Long Rod Motor/Indy Dan

[gman086]

Dan,

Could you please address the difference in stock pistons between what's been used in the Pro and what was used in the 2010 and previous CFI4's? The "other" guy is insinuating that the quality of the older pistons was far better and your comment on giving a 5 year warranty with those pistons (your LRTM5) seems to lend some credence to that suggestion. Also, how is the power of the LRTM5 compared to your long rod motor?

Thanks,

G MAN

 

[LoudHandle]

Dan,

Could you please address the difference in stock pistons between what's been used in the Pro and what was used in the 2010 and previous CFI4's? The "other" guy is insinuating that the quality of the older pistons was far better and your comment on giving a 5 year warranty with those pistons (your LRTM5) seems to lend some credence to that suggestion. Also, how is the power of the LRTM5 compared to your long rod motor?

Thanks,

G MAN

Price difference would be helpful as well.

 

[Hondaracer315]

I know this is the pro forum but how much is it to basically fix a grenaded 08 700 holes in cases. I want to long rod my dragon with an 800 but I'm from ak and shipping sucks. I am looking at buying a fix kit instead for an 800 i found. What is wrong with the fix kit for the 800's, it is cheaper to fix the sled that way? I am not hijacking but pms makes fix kits for the pros too. That is why I am asking what is so good about a long rod motor for $3500? Prove it to me why I shouldn't just go the fix kit route?

 

[tdbaugha]

I know this is the pro forum but how much is it to basically fix a grenaded 08 700 holes in cases. I want to long rod my dragon with an 800 but I'm from ak and shipping sucks. I am looking at buying a fix kit instead for an 800 i found. What is wrong with the fix kit for the 800's, it is cheaper to fix the sled that way? I am not hijacking but pms makes fix kits for the pros too. That is why I am asking what is so good about a long rod motor for $3500? Prove it to me why I shouldn't just go the fix kit route?

Three year warranty.

That speaks volumes.

 

[LoudHandle]

I know this is the pro forum but how much is it to basically fix a grenaded 08 700 holes in cases. I want to long rod my dragon with an 800 but I'm from ak and shipping sucks. I am looking at buying a fix kit instead for an 800 i found. What is wrong with the fix kit for the 800's, it is cheaper to fix the sled that way? I am not hijacking but pms makes fix kits for the pros too. That is why I am asking what is so good about a long rod motor for $3500? Prove it to me why I shouldn't just go the fix kit route?

First, the pistons are not the issue, they are a direct result of other issues which are never addressed with anybody else's drop in piston kit regardless of price, manufacturer, or type of piston. The other kits may buy you a little more time or may well actually get less depending on which one you choose. Only Indy Dan and his long rod kit effectively deals with the rod ratio issue and the out of tolerance stock cylinder. The stock rod ratio aggravates the poor cylinder tolerances, which is first manifested as collapsed pistons and broken skirts ( both piston and cylinder). This fact is why the stock pistons have gotten a bad reputation. When you consider the conditions the stock pistons must endure thousands of times a minute they are near bullet proof. You put some of these drop in kits in and you get less than half the life of the stock piston! Choose wisely!

The Indy Dan long rod corrects the side load on the piston via the longer rod and as a consequence you get additional crank case volume which the small block 800 needs to be volumetrically efficient, which you can feel in additional performance. He also modifies the cylinder skirts to strengthen them and support the piston near BDC. He then replates the cylinder and diamond hones it to the correct size and shape for the pistons. In essence you get a fully blueprinted engine, that is built correctly that has a warranty at least three times better than the factory's.

I have two Indy Dan LR's in Valdez, and shipping is not that bad if you regular parcel post it.

Again choose wisely! But it is your money feel free to piss it away on a drop in kit.

 

[tdorval]

I hear a lot about rod ratio's, but don't usually hear the actual numbers. What is the rod ratio on the polaris motor? And for comparison sake what is it on the current cat and doo motors? Is there an acceptable rod ratio limit in modern 2 strokes and what would that be? Not discounting Dan's work because it is top notch, but I typically like to know the numbers instead of just believing when someone tells me "the rod ratio is the problem" I'd look all this up but I don't have the time and know someone on here has it on the top of their head.

 

[tdorval]

Also, when you say some drop in kits are getting half the useable mileage compared to stock, could you say which brands, as I haven't seen much on which are doing poorly and which are doing great. If you want to pm to keep any bashing issues down thats fine but I'm sure there are many that would like to know if a certain brand is doing that poorly.

 

[Jaynelson]

FWIW - you guys posting questions to Dan. Pretty sure I remember a post saying he wouldn't be on the forums for the summer or something to that effect.

 

[rmscustom]

I hear a lot about rod ratio's, but don't usually hear the actual numbers. What is the rod ratio on the polaris motor? And for comparison sake what is it on the current cat and doo motors? Is there an acceptable rod ratio limit in modern 2 strokes and what would that be? Not discounting Dan's work because it is top notch, but I typically like to know the numbers instead of just believing when someone tells me "the rod ratio is the problem" I'd look all this up but I don't have the time and know someone on here has it on the top of their head.

Its been said on here that the polaris rod ratio is the same or better than the bomb proof Suzuki mill.

 

[Hondaracer315]

I have heard nothing but good things about the pms kits. Tell me why the pms kit doesn't work that well in the 800? From what pms has explained to me they have addressed all the problems with the 800 by creating the fix, some say wiseco pistons are bad I don't think so but everybody has their opinion so please don't just say oh seizeco's are the problem. I haven't read where the wisecos have caused any problems yet in the fix kit.

 

[LoudHandle]

Its been said on here that the polaris rod ratio is the same or better than the bomb proof Suzuki mill.

This is true, but they also are made much beefier, and as a result they weigh more. Heavier cylinders, heavier pistons, so they can take the side load the ratio creates. Additionally the cat cylinders are likely the correct size and not cone shaped. You really can not or should not compare them as there are so many differences your comparison is useless.

 

[rmscustom]

Couple of unbiased no agenda questions...

Will a lighter piston create less side loading vs a heavier one?

Are the "fix kits" trying to address the side loading problem with raising the cylinders and using a taller piston vs a longer rod?

 

[rocket]

Piston weight isn't where the side load comes from, the load comes from the angle the rod moves through while the piston is making it's stroke in the cylinder. A longer piston will help reduce the amount the piston rocks in the bore (improves support of the piston due to longer length). But, unless the rod geometry changes, the side load remains the same, though it is applied to the cylinder differently due to the longer length of the piston.

 

[rmscustom]

Piston weight isn't where the side load comes from, the load comes from the angle the rod moves through while the piston is making it's stroke in the cylinder. A longer piston will help reduce the amount the piston rocks in the bore (improves support of the piston due to longer length). But, unless the rod geometry changes, the side load remains the same, though it is applied to the cylinder differently due to the longer length of the piston.

I realize where the load comes from. My question is will a lighter piston installed on the end of the same rod produce less side loading than a heavier one?

 

[LoudHandle]

I realize where the load comes from. My question is will a lighter piston installed on the end of the same rod produce less side loading than a heavier one?

Without getting into a complex discussion of physics and the relationships that are involved between weight, clearances, angles of forces, acceleration and deceleration, etc.

By weight; I was referring more to the cross sectional wall thickness rather than actual mass. The cat piston has a thicker cross sectional wall thickness and as a result is much more robust and less prone to fatigue from excessive piston to cylinder clearances of which I'm assuming Cat has a better QC program and / or better vendor.

The rod ratio of the Polaris when combined with the out of spec cylinder and the thinner cross section of both the piston and the cylinder is what causes the piston to fail prematurely regardless of what piston you put in the out of spec cylinder.

IMO the actual piston weight is trivial; as the bigger multiplier in the equation is the acceleration and the distance you give it to accelerate. Hence my choice to have to cylinder geometry corrected and resized to the piston thus eliminating the largest contributor.

 

[RKT]

I hear a lot about rod ratio's, but don't usually hear the actual numbers. What is the rod ratio on the polaris motor? And for comparison sake what is it on the current cat and doo motors? Is there an acceptable rod ratio limit in modern 2 strokes and what would that be? Not discounting Dan's work because it is top notch, but I typically like to know the numbers instead of just believing when someone tells me "the rod ratio is the problem" I'd look all this up but I don't have the time and know someone on here has it on the top of their head.

Polaris Rod Ratio: 1.89
Ski Doo Rod Ratio: 1.74 (they have no issues even with a single ring piston)
Arctic Cat Rod Ratio: 1.89 (no issues either)

So, the rod ratio of the Polaris is BETTER than Ski Doo and equal with the Cat (same bore and stroke).. YET. the Polaris has issues with piston failure and the CAT and Ski Doo do NOT... So, how is the problem the rod ratio?

Also, WHEN you install the CORRECT piston (one that addresses the OEM piston issues) the failures DISAPPEAR!! Yet, the rod ratio remained the same!

The REAL issue IS the PISTON... there are other issues associated with this engine's design but the rod ratio is NOT one of them.

 

[RKT]

Without getting into a complex discussion of physics and the relationships that are involved between weight, clearances, angles of forces, acceleration and deceleration, etc.

By weight; I was referring more to the cross sectional wall thickness rather than actual mass. The cat piston has a thicker cross sectional wall thickness and as a result is much more robust and less prone to fatigue from excessive piston to cylinder clearances of which I'm assuming Cat has a better QC program and / or better vendor.

The rod ratio of the Polaris when combined with the out of spec cylinder and the thinner cross section of both the piston and the cylinder is what causes the piston to fail prematurely regardless of what piston you put in the out of spec cylinder.



IMO the actual piston weight is trivial; as the bigger multiplier in the equation is the acceleration and the distance you give it to accelerate. Hence my choice to have to cylinder geometry corrected and resized to the piston thus eliminating the largest contributor.

Actually the Polaris piston is THICKER than the CAT piston....AND the SKi Do piston is THINNER than the Polaris or the CAT and has a WORSE rod Ratio.

Thicker piston and yet it still fails.... Again.. this all points to the PISTON as the issue..

And the FACT that AFTER you install a GOOD piston, the cylinder failures disappear.. Again.. PISTON ISSUE.

 

[LoudHandle]

Actually the Polaris piston is THICKER than the CAT piston....AND the SKi Do piston is THINNER than the Polaris or the CAT and has a WORSE rod Ratio.

Thicker piston and yet it still fails.... Again.. this all points to the PISTON as the issue..
And the FACT that AFTER you install a GOOD piston, the cylinder failures disappear.. Again.. PISTON ISSUE.

And I suppose your piston is the "correct piston"? Why then have I gotten a few PM's from former customers of yours that have stated that after installing your "correct piston" they got less than 500 miles before your piston collapsed as well?

 

[RKT]

And I suppose your piston is the "correct piston"? Why then have I gotten a few PM's from former customers of yours that have stated that after installing your "correct piston" they got less than 500 miles before your piston collapsed as well?

Ya know.. making up stories is really not helping anybody.. How about we stick to the truth... I am sure you are the 1st person everybody thinks of to PM whenever there is any Polaris issue?? Really??

If the pistons were having ANY issues you would hear about it on the internet.. VOHK uses them in turbo and N/A applications.. ZERO failures!! Boston Racing uses them as well.. The list is endless...

MANY dealers have converted to this piston and immediately noticed a power improvement and that the "death shake" was eliminated.. Again.. no failures.... the list goes on and on.... These pistons will NOT fail nor collapse..

We tested them for a year before releasing them.. at 2000 miles they were .0005" smaller than when they were installed...

FACTS not hear-say..

Simple as this.. If you have a tire on your car that keeps puncturing snd you switch to a better tire and the punctures disappear.. IT IS NOT THE RIM causing the punctures...Just sayin... If the real problem was the rod ratio.. you would NOT be able to fix it with a piston change... It really is that simple..

 

[LoudHandle]

Ya know.. making up stories is really not helping anybody.. How about we stick to the truth... I am sure you are the 1st person everybody thinks of to PM whenever there is any Polaris issue?? Really??

If the pistons were having ANY issues you would hear about it on the internet.. VOHK uses them in turbo and N/A applications.. ZERO failures!! Boston Racing uses them as well.. The list is endless...

MANY dealers have converted to this piston and immediately noticed a power improvement and that the "death shake" was eliminated.. Again.. no failures.... the list goes on and on.... These pistons will NOT fail nor collapse..

We tested them for a year before releasing them.. at 2000 miles they were .0005" smaller than when they were installed...

FACTS not hear-say..

Simple as this.. If you have a tire on your car that keeps puncturing snd you switch to a better tire and the punctures disappear.. IT IS NOT THE RIM causing the punctures...Just sayin... If the real problem was the rod ratio.. you would NOT be able to fix it with a piston change... It really is that simple..

They are not stories, they are fact from sources I trust. They may well be the exception, but I will leave that decision to the customer.