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New 850 Twin Ring Long Rod Motor

indydan

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850 Twin Ring Long Rod.JPG


First start up

This motor was taylor built for Turbo application, less Transfer timing & Exhaust Duration for more low end torque.

This motor was built with 2015 800 RMK 85mm Twin Ring oem Polaris Pistons

Rods are a little less then a 1/2 inch longer then the stock 850 rod

The Turbo specific motor does not use a cylinder spacer.....This Motor is built with oem Twin Ring 85mm Cast Polaris Pistons.


Dan
 
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diamonddave

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Nice work Dan...amazing how smooth that thing sounds.

Can you elaborate on how you were able to use this longer rod with a 2015 piston and not use a cylinder shim?
 

Prayn4snow

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Can’t wait to see this out on the snow. Good work Dan. If you haven’t been to Indy specialties shop you’re missing out on a treat Dan comes across harsh online but he comes with years of valuable experience and know-how. In person he’s enjoyable to talk with and can quickly get over your head with his depth of knowledge of engine and clutch building.
Enjoying a drink and a burger with him in his town and you’ll see that he’s well known and respected.
“If” my 850 ever goes down it would be hard not to bring it to Dan.
 
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richracer1

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Nice work Dan...amazing how smooth that thing sounds.

Can you elaborate on how you were able to use this longer rod with a 2015 piston and not use a cylinder shim?


My guess would probably be due to the 850 piston being a bit longer than the 800HO piston.
 

indydan

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Nice work Dan...amazing how smooth that thing sounds.

Can you elaborate on how you were able to use this longer rod with a 2015 piston and not use a cylinder shim?

A quick break down.

The first time i saw the pin location of the 85mm 850 Single Ring Piston i thought I have to see if can get the Small Block 85mm Twin Ring 800 piston into that motor.

So we drew up the 850 motor on CAD, And we drew it with both pistons to figure out where everything landed so i could figure out what rod length would work.

Plus i felt the rods are kinda on the weak side simlar to the 800 XM Ski Doo motor.

So i made them pretty beefy.

Dan
 
S
Apr 27, 2008
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The first time i saw the pin location of the 85mm 850 Single Ring Piston i thought I have to see if can get the Small Block 85mm Twin Ring 800 piston into that motor.
Is that Polaris making room for a long stroke 950?
 

indydan

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Is that Polaris making room for a long stroke 950?

absoltely not......There mostly will never be a 950 Twin form Polaris without a counter balance shaft.

Ski doo built one of the most badazz 951 twin cylinder ( counter balance shaft ) motors i have even seen.

It is an absolute monster........My guess is.... it weights 150 pounds plus with motor mounts...... it rivals a tundercat triple in weight.

Polaris had proto-type motor of the 2019 850 which we all know is an 840...some the proto-types were 80mm stroke and they were pushing the 950 area some bigger cylinders..and they were
dropped and discontiuned.

if there ever is a 950........the mountain segment wil prove it to be a massive failure.



Dan
 
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indydan

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Guess your right.
Makes more sense that they put some distance between the piston top and the top end bearing to reduce heat to the bearing.

When you carburate a 800 small block the wrist pin bearing stops turning blue.

with no fuel in the case is hard to keep the bearing cool.

All Polaris has to do is drill a hole in the rear of the piston in the correct spot and the bearing will cool down.

I have seen few blue 850 bearings already.


Dan
 

BeartoothBaron

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Stop keeping me in suspense, I'm getting blue bearings here! Would that be a hole in the piston skirt, in line with the transfer port? If so, that sounds like a similar concept to the CTEC. It seems to me that Cat hit on a great solution to the rod bearing problem, but I'm curious what you think of that.

With regard to the blue bearings you've seen, do you think it's long WOT runs, or a higher percentage of engine time at WOT causing it? Also – hopefully not opening a can of worms here – but any idea if the oil being used makes any difference?
 

indydan

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Stop keeping me in suspense, I'm getting blue bearings here! Would that be a hole in the piston skirt, in line with the transfer port? If so, that sounds like a similar concept to the CTEC. It seems to me that Cat hit on a great solution to the rod bearing problem, but I'm curious what you think of that.

With regard to the blue bearings you've seen, do you think it's long WOT runs, or a higher percentage of engine time at WOT causing it? Also – hopefully not opening a can of worms here – but any idea if the oil being used makes any difference?

BINGO !!

You are correct on the CTEC concept ! I machined relief holes in several Polairs CFI-2 pistons over the years.

i think the blue wrist pin bearing thing is simply the lack of ( solvent ) in the crankcase I.E. gasoline ....

This the ONLY reason i stress Polaris oil only in their EFI motors... the oil must have a super low viscusity to move with ease in the case and it still has a hard time getting to the upper rod bearing.

I like the Cat CTEC move alot.

Dan
 
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indydan

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Pre-Season

The Long rod 850 motor is ready to go.....spring / early summer 2019 Long Rod builds will receive a discount on all PTO bearing & case updates, and center oil-cavity modifications

The 2019 850 Long Rods motors will get a 50% discount on the all updates.

850 Long Rods must be secured before June 1st to receive the 50% discount.

Any 2020 Long Motors ordered before June 1st will receive -10% discount on pre-season orders.

We only have a Limited number or Long rods this season.

We also just released our 2020 updated 850 Turbo billet head.

Also all pre-order 850 billet head sets & Turbo heads will receive -15% off orders before June 1st.

Next week our website will be update with correct pricing.


Thank you

Dan
 
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