P3R Crankshafts

[FSG]

What math went into deciding the rotation of the polygon in relationship to the centerline between the crank pin and the crankshaft centre?

It could easily have been different as the pix below show but the math/vectors would have come into play, any mechanical engineers want to provide some thoughts?

[No Cents]

  I'm just nothing but impressed with the looks of those flywheels every time I see them. I couldn't even stop and talk to them this year at the Expo because I know I would just want a set of them even worse if I did. 
  I hope someone will be able to answer your question...I know I certainly can't.

[Hilly13]

They do look the goods don't they.

[hulkss]

I hope someone will be able to answer your question...I know I certainly can't.

Here's my view: Peak cylinder pressure occurs just after top dead center during the power stroke. You would want a corner of the polygon pointing up the rods at that time so the flat opposite side was carrying the load into the flywheel.

[koko3052]

 

[FSG]

hulkss        that's my train of thought as well but thought I'd ask others 

[speedzter]

I'm sure there has been hours of CAD stress analysis/simulations done to arrive at the final design.
Anything else has to be speculation.

[jam65]

I like their product but S&S is still on my buy list based on $. Also, they want your current wheels in exchange. Mine are Darkhorse U.S. H beams and the only exchange that I have.

[sfmichael]

these are beautiful   

[PoorUB]

any numbers on how many they have sold? Failure rate?

[kd]

Is that a compound pinion shaft? It looks like a weld at the step behind the pinion gear flat.

[FSG]

No

[rbabos]

I seem to be looking at pics of 3 different wheels here. Alignment is different on all 3 of them so it means nothing in the big picture where the 3 points are set. It's either locked or not .What I'd like to know is how they get such a precise alignment each time. Hell of a concept here but wonder what the rebuild process is like if needed.
Ron

[koko3052]

Hey Ron, you need to re-read the second line in FSG's statement...and put your lookers on when looking at the other pics of the crankpin.
That crafty bugger has rotated the crank pin with an inserted photo.

[Ohio HD]

Hey Ron, you need to re-read the second line in FSG's statement...and put your lookers on when looking at the other pics of the crankpin.
That crafty bugger has rotated the crank pin with an inserted photo.

  Saw that too, but I also know where he got them.   

[rbabos]

Hey Ron, you need to re-read the second line in FSG's statement...and put your lookers on when looking at the other pics of the crankpin.
That crafty bugger has rotated the crank pin with an inserted photo.

1.5s to the rescue. I see that now. Never mind my stupidity.
Ron

[Hossamania]

Hey Ron, you need to re-read the second line in FSG's statement...and put your lookers on when looking at the other pics of the crankpin.
That crafty bugger has rotated the crank pin with an inserted photo.

1.5s to the rescue. I see that now. Never mind my stupidity.
Ron

Don't feel bad Ron, it took me a couple extra looks to figure out what was going on too.

[Ohio HD]

Hey Ron, you need to re-read the second line in FSG's statement...and put your lookers on when looking at the other pics of the crankpin.
That crafty bugger has rotated the crank pin with an inserted photo.

1.5s to the rescue. I see that now. Never mind my stupidity.
Ron

I use 2.0 or 2.5's   

[build it]

Rebuilds are done exclusively through p3r, standard is static balanced, you pay extra for dynamic  balancing. I don't see how this design would impede spread.

It does look like the crank pin is pressed into the polygon which is then pressed into the wheel. How would that eliminate slip? Am I seeing that pin arrangement correctly?

[PoorUB]

It does look like the crank pin is pressed into the polygon which is then pressed into the wheel. How would that eliminate slip? Am I seeing that pin arrangement correctly?

Pretty sure the round deal is a plug to seal off the hollow shaft. The ends of the pin are triangular.

[build it]

It does look like the crank pin is pressed into the polygon which is then pressed into the wheel. How would that eliminate slip? Am I seeing that pin arrangement correctly?

Pretty sure the round deal is a plug to seal off the hollow shaft. The ends of the pin are triangular.

You're probably right.

[BVHOG]

I think S&S has more than proved that a round pin can be made to hold up quite well. I don't care if you use a hex shaft for a pin, the rod  bearings will not hold up any better than any other setup

[HD/Wrench]

To me that looks like another version of a an item to stop the pin from moving. I doubt it really matters where you put it. Round pin with a triangle pressed on the end of it . could have been square or octagonal.. 3 points is less machine work .

I never spoke with them,... I tuned a bike that had that crank it from what the customer said . Do you know whos rod they use by chance FSG ? 

[No Cents]

   Steve...I asked them what rods they used a few years ago and they told me they basically offered different options for rods just like Darkhorse does. I'm pretty sure they told me the rods they had in their displayed flywheels at the Expo were Carillo...if memory serves me correct.
   The P3R guys said each set of flywheels are custom made to order from the options you choose. I got that info at the Expo a few years back when they 1st showed their product. I don't know if anything has changed since then because I just couldn't bring myself to stop at their booth this year and talk to them. I knew if I did...I would end up spending money that I don't need to right now.

Ray

[Don D]

Rods are Carillon now

[Schex3x]

The sprocket shaft looks like a polygon press fit.

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[turboprop]

1. Interesting design.
2. Funny how the discussion on these occurs annually, in sync with the V-Twin Expo.
3. What is the capability gap that S&S & Darkhorse crankshafts are not meeting that justifies the additional expense of these?

[jmorton10]

3. What is the capability gap that S&S & Darkhorse crankshafts are not meeting that justifies the additional expense of these?

That's my question too (although they are beautiful)

~John

[HD/Wrench]

Just because you can is the simple answer . Same can be said for many things..

[Buffalo]

 They ask you to send in your flywheels, so does that mean they modify your existing wheels? If so, from 05 onward aren't you using inferior cast cranks,, not forged! For the price, I would think the entire unit would be made from the finest FORGED steel money could buy.
I'd stick with S&S and know they are good, at half the price. fwiw Buffalo

[kd]

Very good point.

[HD/Wrench]

They ask you to send in your flywheels, so does that mean they modify your existing wheels? If so, from 05 onward aren't you using inferior cast cranks,, not forged! For the price, I would think the entire unit would be made from the finest FORGED steel money could buy.
I'd stick with S&S and know they are good, at half the price. fwiw Buffalo

good question as if that is the case I would go S&S as the base material is stronger

[KingofCubes]

I go with R&R flywheels because the base material is even stronger and heat treated harder and balanced twice. The next week link determines weather to spend the extra guetos because the Timken bearing insert will only stand so much pounding. Waiting to see what these forced induction engines do to the lower end. 

[build it]

I go with R&R flywheels because the base material is even stronger and heat treated harder and balanced twice. The next week link determines weather to spend the extra guetos because the Timken bearing insert will only stand so much pounding. Waiting to see what these forced induction engines do to the lower end.

Stronger how? Balanced twice?

Didn't you build Ray Wheelers bottom end?

[Deye76]

" base material is even stronger and heat treated harder"

In 48 years of improving the power output of my motors, never have I had a failure because of flywheel base material or heat treating not being adequate. 

[KingofCubes]

I go with R&R flywheels because the base material is even stronger and heat treated harder and balanced twice. The next week link determines weather to spend the extra guetos because the Timken bearing insert will only stand so much pounding. Waiting to see what these forced induction engines do to the lower end.

Stronger how? Balanced twice?

Didn't you build Ray Wheelers bottom end?

I did Ray's bottom end so long ago I can't remember what I did. His old flywheels were trash and were probably replaced with S&S forgings machined by R&R before they changed to their own forgings. R&R uses 4340 rather than 4130 treated to 10-15 clicks more Rockwell points over most others. The first go around is drilling for static check, then the whole assembly is 2-plane dynamic balanced.

[build it]

I go with R&R flywheels because the base material is even stronger and heat treated harder and balanced twice. The next week link determines weather to spend the extra guetos because the Timken bearing insert will only stand so much pounding. Waiting to see what these forced induction engines do to the lower end.

Stronger how? Balanced twice?

Didn't you build Ray Wheelers bottom end?

I did Ray's bottom end so long ago I can't remember what I did. His old flywheels were trash and were probably replaced with S&S forgings machined by R&R before they changed to their own forgings. R&R uses 4340 rather than 4130 treated to 10-15 clicks more Rockwell points over most others. The first go around is drilling for static check, then the whole assembly is 2-plane dynamic balanced.

Interesting process, thanks for sharing.

[FSG]

it's a bit clearer now

[kd]

So the plug is simply machining access. 

[Ohio HD]

Plugs the oil galley, as well is the press to expand the pin into the flywheels.

[kd]

Actually I can see that the diameter of the hole is large enough that it probably could expand the pin for a tighter fit. Is that actually the case though? It would take a decent interference fit and a hard plug.

[Ohio HD]

Sure, S&S and Darkhorse both use plugs to expand the crank pin into the flywheel.

[Ohio HD]

This is a DH crank, their plug system, and they weld as well.

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[FSG]

and looking at this the P3R is a 5 piece crank

if there is a .009" interference on the crank pin I wonder what is on the sprocket shaft and pinion

[Ohio HD]

I wonder why even use a five piece pressed design? Seems like it just adds to complexity and cost.

[build it]

I agree on the 5 piece being less than ideal compared to a 3 piece; p3r has a modular setup, break one part and that alone can be replaced, there's something to be said about that. These cranks are only serviced in house at p3r, according to Dave Minton, the owner; this was a deal breaker for me.

The machining on that crankpin is nothing short of magnificent.

[Ohio HD]

I agree on the 5 piece being less than ideal compared to a 3 piece; p3r has a modular setup, break one part and that alone can be replaced, there's something to be said about that. These cranks are only serviced in house at p3r, according to Dave Minton, the owner; this was a deal breaker for me.

The machining on that crankpin is nothing short of magnificent.

I would have to agree 

[kristian]

yah got more hits on the other forum with the same topic.......chaching!!!

[Ohio HD]

This is responding to an old thread on the P3R flywheels. I was researching crankshafts a month or so back to see what may be new on the industry for the 124" Twin Cam I'm building. I came across a few sites that speak to problems that P3R had been experiencing. And it appears that they may have closed the doors on their crankshaft production. Their website is also no longer up.

I'm not going to post the other site links I found on this subject. Unfortunately it looks like not enough R&D went into their new design.


https://www.p3rflywheels.com/

[jsachs1]

I have used prolly 7 or 8 P3R flywheel sets in big inch S&S engines, some with power adders. [attach=0,msg1398891]  The last 2 sets I used had several improvements made in the pinion shaft area. No problems to speak of. Company went out of business for several reasons.
John

[Deye76]

"I came across a few sites that speak to problems that P3R had been experiencing."
I know a guy that drag races a bagger, the P3R failed multiple times, he's now using Darkhorse.

[Ohio HD]

I never could understand why they chose the profile they did for the press fit. I would have made a simple radius square, or an oblong It can't slip, and machining the parts would be easy, and easily measured.


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[Deye76]

What I heard, a couple pounds of boost and 1 or 2 passes and they were toast.

[hrdtail78]

Sure, S&S and Darkhorse both use plugs to expand the crank pin into the flywheel.

I know this is old but......   That is a mighty beefy pin to expand compared to the size of the plug.  It was explained to me that the plug isn't for a tighter fit, but to help keep the pin round during operation.  I heard it years ago and it was from John (DH) or Scott (S&S.)   Back in the Vtwin expo days.

[cheech]

This is responding to an old thread on the P3R flywheels. I was researching crankshafts a month or so back to see what may be new on the industry for the 124" Twin Cam I'm building. I came across a few sites that speak to problems that P3R had been experiencing. And it appears that they may have closed the doors on their crankshaft production. Their website is also no longer up.

I'm not going to post the other site links I found on this subject. Unfortunately it looks like not enough R&D went into their new design.

 
https://www.p3rflywheels.com/

I came across all that about a year ago or less also.
I hadn't heard anything about them in a while, thought where they been.
Read some drama.
I took it as he got involved with the parent company, released that.
Then downhill from there. The parent I take it is still operating.
Just not in the motorcycle industry.