Hot Rods connecting rod

[2strokesmoker]

The piston refers to the rod length, NOT the stroke.

 

If you have stock cylinders and a longer stroke crank, you either have a spacer at the bottom of the cylinders or a head/domes that are cut recessed for the added stroke.

 

The 795 series, or racers choice series, have the wrist pin hole moved 5mm closer to the crown of the piston (top).

The 795 series dome also has the same profile as the standard banshee piston (513 or 573 series, I forget...someone correct that)

 

Do a search on a squish test. It involves a piece of solder through the spark plug hole, smashing it down with the piston (against the head) and measuring that thickness.

 

From .040 to .060 is the norm, depending on your setup. A mid 40 to low 50 number is the average...

 

 

Winner, winner, winner chicken dinner!! Thats what I was looking for! :thumbsup:

 

[Bansh-eman]

tell me this... whats the load capabilities of the needles bearings... how much force is placed on them in a stock configuration.. Then tell me the load on them in a 115mm rod setup.. Tell me how much longer bearing life is extended.. YOU DONT KNOW!!! therefore its your opinion. Changing the rod angle will affect the bearings life VERY LITTLE. Until you can prove otherwise... its a matter of opinion. brosif....

 

I'll stick with my opinions.. Last time I checked.. My bikes have ran like tops so they must be working. You can keep your physics and trig.

 

I'm done here.

It is nearly impossible for anyone outside of a lab to tell you the exact numbers. There are tons of things that need to be known, like burn efficiency for the type of fuel, to get a real number. Regardless if it is 10psi or 10,000psi, the fact still remains that when a force is being applied on multiple connected solid objects that the force WILL be transferred and that reducing the angle you lessen the amount of stress (force) being applied. Because I can't whip out the formula and give you hard numbers does not negate the fact that it remains a fact.

As far as your bikes running fine, like I said the rod length makes zero for power. Nice job trying to toss that out there as if it makes a difference. The argument wasn

[shanYE west]

It is nearly impossible for anyone outside of a lab to tell you the exact numbers. There are tons of things that need to be known, like burn efficiency for the type of fuel, to get a real number. Regardless if it is 10psi or 10,000psi, the fact still remains that when a force is being applied on multiple connected solid objects that the force WILL be transferred and that reducing the angle you lessen the amount of stress (force) being applied. Because I can't whip out the formula and give you hard numbers does not negate the fact that it remains a fact.

As far as your bikes running fine, like I said the rod length makes zero for power. Nice job trying to toss that out there as if it makes a difference. The argument wasn

[Bansh-eman]

It is impossible to predict time. Once again you go off spouting rhetorical questions. It doesn't matter if it is steel, aluminum, titanium or any other metal or compound. You cannot predict time. If you could then everyone would know that their motor is going to break down ahead of time rather than after it breaks. There are hundreds of factors that are going to determine if a bearing or any other component gives out prematurely. Metal particles, how often they clean filters, how much debris has been sucked in, the type of fuel, of lean or rich they run the motor. The list doesn

[dajogejr]

If the real difference only matters to someone in a lab, what difference does it make to a simple ATV rider?

 

That's kinda like saying, in lab results this oil will make this engine last 400 hours.

This oil, 350...

 

But you lean it out and smoke a piston anyways....

 

I understand and can appreciate your ideas Greg, but in this case...it's a boost bottle idea.

Sounds good...theory behind it...but not much use in the real world because of all the other circumstances and effect generated by it....

[Bansh-eman]

If the real difference only matters to someone in a lab, what difference does it make to a simple ATV rider?

 

That's kinda like saying, in lab results this oil will make this engine last 400 hours.

This oil, 350...

 

But you lean it out and smoke a piston anyways....

 

I understand and can appreciate your ideas Greg, but in this case...it's a boost bottle idea.

Sounds good...theory behind it...but not much use in the real world because of all the other circumstances and effect generated by it....

The question was asked, so I answered

[Bansh-eman]

All of it comes back to theory. We don't have hard evidance how much and if it actually releives the piston from attempting to shove it's self through the cylinder, or that it allows more power from longer dwell times at TDC.

Every bit if it comes back to theory of physics and trigonometry. Mathmatically, what we say makes sense, but becasue we have no means of measuring it to prove it , it remains a theory.

 

The one thing that is a proven fact is that by reducing the amount of direct force applied that you reduce stress and extend potential life (life being it's ability to function in it's role as a component), assuming there isn't a failure caused by something else. This goes for all materials that are solid, be it wood, minerals, metals, whatever. Rotating or not. It applies to force in general, not just motors.

Edited May 13, 2009 by Bansh-eman

[dajogejr]

Winner, winner, winner chicken dinner!! Thats what I was looking for! :thumbsup:

 

 

Well...the original post got what he wanted, that's the important part...

 

And I'm sure as hell not going to tell anyone to let the thread die.

 

That would be like Ron Jeremy telling the porn industry to stop making films...hypocrite of the year....LOL.

 

Here's my final thought... the longer rod will put less stress on the rotating assembly by lessening the angle through the duration of the stroke. Bearing wear is quite a bit harder to prove.

However, do I feel the need to put on a white coat and prove any of this? Nope....my bike runs fine too....

FouledOut and I probably have two of the strongest and longest running bikes in our group (notice...I didn't say fastest, just strong and long lasting.... )

 

:biggrin:

[Bansh-eman]

lol fastest means nothing if it can only do it once :biggrin:

 

I don't see the need to let it die. This has probably been one of the most productive posts/arguments we have had in a while on here. God knows we can only handle so many "do boost bottles really work" posts.

 

Edited May 13, 2009 by Bansh-eman

[dajogejr]

I disagree...

 

Don't tell those guys from Puerto Rico that...those nitrous hounds had no problem rebuilding a motor after a pass.

I'm not making fun of them...I commend them for trying to take the drag racing sport to the next level...

 

You don't see any NHRA crew twiddling their thumbs between rounds...they're scurrying like cockroaches rebuilding, replacing, etc.

 

(I'm talking about the PR team that was at Gilbert this year for the PS race, by the way....)

 

 

[2strokesmoker]

I disagree...

 

Don't tell those guys from Puerto Rico that...those nitrous hounds had no problem rebuilding a motor after a pass.

I'm not making fun of them...I commend them for trying to take the drag racing sport to the next level...

 

You don't see any NHRA crew twiddling their thumbs between rounds...they're scurrying like cockroaches rebuilding, replacing, etc.

 

(I'm talking about the PR team that was at Gilbert this year for the PS race, by the way....)

 

 

 

WOW!!!!!!!!!!!!!! This is some serious shit. Cant wait til the next can of worms! :thumbsup:

[Chariot Performance]

Maybe both sides can be right on the minimal bearing wear/stress issue. The truth may be in the effect of the minimal difference. If your setup is on the edge, and let's face it all banshee guys bring their bikes to the edge, a slight difference may make the difference! If on the edge, possibly even .1 of one percent may mean the difference between explosion or not. Not to say this is the case but over each component in the engine if we UNTHEORETICALLY add up all the increases or decreases in extra stress etc then each little improvement counts.

 

I am reminded of the nitro bike at the recent race which exploded all over the track. I bet he was .1 percent over the edge and that was enough.

 

Just thought I'd muddy the waters a bit. I recognize a lot of these guys as our customers and we are very thankful for that.

Jerry

Edited May 13, 2009 by Chariot Performance

[2strokesmoker]

Maybe both sides can be right on the minimal bearing wear/stress issue. The truth may be in the effect of the minimal difference. If your setup is on the edge, and let's face it all banshee guys bring their bikes to the edge, a slight difference may make the difference! If on the edge, possibly even .1 of one percent may mean the difference between explosion or not. Not to say this is the case but over each component in the engine if we UNTHEORETICALLY add up all the increases or decreases in extra stress etc then each little improvement counts.

 

I am reminded of the nitro bike at the recent race which exploded all over the track. I bet he was .1 percent over the edge and that was enough.

 

Just thought I'd muddy the waters a bit. I recognize a lot of these guys as our customers and we are very thankful for that.

Jerry

 

 

Yeah there nothing like job security these days!!! :yelrotflmao:

[shanYE west]

since the original question was answered and eveyrone is willing.. i'll keep going.

 

 

All of it comes back to theory. We don't have hard evidance how much and if it actually releives the piston from attempting to shove it's self through the cylinder, or that it allows more power from longer dwell times at TDC.

Every bit if it comes back to theory of physics and trigonometry. Mathmatically, what we say makes sense, but becasue we have no means of measuring it to prove it , it remains a theory.

 

The one thing that is a proven fact is that by reducing the amount of direct force applied that you reduce stress and extend potential life (life being it's ability to function in it's role as a component), assuming there isn't a failure caused by something else. This goes for all materials that are solid, be it wood, minerals, metals, whatever. Rotating or not. It applies to force in general, not just motors.

 

 

Exactly my point... With out no hard evidance.. its therory.. and a therory is a educated opinion untill is proven a fact.

Until you can prove (with hard evidance) there is a significant load reduction on the bearings that would create a noticeable increase in bearing life .. then your statements are theory.

 

Is there extended bearing life?? maybe... I never said there wasn't.. I just said it would be minimal if any and it is not a key benifit to using the long rod. And thats my "theory" on that.

 

Now heres my theory on this..

 

as far as direct force.. it does matter if its a rotating assembly.. the only DIRECT force on the bearings/rod is at TDC and BDC --> ------- <--- is a dricet force.. you move that rod in the middle.. Its no longer direct and the crank will spin and there is no more force on the bearings because there is no resistance.. to have force on a part... there must be resistance.

 

What generates the force on the bearings? resistance.. where is the resistance? Compression. then the rod angle has no affect on the load of the wrist pin and neeldle bearings. Force is applied directly to the piston (from compression) and from the piston DIRECTLY to the wrist pin and bearing. the needle bearings are designed to take the force from all angles.. where does rod angle come into play here? remember.. physics stats for every action there is a opposite and equal reaction... force is applied directly (opposite and equal) I also highlighted a part in your quote that has to do with the law. les angle.. equals less dirct force on the sidewalls.. Compression is your constant force.. if compression remains the same (constant) unless compression is changed.. the angle of the rod will not change the amount of force applied.. only the angle at which it is applied (hence.. less side wall force)... the bearings are designed to take loads from any angle and the load on the bearings will not change until compression is changed. 165psi is 165psi.. it dont matter what angle..

[2strokesmoker]

since the original question was answered and eveyrone is willing.. i'll keep going.

 

 

 

 

 

Exactly my point... With out no hard evidance.. its therory.. and a therory is a educated opinion untill is proven a fact.

Until you can prove (with hard evidance) there is a significant load reduction on the bearings that would create a noticeable increase in bearing life .. then your statements are theory.

 

Is there extended bearing life?? maybe... I never said there wasn't.. I just said it would be minimal if any and it is not a key benifit to using the long rod. And thats my "theory" on that.

 

Now heres my theory on this..

 

as far as direct force.. it does matter if its a rotating assembly.. the only DIRECT force on the bearings/rod is at TDC and BDC --> ------- <--- is a dricet force.. you move that rod in the middle.. Its no longer direct and the crank will spin and there is no more force on the bearings because there is no resistance.. to have force on a part... there must be resistance.

 

What generates the force on the bearings? resistance.. where is the resistance? Compression. then the rod angle has no affect on the load of the wrist pin and neeldle bearings. Force is applied directly to the piston (from compression) and from the piston DIRECTLY to the wrist pin and bearing. the needle bearings are designed to take the force from all angles.. where does rod angle come into play here? remember.. physics stats for every action there is a opposite and equal reaction... force is applied directly (opposite and equal) I also highlighted a part in your quote that has to do with the law. les angle.. equals less dirct force on the sidewalls.. Compression is your constant force.. if compression remains the same (constant) unless compression is changed.. the angle of the rod will not change the amount of force applied.. only the angle at which it is applied (hence.. less side wall force)... the bearings are designed to take loads from any angle and the load on the bearings will not change until compression is changed. 165psi is 165psi.. it dont matter what angle..

 

Im with fouledout421 on this. He seems to know his shit pretty damn good. Keep up the good work bro! :thumbsup: