? And it appears to be a 4 stroke so if so ...why make smaller ???? Are you trying to improve bottom and mid range more??? Just curious, as making them sammler is the only thing it could possibly improve to a point. The intake area is much better area for shape charging and obviously duration ....... just curious, looks like a sweet project.......... and good luck on the rediculously tedious porting......

        Comment


        • #5
          I've looked at the pyrex cups before - in this case it's physical size more than the ability to see that's the problem. Plus - the clear glass will get contaminated quickly in these ports - they're 40 years old and not particularly clean - but perhaps still worth looking at.

          Yes Plummer - they're 4 stroke heads. 40 years ago Honda heads were not particularly well designed from a flow standpoint. Both the intake and exhaust ports are too large, and the exhaust port is funnel shaped with the exit almost 1.5" in diameter. Proper size exhaust pipes for these bikes are around 1", so there's a nasty step back the wrong direction to hurt flow out of the port. The port should be more like 1", and we have learned that flat floor d-shaped exhaust ports flow and work best.

          I'm using epoxy in the intake port to fill it in and reshape it a bit - it doesn't need to be much smaller, just a bit (and more tapered in the right spots). It's not too badly shaped already, does need some work in the bowl and around the valve guide. The exhaust port is the one that's the most poorly shaped and reshaping it should really help these bikes.

          I haven't heard about the ti epoxy - anyone have a link?

          Thanks for the replies already!

          Michael

          Comment


          • #6
            Titanium epoxy wont work on the exhaust side,to much heat and to many heat cycles will have it breaking apart.can you make an insert and weld into the port? then all you would have to do is clean it up with a dremel or like wise.Good luck.
            Miller Pipepro 304
            Miller Bluestar 2E
            Miller Syncrowave 250
            Lincoln HD 175
            Victor Jr. torch
            Purox angle head torch
            Smith torch
            Atlas Lathe
            Bridgeport mill

            Comment


            • #7
              Originally posted by bateman147 View Post
              Hi all -

              I'm filling in the floor of the exhaust ports of some motorcycle heads for vintage racing. I've had some success, but it's sure hard and I could use some help getting "over the hump" so to speak.

              One issue is of course that the heads are 40 years old, and very contaminated. I've been bead blasting the ports, die grinding to clean and washing with carb cleaner or acetone (whichever I happen to have at the time). That seems to work ok, once I get going. Getting things clean enough to weld seems to take several iterations of weld/grind/weld/grind. They're of course way too small for a stainless brush, even a cut down one.

              Another issue is that I'm more than maxing out my machine - a Synchrowave 180 (and the breaker it's on). I could use more power. I am pre-heating before welding and it helps but not enough.

              The third issue is just a matter of size, the ports are very small and difficult to reach into far enough. I could use an arc bender... :-)

              It's very hard to reach in the ports at all, even with a way too small cup on the torch, especially as far in as I need to reach in and fill for best flow. I would usually be using a gas lens, but there'd be no way to see or put in filler with a gas lens setup - the cup would pretty much fill up the port. Also, the port forms a nice venturi to drag air into the weld no matter what you do with gas flow. I've tried using alum. foil stuffed into the valve seat with moderate success there. I've thought of using a gas lens and rediculous tungsten stick-out but haven't tried it.

              What I've been using so far that's worked as well as anything is a 1/8" pure tungsten, a #5 cup which is about as large as can fit in the port, and about 20-25 cfm of pure argon. To reach way in I have to stick the tungsten too far out and have a lot of problems with oxygen contamination and arc wander around to other parts of the port as it's almost impossible to get much of an angle at the floor of the port. The part of the port near the exit is a piece of cake by comparison.

              The first pic I've attached is an unmodified port - It's hard to see but you should be able to get relative size by the torch - it's a WP20 size with a #5 cup.

              The second and third pics show partially modified ports.

              The fourth pic shows a partially modified port on a later model head, with much more shrouding around the exhaust port exit making it even harder to reach in the port.

              I do have a weldcraft water cooled bendy torch that's straight, but it's no smaller around than the #20 with the gasket under the cup, so it won't help in this case. Would be the bomb probably in deeper slightly larger ports.

              So far my best success for getting weld far enough in to reach the "short side turn" and make an effective change is to put a blob of filler partway into the port, and use arc blow to shove some of it in farther. I'm definitely maxing out my maching trying that, and it takes a lot of weld/grind/weld/grind cycles to do anything remotely effective.

              I've been doing a lot of research both here and on weldingweb.com and it looks like some of you might really be able to help with some advice on gasses, etc. Also, if anyone has any ideas about arc redirection or how to weld in really tiny ports.

              Now - these don't have to be quality welds, inclusions are even okay I suppose though I like to do quality work always. What I'm doing is reshaping the ports for better flow and proper size. We've learned a lot about proper port size and shape since these heads were made.

              From what I've read, it looks like I want to experiment with helium mixes at least, possibly straight helium and DCSP. I do have an XMT300 with an HF-251 box in the shop as well (usually hooked up to a 22a wire feeder) - which would entirely solve the power problem if DCSP and helium is the answer.

              It also sounds like a helium/argon mix with the Syncrowave might be worth trying, either buying a bottle of mix or trying to mix my own from a separate helium bottle and a y fitting. I've been watching ebay for a smiths mixer for several months, and I'm sure I will eventually fine one, but right now they're not coming up.

              My inclination is to buy a bottle of helium and try both about a 50-60% mix of helium/argon with the syncrowave on AC and a y fitting, and straight helium and DCSP with either the syncrowave or the xmt.

              Any advice appreciated. If I can make this significantly easier and quicker than it is right now I think there'll be a market for modified ports. As it stands I'm doing this for my own racer and a couple of my sponsored "development riders."

              Thanks -

              Michael
              www.batemanracing.com

              Michael,
              At work I use a weldcraft MT125 I believe, It has a skinny neck and uses quartz cups, Ideal for ports. Preheat to about 450 F on air cooled heads ( they arent heat treated normally ). Watch out on some of the older castings as they used a high copper content, using 4043 can cause some issues as a weld likes to have either a few percent si, or a few cu, but not both! Thermal cracking issues can follow. 4145 is the preferred alloy on the high copper castings common in the older cylinder heads, but do your homework first.

              -Aaron
              "Better Metalworking Through Research"

              Miller Dynasty 300DX
              Miller Dynasty 200DX
              Miller Spectrum 375 extreme
              Miller Millermatic Passport

              Miller Spot Welder
              Motor-Guard stud welder

              Smith, Meco, Oxweld , Cronatron, Harris, Victor, National, Prest-o-weld, Prest-o-lite, Marquette, Century Aircraft, Craftsman, Goss, Uniweld, Purox, Linde, Eutectic, and Dillon welding torches from 1909 to Present. (58 total)

              Comment


              • #8
                As far as eliminating the venturi effect your getting I'd try to run an argon purge. The positive flow of the argon will keep air from sucking back into the port while welding. I'd recomend using premixed argon/helium till you find a gas mixer before I'd go with a Y conector. You cant't garuantee that the gases will mix properlywhen they combine when using a Y conector.

                Comment


                • #9
                  head trouble

                  bateman 147
                  is there any way to purge through the head?
                  gil

                  Comment


                  • #10
                    Originally posted by Portable Welder
                    I have afriend of mine that has about 5 torches hanging off his aero wave uses several torches with different configurations. the one has a clear cup on it so he can see through the cup abd the tungsten id inly about a 1/2".
                    Its all about having the right torch for the job at hand,
                    Be carefull with what your blasting with because it can empregnate itself into the aluminum, use a carbide with big flutes designed for aluminum and let the tig torch pull the contamination to the top and knock the suut of the top and keep cleaning untill theres no more suut, then you can try using filler metal after its clean.
                    Your right portable, Razor is the MAN!!!! He uses a mt125, wp17 flex, a speedway wp-20, and i can't remember the other 2. I've learned a ton from him. I can beleive he doesn't have a dyn 700 yet.

                    Anyways,

                    Doesn't matter what you do, you will always fight the carbon from combustion. They are probably real pourous. Helium mixes help. I run 75 he / 25 ar big thick cylinder heads {bb chevy and the likes} and 25he / 75ar for the small stuff {harley , intakes, and misc aluminum.} You have to be careful with helium mixes. It makes things so hot that you can get straition cracks in the toes of the weld bead.

                    They do make long skinny cups that you may be able to get down in there. I think lava makes the cups. The problem with the mt-125 for the air cooled app is that it tops out at 50a. Heck the water cooled version tops out at 125 with the glass nozzle and 160 with the quartz nozzle.

                    I feel your pain with the old crusty heads. I currently have a set of old harley flat heads that are a mess. They look clean, but the carbon and oil keep leaching up into the weld puddle.
                    Mike. R


                    Dynasty 300dx tig runner w/ 3 torch Versa-Tig torch changer {wt-20f, wt-24f, mt-125}
                    MM 251/30a/4015 roughneck
                    Miller portable spot welder
                    Inferno >>> Big Window Elite

                    Comment


                    • #11
                      Heh there BlackPlague your right Razor is the best.
                      One of these days if I get the right job I just may make the investment on the multi torch box, but as of right now I take my Dynasty 300 out to my customers for the right tig aluminum jobs and the multi torch box may make it to inconveniant.

                      Where are you out of Backplague, My company is Alexander Welding my shops in milan but I'm originally out of Garden City.
                      We may know alot of the same people alot of my friends are Drag Racers.

                      Comment


                      • #12
                        Hey portable,

                        I run Ridings Welding Service out of washington twp. I bet we know a lot of the same people. I'm known for transmissions and converters long before the welding took over my life. I got a 3 place versa-tig off e-bay 2 yrs ago right before christmas for 750.00 shipped and that had two torches with it as well. It was a major score. It's handy when welding cylinder heads. I made a little stainless stand to put it right above the power source on the tig runner. I find it funny going from a 330a/bp to the dyn 300 the space and power you save!!!.
                        Mike. R


                        Dynasty 300dx tig runner w/ 3 torch Versa-Tig torch changer {wt-20f, wt-24f, mt-125}
                        MM 251/30a/4015 roughneck
                        Miller portable spot welder
                        Inferno >>> Big Window Elite

                        Comment


                        • #13
                          Originally posted by 1428turbo View Post
                          Titanium epoxy wont work on the exhaust side,to much heat and to many heat cycles will have it breaking apart.can you make an insert and weld into the port? then all you would have to do is clean it up with a dremel or like wise.Good luck.
                          As I have seen Ti puddy fail once in a 2 stroke with NOS, but I have also seen it do just fine for many trail miles and lake race events and Asphalt runs. Normal trail EGTs of 1050-1250 . 1250 on the long miles of WOT throttle . And normal 1080's at 8000 RPMs for all day riding cross country or just a rip down the trail. 14.7:1 on the race heads and 12.5:1 comp on the trail heads.

                          I am guessing but I am thinking this motor prolly won't see that high for very long and since its a 4 stroke there is no worries about scavaging gases drawing puddy back in the cyl.. So unless its gonna see 1300-1400+++ It might be worth more research.

                          Bateman, nice info. I guess I am thinking and this is just my opinion that maybe an alteration to the flange would work also. I would think that the biggest EXH outlet would also help to cool EGT's and provide Optimum power. If the back pressure is there from the step down to the flange then heck yeah that is a big issue with the gas escaping and probabbly effecting intake flow as well. Good luck and great info in the thread.


                          Hello to the Michiganders, I live at Milan Dragway on Wednesdays and the occasional weekend. About 5 miles from Washington TWP. Shelby TWP.

                          Check out the CK worldwide INC, website they have plenty of tig torches you probablly could put to use. They are cheap too. WP-20-25 FV weldcraft = 192.00 and the same torch but also with a flex head from CK and its 122.00 but also includes Tung,cup,and collet. Check the CK24 and the CK200T. I have been told these are great Torches and supposed to be cooler running than the rest of the market. Fitings are all mechanical , no wire ties or presso fittings.

                          http://www.ckworldwide.com/master.htm

                          Comment


                          • #14
                            Thanks everyone for the ideas and encouragement -

                            I'm only marginally interested in the putty at this time Plummer as I like to weld - I'm really hoping to make the welding work. I will definitely keep it in mind though. The torch I'm using now is already a wp 20, and I do have #24 torches as well, though they're too big to fit in the port and air cooled, so not enough amp capacity.

                            I'll be trying an even hotter preheat - folks have mentioned up to 500 degrees -I'm definitely not that hot yet - probably 3-400 tops.

                            I am interested in the MT125 Aaron mentioned - but looking at the price I could see tying up 6-800 bucks in one all set up with consumables and spares, and breaking only one quartz cup would set you back 40 bucks!

                            If I can make enough dough doing these ports it might pay for a torch like that - but I would want to have stepped up to a dynasty before that I think, meaning I need to sell more port work and race parts, and vintage racers are notoriously cheap. Until they're getting beat consistantly...

                            These are low hp roadracers - a stock F-160 class (a gentleman's agreement sub-class running within 250 vintage) racer based on a honda 160 and pretty close to stock engine only makes 13-14hp. The 175's that these heads are for also run in 250 vintage, but make up to 25 hp. The 175's have better valve sizes in addition to 5 speeds instead of 4 and are run with less restrictive rules, allowing cams, etc. The "fast" guys are making 24-25 hp right now. My development rider (I haven't raced myself for a couple of years) is running a motor with my parts and ideas in it, and it's only making 18 hp at peak. But - he's walking away from the 24hp motors like they're tied to an anchor. Probably 10mph faster leaving the corners, with greater speed down the straight even. It's not all about peak power. Everyone is convinced we're running a cheater motor - don't believe that we're still running a stock cam and lightly shaved head without even any porting yet. Pretty easy to overcam a small motor with a wide ratio gear box... I can't wait 'til some sucker that's being beat by better riding and a more useable engine package ponys up the bucks to protest my motor - that'll be a good day for my ego. :-)

                            Everyone's running exhaust pipes around 1.25" - by my calculations these motors should be running closer to .75" for best gas speed - though the math does break down some for these small displacement bikes. I haven't had time yet to try a bunch of different pipe designs/sizes on these bikes, but the exhaust port in the head is definitely too large as stock and poorly shaped for flow.

                            Not too many people realize that there really should even be a step between the exhaust port and header - say a flat d shaped port where the exhaust pipe is larger than the d shape - the step discourages backflow through the exhaust port when the acoustic tuning of the exhaust system pulses are working against you instead of for you tuning wise. Can really help tune out the classic 2-1 dip in the power curve at 5k or so while making even more power on top.

                            Most motorcycles (at least up to the last couple of years) do better with smaller ports than stock - even on the intake side. It is really fascinating and what I like to do. I gave up an engineering career to work on bikes and cars at a shop called MAXRPM Motorsports in Washington (www.maxrpmmotorsports.com) I'm starting to see the fruits of all the years I've spent studying and doing - motors I build to my ideas regardless of the class and useage are consistantly fast. Of course there's always improvement to be had and I am by no means a great tuner yet. Just a good student.

                            I'm still interested in trying a helium mix for this - remember I'm not after quality welds here but build-up where I want it - it doesn't matter if this mix is off a bit if it improves things enough to make it work.

                            I'm also still interested in trying DCSP and straight helium, though I understand that for that I'd really need some pretty pure helium, and the ports are awfully dirty for DC work. It'd be an interesting experiment.

                            Thanks again for the good discussion -

                            Michael

                            Comment


                            • #15
                              Oh yeah -

                              as for purge I've been thinking of leaving the intake valves in and bolting a plate over the combustion chamber, purging up through the port from the back side so to speak - maybe with that I could try a super-extended bent tungsten and get some heat directed where I need it. Part of my problem with welding as deep in the port as I need to be is just flat the angle I'm welding at - the arc isn't really directed where I need it and most of the heat is glancing off. I'm sure the MT125 Aaron mentioned would help there with arc direction - who knows maybe I'll end up selling lots of port modification services and will be able to afford both a new dynasty and a couple of really expensive torches... :-)

                              Michael

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