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firewall
robertst - 20/12/06 at 05:23 PM

is it really not that good to have 1.5mm plate as a firewall? it's what i have now.

should i just change it to 3mm plate? we're looking at what.. 2kgs more?

Jon Ison - 20/12/06 at 05:38 PM

mines 0.7mm thick.

kb58 - 20/12/06 at 05:42 PM

As long as it's not structural, you can use really thin material. The only practical limit is that it might start "drumming", or resonating.

robertst - 20/12/06 at 06:00 PM

i was thinking in terms of the brake M/C being attached to it and stuff..

i know it might flex, therefore giving a spongey feel to the braking, but there's really no way the panel might come off in case of hard braking right?

[Edited on 20/12/06 by robertst]

Peteff - 20/12/06 at 06:02 PM

Or a bulkhead.16g is what I used, leftovers from the floor in the spirit of locosting. Brace the M/C mount with some 3mm plate where it bolts through.

[Edited on 20/12/06 by Peteff]

Jon Ison - 20/12/06 at 06:05 PM

If its for bolting stuff like master clys too then its a different story.

CairB - 20/12/06 at 06:32 PM

Have you considered using the lightest suitable for the panel then putting stiffening struts where needed for the brake cylinder.

I mounted my cylinder on some pieces of angle that was bolted to the stiffer region.
That was on an Indy.
I think that they fitted a thicker plate on later ones but I have afeeling that mine wins on the weight / stiffness stakes.

Cheers,

Colin

kb58 - 20/12/06 at 06:55 PM

I agree with the above, the brake pedal area definitely must be reinforced. There's a lot of force on it, and regardless how think the firewall is, you really need a boxed-in area around the pedals.

Dick Bear - 20/12/06 at 07:14 PM

I second that suggestion!!!!!

Dick Bear

robertst - 20/12/06 at 07:42 PM

quote:
Originally posted by Peteff
Or a bulkhead.16g is what I used, leftovers from the floor in the spirit of locosting. Brace the M/C mount with some 3mm plate where it bolts through.

[Edited on 20/12/06 by Peteff]


oh crap the firewall is what goes in front of the scuttle right?

i meant the bulkhead...

so if i change the current plate with 3mm would that do? just on the driver's side right? or should i take advantage i'm getting into this and change the passenger's side too?

cheers.

[edit] ok, i read kb58's post again, so even if i do use a 3mm plate, i still need a reinforcing box around the M/C? so maybe the option of using stiffening struts as CairB suggested is better?

[Edited on 20/12/06 by robertst]

[Edited on 20/12/06 by robertst]

kb58 - 20/12/06 at 07:52 PM

The thing is, the bulkhead/firewall goes crosswise, while your foot pushing on the pedals is trying to bend it forward.

If you go to tiltonengineering.com, they have some pictures of how to mount master cylinders. They have chassis tubes right there, that bolt to the assembly.

Remember, if the pedal assembly moves even 1/16", it gets multiplied up through the pedal, so your foot is going to feel about six times the "squishiness."

paulf - 20/12/06 at 08:18 PM

I fitted some 25mm tube to bolt the mastercylinder through i put a tube across between the 2 vertical tubes and then added 2 upright tubes between it and the tube across the floor
where the mastercylinder bolts, also put a sleeve through each upright for the bolts to go through and used 16g steel for the panel.
It is totally solid and impossible to flex with the brake pedal.
Paul.

Marcus - 21/12/06 at 09:07 AM

THis was one area Mr SVA paid particular attention to (and rightly so). If, even the slightest, movement of the master cylinder was seen - that was a fail. I used 3mm steel for mine and I was still a bit dubious, but it passed ok (after I'd remembered to put locking nuts on it!).