the math needs answer

[Pops1967GTX]

 

[GetX'd]

Who the hell can do math like that? If the car runs smooth the math is right - if it doesn't the math is off....

 

[mopar 3 B]

Formula is worthless without some info. something has to be known. What are the knowns?

 

[Coronet 500]

This is why I didn't go into engineering, even though I was good in math doing this **** all day would drive me crazy.

 

[TetanusShot]

According to that equation, a stock street hemi making 490 tq has 3136 lbs of force downward on the piston crown when the crank is at 90 degrees at the peak tq rpm.

That assumes the pistons don't have offset pins. Stock mopar pistons do have offset pins and would be a real PITA to account for.

 

[Richard Cranium]

If the car runs smooth the math is right - if it doesn't........

Fixed.

 

[RJRENTON]

Gentlemen,
Mopar 3B is correct, the formula cannot be solved unless a few known dimensions are given. Using Mathcad or some other problem solving method, the formula can be solved simultanesously, that is one variable solved by expressing it interms of the other, then substituting some known dimensions, produce the results wanted/expected. How ever the last pix shows the result of the yield point of the rod material being exceeded....sort of looks like a SB Chevy that exceeded 9000+ RPMs....the section width (section modulus) of the rod looks too narrow to be a Mopar rod. BTW...the off set piston pin dimensions only affect the piston's trust face loads not the load imposed on the rod.
Cheers,
RJ Renton

 

[GetX'd]

Gentlemen,
Mopar 3B is correct, the formula cannot be solved unless a few known dimensions are given. Using Mathcad or some other problem solving method, the formula can be solved simultanesously, that is one variable solved by expressing it interms of the other, then substituting some known dimensions, produce the results wanted/expected. How ever the last pix shows the result of the yield point of the rod material being exceeded....sort of looks like a SB Chevy that exceeded 9000+ RPMs....the section width (section modulus) of the rod looks too narrow to be a Mopar rod. BTW...the off set piston pin dimensions only affect the piston's trust face loads not the load imposed on the rod.
Cheers,
RJ Renton

Thats what I meant to say.....

 

[satman72]

After 1+1=2; I'm done.

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Fixed.

That would make a great lamp!

 

[chipper]

Looks like a job for a new 12t press.

 

[bigmanjbmopar]

The size of the rod is equal to the angle of the dangle.

 

[moparstuart]

Hyrdo locked ,been there done that

 

[1wild&crazyguy]

Gentlemen,
Mopar 3B is correct, the formula cannot be solved unless a few known dimensions are given. BTW...the off set piston pin dimensions only affect the piston's trust face loads not the load imposed on the rod.
Cheers,
RJ Renton

This

 

[TetanusShot]

the off set piston pin dimensions only affect the piston's trust face loads not the load imposed on the rod

The diagram and equation are for the load straight down through the crown or "thrust face" as you put it, when did we start talking about rod loading? Besides that, the pin offset definitely affects both. Do a load force diagram, derive the equation, and you'll see what I mean.

 

[1wild&crazyguy]

The diagram and equation are for the load straight down through the crown or "thrust face" as you put it, when did we start talking about rod loading? Besides that, the pin offset definitely affects both. Do a load force diagram, derive the equation, and you'll see what I mean.

How many after market performance pistons have an offset pin?

They don't.

 

[bigmanjbmopar]

And they say I'm wound up too tight geez, guys this isn't moparts just have a conversation and respect the opinion who cares if it's nuts or nutz?

 

[khryslerkid]

I for one am not going to use ball bearings so thats as far as I'm going on that equation! Looks like a 2 stroker anyway...

Pops, looks like you've done it again! LoL

 

[HT413]

lol, the only people who care about this are the mechanical engineers who design rods, pistons, racing blocks, bearings, etc. for the rest of us, a dyno does a great job.

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Btw, well done, POPS, for getting everyone to talk about nothing lol. Kinda reminds me of a Sienfeld episode.

 

[Bb70charger500]

Answer is 3
Anyone can get it you just need a little alcohol

 

[HT413]

Thinking more about this (thanks pops), I'd bet no one uses this equation as it only considers static loading in a highly dynamic event.