What's on your bench?

[ny15]

So secretive

 

[MustangMike]

Mike......my eyes ain't good enough to see them pictures my friend.

You do open up the thumbnails, right?

 

[mdavlee]

You do open up the thumbnails, right?

They're still real small on the PC

 

[dall]

the pictures are taken from to far away need closer pics

 

[MustangMike]

OK, Close Ups:

 

[MustangMike]

Pulled that stupid saddle to get the close up pics, was trying to hold the phone camera in one hand and a light in the other, and ripped my finger open on the felling spike! Paper towels were close by, and controlled it.

Hey, that saddle is not T-27, it is T-20, guess they don't want you removing it. Surprised I did not have to "break free" either of the bolts holding it, but they were snug and seemed to have mild resistance all the way out.

 

[mdavlee]

It does line up. There was something caused that to break but I don't think there's enough slop to hit with the cylinder on.

 

[MustangMike]

I'm thinking if the tolerances are real close and the piston got over heated, it may have touched. I can't find anything else to blame!

 

[MustangMike]

I don't know how to save it, but when I expand photo #1, I can see a slight dent at the end of the nipple, and "damage scratches" on the inside of the case above it. I can also see them in photo #3, but it is blurry in that one.

I'm now all but sure this is what happened.

 

[paragonbuilder]

I still find it hard to believe that piston would break and the impulse nipple look unscathed...


Sent from my iPhone using Tapatalk

 

[MustangMike]

Not totally unscathed, and a hot piston at 15,000 RPM may be very brittle.

 

[dall]

i dont think the nipple would hit either it may stick out of case but the case is indented

 

[mdavlee]

I bet the piston broke first and the piece came loose and hit the nipple. The crank pushed it all around in the case as well.

 

[dall]

you can see scuff marks in the case so i am with mike here on this one

 

[MustangMike]

OK, then why did this happen?

I just checked it again. If you look straight down, perpendicular to the base, the nipple does protrude a bit. If you take a straight edge, go across the bolt holes in the cylinder to see where the piston would be, then a straight edge across the bolt holes in the case, it is very, very close.

I'm not convinced it did not get hot, expand a bit, and contact it. You need about 20/1000 gap in the squish to make up for expansion, and the dome is a lot closer to the pin.

I'm not sure that I'm right, but I will tell you, the tolerances are very tight.

I think before I re assemble, I will block off the crank with a piece of paper and take my 12V sharpener with a diamond stone and take it down a bit. It can't hurt.

 

[dall]

clean it good when done grinding it down and make sure the nipple is clear

 

[VinceGU05]

i still dont like the look of the color inside the case. crap mix or fuel used i think. thin aluminium would deform and not break up if only touching it. if it was to hit the nipple by a 1mm plus i would say yeah for sure. i am still going with my original thoughts.

 

[VinceGU05]

can we get a close up of the piston from underneath?

 

[Stump Shot]

Who thinks of these things?

 

[dall]

Who thinks of these things?

View attachment 33757

that looks like a 026 carb