How thin can you make a piston?

[Nutball]

How thin can the crown be without blowing a hole through it? How about the skirt thickness too? This would be useful info for making pistons lighter.

 

[huskihl]

The top ring pin will usually work it’s way out before the dome is too thin. I only left .070” above the pin. Not quite enough

 

[Nutball]

I'm thinking more about grinding from underneath, but good to know about the pin.

Maybe peen the aluminum around the pin to hold it in? Or come up with some method of drilling half way through the pin and installing another pin to lock it in, then peen over the second pin.

 

[popopboat]

Ive seen that someone posted a picture how he made a hole through the piston with the piston stop, crown was really thin, maybe half a MM or so... i was quite suprised.
but it was working prior to that, not sure for how long tho.

 

[Lightning Performance]

If your going to make it thin better coat the top with something to reflect heat.

 

[Nutball]

Good point. What about heatsink fins on the underside?

 

[drf256]

When I cut an 026 piston’s dome off, I’m only left with .010 in the center of the crown. Haven’t ever had and issue. The sides are unchanged.

 

[popopboat]

What do you use for cutting crown/skirts.
How much weight have you reduced?

 

[drf256]

What do you use for cutting crown/skirts.
How much weight have you reduced?

Not done for weight reduction, I’ve never even weighed.

The jug geometry is such that cutting the piston and squishband flat allows a physically lower exhaust roof than what can be achieved with the domed piston. I can get from around 94-96* stock down to 105 in most jugs.

This was Treemonkey’s idea originally. I just copied him.

 

[popopboat]

Not done for weight reduction, I’ve never even weighed.

The jug geometry is such that cutting the piston and squishband flat allows a physically lower exhaust roof than what can be achieved with the domed piston. I can get from around 94-96* stock down to 105 in most jugs.

This was Treemonkey’s idea originally. I just copied him.

Oh, i misunderstood, i thought that you were talking aout inside of the piston.

 

[Lightning Performance]

When I cut an 026 piston’s dome off, I’m only left with .010 in the center of the crown. Haven’t ever had and issue. The sides are unchanged.

I'm guessing that would fail on a bigger saw bore. Amazing what you can get away with in a 45mm and smaller bore sizes.

 

[Ketchup]

I took a piston down to .040 above the ring pin in a top handle. Pin never moved but the saw had other problems.

 

[Nutball]

I took a piston down to .040 above the ring pin in a top handle. Pin never moved but the saw had other problems.

like what??

 

[Ketchup]

Piston fit. I tried to put a trimmer piston into it but the wall tolerance was too close. It heat transfered in weird splotches. Didn’t really make much power either.