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Chippy63

Heat insulation in fuel rail brackets

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I have noticed that on the first efi manifold (stag v8) that I made using Bosch 3 plastic injectors that the fuel rails get very hot after a run and the car is turned off . As the injectors are plastic I can only think that this is transferring through the mounts. Anyone made mounts with a thermal break in them? Or am I over worrying? I guess I could look into keeping the fuel pump on for a while after shut off.

Cheers Steve

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I guess it could be heat radiation as the fuel rails are very close to the plenum box which could draw heat up from the heads. The new manifolds puts the rails out away from anything else .

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I would say I've not had any issues with the running but the new one is using shorter metal cased injectors so more chance of heat transfer I would think.

Steve

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Meant to comment on this before.

The fuel rail on my Vitesse also gets very hot. It’s actually three sections of OEM Peugeot fuel rail from two different cars TIG’d together and was intended as a temporary prototype in 2005.....

It sits above the tubular steel inlet and tubular stainless steel 6-3-1 exhaust and is attached, fairly crudely by 3 re-shaped jubilee clips. This is sufficient because the metal bodied injectors are deeply pocketed in the manifold.

I had concerns about heat transfer, and especially cooking the injectors themselves. However, 13 years + and >45k miles later and I have had zero issues with it. No cooked injectors (and they were already old and well used in 2005), and no vaporisation problems, even stuck in traffic at 35C ambient.

The biggest problem I have is that ally the fuel in the system gets quite warm after prolonged running in hot condition making the tank overflow when refilled as the fresh fuel warms and expands. Design fault with the OE tank which has near zero expansion room.

My point? Yes, the fuel rails will get hot. You may be able to mitigate a little, but probably not very much. But don’t worry, it really doesn’t seem to matter. At ~3Bar operating pressure the fuel won’t boil.

whether the later all-plastic injectors are as tough..... I dunno. Used those on the PI, also deeply pocketed, and had no issues, but testing time was much shorter.

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