Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: Molnar rods [Re: AndyF] #2174903
10/14/16 10:57 PM
10/14/16 10:57 PM
Joined: Oct 2007
Posts: 4,209
New York
polyspheric Offline
master
polyspheric  Offline
master

Joined: Oct 2007
Posts: 4,209
New York
horsepower has nothing to do with it. It is a function of piston/pin/ring weight and RPM

X2, reciprocating weight X RPM^2 (with a tiny adjustment for rod thrust angle) determines rod breakage.


Boffin Emeritus
Re: Molnar rods [Re: polyspheric] #2175199
10/15/16 12:41 PM
10/15/16 12:41 PM
Joined: Apr 2003
Posts: 3,521
Tulsa, Oklahoma
340Cuda Offline
master
340Cuda  Offline
master

Joined: Apr 2003
Posts: 3,521
Tulsa, Oklahoma
Originally Posted By polyspheric
horsepower has nothing to do with it. It is a function of piston/pin/ring weight and RPM

X2, reciprocating weight X RPM^2 (with a tiny adjustment for rod thrust angle) determines rod breakage.


Could you go through a calculation of this for us?

Re: Molnar rods [Re: AndyF] #2175278
10/15/16 02:41 PM
10/15/16 02:41 PM
Joined: Jan 2003
Posts: 4,395
The Pale Blue Dot
Skeptic Offline
master
Skeptic  Offline
master

Joined: Jan 2003
Posts: 4,395
The Pale Blue Dot
Originally Posted By AndyF
Wait until you see the pistons for this engine. JE is designing a Mopar big block piston based off the LS design. The sides are moved in so the pin is shorter than normal. Should be really lightweight.
A modern design piston for our antique motors shock panic beer That's almost a unthinkable as a modern combustion chamber or a cam not designed 50+ years ago.

Re: Molnar rods [Re: 340Cuda] #2175303
10/15/16 03:33 PM
10/15/16 03:33 PM
Joined: Dec 2013
Posts: 4,687
Wichita
G
GY3 Offline
master
GY3  Offline
master
G

Joined: Dec 2013
Posts: 4,687
Wichita
Originally Posted By 340Cuda
Originally Posted By polyspheric
horsepower has nothing to do with it. It is a function of piston/pin/ring weight and RPM

X2, reciprocating weight X RPM^2 (with a tiny adjustment for rod thrust angle) determines rod breakage.


Could you go through a calculation of this for us?


Don't encourage him...


'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

Re: Molnar rods [Re: GY3] #2175436
10/15/16 08:19 PM
10/15/16 08:19 PM
Joined: Jan 2003
Posts: 6,354
Aurora, Oh.
M
max_maniac Offline
master
max_maniac  Offline
master
M

Joined: Jan 2003
Posts: 6,354
Aurora, Oh.
Originally Posted By GY3
Originally Posted By 340Cuda
Originally Posted By polyspheric
horsepower has nothing to do with it. It is a function of piston/pin/ring weight and RPM

X2, reciprocating weight X RPM^2 (with a tiny adjustment for rod thrust angle) determines rod breakage.


Could you go through a calculation of this for us?


Don't encourage him...



iagree

Re: Molnar rods [Re: max_maniac] #2177074
10/17/16 05:49 PM
10/17/16 05:49 PM
Joined: Jan 2003
Posts: 16,376
D
dogdays Offline
I Live Here
dogdays  Offline
I Live Here
D

Joined: Jan 2003
Posts: 16,376
Actually there is a spreadsheet that has the program built into it to calculate acceleration and velocity of the piston for any stroke, rod length and rpm. I have it on my computer, don't know how to attach it, maybe I'll figure it out.

R.

Note in the spreadsheet the max acceleration numbers are always at the top, where velocity = zero. These numbers have units of ft/sec^2. To convert to Gs we divide by 32.2.

60,085 / 32.2 = 1,866 Gs. At that point a 500 gram piston is exerting an outward pull of 933kg or 2,055 lb.

rodratio (version 1).zip (18 downloads)
Last edited by dogdays; 10/17/16 06:19 PM.
Page 2 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1