Piston worries

[gmorgan]

Guys I have a good running 2.5 Super Magnum 225 on my XB2003, and it will turn just about any 28P Chopper on a 1.87 gearcase 7500 to 7700 rpms with a fishing load, me and half a tank of gas. I rebuilt my motor two years ago and installed .010 over WSM cast pistons. I’ve had a few friends caution me about turning these pistons that high. Should I be worried about piston fatigue failure? I’ve asked WSM, and they would only say that their pistons are as good as the original cast pistons. Please let me know your opinions.

 

[gmorgan]

I sure would appreciate some knowledgeable opinions on this subject.

 

[dubmoney]

You will probably get better response on the question on scream and fly. There are more engine builders and people pushing cast pistons to the limit. from what I have read, 6800 to 7000 is all I have seen guys running cast pistons, but I honestly have no experience with the failure point.

 

[gmorgan]

I run WSM and Vertex. Many run Vertex into the 8s (like me), just don't lay it to the wood all day. WSM is another quality piston IMO better than OEM. I've heard of some even going to 9's in a drag situation. Perhaps the chemists/metallurgists out there can comment on silicon content. Some also top pin and weld.

If you're running a PM above 7000 make sure it has the upgrades--primarily connecting rod bolts, oil delete, etc.

Thanks for your responses, men. I am more of the type boat owner that will string one out close to whatever the top number is and then slow down. I have never wound one up and left it there for miles.
I have big rod bolts and steel caged bearings and run a 260 style fuel system with a slide front and Brucato A6 programmed ECU and a 16-amp Diamond flywheel.

 

[Jon]

Like Mark said, if you've got the other PM stuff tackled, there are quite a few who run those pistons very high. The only thing I don't know of is anyone turning that many RPM's with a full fishing load. How fast are you going ?

 

[xb03]

My mostly stock 225pm turned 7500 all day long @ 40:1 oil, never had any problems.

 

[gmorgan]

My rod bearings are steel cage bearings.

 

[chad202]

Gary, what does your engine temp run?

 

[gmorgan]

Chad, my engine temp varies with the lake water temp. I am running a SuperMag 225 on a 280 plate and tuner. I run washers in my heads. During the winter, I hope to get up to 100 degrees, and during the summer if I am just moping around at 3,500 rpms, it may get up to about 140 degrees. I run holes in my washers during the winter that are about .092, and in the summer, I run a washer with a hole about .128, I believe, whatever the stock Mercury hipo washers are.

 

[Jr in Jax]

The cast pistons are much less likely to cold seize. I have heard nothing bad about the WSM and the Pro Marine pistons.