Electric Fuel Pump Mount

[Sidecar Bob]

I read that one of S. Honda's early manufacturing ventures was producing piston rings for Toyota. Unfortunately no one told him they needed to be made of a special type of steel so he used mild steel and they were not usable (some renderings of the story say that some of the rings were used in production and Toyota had to repair or replace the engines that failed because of the bad rings).
After that he went to the library and studied metallurgy so that it wouldn't happen again.

[cfairweather]

Unfortunately the mount must be made out of aluminum. I thought the plastic I chose would be able to take the heat, but I am now convinced it must be made out of aluminum. This story is similar to the the one Bob shared above . There is some good news though, and that is, I have a great design for a mount. Unfortunately, I don't have a CNC machine to mass produce these, but I can make an occasional one by hand.

[Fred Camper]

Engines today have significant nylon bolted to the block so not sure you are required to use aluminum. Many intake manifolds today are plastic and doing fine. But materials for 3D are limited and not sure there is one similar to the automotive nylon used.

[Sidecar Bob]

2 questions:
A) What is the nozzle temperature of the printer?
B) What is the temperature of the part it will be bolted to?

If A is enough higher than B it might work but if B is higher than A or even close to A it won't work. (this is pretty obvious so it is probably what lead to post #47)

Another consideration is UV resistance but I'm sure you've already thought of that too.

[cfairweather]

The 3D printer I used doesn't have a nozzle as it is a resin printer. A laser is used to fuse the resin. I used a resin called Grey Pro by FormLabs and it will start deflecting at 77C (170F). When the fan kicked on, I started noticing a minor leak where the bracket covered the hole so I tightened the bolts and they were loose because the plastic was starting to slightly deflect. I am confident this resin was not capable of the heat of the oil. FormLabs have two other resins that would be able to take the heat but neither are well suited for this application. Yes, there are other plastics that could work, but I would need to make a mold and inject the plastic. Today I made an aluminum bracket and went for a ride. I think the aluminum bracket looks better than the plastic.

[Sidecar Bob]

I wonder if a thin piece of (metal of your choice) between the plastic and the hot part would help?

[cfairweather]

Yes, I believe that would be enough to solve the issue.

[Rednaxs60]

1/8" or 1/16" aluminum spacer would probably work.

[Fred Camper]

I do agree with cf as once you use a spacer the plastic could still soften and ooze out the sides so a straight aluminum part sounds like a better solution considering the limitations of the printer.

[cfairweather]

I have been working on an aluminum mount and here are some pictures. The 1 1/2" (38mm) gauge is made by Marshall and it is ok to mount it in a horizontal position, per their tech support. This is good news because some of the liquid filled gauges can only be mounted in a vertical position. Take a look at the "chrome" ring that holds the gauge. I made this from two inch aluminum pipe with 1/4" wall and polished it to a chrome-like finish. One stainless steel M4 screw attaches the ring to the mount. The mount was made from 2 1/2" X 1/4" thick 6061 aluminum flat stock.

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[Sidecar Bob]

Looks nice.

[redglbx]

So CF, what kind of oil pressure does your wing run ? Just curious.

Some are going to just freak once they actually know what it is.

[cfairweather]

When cold, it runs around 70PSI, even at idle. As it worms up, the pressure drops, which is normal. When hot, it will run 50-60 at higher engine speeds and 10-20 at idle. A typical SOHC CB750 will drop to about 5 pounds when hot, at idle, then jump to 50-60 at the RPM increases. If you have a CB750, I highly recommend running 20-50W oil to maintain better pressure. These are estimates as I really haven't analyzed the exact amounts at different temps.

[CYBORG]

I have a few gauges on my 78, and I have simalar numbers on my oil. And I use the same weight oil. I was taught that 10lbs for every 1000 RPM was normal on most engines. Hot idle at 10 psi is a little scary at first, but over time I got used to it. The factory manual comferms it's O.K.