Decarbonization

I just went through this with my 88.5 Testarossa, engine out, major service. Since I had the engine dismantled to a long block; ie no fuel injection, the intake ports were very easy to access. 1 cyl at a time, set to TDC, so both valves are closed. I poured all metal safe paint stripper, waited 15 min, dilute with paint thinner, shop vac out. Followed by my harbor freight hand held bead blaster. I used 40 grit walnut shells. Blast the living snot out of it. Followed by shop vac, air nozzle. Except for the heat discoloration of the intake valves, they came out looking spotless. Even if the is a slight residue of walnut shell captured between the valve face and seat, IMO, soon as the fuel and flame hit it, you will have harmless ash. This is what I did, and it worked!

 

http://www.ferrarichat.com/forum/technical-q-sponsored-algar-ferrari/465589-walnut-shells-cleaning-intake-ports-di-engines.html

 

We used to run a cocktail of Kerosene and other cleaners though a vacuum port on the intake. It worked well. Another benefit was for porting heads. You could see where the ports flowed the best based on residual carbon areas guiding where to grind.