You hit it on the head mxwrench, the reasion the same engine with puddy in and and one with out is the crank will be lighter thats were the extra paformance comes from the ultamate crank would be so light and supper blanced like most top of the line on-road engines. As some people have noticed over the last cupple of years this has been an added feature to some off-road engines blance of the crank to piston is critical in making an engine that kind on its parts like bearings and rods wile aheaving the rev harder and faster off-road engine are now starting to get to the point of paformance that then need better blanced cranks to acheave higher rpms for longer times and faster smoother spin up. I have run a sirio bk evo 2 engine with a sirio 21 wcr crank and the paformance difrence was instantly noticable it reved much harder but the bigest difrence was it got there quick and smooth. regards jeremy.

Sirio2127

Thoose two cranks probebly have some really differetnt timingnumbers and you can not compare them to a heavy or light crankshaft.

In theory, if a crank is 5 grams ligter and you monunt a flywheel that is 5 grams heavyer you will be at the same point. It is the complete mass that desides the aceleration of the engine, not the weight of the crank itself.

The wolfram slugged cranks are a different story. You change the balancing factor of the engine. This changes the self resonating ( in lack of better words) frequency of the crank. When a cranksafts meets it own resonating frequency it takes alot of energy to overcome this. When you slugg a crank you move this frequency upwords and get higher rpms.

MRX 4; i agree with you. There is a lot moore bottom end with the paste inside the crank, even if it is not any lighter.

Mxwrench:

Dynos are important to manufacurers and have been in the auto industri for decades, and will certanly make its difference in our hobby. But, as anything else here not evrything can be messured, somethings still go bye feel. I am a little surprised that you can not see the difference between a standard crank and a crank with paste that is not lightened on the torque curve. I can understand that you can not see it on the HP curve since it is on low rpm. There is a difference and i you take two standard cranks and fill one, and not the other i am shure you can see the difference. I f you try it on the track you will understand what i mean.

I am very interessted in whet you can read out of the dyno, do you run engines for customars? Can i send you an engine and you make a dyno run? Whats is your fee? I have a few pipe that i would like to be messured and two engines that i have done myself.

Please e-mail me on [email protected]

Thanks.

Anders

DAME I DIDN'T THINK THIS "PUTTY THREAD" WOULD HAVE TWO PAGES........
BUT ANYWAYS I HAVE LEARNED ALOT FROM READING OPINIONS FROM EVERYBODY..THANKS AGAIN AND KEEP IT GOING

Threebond 1211 works very well and is very easy to manage as its more of a liquid... i tried this on a Picco .12 along with a slightly worked crank and sleeve. I seem to have had trouble with keeping it idle at first but after about 20 min of breaking the motor back in and running some fuel through it, well it worked.

Increased bottom end was noticable, high end seemed the same and most of all an increase with overall run time of almost 12-14 minutes on one tank(75cc?)

threebond 1211 is the best ive seen.


As far as brians dyno not being accurate, far from true. Its as accurate as a SAE Corrected Real life Car Dynojet Dyno. Its not some silly play toy prop dyno.

I also beleive that this red thingy doesn't do anything.

"am", i don't thing anyone can tell a difference from this change on the track...we barely see the difference between two different top engines at this point,imagine trying to see a very small difference between the two cranks.
No-way!!!

The mass that is removed is in the center of the whole rotational masses so the effect is even lower.
The biggest difference would be between a flywheel of 40mm diameter and one of 30mm diameter.
In this case you have less mass away from the center and this lowers the total rotational mass more.

How are you guys applying your silicones. Most all of them come with a clear extension nozzle that has different spots through it that you can cut it. I cut on the last one so its small amount coming out.

The problem is , what do you do when you goto put this stuff away at the end of the day. Not one of mine come with a cap for this piece , as well If you take off the extension and cap your stuff ok , your silicone wont dry out , but now the extension is filled and dries out , you pretty much cant use your extension again , or youll end up wasting a lot of silicone each time.

Anyone have any suggestions on how to keep your silicone in good shape or is everyone not using the extension. Id figure it would be real tricky without the extension.

Hello everyone,

there is a BIG misunderstanding about the silicone insert in crankshafts.

This insert is NOT put there to enhance performance!!!!

When an engine is modified (as in JP, Murnan,etc) the crankshaft is drilled out (towards the clutch) to make it lighter. The whole needs to be closed to keep crankcase volume consitant. Here is where the silicone is used. It does build a ramp that might help with gas flow, but that is NOT the primary reason to put it in.

Smearing silicone into an un-drilled crank is crap and won't do anything!

Well given that the air enters a chamber , that chamber is now shortened. Will allow the air to travel through that chamber or volume quicker. As well its guiding it away from a pocket that was there that was more or less a dead end for air. Keeping air around that area preventing new air to travel in. Now its ushered away more quickly and effectively , allowing more fresh air to come in.

At least thats my theory.

I believe it makes a difference not a mega difference but a noticeable one.
Its helps the airflow through the engine to be more efficient which can be noticeable in throttle response and fuel consumption.
If you dont understand the tuning of a engine and tuning of the clutch then I dont think you would notice the improvement because they compliment each other.

Sure there is more experience guys that can contribute from a hands on experience or one of the mod specialists.
My 2cents from experiance.

thats what every modder does.

And it still makes a difference cause it lowers the crank case volume.

Wrong, only the modders that don't know what they are doing, do this!

Maybe we get Uriah, Edward or Dennis in here, I guess you'd believe them rather than me.

Edward did mention to me previously that it doesnt do anything but its made a difference to my PR12.It would be great to get Ed or Uriah on here to explain.Im all ears as they can explain what has happened or what we are assuming has happened.This is the beauty of this hobby and the medium we have on this thread.

all im saying is that the ramped induction does see a slight improvement. not saying ahguge gain is there. No modders out there that are popular actually hog the crank out to the end just for ramping the induction. the only thing they do is rouch up the back wall so the filler will hold better. I dont need edward or dennis in here. mxwrench has already layed the facts down.

but what do i know?

Oh, so all the real fast engines like Murnan's or JP's are drilled for their personal amusement?

Sorry I didn't know that. I actually started modding engines at the same time as Uriah Murnan (we raced at the same track), so I guess I've been doing everything wrong all those years.

DAMN!