E200STLERK piston to wall clearance ?

[fonz]

Need specs on 1994 200 V6 Evinrude Looper. Shop manual just gives new standard bore size of 3.6845 - 3.6855. put new set of rings in bore and almost t loose, specs are .019 to .031 ring gap. I'm at .029 with brand new rings. What piston to cylinder wall clearance should there be ?

 

[faztbullet]

Mike the cylinder as ring gap not a good way to judge. Likely need bored if a open deck block

 

[fonz]

Mike the cylinder as ring gap not a good way to judge. Likely need bored if a open deck block

My machine shop thinks .004 would be good clearance if we bore out bigger. Is this in the ball park ?

 

[faztbullet]

Depends on the piston...bore to oversize spec...example .020 will be a finished bore of 3.705. Bore to 3.703 and use rigid hone to get 3.705.+/-.0001. If using a forged piston add .0015 for total of 3.7065

 

[timguy]

A good guide is .001 to each inch of bore. Ring end gap is important for ring expansion, so in other words observe the minimum required gap specified by the ring manufacturer.....which can also vary by ring material. In no way is ring end gap practical or accurate to calculate piston to bore clearance.....or proper bore size