Minimum o-ring / o-rings / o ring / o rings set?

[khel]

FredT once bubbled...


If actually doing it according to the book:
3/8" LP port uses a 3-903
7/16" HP port uses a 3-904
1/2" LP port uses a 3-905

The cross section and size for those joints are defined by SAE, MS33656, and MS33657 to provide consistant sealing specs. They are NOT the same as the 2-0XX series! All are available in Viton (Parker compound V884-75)


FT

So, as far as I understand, I should order
3-90x instead of 2-0xx ??

Thanks

khel

 

[RiverRat]

So, as far as I understand, I should order
3-90x instead of 2-0xx ??

Thanks

khel

I've had the same question, all docs I've seen so far reference 2-0xx. I'm trying to cross reference now with a vendor. According to FredT there is a size difference.

 

[lairdb]

I've had the same question, all docs I've seen so far reference 2-0xx. I'm trying to cross reference now with a vendor. According to FredT there is a size difference.

2-xxx are specified in imperial measurements, 3-xxx in metric.

AirOil has a great size reference here.

Putting everything in decimal inch terms, as AirOil's crossreference does:
A 2-011 has an actual ID of 0.301 and crosssection of 0.070.
A 3-903 has an actual ID of 0.301 and crosssection of 0.064.

Whether those are "close enough", and which is "correct", is left as an exercise.

--Laird

 

[RiverRat]

I have a question maybe someone can answer. I just popped the o-rings out of my PST E-7 100's with Thermo convertable valves. Looks like "fat" o-rings in there, although the "skinny" 2-014's fit and appear to have the same ID (inside diameter).
Does anyone know what is supposed to be used in these valves? Standard 2-014 o-ring or the "fatter" version I've heard about?