On the sj plenum you have tocut a hole and make a bulge. There is plenty of room for the purge valve this way
Frank
Talked with Don. He said I can remotely mount it on the other side of the engine (great idea). He said an 8 inch line or so would not make that much of a difference. By the way if you mount the purge valve remotely, you don't have to use stainless steel fittings. Alum AN fittings work fine. Don't ask me why. Thanks to all for the ideas.
Go down to your local hydraulic hose emporium and buy the same thing in steel (as opposed to stainless steel) cut the thing in half at the middle and grind a 10 to 15 degree angle on each cut face.
Then simply weld the two halves back together.
I have done this several times when I made fittings for my wingroot fuel pump system.
Frank
I'm with Frank, cut/weld to make your own fitting. I just did almost the exact same thing two days ago.
What are you going to attach the valve to?
Frank
I for one am not comfortable with welded fittings on fuel, especially in a high vibration environment. I have seen too many professionally tig and gas welded things break on race cars and such from the vibration. Don at airflow doesn't come out and say it, but I will bet the requirement for stainless is because the aluminum fittings were cracking.
Of course each to their own level of comfort but and I can see how a sloppily TIG welded fitting could fail, but if its done with care there is no way such a fitting would break..for me I turn the gas down and oxy acetylene is a sloow process and this enables you to be sure you have proper flow into the joint.
I have hacksawed thru several of my test welds and they look like a single piece of steel..
If you take that approach then you would never hang an engine on an engine mount, let alone fly a rag and tube airplane as the whole fusalage is welded!..
As to the aluminium fitting..well yeah, its aluminium, not steel...But you can't compare that failure to a welded steel fitting as its waay stronger.
Frank
I don't have a problem with welded stuff in general. My last race car was an all 4130 tube chassis that I tig welded together and it never broke. I also don't have any problem with the welds you did on your root mounted pumps. I just don't think a welded fitting should be used on a fuel component which is bolted to the engine (and shares some of the mounting loads as well). The risk of breaking is low, however, the results of the fitting breaking would almost certainly be a life threating event. The thing about welding something is not the weld its self, but what it does to the metal if it isn't done properly. Most fractures occur next to the weld in the original base metal and not in the weld.