Forged or Cast?

[redneckboater]

Hi all,
I have a 1989 Force 125hp Outboard and im about to rebuild the engine for the second time.

On the first rebuild only one cylinder failed but I rerung and honed the other three cyclnders since I was in there. And here I am again 3 years later and a different two pistons failed in the same way as the one did the first time. The rings just pulled thru the top of the piston without damging the cylinder walls (minimal scuffing easily cleaned up with a hone). Almost like they get caught on the ports.

This motor gets run very hard in the summer used primarily for wakeboading and other water sports and very little just cruising. So my question is this will a forged piston be able to handle more stress and not fail like the cast ones? Or do I have another problem than just weak cast pistons?



Thanks for any advice!

 

[Frank Acampora]

Re: Forged or Cast?

The stock cast pistons --and I assume the Sierra or vertex ones have a semi-keystone top ring. I have seen numerous pistons where this ring breaks out of the top groove and breaks the top piston land. They seem to be prone to flipping top rings. On rebuilds, I like to use Wiseco pistons because they are easier to install on the rod and are forged. The extra cost does not factor into the equation at all. I have several engines with these pistons and have a lot of hours on them with no problems.

In fact, once I inadvertently set timing to 42 degrees advance--Don't ask--Alzheimers--long story-- The pistons were damaged but not destroyed and I suspect that it was because of the extra strength of forged pistons.

So: What have you got to lose? Maybe 100 bucks more? The decision is yours.