wiesco vs. pro-x vs. WSM vs. OEM

[Idok]

we need a good piston discussion over here, so.........

seems as though most peeps are running pro-x, but lots running wiesco's as well.....

getting ready to build my new magoo motor and have to make a decision here pretty soon...now, Ill probably just put in whatever paul tells me to run, but whats been happening lately on the piston scene?????








:sneaky:

[Frosty]

I too like Pro-X and OEM myself. I'm running wiseco's in my blaster because the price was right.

[MADMAT]

Good thread. I just ordered Pro-X but I was wondering about those WSM's on EBAY.

[Idok]

ill probaby go pro-x...i like to drop my ski in the water and hammer down....F warming up!

[Matt_E]

I am going to put Sudco 83mm pistons in my engine in a couple of weeks. The look identical to Pro-X.

[ski4]

pro x this time round
used old wiseco once in a 750 sx and ran hard and strong for for years with no trouble ( just have to be very spot on with the clearance piston to wall, they are not forgiving i am told)

[Mile9c1]

Sudcoo are OEM equivalent, so are ART pistons. One of the nice things about cast is since they use a smaller bore, if you mess your engine up you might be able to get away with a hone and same size Weisco pistons. Just my opinion.

[butti]

i use weiscos.i dont miny babying it untill it warms up:burnout:

[steve802cc]

Here's what I've heard.

Round tops.
Pro-X and OEM are very similar in quality and construction and seem to last well.
Wiseco weigh less which should give better throttle response but don't last as long as Pro-x or Oem before needing a re-ring or rebuild. Also with Wiseco you do need to be a little more careful with warm up and initial piston to wall clearance since they expand more or quicker than Oem pistons. Good pistons for people who don't mind doing a little more maintance.

Flat Tops vs Domed Pistons
Flat tops are not truely flat they just have a flatter dome.
An example of a flat top piston is a Kaw 750 piston. Yamaha 701's are domed.
The flat top pistons make a little more power. I've heard aprox 1.5 hp per side.
In the old days you would install Kaw 750sx type pistons in the Yamaha 701 motor to make a flat top motor. Wait it is not that simple. The piston ring ends lined up with the transfer ports instead of inbetween the ports and I believe the pistons were just slightly too tall requiring you to grind the squirt. Also the wrist pins height to the top to the piston is not the same from the Kaw to Yam pistons. To make this motor you also had to recut the cylinder head and possible deck or mill the cylinder.
I believe you can now buy aftermarket flat top pistons made special for the Yamaha motors but I'm not 100% sure what kind of motor modifications are required. Ask Paul/JrMagoos about this one.

Later
Steve

Please correct me if I've made any mistakes.

[Mile9c1]

Riva sells Yamaha flat tops now.

[Mouthfulloflake]

Here are some pics comparing pro-x to Wiseco
these are Kaw 750 pistons, but you can get an idea of the differences in a cast vs forged piston from these.

Wiseco on the left, pro-x on the right.

notice the extra bosses in teh wiseco wherethe pins to locate the rings go in.
beefier around the piston pin also.

[Mouthfulloflake]

and a couple more.

this is prox on the left, and wiseco on the right.

[SUPERJET-113]

I've always used Wiseco's with no problems whatsoever. As menttioned as long as they are set up right, and you warm your boat up on the trailer, then in the water a bit, no problems.

Dont think this has been metioned about pistons..
If a skirt breaks on a cast, it crumbles into many pieces and can trash a whole motor whereas a forged piston is a stronger and lighter piston and if it does break it will only be 1 piece or so and wont crumble and will hopefully fall to the bottom of the motor and not do a bunch of damage that a cast piston breaking would do. Thats another reason why racers like the Wiseco's.
I have no problem using Pro-X or OEM, Art, Sudco either. Still leary about WSM, even though I hear the "Platinum Series" is suppose to be decent according to a buddy of mine that has a rental business and rebuilds all his own cranks with WSM kits. I still wouldnt use WSM just because of a bad experience I had a long time ago trying to use one of there piston kits in a ski i was going to sell. The rings lasted like 3 hours of riding before their tension gave out and I slowly lost compression. I thought the rings look EXTRA cheesy to begin with... Anything but WSM IMO..

[Mile9c1]

Wiseco on the left, pro-x on the right.

Which one's heavier? Historically, the forged pistons have been heavier.

[fitzen101]

wisecos! they are lighter and stronger than the cast pistons. stay away from wsm and sbt as they are junk. pro-x or oem are your best bet for cast pistons. these days the wisecos don't expand as much as the wisecos from yesteryear because of a newer blend of material and manufacturing now used. when all is said and done you need to pay extra attention to who bores your cylinder, this is where most problems originate. believe it or not a LOT of people don't know how to bore a cylinder right, sad but true. make sure they are straight, round and to spec. and ALWAYS check your squish!

[waxhead]

if a large bit falls to the bottom of the engine then the crank will pick it up and smash it every where anyway
so i dont see the issue about how they break up as being that helpful
i have used wisecos i prefer to use cast now
i was having issues with skirts collapsing and this was on a torque plated cylinder

wiseco gave me my money back on 12 pistons so even they acknowlodeged a problem
however this was a year ago so they may have changed since then

[Mile9c1]

a torque plated cylinder


What??

[waxhead]

torque plated cylinder
you bolt the manifolds on the cylinder
you machine the centre out of an old head and the centre out of an old set of cases
that way when you bore the cylinder is already pulled the same as if it was torqued up as in the same when you have your engine put together
when you bolt up a cylinder you will find they pull out of round and this gets over the problem
it makes for a perfect round cylinder for your pistons to run in

[Mile9c1]

Gotcha. I've heard of that, but never called that.

[waxhead]

it correct name is torque plate bored cylinder

well thats the correct name down here

you guys more than likely have a different name
its works well

[SkiDaddy]

I wonder how much difference that makes on a freestyle SJ engine after a few weekends? What do you think Wax?

[waxhead]

well every time you have a rounder bore you are going to get better sealing as well as a more uniform load on the rings
i would say as the engiones were wearing out that you would actually have more power for longer
bear in mind its not like you are going to rip past the same engine with out torque plate boring
but in a race ski every little bit = a large bit

[SkiDaddy]

Interesting to be sure. I'll have to ask the gent doing the boring & porting about that......:sneaky:

BTW who has the best prices on Pro-X piston kits (pistons, rings, pins, clips - pin bearings not included) for third over? It's $148 for stock & first over at ParkerYamaha but they don't list 2nd over & up.:rolleyes:

[Freestyleriverrat]

I am running Wiseco pistons in the motor Paul just did for me. I don't mind warming it up before I run, I do that anyway each time I go out just to check stuff. They are stronger and lighter, I guess time will tell how they perform and hold up.....this is my first time using them.

[Metal4130]

When you guys install these pistons do you ever lighten them to get better performance? Also do you weight them to make sure they are the same weight before you install them so they balance correctly? I know in the R/C boat engines they do a lot of piston lightening. I was just wondering if they do this in the pwc engines.

[SkiDaddy]

I've not lightened a piston; for recreational use where longevity is a concern (RC pistons run what, maybe 30 actual hours before replacement?) I'm more concerned with fatigue and wear on the cylinder wall.

[WaveDemon]

When you guys install these pistons do you ever lighten them to get better performance? Also do you weight them to make sure they are the same weight before you install them so they balance correctly? I know in the R/C boat engines they do a lot of piston lightening. I was just wondering if they do this in the pwc engines.I'd like to know also. I don't think you'd hurt the life span if you just took the heavier rod and piston and made them weight the same as the lighter ones. On small block chevy's you grind the rounded outer edge (length wise) of the rod and I think the bottom of the piston pin boss on the piston.

edit: another place to lighten without hurting strength is in any casting marks...

[waxhead]

i have never lightened a piston for a pwc

[Mile9c1]

I've heard of people making holes in piston skirts to feed boost ports. Or something like that. But just because that's how the ports were setup to run.

IMO it's definitely not with the breakage risk to try to lighten them, it's not like Weisco or Pro-X said "hey, let's add a bunch of extra metal to this piston to slow it down".

What I'm really wondering is if anyone's weighed the same size Weisco and Pro-X piston back-to-back, to see what the difference is.

[Freestyleriverrat]

I've heard of people making holes in piston skirts to feed boost ports. Or something like that. But just because that's how the ports were setup to run.

IMO it's definitely not with the breakage risk to try to lighten them, it's not like Weisco or Pro-X said "hey, let's add a bunch of extra metal to this piston to slow it down".

What I'm really wondering is if anyone's weighed the same size Weisco and Pro-X piston back-to-back, to see what the difference is.

Some one must have a set to weigh somewhere. Magoo? Wax? Have any in your shop?

[SUPERJET-113]

When you guys install these pistons do you ever lighten them to get better performance? Also do you weight them to make sure they are the same weight before you install them so they balance correctly? I know in the R/C boat engines they do a lot of piston lightening. I was just wondering if they do this in the pwc engines.

FWIW - The machinist that does my boring, balances the new pistons i give him. They're so close to begin with, it doesnt take much to have a perfectly balanced/matched set.

[Matt_E]

Actually, I have a set of Wiseco's and a set of Sudco's. Unfortunately, the Wiseco's are for an 84mm bore, and the Sudco's at 83mm.

[orange flattop freestyler]

Ive run both but have Wiseco flattops in her now and "touch wood" never had a problem :biggrin:

I think the Wisecos are a much nicer piston, the quality looks much mcuh better and the weight difference is VERY noticable :biggrin:

[waxhead]

i have some 83s as well
i can weigh them and see what they are

[robertg]

84mm OEM 388 grams, 84mm Wiseco 331 grams.

[Matt_E]

57 grams difference...that's 2 ounces lighter for the Wiseco.
Nice difference.

[egbrig]

Wiseco's are forged therefore the metal structure is much more dense which allows for a thinner wall to maintain the same strength but needs less material or its lighter for the same strength. Art, Pro-x, OEM are cast hypereutectic pistons. Hypereutectic means it has a 16% silicon content for strength and durability, also a Hyper*** pistons thermal expansion rate is less than a forged pistons expansion rate . You could think of it as in a cast piston the molecules are father away from each other so it takes more heat to make them move away. Wiseco's are not as hard as their cast counterparts, you can see this when they stick. A forged pistons molecules are hammered real close to each other, stronger yes but will expand more. Wiseco's are ok depending on how they are set up and for what and how they are used. You really don't need to balance the pistons they come close enough for most aps. What really matters is what is the application and how everything is set up.

[jacob06]

if the wiseco piston is 2oz lighter,then could adding 2 of them be said to remove 4oz or a 1/4 lb of the rotating mass of the motor?not to steer off topic,but how much lighter is an aftermarket flywheel than the oem?(i would really like to know)but if the effects of adding lighter pistons are similar to an aftermarket flywheel,then the choice should be clear.the no wake zone is for warming up.i vote wiseco

[Metal4130]

Whell you can get your stock flywheel safley lightened up to 5 oz's by pro-tec or jr. magoos.

[SUPERJET-113]

84mm OEM 388 grams, 84mm Wiseco 331 grams.


NICE!!!:hail:

[Phill]

Hey you guys talk about warming up when running forged pistons....how much time are you talking about? 30 seconds? 3 or 4 minutes?

[steve802cc]

I warm all my motors up forged pistons or not for 3-5mins before getting on the throttle hard.
Steve

[Matt_E]

It helps to not have the pistons installed backwards, Phill.

*Ducking and running*

[Phill]

It helps to not have the pistons installed backwards, Phill.

*Ducking and running*


Well if I remember that night correctly, YOU were the only one to have done this more than one time....so I hold you fully responsible.


And I will be taking the cylinders to the shop soon....

[Phill]

torque plated cylinder
you bolt the manifolds on the cylinder
you machine the centre out of an old head and the centre out of an old set of cases
that way when you bore the cylinder is already pulled the same as if it was torqued up as in the same when you have your engine put together
when you bolt up a cylinder you will find they pull out of round and this gets over the problem
it makes for a perfect round cylinder for your pistons to run in


How important is this for a recreational motor.....is this only used for a race motor?

[Matt_E]

Don't worry about it.
I would get over to the shop ASAP if you want that thing done by Friday.

[Phill]

I sure I will be gone by the time it gets done

[Matt_E]

What are you waiting for, fool? Get over there!

[yamaslut]

awesome thread.... I have always used Pro-X w/ great success.
I don't like to even think or worry about warming up, so they are perfect for me... As far as weight difference goes... not a factor in a surf boat... IMO

[ski4]

i never really put much thought into warming up my old 750 motor with wiseco's, i rode in some cold ass water too ( 34 degrees or so), never had a problem
although maybe the no wake area saved my hide getting out to the open water

[93SJ760]

I've run WSM's in my 650 for 2 seasons without a problem. I originally had the cylinders bored at just about .003" clearance I believe. I think my machinist told me .003" for cast and .005" for forged. It's been a while so I'm not sure if I'm getting the clearances right... they both seem to be pretty tight to me I think at .005 it would be hard to slide in.

Anyways I had no problems for 2 yrs at which time I tore it down to build a 701 and it still looked good inside. Only issue was before installation had to send one piston back because the ring wouldn't fit due to a misinstalled ring end-pin.

In my 701 I ran Wiseco's which had a lot more scuffing on the sides when I took it apart to rebuild due to detonation damage. Got a little too cocky and filled it up with regular on almost 190psi cranking. Made it about 1/2 mile.

I have a new 84mm WSM in the garage that I could weigh if I had a scale. maybe I can bring it to the post office and ask them.

Tyler

[#ZERO]

When cast pistons are over heated, the skirts become very brittle. They have been known to fall apart into many pieces and will damage internal engine components.

[Mouthfulloflake]

When cast pistons are over heated, the skirts become very brittle. They have been known to fall apart into many pieces and will damage internal engine components.


I have been there and done that with WSM pistons.

Never again, ANYTHING but wsm pistons.

proX, wisecoe, art,sudco.

ANYTHING but WSM

I posted some pictures in a thread on PWCyesteryear, showinf the differences in prox and wiseco pistons.

[SUPERJET-113]

When cast pistons are over heated, the skirts become very brittle. They have been known to fall apart into many pieces and will damage internal engine components.

Ya, CRUMBLE into tiny pieces and easily suck through your cylinder ports and ruin your top end along with your crank. Wheras a forged is stronger and if it does break it will only be a piece or 2 and wont make it to your top end to destroy it. Ever seen a cast crumble like a cookie? not pretty!!:frown: