So…? K-B pistons have mutable top ring gap setting why then is there such a big difference in gap between street and tow. 4.400 x .0065=.028 street

So…? K-B pistons have mutable top ring gap setting why then is there such a big difference in gap between street and tow. 4.400 x .0065=.028 street
X .0080=.035 Tow. Keeping in mind this is a mildly built motor what is the reason for the gap offset. Will It hurt to run a top ring gap of .026 reason for this question is ethanol in are gas out here in Oregon its bad out here real bad even at 91%

bigboat wrote:So…? K-B pistons have mutable top ring gap setting why then is there such a big difference in gap between street and tow. 4.400 x .0065=.028 street
                                                        X .0080=.035 Tow.            Keeping in mind this is a mildly built motor what is the reason for the gap offset. Will It hurt to run a top ring gap of .026 reason for this question is ethanol in are gas out here in Oregon its bad out here real bad even at 91%                                                                                                                                                                                                                          

It has to do with projected combustion chamber heat transferred to the piston ring and the material of the piston to retain heat.

Whether or not they are correct is certainly debatable.

It should be mentioned that the special, wide ring end gap that is being discussed here applies only to the KB line of hypereutectic pistons. It does not apply to the KB line of forged (Icon) pistons nor does it apply to the KB line of cast (Silvolite) pistons.  Those product lines use typical ring end gaps.

bigboat, you are overthinking this relative to the fuel you will be using--just do what KB advises. In one of the engines with KB hypers that I built for a towing vehicle, I set the top rings end gap at 0.032" and it runs great, has perfect cylinder pressure, and uses zero oil. Wide ring gaps on even typcial pistons is not necessarily a big red flag, and with the KB hypers specifically the ring end gap actually "closes up" to a more typical ring end gap as would be used on a more common/typical pistons.