Return Caps Rev. 1.0
#31
Update:
The caps are still bone dry.
I spoke with my father and he informed me the cost of brass has come down since I bought a foot of it for my set. I paid over $40/LF for the large stock for the barrels.
I am not looking to make any money on this, just keep the old man busy as he loves doing stuff like this. He'd still feel more comfortable with more testing on my truck and so would I... That being said, I'm trying to come to terms with him for a price for a set of caps. There are a few things that will factor in here:
- cost of brass
- labor
- soldering option (you can choose to solder your own caps)
- quantity (if enough folks want these, he will have his friend CNC them)
He is currently getting a quote to have his friend CNC machine these. The guy he's getting a quote from is an old machinist like my dad, but he bought his own CNC machine, so I'd expect very little overhead.
These caps are for the 6.9L IDI. I've never seen a cap for the 7.3L IDI, but know they're different. IIRC, the location of the barbs is on the outside of the cap. Could you use the old style caps for the 7.3L?
If you're seriously interested in a set of brass caps for your 6.9L IDI, please let me know.
The caps are still bone dry.
I spoke with my father and he informed me the cost of brass has come down since I bought a foot of it for my set. I paid over $40/LF for the large stock for the barrels.
I am not looking to make any money on this, just keep the old man busy as he loves doing stuff like this. He'd still feel more comfortable with more testing on my truck and so would I... That being said, I'm trying to come to terms with him for a price for a set of caps. There are a few things that will factor in here:
- cost of brass
- labor
- soldering option (you can choose to solder your own caps)
- quantity (if enough folks want these, he will have his friend CNC them)
He is currently getting a quote to have his friend CNC machine these. The guy he's getting a quote from is an old machinist like my dad, but he bought his own CNC machine, so I'd expect very little overhead.
These caps are for the 6.9L IDI. I've never seen a cap for the 7.3L IDI, but know they're different. IIRC, the location of the barbs is on the outside of the cap. Could you use the old style caps for the 7.3L?
If you're seriously interested in a set of brass caps for your 6.9L IDI, please let me know.
#34
#35
#36
I am not looking to make any money on this, just keep the old man busy as he loves doing stuff like this. He'd still feel more comfortable with more testing on my truck and so would I... That being said, I'm trying to come to terms with him for a price for a set of caps. There are a few things that will factor in here:
#37
The later style has larger barbs to coincide with the larger fuel line used. My guess for larger size was to more easily flow the fuel through, also why they are offset. Offset barbs lets the fuel flow almost straight through from one side to the other. The centered barbs causes the fuel to split and run around each side. A larger barb/line would decrease the pressure slightly, which could lessen the chances of a pressure leak when running (but would have no affect on air leaking in with the engine off). If I recall, the later style, larger barbs have more aggressive ridges, which would seal to the fuel line better, lessening leaks from the hose connections.
After writing this and thinking about it, the later style (that everyone calls 7.3) seems more designed to efficiently move the fuel through to the return system minimizing the time it spends at each injector. By passing the fuel straight through, it would also lower any effect it has on cooling the injectors. And the more I think about it, the more I realize that the return line CAPS do NOTHING to cool the injectors. The function of the caps is to collect the excess fuel and move it back to the tank. Hence the dead-headed single barb turbo caps aren't a bad thing at all.
So for a 7.3 engine, check the size of your return line, and what the present caps look like. Alternately, a set could be made up with larger barbs, but still centered, for the later style engines. Maybe put a marking for the hose size/engine style on them to differentiate the two styles.
Well thats my two cents.
#38
That's probably correct, the 7.3 that I had in my Chevy came out of a '90, and I couldn't say what the '88 or '89 had, and I used that system for the 6.9 that I swapped in. The hose size isn't that different and shouldn't have much, if any, effect on the return flow. The later IP and fuel filter barbs would need to considered if these caps go into production. Just don't want anyone getting mad because things don't fit their set up.
#41
I spoke with my father and talked him down to $160 per set + shipping.
Ford charged me between $8 & $10 per cap, so that's between $64 and $80 per set from Ford. Caps you get in the $50 return line kits aren't even nearly as substantial as Ford's caps. I could not prevent an aftermarket cap on my front, passenger side injector from leaking. I threw in the towel and installed a Ford cap which worked.
My caps are still dry and no signs of air intrusion. These caps are solid brass and machined with precision. They do not distort or disfigure by applying ample pressure to them in your hands. You don't have to worry about bumping the caps with your hands while working on the top of the motor and causing leaks or breaking the barbs off the caps in the cold. They will not become brittle.
Advantages:
This is the price for my dad machining them with current demand. He's speaking with his friend who has a multi-axis CNC machine.
Ford charged me between $8 & $10 per cap, so that's between $64 and $80 per set from Ford. Caps you get in the $50 return line kits aren't even nearly as substantial as Ford's caps. I could not prevent an aftermarket cap on my front, passenger side injector from leaking. I threw in the towel and installed a Ford cap which worked.
My caps are still dry and no signs of air intrusion. These caps are solid brass and machined with precision. They do not distort or disfigure by applying ample pressure to them in your hands. You don't have to worry about bumping the caps with your hands while working on the top of the motor and causing leaks or breaking the barbs off the caps in the cold. They will not become brittle.
Advantages:
- Brass - more substantial, does not distort, will not become brittle
- Tolerance is far superior - Ford was off by over 1/100th of an inch, aftermarket was far worse - even out of round, brass is +0.002" -0.000" and roundness w/ concentric tolerances are far superior
- Longer barbs - clamps can fit w/o issue and don't pinch on one side at the nipple
- Maintenance cost - should only have to replace o-rings
- Life expectancy - I doubt I'll ever buy another set of caps
- More difficult to install - does not distort/expand when pressing over o-rings and does not give you that pop/snap/click when fully seated
- Will discolor over time - brass is a metal and will probably turn a greenish color over time, nature of the beast
- Cost - cost is 2-3 times as much as the plastic caps
This is the price for my dad machining them with current demand. He's speaking with his friend who has a multi-axis CNC machine.
#43
I spoke with my father and talked him down to $160 per set + shipping.
Disadvantages:
Disadvantages:
- More difficult to install - does not distort/expand when pressing over o-rings and does not give you that pop/snap/click when fully seated
- Will discolor over time - brass is a metal and will probably turn a greenish color over time, nature of the beast
- Cost - cost is 2-3 times as much as the plastic caps.
i didnt get a pop/snap/click when i installed my plastic ones either.
you can always take them to a powder coater and have them clear coated. powder coating is non porous so it will stay as you got it, clear coat paint is very porous and you will still get the same issues as uncoated.
cost is high for caps, but not for these caps. how many of us have broken a plastic cap while jerkin around under the hood? too many so metal is an advantage