rcrobby82

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Hello everyone, I recently aquired a 60cc McCulloch engine from a pro mac 610 chainsaw, i will be mounting it on a 27% edge. I was wondering if anyone has converted this engine before, what results they got (prop,rpm) but most of all what did they do for a muffler? i can use a inverted style or a wrap-around style but have had no luck in finding any information on this engine. Please help me if you can with any information,links. thanks!!

KenLambert

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this was one of my first conversions ,while it is on the HEAVY side it has a long stroke and don't seem to turn the RPM's it will fly the plane i still have one on the shelf.If you take it apart ( unbolt the rod from the crank) whatch for all the pesky needle bearings going every where. good luck.

rcrobby82

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what type of muffler were you using? i dont plan on tearing the engine apart that far. thanks for the pointer

KenLambert

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I make the mufflers from aluminum .I make them for all type engines

KenLambert

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this is a pic of the engine , I made this one before I had any machinery or tig welder so it looks a little rough,(ok a lot rough)

rcrobby82

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i see in the pics it looks like you have copper tubing or something blocking the crankcase hole, how did you go about perminantly blocking it off? i see you have it set up for EI, which system did you use? this is my first gas engine, and conversion so i do not know much about them yet, how much if possible would it be to make a muffler for me. i have a lot of ideas but dont know which way to go (the cheaper the better, but still reliable) i also have been told thad needle bearings are not that good for aircraft engines? any discussion on that? thanks again for all the help!!

KenLambert

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these have rollers the needle bearings are on the rod which are fine a nice muffler will run 35.00 shipped ,i used c-h ign.and the hole in the case has a nipple with a peice of fuel tubing pluged, you could judt put a srew in it ,i was going to use it for a smoke pump eventually .if you want a muffler let me know.

Rupurt

Ken

What diameter electrodes are you using, the smallest i can get locally are 1/16. Have you tried the 0.40 if so do you think its worth ordering them. I am trying to weld 0.5mm ally sheet, I can do it with the 1/16 tungstens but the bead size is a bit big.

RunningMan

Are you using pure tungstun? If so try to get some zerconiated (zerconium) tungstuns, as they will hold a sharp point on AC instead of the blob at the end that you get with pure. Makes Tig welding thin aluminum a lot easier. Of course Thoriated tungstuns don't work on AC.

Steve

Rupurt

Thanks runningman i do indeed have zirconiated tungstens. Here in South Africa these machines arent very common and there are even less people welding thin ally. The local lincoln electric agent has actually got a box of 0.40(1mm) zirconiated electrodes but unfortunately they dont have collets and collet bodies and they havent been able to find any for the last 3 months.(as if they actually looked)

So what i am really trying to say is will a thinner electrode help with welding the thin aluminium.(sorry aluminum)

KenLambert

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the smallest I use at this time is the 1/16 pure ground to a fine point

Rupurt

ok, cool thanks.

rcrobby82

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that muffler sounds like a cool deal,could you give the dimensions of it so that i can make sure it wont interfere with anything in my engine compartment, is there a possibility of a wraparound style muffler, if so how about some dimensions on that too. what kind of performance gains/losses does your muffler produce? sorry for so many questions i am trying to learn as much as possible. again thanks for all the help!!

KenLambert

My Feedback: (107)

I can make either one a wrap around would run 85.00 shipped and you give me the demension you need it to be and that way it is made for your application and there is no problem with fit ,That is for either muffler

RunningMan

Are you using a foot pedal or a switch? Welding thin stuff is really more about technique than equipment. Small tacks first about an inch or so apart, then skip weld it fully. The point is to keep the part from getting too hot. Copper heat sinks near the weld help alot. Use the thinnest filler rod you can get, and just get a puddle started on both pieces and dip the rod guickly to fill the puddle, and move on. Takes practice but once you get the rythem it goes easily.

Steve

Ps It sometimes helps have your shielding gas directed at the back of your weld, for instance filling the muffler with argon by tapping of the supply line from the torch.

Rupurt

I am using the foot pedal. Thanks for the advise. Good equipment helps (If I hadn't forked out for the auto darkening mask I think I would probably still be producing scrap) but i do agree "it's all in the wrist".

rcrobby82 I apologise for hijacking the thread.

KenLambert

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I also use the foot peddle

rcrobby82

My Feedback: (14)

i will have to get some dims( i have to mount the engine on the plane first) it looks like ill be getting a muffler from you. no offence taken rupert i work at steel fab place doing CAD work for them, i have welded before myself so your conversation is interesting to me anyway, never tried tig though(mostly mig, stick) so have fun!!

Rupurt

Steve.

I have the lincoln precision tig 185 and its got a AC wave balance control knob to adjust the cleaning and penetration is it a good idea to put it in the middle or should I have more cleaning (Electrode positive i think) becuase penetration isnt really an issue, the only problem I have with that is the torch gets hot quickly and the electrode balls up.

KenLambert

My Feedback: (107)

I have mine set on 2 (miller sycrowave 180 new style digital ) it seems to weld good as far as the machine .I am getting alot better each time I use it .My torch will heat up but not that much . I use it without gloves

Rupurt

How do you suppose bcm weld their mufflers. I would like to be able to weld like that but its probably automatic welding which I could never hope to replicate.

Hey Ken why dont you setup a cnc welder you appear to have the expertise.

KenLambert

My Feedback: (107)

If only I were that smart and had the means

Rupurt

Just a thought? My farther does a lot of work for a company that makes catalytic converters they have hundreds of automatic welders, all mig though.

RunningMan

With pure tungstun the electrode is SUPPOSED to form a molten ball. To use a pointed electrode you have to use the ziconiated tungstun. Clean your surfaces well with a STAINLESS STEEL wire brush, regular steel introduces impurities that make holding a steady arc difficult. Also connect your ground to a piece aluminum plate and weld your piece on that, welding aluminum on steel causes arcing and makes good control difficult. Also grind the tungstun to look more like a needle then a pencil ie a fine gradual point and grind it so the grinding marks are parallel to the long axis that is hold the tungstun tangent to the grinding wheel.
As far as balance is concerned its probably best right now to center it. It basically adjusts how much current is moving from the workpiece to the electrode, which heats the electrode more, and how much moves from the electrode to the workpiece, which blasts the surface more.
Not a good idea to Tig weld without gloves, all the short wave UV can start a melanoma. not a good thing.

Good Luck

Steve

Journyman Welder, Naval Ship R+D Center '78

Rupurt

Thanks Steve. I worked most of that stuff out already(cleanliness so important!) and I always weld with long sleeves and gloves but my zirconiated electrodes always form a ball straight away. They are the white tips so I assume they zirconiated.

Thanks guys very much for your help talking to experienced people is invaluable.