I pulled the primaries out of my 20b rail last night in preparation for testing them on my newly constructed flow bench and ran into a few problems.

1) I'm an idiot and threw them into a bucket of carb cleaner before removing the o-rings. Now they're broken / swollen, duh. Does anyone have the actual dimensions of all 3 o-rings (CS and ID/OD)? There have been many threads, but none with a simple response of "they are A x B and C x D." Can we please have one for the FAQ? The 20b are the same as the FD primaries as far as I know.

2) One of the fuel windows on one of the injectors is varnished shut with fuel varnish. I'm hesitant to apply any force (my usual method) whatsoever for fear of tearing the very fine mesh. They've been through a 24hr soak in carb cleaner, but it hasn't budged. Can anyone recommend a chemistry only solution for removing it?


This is before the soak right out of the rail. The body cleaned up nicely, along with the rest of the windows.

 

I have not seen the correct o-ring size posted before. I believe it's some metric size that doesn't exactly arrive from the hardware store.

I recommend you send the injectors to an ultrasonic cleaning service. They will clean, and verify the flow of the injectors and send them back with new o-rings. Cleaning without flow testing is a very risky idea. (I know firsthand).

 

I'll bet the solvent professionally used has more to do with injector cleanliness than the ultrasonic bath. Also, I'm not worried about size mismatch, since I can specify cross section (CS) and one of the major diameters (ID / OD)