Engine compartment heating, on shutdown

[svyolo]

I screwed up my mounting for my 2 EFI pumps (rudder cable rubs). I was always planning on putting them under the front seats. It is by far the strongest part of the fuselage (if they don't survive a crash, neither would I). I still think I would rather have them north of the firewall.

I know on shutdown, the top part of the engine compartment gets very hot from residual heat from the engine. But my guess is, absent a strong wind, the engine compartment turns into a "chimney", i.e. hot air rises and goes out the inlets, and cool air comes in from the bottom.

I was thinking of mounting a plate across the two lower legs of the engine mount, and put the pumps there. It will be protected from radiant heat from the exhaust.

Any experience with that part of the engine compartment? I have EFI, not an engine driven fuel pump. I will look up the temp specs on the electric pumps, but I don't think they are meant to run in a high temperature environment.

I think a lot of the Rotax EFI engines are putting similar pumps in the engine compartment.

Also, how well do 4130 engine mounts hold up in a crash? Leaking fuel right above the exhaust is also not a good thing.

[Ed.Meyer]

I know what I am about to say does not answer your question about the engine compartment heat, but in our Patrol, we mounted the pumps under the floorboards which worked out fine. I would also be leery of the hot side of 5he firewall.

[svyolo]

I believe the engine driven pump on MFI is mounted in the same location, so I am not sure the fire risk is any greater in a crash Just wondering how hot that area gets after shutdown. I don't think electric pumps like a lot of heat.

It looks like the Walbro pumps are good to 150 or 155F (65C).