:::RHMT::: Real Home Made Turbo
General Category => General Discussion => Topic started by: AbaZ on October 26, 2009, 07:58:29 PM
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That is the question,
I have a cast aluminum piston that has a indentation in it about 3mm deep and about as round as the small end of a valve. So heres the question, Should it be welded? can it be.. and how long will it last?
The first thing you are going to say is.. fuck just buy a piston, but when dealing with buying/selling cars an extra 45 bucks for a piston and the 30 mins to press it out when your overbudget isnt going to work.
So how about just whizzing the top with a rolac and calling it good? Well that is what I normally do, however a couple cars ago that I sold came back with a dead cyl #1. I looked down the hole and that small 3mm indentation had burnt all the way through. So what I do now is pull every piston and check the bottom sides of the pistons to see if there is any cracks/marking.
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.realhomemadeturbo.com%2F2009%2Fmisc%2Fpiston.jpg&hash=8a6e564441909e4e8cfa040b7abce55e2ec25cef)
this is the piston, bad pic. I buy lots of 03-05 Kia Rio's with blown up tbelts and try to scrap them back together.
Any input would be appricated.
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JB Weld
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I'm no expert, but if you do weld it, I would get it clean clean clean where it's going to be welded, and bake it in an oven to get it preheated well before welding it.
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Welding it would be true to the nature of this website
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I would weld it. O0
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i want to see it welded
any tips Passenger?
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So how about just whizzing the top with a rolac and calling it good?
Ive done this a couple times on dsm failures with no issues.
Sold AS IS ;)
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deburr and run the bitch!
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my question is: how long does it have to last? that should determine your answer jeff. if it is going in a car you intend to keep for a while, i'd replace it with a new one. if it is going in a motor you intend to beat the piss out of until it grenades, then weld it.
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ok Beau just welded it, and complete failure. it distorted all to shit, the wrist pin is jacked.
ok next time I'm tapping it out. I like that idea.
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it was what, 1cc? it would have hurt nothing to run it
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ok next time I'm tapping it out. I like that idea.
+1
Sometimes c0mpl3x says something really good.
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it was what, 1cc? it would have hurt nothing to run it
Well no shit, its not the big burr that I'm worried about, its the underside of the piston when this happens. small chunks come off and make it thin. Then if you run it, just from combustion inside the cylinder it burns right through that hole.
I'm down for trying the tap/trick, what should I seal the threads with? JB weld 8)
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How many of these cars do you buy/sell ???
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I'd use a 1/4" pipe tap probably, 1/4" pipe plug, seal it with some JB, and grind it down flush. In for pics.
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How many of these cars do you buy/sell ???
5 this year..
like I said my piston is fucked I gotta buy one. I tried fitting some a6 pistons in, little sloppy.
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How many of these cars do you buy/sell ???
5 this year..
like I said my piston is fucked I gotta buy one. I tried fitting some a6 pistons in, little sloppy.
Awesome!
:D
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JB weld is only good with temp < 500F tho :-\
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And aluminum melts at the 1200F. Doesn't mean that the piston actually gets to those EGT temps. You've got 250F crankcase temps on the other side, as well as windage oil cooling it down, and the heat soaked up by the skirt/sleeve. If nothing else, it would be for plugging the gaps in the threads. If 2/3 of it melts, it still holds. You'll obviously want to use an aluminum plug. Just be careful with the sharp edges, since the threads alone are enough of a stress riser for cracks to form at.
This reminds me of some mag article I saw posted a year ago, and it was old itself ('99?). I think it was a Miata owner wanting mroe compression for racing, and he epoxied COINS (jb or devcon) in each piston dish. Didn't get detonation, just more power. IIRC it was a road-race class where you had to use all stock engine parts, and the rules didn't say you couldn't mod stock pistons. Supposedly they won half the races that season, before anyone found out - and let them keep the wins.
Cliffs: jb weld some big coin over the hole, get more power, call it a day. :noel:
btw found the link!! http://www.boostedmiata.com/technical/AC_05518.pdf (http://www.boostedmiata.com/technical/AC_05518.pdf)
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I figured you were dumping it without recourse
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FIX'D
J.B. Welding it would be true to the nature of this website
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Shit I am a bit late but I could told you this wouldn't have worked, not only did you distort the shit out of the piston, it would have lost all its temper, there are welding methods around this but its kind of tricky, not good for long term reliability. A 1/8" npt plug from the bottom side would have worked allright, but would add extra wear to your rod bearings, better than welding, but not quite as good as another non damaged piston.
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And aluminum melts at the 1200F. Doesn't mean that the piston actually gets to those EGT temps. You've got 250F crankcase temps on the other side, as well as windage oil cooling it down, and the heat soaked up by the skirt/sleeve. If nothing else, it would be for plugging the gaps in the threads. If 2/3 of it melts, it still holds. You'll obviously want to use an aluminum plug. Just be careful with the sharp edges, since the threads alone are enough of a stress riser for cracks to form at.
This reminds me of some mag article I saw posted a year ago, and it was old itself ('99?). I think it was a Miata owner wanting mroe compression for racing, and he epoxied COINS (jb or devcon) in each piston dish. Didn't get detonation, just more power. IIRC it was a road-race class where you had to use all stock engine parts, and the rules didn't say you couldn't mod stock pistons. Supposedly they won half the races that season, before anyone found out - and let them keep the wins.
Cliffs: jb weld some big coin over the hole, get more power, call it a day. :noel:
btw found the link!! http://www.boostedmiata.com/technical/AC_05518.pdf (http://www.boostedmiata.com/technical/AC_05518.pdf)
Holy crap, people have actually done it. What do you guys think? Should I try this on the next one I get? I have devcon and jb weld. Which to use? How hot does the top of a piston get in a completely stock NA 1.5l NA. What is JB weld rated at? or Devcon.
This is so backyard nig. I love it.
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i probably woudl have ground it down smooth, assuming there was enough material left. a few compression points in one cyl wouldn't keep you from flipping a beater
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The crown of the piston is always 1050-1100 degrees, boosted or NA.
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High temp lab-metal can withstand 1000F
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.caswellplating.com%2Faids%2Fimages%2Flab_metal2.jpg&hash=e108cdb67ada06b9fdf6e9ef1bf5b4c6b84c77c9)
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I'm wondering if that epoxy held it more with suction if it indeed melted some. The Devcon FasMetal 70 I have next to me is not intended for 250F+. My oil pump is still kicking with it inside, though. I opened it up after 2k miles to check.
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The crown of the piston is always 1050-1100 degrees, boosted or NA.
Mr. Davis what is your thoughts on JB weld ontop of a piston. How really is it? ;)
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I've put JBweld on my downpipe and it cracked and fail. I don't imagine how it is on a piston.
Only time I saw JBweld fail :P
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And aluminum melts at the 1200F. Doesn't mean that the piston actually gets to those EGT temps. You've got 250F crankcase temps on the other side, as well as windage oil cooling it down, and the heat soaked up by the skirt/sleeve. If nothing else, it would be for plugging the gaps in the threads. If 2/3 of it melts, it still holds. You'll obviously want to use an aluminum plug. Just be careful with the sharp edges, since the threads alone are enough of a stress riser for cracks to form at.
This reminds me of some mag article I saw posted a year ago, and it was old itself ('99?). I think it was a Miata owner wanting mroe compression for racing, and he epoxied COINS (jb or devcon) in each piston dish. Didn't get detonation, just more power. IIRC it was a road-race class where you had to use all stock engine parts, and the rules didn't say you couldn't mod stock pistons. Supposedly they won half the races that season, before anyone found out - and let them keep the wins.
Cliffs: jb weld some big coin over the hole, get more power, call it a day. :noel:
btw found the link!! http://www.boostedmiata.com/technical/AC_05518.pdf (http://www.boostedmiata.com/technical/AC_05518.pdf)
Hahahahahahaha. I'm hesitant to comment.
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The crown of the piston is always 1050-1100 degrees, boosted or NA.
Mr. Davis what is your thoughts on JB weld ontop of a piston. How really is it? ;)
Since we have a documented case of it working, I'd try it with a good measure of confidence. It's the same theory behond why EGTs are hotter than the melting point of the head/piston with no ill effects - there's enough engine/mass to help thermally transfer excess heat away from the "hotspots" so bad shit doesn't happen.
I'd use the 1000 degree stuff ktown posted up, though, if it were my labor. :mexi:
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Only time I saw JBweld fail :P
seen that a many times when people use it for radiator fixes
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Only time I saw JBweld fail :P
seen that a many times when people use it for radiator fixes
I've used it to fix cracked plastic radiator tanks many times. Just drill a hole to stop the crack from spreading, and JB it up. Our F150's been running a JB'd radiator tank for about a year, still not leaking.
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i'm talking holes in the aluminum tubes
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I have used JB weld to fix a rim that had a chuck missing from it before I powder coated it. The rim reach a temp of 400F for 20 min and the JBweld help up fine.
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I'm gonna jb weld these
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.realhomemadeturbo.com%2F2009%2Fmisc%2Fengineshit3.jpg&hash=2b30e3356aad1813bb4eb8805b7f76dd53206f29)
and if that works, I'll try this motor
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.realhomemadeturbo.com%2F2009%2Fmisc%2Fengineshit1.jpg&hash=3ee726eeb5f944ae1f69f1949b4704958f50b27e)
lol jk on both ;)
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Out of curiousity, what does a Rio with trashed timing belt sell for? How extensive is the engine damage, usually?
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Out of curiousity, what does a Rio with trashed timing belt sell for?
bout 500 or less out here.
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Out of curiousity, what does a Rio with trashed timing belt sell for? How extensive is the engine damage, usually?
depends on mileage, options etc etc. I try not to spend more then 500 on one with under 80k miles and semi straight. What you see in the pictures is about 75% on how they come to me. Sometimes I can clean up the pistons and slap a head on, or just replace 1 or 2 pistons. Really varies, I got the super hook up on parts, retail heads are 675, my cost is 430 (fully loaded brand new). They are not huge money makers for me. But they are so god damn easy to work on and sell fast. Someday I'd like to try and build one of these engines blindfolded. ;)
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Out of curiousity, what does a Rio with trashed timing belt sell for? How extensive is the engine damage, usually?
depends on mileage, options etc etc. I try not to spend more then 500 on one with under 80k miles and semi straight. What you see in the pictures is about 75% on how they come to me. Sometimes I can clean up the pistons and slap a head on, or just replace 1 or 2 pistons. Really varies, I got the super hook up on parts, retail heads are 675, my cost is 430 (fully loaded brand new). They are not huge money makers for me. But they are so god damn easy to work on and sell fast. Someday I'd like to try and build one of these engines blindfolded. ;)
I know a guy who retired from working for the Wyo. DOT. buy Kia Sophias, Rio, and Sportags usually between $100 and $500. Then fix them and sell them $1,500 or more.
He helps me find Honda/Acura parts in JY and his other connections.