I'm going through my 1996 Summit 670 to replace the rotary valve gear and was thinking about freshening up the top end. Are SPI pistons the way to go or is there a better brand that you all are using for this motor? Thanks
My son and I just did the top end of our 96 summit 670. We used the SPI pistons and rings. They measured up good and looked great to me. We have 50 miles on it and it sounds and runs good.
make sure that you don't end up with "X" pistons which are flat topped.
I prefer Doo OEM pistons over jobbers, especially Wiseco which require ring end gap trimming and need to be warmed up more to keep from 4 corner scuffing.
i have heard SPI are ok
I put SPI in both my rotax 500 and 670x when I freshend then up.Fit perfect with no need to trim....Have rebuild severals friends engines with them too.Highly recomend them.