[Chrisred]

Can anyone tell me what size and type walnut shells I need for intake valve cleaning?? Got the BMW machine.

[JamesM3M5]

3393K41 from McMaster Carr is a 15# bag of the finest walnut media. Should do one car easily.

Dry out the sticky, oily carbon deposits with brake cleaner, first. Spray liberally into the ports where the valves are 100% shut (should be 4 of 6), and let soak for a few minutes. Suck out with a Mityvac or blow out with lots of rags covering the port and compressed air. It is not recommended to suck out flammable liquids/vapors with an electric vacuum cleaner!

You can reuse the media if you're running short. Just use a clean shop vac and sift it out in a cheap sieve. Short bursts of walnut (1-3 seconds) followed by 5-7 seconds of air will ensure you don't run through your shells too quickly. Use a rotating/sweeping motion with the wand inserted very shallow in the port when pushing shells, then drop down and push air down against the backs of the valves to clear all the excess shell media out. Then check progress and manually pick/dislodge the thicker deposits around the valve stem and valve head and seat, and repeat.

[Chrisred]

Thx :

[JamesM3M5]

Oh, and if the machine just shoots air (no shells) and doesn't stop, the agitator valve at the bottom of the tank is clogged with a bit of shell that is too large to fit. You will have to discharge the air from the tank and unscrew the collar around the bottom valve. Once that's cleared out, reassemble. It does not happen unless you use media that is too coarse.