I am new to the forum. I have been building bikes for years and I have purchased my first classic Buick. I am working on a 65 Rivera that has been parked since the late 90’s. Due to a broken ring one cylinder has a .010 tapper. The smallest oversized piston I have been able to find is .030. Does anyone have or make a .020 oversized set. I just hat taking more metal out than I have to. Thanks Jeff Goorman.
When you click to the 401 ordering sizes it shows "standard" and then jumps to .030 over. Maby they have them though?
Zollner used to make 0.020" over, been out of production for years tho. You can try the Martins at Centerville Garage, they buy up a lot of old stock.... outbid me countless times on eBay! https://www.nailheadbuick.com/ The replacement cast pistons, Silvolite, Sealed Power, Egge, etc have a lower compression height which hurts performance. Add the thick composition head gasket and you kill performance even more. It's tough to find good parts to rebuild a Nailhead properly. Tom on this board can hook you up with custom made forged pistons but they're gonna cost more than the cheap castings.
I have already checked with TA performance and they said their supplier no longer makes them. Russ and Matt have been a huge help sourcing parts but they are in the same boat that the smalles oversized they offer is .030. That is why I thought I would see if anyone else would be able to help.
Trying to determine my options before I make more phone calls. So no I have not yet reached out to Tom.
jeffrro1, Sometimes you need to think outside of the box looking at more commom bore sizes that rings are available for which is what I normally do. One size is a .030" overbore of 4.195" which is .0075" more than the stock 401 bore of 4.1875". with the clearance needed of .003"-.0035" now gives a finished bore of 4.198"-4.1985" or approx. .010" over. Another is a .060" over with a piston size of 4.211" which is .0235" over + clearance. These come with 1/16th. rings. Top moly, 2nd. cast & a quality 3/16ths. oil ring.They are all +5 rings meaning the ends gaps need to be filed to fit. ALL are custom made forged pistons including pins & pin fitting. Of course being custom & forged they don't come in anywhere near close to off the shelf cast pistons in $$$ cost. Tom T.
Thanks for all the input. I was able to source a set of .020 oversized pistons. It appears I got their last set on the shelf.
