no piston size

versuspop · Post by **versuspop** » Sun Apr 03, 2011 4:28 pm

my pistons on my ca77 have no size markings. neither do my rings. the only markings anywhere are on the skirts which say C77 on one side and ART on the other. how do i determine correct size to use. also, there is A LOT of carbon on the crowns and on the valves. is this abnormal?

G-Man · Post by **G-Man** » Sun Apr 03, 2011 4:31 pm

Measure the piston diameter at the bottom of the piston skirt, at right angles to the thrust face. Standard bore is 60mm. Oversizes are in increments of 0.25mm.

G

Goodysnap · Post by **Goodysnap** » Sun Apr 03, 2011 4:48 pm

If my memory is correct the oversize would be cast into the top of the crown. Probably find it after cleaning off the carbon. The carbon buildup was noticable on mine as well. Nothing to be concerned of really. Just thouroghly clean and inspect. If no markings I would assume standard bore. The rings are marked too, on the flats. Might need a mag. glass to see em though.

versuspop · Post by **versuspop** » Tue Apr 05, 2011 11:44 am

cleaned carbon off. no markings other than arrow. showed slightly less than 60mm. (59.78-59.96) discrepancy due to harbor freight calipers?

G-Man · Post by **G-Man** » Tue Apr 05, 2011 12:24 pm

Looks like you are on standard bore. You now need to inspect / measure the liners to determine if you need to go to the next oversize.

G

versuspop · Post by **versuspop** » Tue Apr 05, 2011 1:22 pm

will do. thanks.