Thats some beast of a turbo when its next to the engine!
Tuning turbo time!
- Thread starter craigb244
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Tuning turbo time!
Scary stuff! I've never heard of anyone doing it. Hope you get away with it.
OP
OP
i looked online and seen people weld forged pistons after valve impact damage. people (americans) weld standard pistons to raise compression for use in methanol drag racing.
LOADS of people weld up holes in the pistons of 2stroke engines after melting a hole in the middle by running lean.
all of these are on top of the piston. mine is only on the underside and purely for strength.
LOADS of people weld up holes in the pistons of 2stroke engines after melting a hole in the middle by running lean.
all of these are on top of the piston. mine is only on the underside and purely for strength.
i dont see why i shouldnt work, but then would the pistons not be off balance and cause more wear on certain parts of the of the cylinders?
OP
OP
they are off balance by my machining. we added enough new metal to bring the weight back to standard
You can't really take much from the drag or 2 stroke people. On the drag cars pistons, spark plugs and aluminium con rods are pretty much disposable items.
I'd worry about distortion (especially as yours are cast pistons) and temper (which, combined with material spec, is what imparts strength to aluminium alloy components). People weld up cylinder heads, but they really need to be heat treated to restore temper (and often distort so much that they are rendered scrap anyway). Cylinder heads have a direct path to the coolant, while the path for the piston is via the ring lands, so the latter are under much more heat stress. Incidentally, one of the many causes slated for K series (and other) HG failure is heat soak back from the exhaust manifold softening the head.
But I hope you get away with it.
I'd worry about distortion (especially as yours are cast pistons) and temper (which, combined with material spec, is what imparts strength to aluminium alloy components). People weld up cylinder heads, but they really need to be heat treated to restore temper (and often distort so much that they are rendered scrap anyway). Cylinder heads have a direct path to the coolant, while the path for the piston is via the ring lands, so the latter are under much more heat stress. Incidentally, one of the many causes slated for K series (and other) HG failure is heat soak back from the exhaust manifold softening the head.
But I hope you get away with it.
OP
OP
hey I've done worse and come off. if it fails all I loose is a set of pistons at which point ill most likely splash out on a forged set
btw the drag car I mentioned was a guy doing it on the cheap lol and it worked
I don't see how 2strokes are differant. they take more force then our engines ever will and one a seen was from a snow mobile which are usually super charged
btw the drag car I mentioned was a guy doing it on the cheap lol and it worked
I don't see how 2strokes are differant. they take more force then our engines ever will and one a seen was from a snow mobile which are usually super charged
2 stroke pistons are generally lighter and better cooled. Difficult to equate 2 stroke forced induction with 4 stroke. They don't really take more force (which isn't the issue, anyway) but less force more often! BWTH
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yeah I know what you mean.
the welder (buisness next door to work who just tig weld alloy for all kinds of stuff) seems to think they will work perfectly
its going to be intresting
the welder (buisness next door to work who just tig weld alloy for all kinds of stuff) seems to think they will work perfectly
its going to be intresting
OP
OP
yeah if it works it will be great. obviosly it is going to depend on the quality of the tig wrlding. I spoke to the welder today about what fingers said. they did it with very little heat input and he said the alloys original strength won't be effected.
they used high silicon 12% filler which is what the pistons are made from
they used high silicon 12% filler which is what the pistons are made from
sounds good so, and tig is usually very low amp welding so hopefully you should get away with it, my only concern would be the exact balance of the piston but cant imagine it being a problem straight away so will be very intresting to see, hope it works out , fingers crossed
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yeah the welding is a work of art. ill get photos once I pick them up.
what is your ballance worry exactly? the weight should be within a couple of grams of original
what is your ballance worry exactly? the weight should be within a couple of grams of original
pics would be great
im just worried that say for example there a little bit more weight on 1 side of the piston, althought you have the overall weight around the same it might look evenly distributed but id would guess they may be off balance on certain perticular spots on the piston but dont quote me on it
im just worried that say for example there a little bit more weight on 1 side of the piston, althought you have the overall weight around the same it might look evenly distributed but id would guess they may be off balance on certain perticular spots on the piston but dont quote me on it
OP
OP
ahh that's not a problem. remember that one half the piston has large valve cut outs for intake and small on other for exhaust so they where not ballanced in that way
Very low amp?? The tig welding I do isn't really very low amp.
Not welded much ally but the stuff we did do required preheating and a fair amount of amps.
And balance, pistons are balanced with overall weight. Just make sure all four are the same weight and they'll be ok.
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no idea I leave it to the pros lol we welded a alloy head at work and that did require pre heating and high amps but that's a large lump of alloy. pistons are nothing so be like tiging sheet.
Yep. Obviously the thinner a bit of metal, the less heat will be required. But, regardless of process, you'll need to put much the same heat in -- the metal doesn't know what kind of welder you're using and won't alter its melting point accordingly.
My TIG goes down to 5 amps, but this only means it will weld thinner metal than my MIG, nothing more.
My TIG goes down to 5 amps, but this only means it will weld thinner metal than my MIG, nothing more.
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...yeah... either way the people who did it reckon it will be all good. and as they are professional alloy tig welders then i dont doubt their words.... only time will tell for sure...
