Can you weld an aluminum piston?

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I'm going to be working on a tractor engine project. Will be looking to increase the bore and can get the sleeves and piston size I want stock, but the pistons look like the pic and need to be flat top for an older indirect injection engine. Can they be welded and withstand diesel compression and heat and if so what is the best way to weld them up. Attached ImagesLast edited by welderj; 11-03-2013 at 10:54 PM.
Reply:I would contact some piston builders and have a set made, or find out who makes these and have them leave out the cupDynasty 200DXPassport plus w/ spoolmate 100victor 315c oxy/(act and prop)Miller digital elitemilwaukee power tools
Reply:I wouldn't weld them, too many things to go wrong not to mention adding a bunch of weight to the thing. Like turk said, I would contact the manufacturer and ask them about getting a set of flat tops made, they may even have a part number that will work in their catalog.
Reply:Pistons are actually usually not round, they are sometimes narrower on one axis, so they are perfectly round when they heat up.  I would not weld them, unless there is a way for a machine shop to check and balance them.  There is probably a way to find them commercially from a good machine shop.
Reply:i wouldnt weld them.
Reply:I have checked with custom piston makers and can get them. There is also a way to get it done with pistons from another tractor brand, but that requires changing the rods too. I will do that if necessary, but what fun would that be since I have a good tig and spool gun just sitting in the shed unused. LOL If noone has done it then it will be plan B I guess.
Reply:I'd send a PM to rojodiablo. He has welded pistons before, for performance gains if memory serves.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I have seen pistons welded.  A a race shop I worked at we had a customer break a valve and ding the piston a few days before a race weekend.  We pulled the engine, replaced the head, and had the ding in the piston welded up.  The welder put the piston in water so that the skirt would maintain its heat treatment.  After welding the piston was dressed with a file, put back in, and the engine ran the whole race weekend.  It was replaced after that weekend, but it did work fine for a few days.
Reply:I guess you could cold weld it like Rojodiablo did. I would chance it. Never let the haz go into solution, and especially the skirts. My choice of filler would be 4943.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:That's how performance pistons used to be made to save big $$$$.The L-88 for my '67 Camaro had standard 12.5:1 piston domes that were welded up and shaped to the combustion chambers to yield 13.2:1.  Long time engine build Tony Feil out of NJ did the work way back in the '70's.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:You have to be careful. Most pistons are cast aluminum alloy and some are forged aluminum alloy. They are not pure aluminum.  Balancing is another issue and you must be careful not to heat damage the ring grooves.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:look up the word hypereutectic and how It relates to pistons. Then forget about welding pistons for diesel enginesLast edited by propanehotrod; 11-04-2013 at 04:20 PM.Lincolin Power Wave 450, Lincoln Powermig 255, Lincoln Pro Mig 140, Lincoln Squarewave Tig 275, Miller Big 40 G(with Hobart Hefty suitcase), Thermal Arc 95S and Esab PCM875 in an already full machine shop.
Reply:Originally Posted by snoeproeYou have to be careful. Most pistons are cast aluminum alloy and some are forged aluminum alloy. They are not pure aluminum.  Balancing is another issue and you must be careful not to heat damage the ring grooves.
Reply:Originally Posted by propanehotrodlook up the work hypereutectic and how It relates to pistons. Then forget about welding pistons for diesel engines
Reply:Now pistons have quite a bit of silicone in them.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Playing with a Case? looks like it from memory.Miller Big 40GMiller HF-251 D High FreqVictor OA Lincoln 135 MigMK 3A CobramaticBridgeport J HeadCronatron OxylanceRadnor ACAG TorchWeldcraft TIG Torches1 blown knee and two 5 Gallon pails away from being a hero.
Reply:The pic came from a case 2394 I just overhauled last week. Thinking about putting those 4 5/8" pistons in a 400 diesel that has 4" now. Did a 930 once before, that started with 4 1/8" but changed the heads on that one to direct injection so the pistons were not a problem. The pulling rules have changed now tho and require stock head type. You can use pistons from a G1000 moline, but you have to switch rods to use them and I just thought this would be more fun. Besides who wants Moline parts in their Case? LOLLast edited by welderj; 11-04-2013 at 07:49 PM.
Reply:Lots of higher HP forged pistons are 2618 alloy, which is crack sensitive when arc welded. http://www.kaiseraluminum.com/wp-con...oduct-2618.pdf4032 is the other forged aluminum alloy commonly used, it is mildly weldable, but not great:http://www.kaiseraluminum.com/wp-con...ducts-4032.pdfI wouldn't try it on any of the cast/hypereu. pistons out there.Thermal Arc 186 AC/DCHobart Handler 125
Reply:Thanks guys, guess I'll have to do some more thinking on this one. I sure was hoping you would all say it would be easy and work great. LOL
Reply:Originally Posted by welderjThanks guys, guess I'll have to do some more thinking on this one. I sure was hoping you would all say it would be easy and work great. LOL
Reply:Originally Posted by welderjThanks guys, guess I'll have to do some more thinking on this one. I sure was hoping you would all say it would be easy and work great. LOL
Reply:Why not just shave the head?...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:It has to be a flat top piston because it's indirect injection. This is going in what was the first type diesel engine where rather than the fuel spraying down onto the piston it sprays across from one side the head to the other into a chamber and burns out of that. If you shaved the head enough to get the compression you need you would be into the injectors and powercel area.
Reply:deck the blocktackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:I'm big into building engines. maybe you could weld pistons back in the 70 and 80s but don't weld the newer ones.   A piston is not even close to being round it has many different curves built into it.  So when it heats up it is round around the ring lands and barrel shape on the skirts .  If you look at the forces acting on the piston and rods . It's not something you want to have let go while revving the engine . You can have custom billet piston made pretty cheap some times if your not in a rush