Rear louvres again

[chris.richard]

The received wisdom from old threads seems to be that the louvre panel needs to be mounted in tension laterally so that they don't sag and distort when warm with engine heat.
Group 4 panels are mounted by a hinge or studs at the top front and onto bonnet pins at the bottom rear. No lateral tension. Do they all sag? Is this not a good way to mount them, if simpler than bolting all round?
I'm scratching my head over the curved top to the rear bodywork and the straight top to the louvre panel, yet pictures don't seem to show a mismatch.

[Chris J]

Chris

My old blue car had/has steel petrol pipe bonded onto the underside of the fibreglass louvres to stop them sagging. They're held in with screws.

The car is 11 years old now, and the louvres are still sagg-less.

I suppose the fact that they were modded from day one helped.

[chris.richard]

Won't do anything for rear visibility though. How was your panel attached?

[SUSIT]

Won't do anything for rear visibility though. How was your panel attached?


thought you were building a rally car Chris? why would you want to see behind you ;)
On a more serious note I liked how Sando fitted his and it improves rearward vis

Stephen

[chris.richard]

Rob, can you let on how your's is fixed?

[Sando]

Hi Chris
I'll try and post a pic later. I sort of went for the Group 4 mounting, but as usual, in the Sando way!

I used a mounting either side as high up as I could get at the sides instead of a hinge at the top. (these were Bike fairing mountings - an M5 ish bolt into a rubber mounted nut that expands when tightened this stops the two pannels rubbing. It does put the top under a bit of tension, but I'm not conviced that is the key. I think the key is to have the top of the louver lower than top of the the opening it fits into, so you are not forcing it in. as per the pic above too..

Then two supports ala later Group 4 cars at the bottom under the the two main supporting ribs, which should stop the sagging completely. These are raised a little too much on mine at the moment, but gives the added benifit of being able to see out the back! I'm not sure if this helps or hinders airflow over them, but I have no overheating problems at all. I think Ken Tomblin has also used this type of support with a more angled mounting accurate to the car he has based his on. (but with correct hinged top too, I think)

cheers
Rob

[Chris J]

Chris

The bonded in pipe wasn't really thick enough to affect visibility. You know that the rear window is next to useless for any field of vision in any case? It's only there for you to check the amount of steam and oil smoke rising from the engine compartment!

The louvres on the blue car had I think, 4 self tappers down each side. With the screw heads under the louvres and screwed into the rear body.

You know how the louvres were fixed on the red rear section? 'Similar to Ken Tomblin's car, but using rubber tube at the bottom of the (bonnet) pins instead of fabricated brackets (like Ken's and the old works cars).

[Sando]

I also left a little lip on the edges to give a bit more strength. If you cut out too much you just get a flexible band across the back that will droop when it gets warm.
Cheers
Rob

[stableblock]

B&Q sell or certianly used to some very stiff 6mm diameter glassfibre tubing. Ideal for glueing to the rear of each louvre to avoid droop.