84-86 85hp .040

[jason32038]

Hey guys and gals. I just want to ask why the manufacturer doesn't reccomend boring over .030?? If they don't reccomend it then why does Wiseco make .040 pistons? I ask because I had one bored .040 3.352 Had the other 2 lightly honed because they were in good condition. After being down for 2 years..she's almost together..painted and ready to run. Is there anything I need to worry about with going .040..what about pre-break in driveway procedures before I take it on the water?

 

[Frank Acampora]

Re: 84-86 85hp .040

The manufacturer does not recommend boring .040 because cylinder liner wall thickness is at this point becoming too thin. There is an increased chance of exhaust port webs deforming into the cylinder.

Why does Wiseco make an .040 oversized piston against manufacturers recommendations? I don't know, but if there were no market for .040 you can be assured that Wiseco would not make them. So, people must be doing rebuilds at .040 over.

Use double oil to break-in and do not rev it. On the water, keep RPM down to 3/4 throttle or less but vary speed.