new coated wiseco pistons, anyone using these???

[89sandman]

have been waiting over 3 weeks for pistons for my 07 M8, my dealer is a very good cat guy. ended up having to get a set from wiseco. asked him about the problems i've heard about them in sleds. he said they used to come uncoated but they are coated now and they have had no problems. was wondering if anyone out there has any experience with the new ones. haven't used them so can still send them back but may not be able to get new ones before the start of season, would hate to just put rings in, have over 5,000 miles on the stock set....

 

[Blk88GT]

I've had really good luck with the SPI coated pistons, but haven't used the Wiseco stuff.

 

[donaldej]

I put wiseco pistons in my 700 wildcat about 6 yrs ago and had sent them in to get coated both with a skirt coating and with a dome ceramic coating by Swain Tech Coatings. There still running today after much abuse. I like forged pistons and i like wiseco pistons and i think the coating is an added bonus, less friction is better .
I have also run wiseco's in several 2 stroke dirt bikes through the years and have great luck with them.

I would use wiseco before using arctic cat IMO. Also MAKE sure you replace the piston pin circlips. Once there taken out there no good, its cheap insurance for like $2.

 

[JHG]

have been waiting over 3 weeks for pistons for my 07 M8, my dealer is a very good cat guy. ended up having to get a set from wiseco. asked him about the problems i've heard about them in sleds. he said they used to come uncoated but they are coated now and they have had no problems. was wondering if anyone out there has any experience with the new ones. haven't used them so can still send them back but may not be able to get new ones before the start of season, would hate to just put rings in, have over 5,000 miles on the stock set....

Freeagent has M8 top ends in stock.

 

[mtn mike on boost]

i have never tried them coated, but have had horrible luck w/ the
un coated wiseco's.they expand differently than stock/ or even the spi cast pistons.
stuck several of these on long pulls and cold seized em once or twice.
i will never run forged wiseco's again.

side note, i am not here to bash at all, just feel pretty strongly about my experiences w/ them.had great luck w/ the spi ones, even in turbo applications

 

[RACINSTATION]

For whatever reason, I have not had good luck with Wiseco as a whole on sleds. We run them in motocross bikes and they are ALWAYS reliable, but not so on a sled or in watercraft. We will be testing the new coated version.

FYI we have M8 pistons in stock if you need.

 

[89sandman]

they didn't show today so i guess i've got the whole weekend to wonder???? they are the only pistons i've ever used on my dirt bikes and quads. what a predicament... hey eric got my clutch off today but didn't have time to ship, will see if i can get it out tommorow if not it will be on its way monday...

 

[diggerdown]

The main thing about wiscos is the fact that you need pretty good clearance between the piston and the bore. About .003" more than a factory piston. The bigger the bore,the more clearance you need. They swell some! As long as you have the clearance and warm you engine up good, they will work well. They are lighter than a factory piston, so it is easier to turn a few more R's. They use to have an awfull time with the ring pins coming out but I have not hear of problems in th elast few years.

 

[m8magicandmystery]

i have coated cast pistons..ceramic dome..i love them...i have had wiseco in the past..always had to machine the bosses for enough clearance for the rod and side bearings to fit..so i always figured if they never took the time to sell something that should fit then i couldn;t trust them..and with all the bashing that they rightfully take i have never seen them defend their pistons in snowmobile applications..??

 

[DonoBBD]

The main thing about wiscos is the fact that you need pretty good clearance between the piston and the bore. About .003" more than a factory piston. The bigger the bore,the more clearance you need. They swell some! As long as you have the clearance and warm you engine up good, they will work well. They are lighter than a factory piston, so it is easier to turn a few more R's. They use to have an awfull time with the ring pins coming out but I have not hear of problems in th elast few years.

Yes hypereutectic pistons need more room to grow. They add more silica to the mix that turns into little air bubbles when cast. This cuts down in the amount of aluminum needed to make the part..... hence making more parts for less cost and lighter parts.

These air bubbles will make the piston expand more than most with less silica in the mix. The air expands when heated. Areas that have less air bubbles like the dome will expand differently and why ample warm up time is needed. With jet skis (spring cool water) and sleds getting into good cooling after a hot run the clearances change effecting the piston more. Dirt bike appz unless you put the cooler into some cold water in the spring you can get away with hypereutectic pistons. The type of aluminum should be a standard rating for pistons.

Cheers Don.

 

[mountainguy]

Pistons

If you hope to get 5000 miles again use OEM if you dont mind boring and replating cylinders use Wisco. One advantage is you will be one of the fastest piston changers around all your friends will be impressed. But seriously i havent tried the new ones and will never run a wiseco in a 2 stroke A/C ever again. I will say they did warranty all the failures but that gets old quick. Hope this helps

 

[clutch]

Dono, Wiseco's are not hypereutectic, they are forged. Hypereutectic are a cast piston with a higher silicon content and can be fit at much tighter tolerances than a forged piston can. There are also a few different alloys of forged, and they require different tolerances between them. I have run wiseco's in sleds before with good luck, but they do require more clearance than a stock piston. That said, I also feel that the most reliable piston is the stock cat.

 

[89sandman]

does anyone know what the piston to sidewall clearence should be???

 

[DonoBBD]

Dono, Wiseco's are not hypereutectic, they are forged. Hypereutectic are a cast piston with a higher silicon content and can be fit at much tighter tolerances than a forged piston can. There are also a few different alloys of forged, and they require different tolerances between them. I have run wiseco's in sleds before with good luck, but they do require more clearance than a stock piston. That said, I also feel that the most reliable piston is the stock cat.

If they are drop forged then they will not be perfectly round when heated. No two pistons will be the same.

Don.

 

[diggerdown]

does anyone know what the piston to sidewall clearence should be???

I thought wiseco had a chart for clearance tolerance, I know I saw one once but I'm not sure where I found it.

 

[Rprecision]

For all the negitives you read about them in snowmobile applications, I would just run OEM and make sure they are ballenced really well.

I have used Wiesco in other applications where they worked like a forged piston should. When you consider the extremes a sled motor deals with, changing the design to a forged piston when they came stock with cast seems alot of work for very little gain ?

I would get intouch with freeagent she's great to deal with !

 

[Barrett]

dont run the wiesco's. run cast pistons in a snowmobile. OEM Cat first choice or SPI second

 

[jsledder]

This reminds me of an oil thread.... A few people that have bad luck with a product will make a lot more noise than the people with good luck.

I run them in every sled I've got, but......... they are all Polaris so whatever difference that makes??? And I've never changed one after putting it in and the oldest sled I have running them is a 92 that I sold last year, and it's still going, pistons were put in in 2004 (and it's far from stock)

They will include a clearance spec sheet with the kit so you'll know what they need to be. If you don't pay attention to the clearance or installation instructions, you'll likely be on here complaining about them.

 

[clutch]

If they are drop forged then they will not be perfectly round when heated. No two pistons will be the same.

Don.

You are right. No piston would be round when heated if it starts out round. Any piston is actually oval in shape when cold, so that as it heats and expands more near the pin boss and head it actually comes in to shape at operating temp. It also has taper from top to bottom for the same reason. Now back to the clearance question, Cat probably says to fit their piston at ..
.0042-.0059. If that is the case I would fit the wiseco at a min of .005-.0067 and like everybody always says make sure it is warm before putting a load on it.

 

[Barrett]

HERE IS THE ISSUE with the forged pistons:
HOW ARE YOU GONNA CLEARENCE THEM PROPERLY!!!!!!
they need to be fitted looser than cast, yet you are stuck with a fixed bore size because of nikasil. Ya you can bore and re-plate, but WHY FORK AROUND. just run an OEM piston and be done with it.
my .02