Best Return Line Setup for Peterson CNC Caps? (1/4" vs 3/16" Hose)

[idiBen]

I'm looking for some advice on the way I currently have my injector return lines set up.

I purchased some Peterson CNC aluminum return caps that I purchased from Classic Diesel Designs. First impression is that the quality is very good. My question comes from the size of the fuel barbs, which use 1/4" return hose connections. My truck originally had the factory-style setup with 3/16" return hose, so I had to use reducers to connect everything to the factory brass return manifold (see attached picture).

My first attempt used aluminum 1/4" to 3/16" reducers from Summit Racing, but I could never get them to seal completely and they would seep fuel. I replaced them with plastic reducers from O'Reilly's, and so far they have not leaked.

My concern is long-term reliability. I'm wondering what the best solution is:

1. Leave the plastic reducers in place and run them until they become a problem
2. Replace the brass return manifold/barb fittings with 1/4" barbs so the entire return system is 1/4" and remove the reducers altogether
3. Stretch 3/16" fuel hose over the Peterson CNC return cap barbs

Has anyone else run Peterson CNC caps with the factory return manifold? If so, how did you handle the hose size difference, and what has held up the best over time?

 

[rreegg]

Sorry don’t have any advice but all I can say is “oof” and will be watching this thread. These fuel return lines will always have the last laugh

 

[8769bigred]

I was looking into getting these aluminum caps as well.... Going to be watching your project!

Thanks for finding out the hard way for us lol

 

[idiBen]

I'm considering the option to make my own 4 way to keep entire return line setup as 1/4. Thinking of this setup:

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I need to see what size fitting runs from the injection pump to this 4 way though.

 

[IDIBRONCO]

My truck originally had the factory-style setup with 3/8" return hose,

Not from the factory it didn't. The only two sizes from the factory were 1/4" and 3/16". That hard return line was the early style and it used the 3/16" return lines. The return line to the tank behind that junction was 5/16" from the factory. If anything was 3/8", it was changed out after it was bought new.

 

[idiBen]

Ah, you're spot on IDIBronco! Both of my post above should say 3/16. Thank you! Going to edit it to avoid confusion.

 

[IDIBRONCO]

Going to edit it to avoid confusion.

I have to admit that I was a little bit confused too.

 

[IDIBRONCO]

Now that I think about it, you might be able to come up with some 1/4" fittings that are similar to what the later style of return lines use and change it all over to 1/4" hose. Here's my return lines from when I redid them last fall. Yes I did run the crossover underneath the intake manifold to avoid the heat from a future turbo.

 

[Austin86250]

Alright, here’s what you need to do, swap the caps out he’s more than happy to work with changed orders, go for this cross over set up,
My truck started out as a early 3/16 set up run then like this get a new ip return fitting 1/8” npt 1/4” barb 90 simply remove that 6.9 ip hard line and connect the tank hose right to #8 cap and your done it’s the simplest and cleanest
The tank hose coming out of the rear 3 way block to the tank is 1/4” on the 6.9

If your going for and spending the money to have as reliable leak free return set up, you want as few connections as possible not spliced connectors and that stupid hard to work with hard return line for the ip with olive seals

 

[idiBen]

Thank you both!

I've seen several different ways people route the return lines. While researching, I came across references to a Ford TSB that eliminated the small return line from the fuel filter head to the #7 injector return cap, and I'm planning to make that change while I have everything apart.

I noticed both of your setups have the IP return connected to the #8 injector return cap, with the line returning to the tank routed a little differently.

Since I'm already replacing the rear fittings, would you recommend rerouting the line off the IP to #8? That would then allow me to replace the rear 4-way fitting shown in my original post with a 3 way instead. Any advantages or disadvantages to doing it that way?

 

[DirtyWood]

Thank you both!

I've seen several different ways people route the return lines. While researching, I came across references to a Ford TSB that eliminated the small return line from the fuel filter head to the #7 injector return cap, and I'm planning to make that change while I have everything apart.

I noticed both of your setups have the IP return connected to the #8 injector return cap, with the line returning to the tank routed a little differently.

Since I'm already replacing the rear fittings, would you recommend rerouting the line off the IP to #8? That would then allow me to replace the rear 4-way fitting shown in my original post with a 3 way instead. Any advantages or disadvantages to doing it that way?

I use the return line routing as suggested by Classic Diesel Designs and the Peterson caps have worked well for me so far. Basically the return lines form a rectangle--plug the return port on the filter head, connect #1 cap to #2 cap and use a brass 1/4 barbed tee to connect the IP return outlet, I routed the return from #7 on top of the intake manifold and around to #8 where it connects to the OEM junction block. If I were in your shoes I would just make up a new junction block. The "rectangle" return line routing has worked well for me and I much prefer it to having a dead-head cap, just my .02.

And FWIW the barbs on the aluminum caps I purchased from Peterson CNC were not 1/4" but actually sized to accommodate the OEM metric hose at 7mm I.D. by 12mm O.D., Choline 2122.0612 7x12 cloth covered fuel hose.

 

[Austin86250]

Thank you both!

I've seen several different ways people route the return lines. While researching, I came across references to a Ford TSB that eliminated the small return line from the fuel filter head to the #7 injector return cap, and I'm planning to make that change while I have everything apart.

I noticed both of your setups have the IP return connected to the #8 injector return cap, with the line returning to the tank routed a little differently.

Since I'm already replacing the rear fittings, would you recommend rerouting the line off the IP to #8? That would then allow me to replace the rear 4-way fitting shown in my original post with a 3 way instead. Any advantages or disadvantages to doing it that way?

This is the digram of how mine is routed if you desire to get different caps
No fittings on this set up just caps and lines
All 1/4”
In my opinion it is the best as there is no connections outside of the caps themselves, less connection points the simpler and on paper less prone to leaks

Especially since the only return line connections being 1/4” hose on the cap barbs that are extremely tight and sharp minus the ip fitting , I feel as if they don’t even need clamps to seal obviously still use them