Cold Air Box Material?

Doc Watson · 10-04-06, 06:05 AM

I need to order the metal for the base of my cold air box. Im using aluminium for the base plate and was thinking of using 2.0 mm sheet. The sides of the box will be held in place by small screws (see the detail on the racing icons site) will this be thick enough to hold a screw in place?? or should I use bolts and nuts to hold on the sides of the box?

I'm thinking the plate needs to be at least 2mm thick as there will be 2 plumbers blocks attached to the base plate which will hold the throttle linkages.

Any thoughts?

Andy

Phil · 10-04-06, 11:05 PM

Doc
I would say that 2mm material is definitely a good thickness as long as you use a 6061, or maybe a 2024 alloy. Also look into some inserts for fastening the sides, not those cheapie aluminum ones but the steel inserts that will give you a nice machine thread that you can clinch up tightly. Lawson products make a nice array of sizes and two tools for setting them. Once you set them correctly you will have no problem.
Cheers
Phil

Peter D · 10-05-06, 09:34 AM

Doc, I would be inclined to go with small s/s nuts & socket-drive bolts, with a dab of Locktite. I don't think that 2mm of aly is enough to secure self-tapping screws reliably (given the vibration).

As Phil suggested, you could use "nutserts" / "riv-nuts" plus the bolts (& Locktite), but you will need to find the counter-sunk ones so that the 2 sheets will pull together flush (these can be hard to find, & the "standard" ones have a lip that sits above the sheet that they are clamped into - therefore preventing the 2 sheets from sitting flush against eachother).

The "nutsert" clamping tool & bits are expensive, but are worth it in the long run - everything on my car which mounts on the tube-frame chassis is now re-done with them. I had originally just drilled/tapped the chassis, but then discovered the "nutserts" - much, much stronger than the tapped holes in fairly thin-walled tube, and you can R&R the bolt as many times as you need, without the risk of cross-threading.

For the cold-air box (given its very prominent position), it might just come down to deciding which looks best - IMHO, the s/s nut/bolt setup will look neater (I could only get the "nutserts" in that gold-coloured zinc passivated finish, & even with 4mm bolts, the "nutserts" are nearly 8mm long).

Hope this helps a bit.

Kind Regards,

Peter D.

Brett James-McCall · 10-05-06, 12:20 PM

Doc,
My local engineering suppliers does the countersunk Rivnuts if you need them.

Brett

Mark Worthington · 10-05-06, 12:55 PM

I'm a little unclear on your intended application, but if the pieces in question don't require disassembly for installation or removal then I would use rivets. If they do need to be disassembled, I'd use Rivnuts. However, due to the thickness of the head of the Rivnut, there will be a gap between the panels. I addressed this by getting some 1/16" thick cork/neoprene gasket material (see page 3268 of McMaster-Carr's online catalog), cutting it into strips the width of the panel overlap, and punching holes in it at the Rivnut locations. I used silicone RTV to adhere the gasket strips to the panel with the Rivnuts. This way the panels will seal up nicely and you can use stainless steel machine in your choice of head type and thread. Make sure you get the correct grip length for your Rivnuts - a lot of people have had problems with Rivnuts loosening up and spinning in their holes but I think it's mostly due to incorrect (too long) grip length.

Dutton · 10-05-06, 01:25 PM

Andy,

My apologies if I have misunderstood, but I'm thinking it would be possible to weld in place a handful of nuts to the underside of the airbox base. I know, I know... welding steel nuts to an aluminum sheet probably won't work too well. If, however, you encapsulate the nut with the weld, the nut should be held firmly in position.

Regards,

T.

Charlie M · 10-05-06, 09:23 PM

Andy,

Use PEM inserts for the threads. We use these extensively at work and they work great.
Here's an example:
PennEngineering Fastening Technologies - home of PEM, SI, Atlas & PEMSERTER brands.
These inserts will give you stainless steel threads and the insert will not protrude above either face of the aluminum sheet.

If this application is something you will never need to disassemble then I would agree with Mark; rivets would be the way to go.

Charlie

Johan · 10-05-06, 11:04 PM

I'm with Mark, either rivet it or weld it.

Doc Watson · 10-16-06, 07:31 PM

I found the answer staring at me in an old picture......it looks like the originals had a bottom plate and then the slanted sides were welded together into one piece and bolted to the bottom........

Thanks for the help though guys....

Andy Watson

JimmyMac · 10-17-06, 04:55 PM

Andrew,
There is a drawing in the JW Automotive parts list showing the bottom plate.
Coincidentally, the distributor shown in your picture is the same as the one in your parts Gallery.

Doc Watson · 10-17-06, 05:54 PM

James,

Is that the drawing shown in Legate's book..... if so I've stared at that plate for longer than I care to admit.... (and with a magnifying glass I borrowed from Mr Holmes..lol)

I've also stared at your indy distributor but am scared to ask if there are others around and what price they are..... but I would like an 'original' distributor rather than a MSD unit.

Am going to order the plate material as soon as I've 'cleaned up' my inlet manifold.... its tough going getting the thing smooth by hand, also my phenolic spacers and weber covers are being shipped today from CA should be with me next week..... more bits for the coffee table... huragh

Andy

JimmyMac · 10-17-06, 06:07 PM

Doc,
I will get you a drawing of the cold box.
I think it's really important that you get the throttle set up correct and safe.

That distributor is probably rarer than the rest of those parts of mine so I would not hold out too much hope of finding one.
IMO a good Boss dual point is about as close as one could get to it without the tacho fixture, however these fetch serious cash in mint condition.
The best lookalike is the 1964 1/2 Mustang dizzy - same chalice shape and with that oiler pot on the side. You could probably get this converted with a Petronix kit or maybe retrofit a dual point plate.

Doc Watson · 10-17-06, 06:24 PM

Thanks for the info on the dizzy James..... will start the search..... and I agree that the throttle and linkage assembly has to be safe.. my life will depend on it.

After looking at the cold air box bottom plate in the photo above I'm probably going to use 3mm aluminium plate as this will also hold the plumbers blocks for the linkage assembly and will not flex at all. I will get the plate cut oversize and initially just cut the inlet manifold holes for the carbs and studs, then when the engine arrives (its being balanced at the moment) I can start to trim the bottom plate to fit around the heads/dizzy etc.

Any drawings or info is welcome....

Andy