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Fuel deflector plate/shield

PostPosted: Sun Nov 01, 2020 5:14 am
by h20hamelan
Any of y'all ever considered some sort of fuel shield for under the intake? Maybe a simple 18ga shield coming down from the intake to chassis!
Protecting of course the electrical from the fuel. i.e distributor or starter (wires or superstition)

https://www.youtube.com/watch?v=0CFuCYN ... F&index=50

Re: Fuel deflector plate/shield

PostPosted: Sun Nov 01, 2020 10:40 am
by nmauduit
my Federal S4se has/had what I believe is an original aluminium shield above the coil (intended purpose would be emission suppression, but if appropriately installed would to some extent serve as a dual use fuel deflector) - I would not rely too much on such a measure to reduce fire hazard though, and prefer to be meticulous about the fuel system itself.

Re: Fuel deflector plate/shield

PostPosted: Sun Nov 01, 2020 4:49 pm
by webbslinger
I made a "drip-rail" out of split 3/4" capped copper tube that is tie-wrapped underneath the air box running the length of the seam between the air box and the backing plate. The aft end has a 1/8" hose barb epoxied into it and from there a tube runs down under the car. That seam is the one place where my carbs occasionally dribble.

There is a YouTube video taken with a camera inside the intake manifold of a modern performance car that shows a bit of fuel sometimes running back out of the trumpets into the manifold. If that still happens with a modern intake it shouldn't be surprising that it happens with carbs.

Re: Fuel deflector plate/shield

PostPosted: Sun Nov 01, 2020 5:27 pm
by Craven
This is how a heat shield is mounted.
Heat Shield.png and

Re: Fuel deflector plate/shield

PostPosted: Sun Nov 01, 2020 8:03 pm
by elanfan1
Correct me if I’m wrong but it would surely be fuel vapour that would ignite so not sure how effective a deflector would be?

Re: Fuel deflector plate/shield

PostPosted: Mon Nov 02, 2020 2:21 am
by h20hamelan
elanfan1 wrote:Correct me if I’m wrong but it would surely be fuel vapour that would ignite so not sure how effective a deflector would be?


True, if it did not have airflow. How much vapour would hang around in the engine bay as your driving on the road. Parked, or at stop...
Then, if one is stopped. I suspect directing and deflecting said fuel would/could be of benefit.

https://www.youtube.com/watch?v=qae25976UgA

Moreover, if something did rupture. Some form of directional effect could benefit.
Do we leave the clutch hose (stainless covering or not) and brake reservoir without any protection from the exhaust or electrical too?

As Lotus Elan facebook had a burnt beauty a couple days back...So, winters here. I am gathering suggestions please.

Re: Fuel deflector plate/shield

PostPosted: Wed Nov 04, 2020 10:57 pm
by webrest7
In a time and place far away my Elan fell victim to fire due to that ridiculous positioning of the coil.
Placing electrical components underneath leaky Weber's was not one of Chapman's great engineering innovations.
Luckily I managed to put it out before the flames took out the entire car.
I didn't muck about the coil was repositioned up on the flat section above the footwell during repair. No way it can cause issues there.
Also have a placed one of those available rubber boots over the coil connections.
All other fixes are just messing about as far as I am concerned.
Take it from someone who has been there, it ain't pretty if you are the chosen one.

Re: Fuel deflector plate/shield

PostPosted: Thu Nov 05, 2020 6:57 am
by Andy8421
webrest7 wrote:In a time and place far away my Elan fell victim to fire due to that ridiculous positioning of the coil.
Placing electrical components underneath leaky Weber's was not one of Chapman's great engineering innovations.
Luckily I managed to put it out before the flames took out the entire car.
I didn't muck about the coil was repositioned up on the flat section above the footwell during repair. No way it can cause issues there.
Also have a placed one of those available rubber boots over the coil connections.
All other fixes are just messing about as far as I am concerned.
Take it from someone who has been there, it ain't pretty if you are the chosen one.

A correctly installed coil should not spark, and isn't a source of ignition. While I wouldn't recommend it, you could douse the coil in petrol and it shouldn't ignite.
The distributor however is a different matter. There are two sources of ignition, the points and the gap between the rotor arm and the contacts in the distributor cap. I have personally blown the cap off a distributor that I managed to cover in petrol while fiddling around with the front carb. Fortunately the bonnet was open, and I had dried most of the petrol off, but the bang frightened the life out of me and the cap was a gonner.
The problem is that it is difficult to move the distributor. I guess the only solution is to make sure the carbs don't leak, or use a distributor-less EFI solution.

Re: Fuel deflector plate/shield

PostPosted: Thu Nov 05, 2020 3:30 pm
by h20hamelan
Andy8421 wrote:
webrest7 wrote:. I guess the only solution is to make sure the carbs don't leak, or use a distributor-less EFI solution.


I am planning on 123 at some point. Finances, kids...

The starter is not a big concern for I, though that is a large positive wire.

Re: Fuel deflector plate/shield

PostPosted: Thu Nov 05, 2020 3:44 pm
by pharriso
Craven wrote:This is how a heat shield is mounted.
DCOE_Heat Shield.png and



Just so we understand the purpose, that heat shield is intended for non-crossflow engines where the exhaust manifold(s) (aka headers) would be situated under the carburettor(s). If fuel were leaking out of the carburettor it would do absolutely nothing....

Re: Fuel deflector plate/shield

PostPosted: Thu Nov 05, 2020 8:16 pm
by Craven
Thread is about a dip tray, I was hoping the illustration would inspire a little creative modification for said purpose. But there again.