Wiseco pistons

[bonitoman]

What symbol does Wiseco have on there pistons besides .30 .Are there any letters? Thanks

 

[Dhadley]

Re: Wiseco pistons

Assuming you mean .030 over, yes. It will show up in the part number like 3173P3 which is the coated crossflow .030 oversize. <br /><br />What exactly are you looking for?

 

[bonitoman]

Re: Wiseco pistons

This evinrude has an M stamped on all 4 and I do not know what company make these. The M is large and on the bottom of all 4.

 

[Dhadley]

Re: Wiseco pistons

Not really sure what you mean. Where is the M stamped? The complete part number is stamped on the dome of a Wiseco. Is it a forged piston? Do you have the pistons out?

 

[bonitoman]

Re: Wiseco pistons

The pistons that I am referring to are from a 95 intruder that has already been rebuilt. Whoever did the rebuild used pistons that read on the dome .30 and a M stamped on them. I have done many rebuilds using pro, vertex, omc pistons but never seen an M on them. I would like to know who makes these.

 

[Dhadley]

Re: Wiseco pistons

Thats a new one on me. I cant remember seeing any with .30 and an M. Youd think it would at least have .030 to be correct.<br /><br />A Wiseco will have the full part number and a run number along with some other stuff on the dome depending on which piston it is.

 

[OBJ]

Re: Wiseco pistons

OMC parts, when OMC was still around, had an "M" inside a square on many of their parts. That's probably what your seeing, original equippment.

 

[bonitoman]

Re: Wiseco pistons

Did OMC build engines .30 from the factory. I thought everything was standard pistons?

 

[Dhadley]

Re: Wiseco pistons

True but it was cast in on the inside of the skirt and the top would have been stamped .030 not .30 along with the part number.<br /><br />Interesting.........

 

[bonitoman]

Re: Wiseco pistons

The engine is a 1995. Would you say it came with .30 from the factory in 95 or someone took this apart at a later date and put these OMC pistons in the motor? Thanks

 

[Dhadley]

Re: Wiseco pistons

Nobody makes a shelf stock .30 piston that I know of. The piston must be a .030 over. OMC did make some repalcement engines a long time ago that came with .020 over pistons but they stopped after they set up Riverside and Flagship. Ive never seen a factory powerhead with .030 over pistons. Some powerheads sold thru the factory that were built at Riverside or Flagship would have oversize pistons but would have been sold as remanufactured.

 

[bonitoman]

Re: Wiseco pistons

I was guessing that it was an upside down W for Wiseco. I never thought of OMC

 

[Dhadley]

Re: Wiseco pistons

I dont think its an OMC if the part number is not stamped in it too. The OMC logo was always cast inside the skirt. OMC would have stamped it .030 not .30 also.<br /><br />What happened that you had to take the heads off?

 

[bonitoman]

Re: Wiseco pistons

It does say .030 with the M. I have to rebuild it since the comprsssion is 120 in all except #3 thats 75. I will put a new piston in that one and have it bored to .040. There is scoring in that cyl.I will put new rings on all other piston in addition to rebuild carbs,water pump and thermostats. I know if they were wiseco pistons you have to replace with wiseco rings. Most other pistons if Omc. Sierra rings should work on all 5 other pistons.

 

[Dhadley]

Re: Wiseco pistons

Looks like you got it under control. If you see any other markings on the pistons once you get them out let us know. This stuff is always interesting.<br /><br />Good luck!

 

[bonitoman]

Re: Wiseco pistons

Thank you Dhadley and OBJ

 

[Dhadley]

Re: Wiseco pistons

Youre welcome!<br /><br />Just for fun -- what plugs were in it?

 

[OBJ]

Re: Wiseco pistons

Just got caught up on the thread.....<br /><br />And along with what Dhadley ask about the spark plugs...let us know what ya' find in the low compression cylinder.<br /><br />Thanks!

 

[bonitoman]

Re: Wiseco pistons

#3 is scored. I will bore it out to .040 and put new rings in all the rest and new piston in #3

 

[Dhadley]

Re: Wiseco pistons

And the spark plugs were..........?