Near disaster

[Duke W.]

Re: Near disaster

Back when my Cosworth Vega was built with a low pressure analog EFI system (basically a Bosch D-Jetronic system built by Bendix with some off-the-shelf parts from Bosch) it was assembled with conventional fuel hose. "Fuel injection hose" didn't exist in the mid-seventies. System fuel pressure is maintained at 39 psi above absolute manifold pressure, a range of 30-39 psig.

I became familiar with SAE 30R9 "fuel injection hose" in the nineties and replaced the three high pressure hoses with SAE 30R9, which has a maximum working pressure of 250 psi. Because of this it has more reinforcing plys and thicker walls, which makes it very stiff relative to SAE 30R7, so it's tougher to make tight bends.

Given the higher fuel pressure of the CV fuel system SAE 30R9 made sense, but I don't think it offers any advantage on low pressure fuel feed systems like on vintage Corvettes and may even be hazardous if it has to bend sharply, which could place excessive stress on the hose.

Modern SAE 30R7 is far superior in terms of durability compared to the fuel hose used when C1/2/3 Corvettes were built four to six decades ago - more durable materials and processes to meet tougher certification requirements including resistance to chemical attack due to fuel additives like ethanol and greater resistance to thermal degradation.

Duke

[Patrick S.]

Re: Near disaster

Several people have mentioned that they install fuel shut off valves in the bottom flex line on 62's. Anyone have pictures? Seems like a good idea, what valve did they use?

[Jim L.]

Re: Near disaster

Several people have mentioned that they install fuel shut off valves in the bottom flex line on 62's. Anyone have pictures? Seems like a good idea, what valve did they use?

The shut off valve I added to my '60 was a simple, brass hardware store valve. It's intended purpose is probably to control flow of natural gas to, say, a heater. In any event, it was cheap and effective.

High zoot valves are available from Jegs and Summit Racing. Here's one for about $30 from Summit:

http://www.summitracing.com/parts/ear-230501erl/overview/

To use this valve, you need to add appropriate fittings.... 3/8 pipe to barb if it connects to rubber hose, 3/8 pipe to 3/8 inverted flare if it connects to hard line. Fittings such as these are easily found at your FLAPS.

Jim