cracked exhaust port webbing on 90 sportjet

I'm in the process of rebuilding a 90 hp sportjet that melted the #2 piston that appears to be due to the top ring becoming unpinned so that the ring gap sat over the exhaust port. The cylinder wall looks salvageable but there are cracks in all 3 webs of the exhaust port. Is it possible to rehone the cylinder and cut back the area on the webs where the cracks are so the rings don't hang up or am I asking for trouble? I have access to a machine shop so would re-sleeving the cylinder be a practical alternative or am I better off looking for a short block?

Re: cracked exhaust port webbing on 90 sportjet

Naw, it just leaned out that cylinder and melted it. Had nothing to do with the ring gap. Best way to salvage the block is to resleeve the cylinder then hone/bore the other two to get them back straight again.

Re: cracked exhaust port webbing on 90 sportjet

Are the cracks visable on the inside of cylinder wall?

Re: cracked exhaust port webbing on 90 sportjet

The cracks are visible but only with the aid of some dye penetrant. Regarding resleeving the cylinder, how much of the old liner should be machined away since it was cast into the cylinder as what appears to be a spiny lock style liner? My concern is that if too much is removed, the surrounding aluminum wall might split if a thermal fit is done. One suggestion was to machine away a small portion of the liner and fit a thin wall liner in its place. Prior to machining the liner, I was going to weld the aluminum webbing to further strengthen up this area. I haven't looked at the carbs yet but was planning on setting the bowl height higher on that cylinder to run slightly richer since a lean condition, as Capt Ken suggested, is probably the culprit here.

Re: cracked exhaust port webbing on 90 sportjet

You will lose compression if the cracks are all through the sleeve and it will only get worse. If the machine work is free all ou have to lose is the price of the liner.