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I've got them dimensioned. There is a very, very slight draft inside for the molding process. The outside draft is much more noticeable. I noticed there's actually a flat spot where the hose barb starts inside the cap. Do you think this flat area is necessary? I would think the o-rings create the seal or cavity within the cap to allow the return lines to pull the fuel back to the tank. Do you think a thicker walled metal design would be advantageous in any way? I'm thinking about going with a meatier metal design for more hose barb options.
Carbon fiber caps would be good. Heat retention was the first thing I thought about back when it was first brought up, machining caps out of some type of metal. Aluminum would dissipate the heat quicker but would still get real hot.
Metal injector, O-ring and metal cap would be a pretty hot combo. Wonder if a metal cap would expand enough under a long pull in summer heat to start leaking fuel? Really a poor setup for return lines.
we have fuel constantly running through them and back to the tank (what doesn't get used) to keep them cool,so i didn't think heat was the major concern with them?
billet alum would probablly be my choice....Aluminums thermal transfer ability is better than plastic, and there is enough movement (both of fuel and air) that I really cant see heat buildup becoming an issue.
The reason I am thinking billet it just strength of the barbs, as well as the ability to not stretch when running under extreme load (the 100* day when you are pulling a 7% grade grossing 18k....not that I EVER do that
The issue I have is I am not seeing how return caps will solve the whole problem...granted when the whole system is maintained and working right it does its job, but to truly increase the relaibility and reduce maintenance you would need to change everything from where the hard lines leave the IP to where the return lines feed back to the tank....I would love to see a flexible fuel line with integrated return tee....all one piece with just the return links between them...no more vibration issues, and a few less seams to leak, but would cost $$$$$$ to design.
Just thinking out loud...I have never had a cap fail, just the o-rings
I've got a 1710 Ford tractor that has a little 3 cyl diesel and the injectors look a lot like the ones for my 7.3 idi. It uses a brass return setup that looks like 3/8" thick spacers with barbs that connect them all. The return spacers are sandwiched with a lock nut. This set-up has worked very well on this tractor and have never leaked on my 87 model tractor that has been rode hard and put up wet since I got it new.
I found some 3/8" ID flexible hydraulic line. I'm not sure how you'd secure it to the top of the injectors w/o a flare in the line. Doesn't the hard line use that flare to seat down in the injector?