piston weight

[steve316]

Piston speed on 3.250 stroke at 9250 rpm is 8170 fpm at 75.4 degrees ATDC with a 5.850 rod. A 6" rod sbc 400 with 3.750 stroke at 9700 @ 74 degrees ATDC is 9981 fpm. I would want the reciprocating weight as lite as possible that would stand up to the application.

[Stan Weiss]

Piston speed on 3.250 stroke at 9250 rpm is 8170 fpm at 75.4 degrees ATDC with a 5.850 rod. A 6" rod sbc 400 with 3.750 stroke at 9700 @ 74 degrees ATDC is 9981 fpm. I would want the reciprocating weight as lite as possible that would stand up to the application.

Steve,
We are not talking the same thing. You are talking peak and I posted up mean / average.

Bore = 4.75 Stroke = 3.525 Rod Length = 6.0 RPM = 10500
Piston Speed is 6168.75 Feet per Minute 1880.235 Meters per Minute
Maximum Piston Velocity 10101.86 FPM @ 74.7924 Degrees
Piston Travel from TDC 1.54627 Inches 39.27519 mm
Bore Rod Angle 16.46702
Cylinder Volume 27.40070 CI 449.01706 cc
Crankshaft Degrees at which Rod and Crank are 90 Degrees 73.62984
Piston Travel from TDC 1.50899 Inches 38.32831 mm
Bore Rod Angle 16.37015
Cylinder Volume 26.74010 CI 438.19173 cc

Stan

[Ron E]

When I was last involved a few years ago, piston deck thickness was as thin as .150" on 4 sq. In. deck sections of competitive 4.750" bore 500" pro stock car and 5.125" bore 160" pro stock bike programs.

Saw Stan posted some piston speed calculations.
Was working with a 825" pro stock program, he was turning 8800 rpm with a 5.750" stroke, makes my head hurt lol.

Along the same theme, the blown allky P/M,s and alcohol funny cars have been going north of 11K RPM. A 526 has (I think) a 4.25" stroke. And, those parts can't be very light...can they?

[David Redszus]

When I was last involved a few years ago, piston deck thickness was as thin as .150" on 4 sq. In. deck sections of competitive 4.750" bore 500" pro stock car and 5.125" bore 160" pro stock bike programs.

Saw Stan posted some piston speed calculations.
Was working with a 825" pro stock program, he was turning 8800 rpm with a 5.750" stroke, makes my head hurt lol.

Along the same theme, the blown allky P/M,s and alcohol funny cars have been going north of 11K RPM. A 526 has (I think) a 4.25" stroke. And, those parts can't be very light...can they?

A 4.25" stroke at 11,000 rpm will have a mean piston speed of 39.58 m/s (7791 ft/min).
More important, it will produce 9892 Gs on the rod. Multiply the piston weight by 9892 to determine the restraining force necessary.

A piston weight of 450 g (16 oz) would become a force of 14700 lbs. How much does your pick-up truck weigh? Would you consider hanging two of them from your con rod?

Since fatigue is a function of reversing force times number of cycles, it is easy to see why components are replaced very frequently.

[LSP]

When I was last involved a few years ago, piston deck thickness was as thin as .150" on 4 sq. In. deck sections of competitive 4.750" bore 500" pro stock car and 5.125" bore 160" pro stock bike programs.

Saw Stan posted some piston speed calculations.
Was working with a 825" pro stock program, he was turning 8800 rpm with a 5.750" stroke, makes my head hurt lol.

Along the same theme, the blown allky P/M,s and alcohol funny cars have been going north of 11K RPM. A 526 has (I think) a 4.25" stroke. And, those parts can't be very light...can they?

750-780 grams, I go way up in the grandstands to watch Pro Mod lol.

[Kensuke]

Wait, so is there a certain converter that can convert grams to horse power and horse power to grams?! I would really like to use it, as it would help me a lot. I am working on a certain project right now, it is a very old and rare porsche car. We are having some really big troubles with the engine, as we do not freaking know what to do with it, and such a converter would help me a lot. I would also need a proper kg to lbs converter, as I am already tired of calculating it by myself, and sometimes I actually forget how many lbs are in a kg.

[David Redszus]

Wait, so is there a certain converter that can convert grams to horse power and horse power to grams?! I would really like to use it, as it would help me a lot. I am working on a certain project right now, it is a very old and rare porsche car. We are having some really big troubles with the engine, as we do not freaking know what to do with it, and such a converter would help me a lot. I would also need a proper kg to lbs converter, as I am already tired of calculating it by myself, and sometimes I actually forget how many lbs are in a kg.

Which Porsche engine do you have?

[MadBill]

Wait, so is there a certain converter that can convert grams to horse power and horse power to grams?
No.
I would also need a proper kg to lbs converter, as I am already tired of calculating it by myself, and sometimes I actually forget how many lbs are in a kg
$10 will get you a Metric/Imperial conversion calculator.

[digger]

E=MC^2 Converts mass to energy

[hoffman900]

There is a good Honda white paper from their V8 F1 engine about piston design, and them cracking due to the rpm’s they were running at the time.

[LSP]

There is a good Honda white paper from their V8 F1 engine about piston design, and them cracking due to the rpm’s they were running at the time.

No, cracking was due to them not designing the piston properly to handle the rpm in the first place

The white paper was toilet paper, used to clean up the mess on the ground after another engineering disaster..

[AaronMcCoy]

I would also need a proper kg to lbs converter, as I am already tired of calculating it by myself, and sometimes I actually forget how many lbs are in a kg
$10 will get you a Metric/Imperial conversion calculator.

Or just type "2 kg to lbs" into Google. Replace values and units as necessary.

[piston guy]

There is a good Honda white paper from their V8 F1 engine about piston design, and them cracking due to the rpm’s they were running at the time.

No, cracking was due to them not designing the piston properly to handle the rpm in the first place

The white paper was toilet paper, used to clean up the mess on the ground after another engineering disaster..

Usually due to inadequate wall thickness on the wrist pins.

[LSP]

There is a good Honda white paper from their V8 F1 engine about piston design, and them cracking due to the rpm’s they were running at the time.

No, cracking was due to them not designing the piston properly to handle the rpm in the first place

The white paper was toilet paper, used to clean up the mess on the ground after another engineering disaster..

Usually due to inadequate wall thickness on the wrist pins.

Being the simplist part to design in the piston, pin, ring package system, I would hope that the perceived superior intelligence group would at least get that correct.

[digger]

No, cracking was due to them not designing the piston properly to handle the rpm in the first place

The white paper was toilet paper, used to clean up the mess on the ground after another engineering disaster..

Usually due to inadequate wall thickness on the wrist pins.

Being the simplist part to design in the piston, pin, ring package system, I would hope that the perceived superior intelligence group would at least get that correct.

like everything its best to use only what is needed as far as wrist pin go. People try to push the limits and get burnt as there is no simple formula to tell you. Personally i think the reciprocating weight is way overrated in the majority of applications as far as importance, more potential pain than gain by making things light.