Hello, I would like to know if these are factory "check valves" for the inlet and out let of the carbs? We are trying to dial up the carbs, but found the inlet check valve has certain resistence to allow pass fuel ( I guess this is normal to prevent flow back and somewhat, "discharge" of the fuel in the carbs, however the outlet check valve (right side in the photos) that goes to the return fuel line, seems to flow freely with out any restriction, acts like it wouldn't exist there, just a plain hose. Also, the inlet check valve is different size vs the outlet check valve for the spigot, bein the outlet check valve smaller in diameter. I was checking at the diagram parts but I can't find those check valves. Any idea? Thanks https://www.ferrariparts.co.uk/PagesExternal/ViewExploded.aspx?PageID=746
Your photo links don't seem to work. The SPC page you reference is for a euro carb 308 - you may need the US carb 308 SPC (as, IIRC, only the US version have the check valve in the return line to the tank). You can download a copy of the 161/78 SPC for '78-'79 US 308 from here: http://ferrari.cdyn.com/
On my Ipad photo links work, though I get an 'exeption message', but can see the pics. Is this from factory? I have a copy of the 161/78 parts book. (coincidentally the only US-SPC I have) And cannot see that inlet valve neither on Tav.11 nor on 12. Best Martin
My '79 did not have a NR valve before the carbs. I checked the one after the carbs (returning to the right side tank) and it has 08 and an arrow on it. It is a very easy blow to open check valve (perhaps 08 is type or the pressure to open?)
Thanks for the link. I tried to post photos here but maybe due my low posts in the forum doesn't allow me. This is a US spec GTB, and the link you provided there are two diagram very close to each other pages 34, 36 & 38, where in 34 page shows the fuel tanks and lines that goes arround the carbs show the valve I'm talking about, item 33 (valvola non ritorno), in page 36 doesn't show this valve, and page 38 where shows few fuel hoses and show only ONE number 13 "valvola non ritorno" but can't see the other one. The item 33 (page 34) & 13(page 36) part in the diagram, looks like it's (judging by the position of the engine, etc) is the return line after the carb, i.e. return of fuel to the fuel tanks. The car has two of them. The return one if we blow through it, doesn't have any kind of restriction, like if it's stuck in open position. Inlet for the carbs does work as it should.
(Finally got your photobucket photos to work -- had to turn off my ad blocker, and couldn't do that at work ). Having that check valve at the inlet is definitely not stock, and isn't necessary nor desirable IMO (but it's body shape seems more like the original check valve). The hose routing on the outlet side going back to the tank is also not stock, but the body shape of the outlet check valve seems larger than the stock check valve.
