Who has a Long Rod Engine Upgrade?

[AKSNOWRIDER]

How much longer of a rod are we talking here?

Why doesn't the piston hit the head with the longer rod?

normally its a small movement...125"-.250"(1/8 to 1/4"), and on most motors you would just make a piston with the pin moved closer to the dome by the same amount(which makes everything fit eactly as it did with a stock rod/piston), I believe one of the kits offered right now uses a longer rod with stock pin placement and adds a spacer to raise the cylinder the needed amount..the other kit..I am not sure on....

 

[Whiz-bang]

Ak, In most cases a longer rod will make more hp but typically takes longer to get there. Back to my question, how are the shops counteracting this? Porting, ignition, pin location? I would love to have a more reliable motor but not a slower revving one.

 

[AKSNOWRIDER]

whiz..every long rod motor I have had has been quicker revving then a std rod motor...now you may need to play with ignition/timing curves to take advantage of it...but over the years of running long rod motors I have never found one to be slower revving then a std ratio motor...

 

[Whiz-bang]

Seat of the pants quicker revving or Dyno pulls comparing elapsed time to peak hp?

 

[AKSNOWRIDER]

both...this was on pro mod style drag motors..some over 2000 hp...

 

[Whiz-bang]

Were you doing back to back comparisons without any other changes other than long rod in one and short rod in the other?
Again I am only trying to understand what/if the long rod guys are doing to adjust for the changes that inherently come with an engine spec change

 

[AKSNOWRIDER]

yep..also side by side in competition, same motor down to cam/induction/chassis/gearing...we did run different jetting/ignition timing(both initial timing and amount and when we pulled timing as we added ea stage of nitrous as well as high gear retard(long rod needed more initial, less pulled on ea stage, but more pulled for high gear))...initial went from 42 degrees to pulling 20 for ea stage of nos to pulling 4 for high gear...the first long rod motor had been run as a std rod motor for 2 seasons before going long rod ..everything stayed the same as far as heads,induction, headers, piston static comp(15.5:1), cam(865/822 lift) valvetrain,we did have to recontour piston domes and valve releifs to compensate for the different piston dwell time due to the long rod..but yeah..a better motor in my eyes ..that was the last std rod motor I ran in comp..everything since has had a longer rod in it...

 

[Whiz-bang]

Makes sense and you really help drive the question home of what are the shops doing other than just a longer rod. A longer rod will imo change some characteristics and will require potentially different porting, piston, ignition timing, jetting, clutching and gearing to optimize the combo.

 

[BB454]

Long Rod

Dan's and Brad's longer rods are 2mm longer is all and they add a spacer to compensate so stock pistons can be used. With the spacer, port timing and everything remain the same, case volume changes slightly is all so no changes needed. Their rods are the same length as the old big block rods I believe. The small block motor actually benefits from the additional case volume. In therory a even longer rod would help side loading but Dan says piston dwell would start to enter in. That is where the piston virtually comes to a stop at the top and bottom of the stroke. Too bad Polaris made such a bastard size rod other wise a longer one could be explored say from the motorcycle industry. I have looked and the lower pin size is unique.

 

[AKSNOWRIDER]

I know this..everyone that has seen either brad or dans long rod motors run(dyno or runs) so far have been very impressed. my guess is within a few years this will be a very common mod in the sled world as people/shops figure out what can be acomplished...

 

[Whiz-bang]

Have dyno runs been completed to prove that the long rods have little to no effect on power delivery of the 800?

 

[1200psi]

Have dyno runs been completed to prove that the long rods have little to no effect on power delivery of the 800?

Hi , everyone I will clarify a few things. We are offering this kit in our 910 motors and 800 motors. In our kits that we produce our rods are 4mm longer than the stock motors . Our kit also features a billet rod. We accomplish this by running a spacer and two gaskets for the difference . We (PAR) also have found that you can also achieve a little better port timing with some different gasket thickness also.

We have dynoed this combo and truly there is a pretty big difference in the characteristic of the motor.

1 more tq the tq is much broader
2 Way less vibration.
3 Engine is much smoother .
4 In a bone stock motor there is only about 3-4 hp diff. in power not a lot of hp but the ticket behind it is the dependability it produces and the more tq it makes.

We are doing a ported version witch we just dynoed that will produce 160 + hp 105 ft tq. with the billet L/R and our porting ,head, pipe.

Our 910 motors make 175- 180 hp and 120 ft tq.

So that being said AK I have read your post, and your are spot on with your post it is a huge hit.

Here is a link to the kit on our site FYI

http://www.poweraddictionracing.com...d=120&osCsid=da98d06b1e704a403e73184b889472cd



Brad

 

[Slingn Snow]

I have had PAR put the long rod kit along with other engine mods and Brad has made this motor rip. It is much smoother and very responsive. After talking with Brad I felt that this is the only way to go if you want reliability and added HP.

 

[AKSNOWRIDER]

hey Brad, Any special reason for going with a spacer over just a custom piston with the pin relocated? I would assume it was to gain crankcase volume and to be able to easily change port heights if inclined?

 

[R44guy]

I have had PAR put the long rod kit along with other engine mods and Brad has made this motor rip. It is much smoother and very responsive. After talking with Brad I felt that this is the only way to go if you want reliability and added HP.

Slingn Snow, would you clarify some additional details as far as which year poo 800 you have and how many miles you have put on it since the engine was done.

Also what other mods did you have done besides my educated guess a head and pipe? Thanks for the post we all want to learn all we can about making these motors last and obviously who doesn't want more power?

 

[Slingn Snow]

Slingn Snow, would you clarify some additional details as far as which year poo 800 you have and how many miles you have put on it since the engine was done.

Also what other mods did you have done besides my educated guess a head and pipe? Thanks for the post we all want to learn all we can about making these motors last and obviously who doesn't want more power?

Sure I have a 2011 Pro with 1700 miles prior to taking my sled to Brad. I haven't put any miles on the snow yet but have put the engine on the dyno and the results were impressive.

PAR did porting, long rod kit, head, and balanced my clutch. They also did all the labor. I had them put O.E.M. pistons back in and Brad assured me that they were within spec. My sled also has a SLP pipe/can and power commander.

 

[1200psi]

hey Brad, Any special reason for going with a spacer over just a custom piston with the pin relocated? I would assume it was to gain crankcase volume and to be able to easily change port heights if inclined?

True, that is something that could be done.

Brad

 

[4Z]

Love the spacer over custom (different than stock) pistons. Lower pins promote rock-n-slap. Plus, if the motor changes hands it is nice to just buy OEM Elko pistons as apposed to hunting down (or even remembering) custom/different slugs.

.02

 

[treedocker]

Northstar in Preston Idaho has made there own kit for the pro that they did last spring and it has a spacer and different pistons and timing change and it is making 18hp over a stock pro and is 1500 installed.

 

[indydan]

Long Rod PRO/Dragon Crankshafts.

Indy Specialty is the company that started the Long Rod Hype.


And it is in fact a great option for these motors and increases dependability.

We do sell just the crankshaft with the conversion, But the cylinders are so far out of spec from Polaris we end up doing a strip & replate on just about everyone that comes in. and then we warranty the complete motor for 3 years.

For some reason they are tapered from top to bottom the wrong way. ( The bottom is most offen .001 to .002 bigger then the top of the cylinder and causes the piston to prematurely collapse from slapping at the bottom and they loose power )



Thanks, Dan