Stock VS. Wiseco Piston Weights

[duneracerweston]

ok so while in the process of building Wall-E to be a .040 11.5:1 wiseco motor i decided to weigh them at the collage and the results shocked me

keep in mind these are raptor 350 pistons not warrior so stock may be different if i can find the stack warrior piston i will weigh it too and add it to this post

Stock raptor 350 piston

bare piston - 287.5g
wrist pin - 66.0g
all rings - 22.0g
total weight - 375.5g


.020 raptor 10.25:1 comp wiseco piston

bare piston - 274.1g
wrist pin - 85.4g
all rings - 19.7g
total weight - 379.2g


.040 raptor 10.25:1 comp wiseco piston

bare piston - 278.4g
wrist pin - 85.7g
all rings - 20.8g
total weight - 384.9g

83mm STD bore JE 12:1 piston specs

bare piston - 271.1g
wrist pin - 69.7g
all rings - 18.3g
total weight - 359.3g

 

[87warrior917]

Wow i cant believe that myself! You'd think they woulda made sure it was lighter... I think i have my stock warrior piston, ill check tomorrow.

 

[duneracerweston]

when i put mine together im going to put a new stock wrist pin in and that alone knocks it down 20 grams

 

[1998yamahawarrior]

Something tells me the wrist pins might be heavier for a reason. I could be wrong, but maybe its stronger?

 

[87warrior917]

Should be forged. But i thought forged parts were lighter.

 

[duneracerweston]

the forged parts can be lighter because it dosen't have to be as thick to be just as strong and best i can tell the wiseco is thicker but made of the same stuff im going to talk to my motor guy and see what he says

 

[duneracerweston]

i compared the two wrist pins and the wiseco is within a mm in length due to the oem having a deeper bevel then the wiseco around the circlip but the wiseco is 31%thicker at 3.61mm thick stock is 2.47mm thick both have the same outside diameter

 

[miami1]

my je 12:1 85mm was 289g (piston only)

i also had the misfortune of getting the wrong valves (wiseco carbon steel) when i ordered my kibble whites and there was right at a 10g differance between the two

 

[mattskn]

I know this isnt the right spot for this, do any of you guys have a used std bore wiseco forsale.pm me

 

[duneracerweston]

i got a .020 over thats used idk if you would want that id go with a new piston used is kindof a guess if the piston will stay

 

[Dino]

You have to keep the weight within a few grams for balance purpose. Anything heavier outside of 5 grams is going to require a rebalance, the counter weight will have to have moly added to it, or you will have excessive vibration to deal with if the piston is to heavy. If the piston is lighter, you will have to take weight off the counter balancer to match the ligher weight. It is a simple science, what you add or take away has to be matched in the counter balancer.

 

[duneracerweston]

You have to keep the weight within a few grams for balance purpose. Anything outside of 5 grams is going to require a rebalance, the counter weight will have to have moly added to it, or you will have excessive vibration to deal with.

tell that to wiseco there .040 piston im putting in mine is 9.4 grams heavier then oem and if you can get away with 9.4 over id rather it be 9.4 under to make it rev quicker

 

[Dino]

On the under side of the piston their are balancing pads, put the piston in a drill press and drill out some weight to get it to match the weight of the stock piston. This is how race pistons are balanced matched in a race car.

 

[duneracerweston]

Ya one quick question have you looked at a wiseco ATV piston before? Its not the same as a car motor

 

[Dino]

Another neat trick to do on stroker motors is to offset the wrist pin to take the side load off the piston, it will keep the piston centered in the bore. Rings will stay seated better, and the skirt will not scuff the bore. Less heat and damage to the bore. Simple race basics that most folks over look.

 

[Dino]

Ya one quick question have you looked at a wiseco ATV piston before? Its not the same as a car motor

Then ball mill some weight off the underside of the top of the piston. You need to think outside of the box. Get creative with your thought process.

 

[beastlywarrior228]

Another neat trick to do on stroker motors is to offset the wrist pin to take the side load off the piston, it will keep the piston centered in the bore. Rings will stay seated better, and the skirt will not scuff the bore. Less heat and damage to the bore. Simple race basics that most folks over look.

What do you mean by offsetting the wristpin?

 

[duneracerweston]

I'm just going to run 10g light and se how it goes dose ive rode it 9.4g light and no vibration over stock

 

[MidwayUSA]

In our experience balancing automotive cranks, 10 grams at the piston end only affects the crank half that. I don't thing 10 grams will matter. Most times when we balance a race crank we add 1.5-2 percent to the upper end for overbalance. For whatever reason, overbalance tends to help bearing life for some reason.

 

[duneracerweston]

just got back from talking to mr. Jessup he says a stock wrist pins with a 12:1 motor is completely reliable and need not worry so i ordered a oem wrist pin to put back in this motor to lighten it up a bit and means it will go faster!!