I am rebuilding a 68 383 that sat since 1973.It has 62,000 miles on it.
I got it running but time was not kind to the internals.
Everything is apart and now I am cleaning things up.
Block,crank,and heads are back from the machine shop.
The top of the pistons cleaned up well.
I removed the rings and the two upper grooves are full of hard carbon.
How do I clean it out without damaging the pistons?
I tried combustion cleaner and a broken ring but this crap is stubborn.
Should I just send them to the machine shop for hot-tanking?
I am doing as much as possible to keep costs down.
Any tips/advice is greatly appreciated.
Thanks

Can't hot tank a aluminum piston. Used to soak them in carb cleaner. Now they make spray gun cleaner in 1 gallon cans that works great and the same as the old carb cleaner. Called spray gun cleaner at the auto paint stores.

soak them in your carb soup. EDIT then break a old ring & on your bench grinder grind the end on the inside narrower to a slight hook shape & square up the broken end & carefully scrape as to not remove any piston material.

Thanks,guys.
I will try to see if it is available up here.
If not I can use GM Combustion Cleens or a Kleen-Flo equivalent

use an old ring broken off... careful they are sharp! then carb clean em dan

If I'm not mistaken, there is a special tool that you spin around the piston a couple times and clean as new. Been over 25 years since I've used one, but they worked great. Maybe you can rent one?

Use an old ring, break it, and ream it around and around until you get all the carbon out.

Then take some parts washer cleaner on an old toothbrush and scrub it real good. This should clean them up good enough without having to hot tank the pistons since your basically just re-ringing them.

Piston Groove Cleaner.



Carb Dip and Piston Cleaner

IF there is a bunch of carbon in there .. there probably is a lot of slop in the ring groove ... not good.

BTW ...what is that spec?

I get the 5 gallon pale of carb cleaner from napa

about a 20 min soak and rinse them..no need to scrape,I then rinse in diesel fuel to keep stuff from flash rusting

i clean 4 at a time

very fast and will clean a lot of the stuff on the engine rebuild

wear gloves and have plenty of vetalation for sure..

somewhere on the web there is an article about cleaning carbon off of aircraft engine pistons where they tested a new liquid cleaner on three different badly carbonned-up pistons and got excellent results... but I can't find the article right now.

this weblink to OTC brand decarbonizing fluid was in my bookmarks:

http://www.etoolcart.com/browseproducts/Decarbonizing-Fluid-OTC7904A.html

when I tried soaking 1994 Magnum 5.9V8 pistons several years ago the fluid they sold at BMW and VW dealerships named
'LubroMoly Ventril Sauber'
took off the carbon deposits the best,
better than
Chevron Techron, or Chrysler ATF+2, or BG Chemtool

Take an old ring, break it and have at it. That's all I did and that's what the instructions in my ring kit said to do as well as the instructions in my mopar fsm. Yes it is stubborn. It helps if you break the ring at just the right length so it's semi comfortable to hold and the right length to scrape good. After I get the caked on carbon out of there I clean it down with solvent.