EFII System 32 (issues & concerns)

[rv8ch]

Assuming the primary mode of vibration is the most significant we will call it the prop balance.

I could be wrong, but I thought that the primary source of vibration here is the cylinder heads flopping around, which is why we have split baffling between the two (or three) heads. I have no idea if the prop vibration has a bigger impact than the heads, but you might want to consider both.

 

[dmattmul]

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Final Engineering Verdict
At 1.2 IPS, the 6061 aluminum tube is a failure risk in high-vibration engine environments. Switching to 7075-T6 or 304 Stainless Steel moves the stress far enough below the material's fatigue threshold to ensure the part will not crack under normal operating conditions.

So if my assumptions were in the ballpark the math supports the failure and I believe the assumption to be correct and the engineering change to ss as a correct remediation to the problem.

The sharp notch is not ideal but is the reality of manufacturing simplicity. (Endmill vs a pipe). There is proven evidence this is not the weak link it the chain as it has a much higher moment of inertia due to the large diameter.

As we know it’s in the execution.
Fly Safe

Interesting analysis. EFII has been using Stainless Steel for at least the last 10 years in their System 32 with screwed fittings into the prime ports. Thanks for the engineering work! The sharp notch appears to have been eliminated also about 10 years ago.

 

[david.demenge]

IO-360 angle valve. Any advice on cylinder #2 oil return line installation? I would like to know how others have worked out the issue of the interference between the injector and the return line from the rocker.

 

[TS Flightlines]

IO-360 angle valve. Any advice on cylinder #2 oil return line installation? I would like to know how others have worked out the issue of the interference between the injector and the return line from the rocker.

This was a IO390 in a RV14A. originally the tee fitting in the #2 cylinder was a AN825-6D, with the supply port facing forward. Made the crossover hose look stupid. We changed the fitting to a An826-6D, supply down. He DID use our modified return tube to clear the snorkle.

 

[Desert Rat]

Hey guys- After skimming through this, I see lots of good observations and lots of folks focused on the fwd end of the fuel line where it goes into the fuel rail, but I didn't see anyone point out that the back end of that fuel line has a 90 oriented such that during the engine wet dog shake it could tend to lever it up and down and work it loose.

I have no experience with EFII systems whatsoever, so maybe it's not a big deal in this application, but generally speaking it's considered less than optimal to have that sort of configuration for a B nut, which as we all know, isn't safetied.

I suggest that wouldn't be a bad Idea to keep the back end of that fuel line from moving by butterflying it to the engine mount tube where I've marked with a red arrow below, just to eliminate that relative movement at the fitting