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Discussion Starter · #1 ·
I recently tore into my 440 because I found some scaring on the exaust side of on piston. When I took the pins out, I noticed that both ends of both pins were blue-ish/purple. I haven't noticed this on others, but that is not to say that it doesn't happen. Can anyone confirm if this is normal?

Also the top(I think) ring of both slugs had some odd marks on them. Sort of like pitting, only on one side. It deffinately has texture to it. Almost like electrolosis? What in the hell causes this?
 

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I recently tore into my 440 because I found some scaring on the exaust side of on piston. When I took the pins out, I noticed that both ends of both pins were blue-ish/purple. I haven't noticed this on others, but that is not to say that it doesn't happen. Can anyone confirm if this is normal

Also the top(I think) ring of both slugs had some odd marks on them. Sort of like pitting, only on one side. It deffinately has texture to it. Almost like electrolosis? What in the hell causes this?[/b]

The bluish color on the pins is due to piston getting too hot.
The pitting on the exhaust side of the piston is from detonation.
Sounds like you were very close to burning down.
 

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The bluish color on the pins is due to piston getting too hot.
The pitting on the exhaust side of the piston is from detonation.
Sounds like you were very close to burning down.[/b]


exactly..... pins dont change from crome color to blueish without a ton of heat, pitting and cracked spark plugs is the sign of a motor that needed about 100 more yards of WOT to make its way back to the trailer via tow rope..... if your jetting is correct check your case seals. if that looks good look for scuffing on the intake side of the piston maybe water from snow dust of just det marks on the tops could be water in the fuel.
 

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Discussion Starter · #4 ·
I think I misled you.... It is the top ring of both pistons... Not the pistons themselves. Except for the scar on the one, they both are perfect. Good wash and plugs were fine.

edit, I will see if I can get some pics.....

[attachment=278875:1226061916.jpg]
[attachment=278877:0102071931.jpg]
[attachment=278881:bore.jpg]
[attachment=278882:cyl_head.jpg]
 

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does anybody know were the best place to get 440 pistons ?
 

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were those scores running thru the ex ports there when you put it together,or are they new? It looks to me like it was borderline lean,or had a lean spot.The streaks on the piston are from hot ex gasses,either getting past the rings down that score,or a defect in the ring at that spot.I think it got hot,why is up for grabs,butthe pitting you describe is detonation,and you could be getting it at only one spot ,or %of slide opening.In any event,those scores have to be removed.
 

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Discussion Starter · #8 ·
The streak is news to me. The engine until now, hasn't been touched. Begining of the year when I got it going from summer, the cyls were within 2 psi. I haven't noticed any marks in previous inspections. The only thing that came to mind is dirt of somekind could have gotten in when I had the pipe off during some service work earlier? Except for that one spot, both pistons and bores are perfect.

Where do you see that it was lean? I would have figured that if it was buring down lean, the edge of the piston would have been eroded away on the exhaust side?

As to where to get pistons, well if you have an 2001 XCF, 02', or 03' Pro-X fan, you're pretty well hosed. I think because each piston is exclusive to each year engine, no one will offer pistons for it. I downloaded Wiseco's complete piston catalog and they skip right over them. I have not seen anything from SPI either. If you want pistons, you will have to go to a dealer. $71.04 a piece.
 

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For what ever reason,I maintain that that piston was going into detonation,the scoreing in the cyl is caused when the ring heats up in the ex port opening and locally siezes to the bore.The heating is very localized at first,causing the minor scoreing at that point.The top of that piston was showing detonationat the silver spot. The wash eyes SHOULD extend outward from the transfers,you can barely see this. When it goes lean,the ring experiences the heat first,it expands and starts to stick in the bore at the hot spot,which is directly centered in the ex port.As it gets hotter,it sticks in the piston and the piston breaks in the groove.Then the heat has a real direct path and melts the area that broke. All this takes place in about 2 seconds.
Useing wiseco pistons will require increasing the skirt clearence to 0.004,or it will sieze worse,guarenteed.Clean up that cyl,use pol pistons and figure out why that jug is going lean.
Those blued pins should tell you the pistons are running hot. The piston crown heat will go to the easiest place,in this case the pins because they are directly under it.I'll bet the bearing cages on the rod small end are blue also,you should change them whenever you change piston/pin setups anyway.While its apart, I'd look REAL close at the rod small end bore as well for signs of overheating.If its discolored anywhere,the heat treat has been compromised and they are trash as well.
 

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I should have been clearer on the pistons i need. 04' liquid 440 $137.00 at the dealer
 

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Those are KITS,includeing rings,pins and clips ,right? Spend the bucks and do it right.
 

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Discussion Starter · #12 ·
trbomax, thanks for your input. I will take a look again at the bearings and rods. I don't remember seeing anything out of the ordinary.

As to the piston "kit", I don't think that they come with the rings and pins. On my engine, they are all sold seperatly. It does come with clips though....Woohoo!
 

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Yes that is the kit. IAPRO-X you are right. your parts all come seperate. I was hoping for a better deal from some littel known dealer in some out of the way town that is starving right now.
 

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For what ever reason,I maintain that that piston was going into detonation,the scoreing in the cyl is caused when the ring heats up in the ex port opening and locally siezes to the bore.The heating is very localized at first,causing the minor scoreing at that point.The top of that piston was showing detonationat the silver spot. The wash eyes SHOULD extend outward from the transfers,you can barely see this. When it goes lean,the ring experiences the heat first,it expands and starts to stick in the bore at the hot spot,which is directly centered in the ex port.As it gets hotter,it sticks in the piston and the piston breaks in the groove.Then the heat has a real direct path and melts the area that broke. All this takes place in about 2 seconds.
Useing wiseco pistons will require increasing the skirt clearence to 0.004,or it will sieze worse,guarenteed.Clean up that cyl,use pol pistons and figure out why that jug is going lean.
Those blued pins should tell you the pistons are running hot. The piston crown heat will go to the easiest place,in this case the pins because they are directly under it.I'll bet the bearing cages on the rod small end are blue also,you should change them whenever you change piston/pin setups anyway.While its apart, I'd look REAL close at the rod small end bore as well for signs of overheating.If its discolored anywhere,the heat treat has been compromised and they are trash as well.[/b]
well said, i agree. not that i know much and could have gotten into that great of detail. but i think he is right. NEEDED MORE FUEL. and you caught her in time brother. go OEM. :beerchug:
 

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Yes that is the kit. IAPRO-X you are right. your parts all come seperate. I was hoping for a better deal from some littel known dealer in some out of the way town that is starving right now.[/b]
That shouldnt be too hard to find around here,better hurry up though before they close up altogether !
 
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