When you say "long skirt" is this perfectly round and even all the way around the skirt?
A primary value of the modern piston is that it is not truly round. It is slightly oblonged
and where the wrist pin is located the piston us not undercut.
Not a great explanation, but I hope you understand it. .......PD
Those are good pistons, it's just that their pin height is not correct for the longest rods. Part of the reason the skirts were long was because the shorter rod had the piston rocking a little more. And no, they weren't round , they have a taper from under the ringland to the bottom of the skirt of about .003
the wiseco dykes ring pistons are great ! seal great last long , do you have any for cool bore cylinders? if so what rod length are they for ? / i was hunting that type of piston several years ago and all i could find was ones for std length rod and for steel bore block (picked up 2 anyway) do you have one for 4.500 rod cool bore .060,.080,.100 oversize // any coolbore for 3.875 rod length dykes ring
i just got out a very old catalog to help my recall wiseco2001ps thru p8 is the piston made for a tecumseh HS40 but can be used in a briggs with a 4 inch rod with 9/16 wrist pin std is like .082 when you put it in a briggs i have a 2001ps now , i called horstman and had them cut a 9/16th pin hole then you must use a 4HP briggs crankshaft , some of the very early open briggs were built like this some folks even used the HS40 tecumseh pistons with 4hrb-10 horstman rod in a briggs
hello Brian . that sure would be nice to have Nikasiled cylinder on a briggs flathead , i have one of the new COPPERHEAD 135cc engines by U.S MotorPower it has a coating like that , ( this engine is much inproved version of the older U,S-820) beefed up block redesigned ports PVL ign. rare earth magnet flywheel ,HR-191 tilly carb single ring dome piston , better cyl head new designed overhead pipe , I did race the briggs and tecumseh flathead OPENs for a long time . had lots of fun raceing them ! i still have some good opens ,also briggs stock apearings I just could not part with them Flatheads ! but when these Clones and other OHV came it , I have gone back to 2cycles less parts insted of more (rocker arms ,pushrods and such) i sure wish i had one of them BULLER Built 2 cycles ! heck i like all the karts and engines from all the eras , i still have some McCullochs from my 1st race kart. I got some 91 B-1 s runnin for fun. i wonder how much they charge to coat a briggs cylinder? lots of cycles have that Nikasil coating nowdays very good way to go for sure !
I would think it would be cheaper to just put a steel sleeve in that cool bore than to send it out for the nikasil . The nikasil
requires special ( expensive ) honing stones for sizing the bore . With the steel sleeve you can use a non chromed piston .