wiseco 1075 different rings?Pistons?

Have a old z1 and just bought 1075 10.5-1 compression pistons and cylinder.Came with a new set of rings.Gave the cylinders a fresh hone and started fitting the rings.All rings seem to fit well except the 2nd ring.The ring is too thick to fit in the groove.Grooves are clean.Grooves are .040 rings are .045.No way to fit.Talked to wiseco as they were ready to close and they said there were a few changes in the ring sets over the years.The ring sets go by the markings on the dome and are usually 2 markings .Mine only have "C"
Question is do any of you have a 1075 wiseco with the letter C on the dome?If so,what rings?

piston # 4052 (# inside piston skirt)
The only marking on top of piston is the arrow for facing front of motor and the letter "C"
Rings-wiseco 2835xc

Some piston rings have a half cone profile ( trapezoidal ) for better gas sealing.
Have you try it upside down to get it fit in the ring groove?

no,markings on the ring go up and thats the only way i tried.

A good machine shop should be able to widen the grooves a little.

WISECO did make 2 different style of rings over the years. found that out when I did my engine. still have the older style pistons some place. ended up using another 1075 kit my buddy had. At the time (15 or so years ago) I could not find the correct replacement rings.

yeah i figured that out too.The ring groove and the ring are about exactly the same size.
twocam,can you find your old pistons and see what markings you have on the dome?
Wiseco says there are 2 markings,mine only have 1(c)

Pic of the pistons?
Steve

sure not a problem. give me a day or so to find them.

Mine have 3 d with an X between them. 4020 cast into the wrist pin boss on the underside.

I just measured the ring grooves. 1.5mm for 1st and second and about 2.75mm for oil control ring .piston skirt measures 72mm

Underside of piston

The 2835XC rings are the correct rings for the 72mm C marked piston so there may be something wrong with either the piston ring groove machining or a mix up with the rings packaging or possibly you have the top and second rings in the wrong grooves as one is thicker than the other ( 1mm and 1.2mm)
The earlier Wiseco pistons used XA rings which are thinner than the XC and the pistons were stamped with an A.