CR3171 Finally going back together!

[albanycobra]

I agree, i love the updates and the work is fantastic.

[Aussie Mike]

As part of the rewire I found I needed a new battery. I also needed to move the battery box in the boot as it hit on the roll bars where they went through the boot floor.

I decided to free up a bit of boot space and relocate the battery to the engine bay. I bought a neat compact battery that only weights 12KG and puts out 525 Cold Cranking Amps which is the same capacity the battery fitted to my XR8 ute. Should be plenty to turn the LS motor over.

There's an empty space in front of the cross member so I figured I'd make a new battery box and bolt it in place. It was a fun project on the milling machine.

It started out as some pieces of 12mm plate but much of it has been machined away to reduce weight. Boxhead calls them speed holes LOL!



It weighs bugger all and is very sturdy.



The battery is a perfect fit and the weight is nice and low down. I'm not 100% sure I like how the top retaining plate turned out. I'll probably pick up some more material through the week and machine up another one. Easy enough as the program is stored on disc.



It was a fun machining project and a distraction from the tedious task of cutting and shutting the wiring loom. Back to the soldering iron, heat shrink and tape tomorrow.

Cheers

[gjkrv8]

Very nice Mike, What type/model of battery did you end up with? Cheers Gregg

[guye]

Very nice as usual Mike.

But isn't it dangerous to have the electrics so close to that nitrous bottle?

[Aussie Mike]

Originally Posted by guye

Very nice as usual Mike.

But isn't it dangerous to have the electrics so close to that nitrous bottle?

It's no problem. The flux capacitor design built into the battery tray dissipates the 1.21 Gigawatts.

The battery is a D975 made by XS Power.

D975 - XS Power

Cheers

[Aussie Mike]

Just checking the specs again and it's only a 2Kg saving over the old Optima Red top. It a fair bit more physically compact though.

[Aussie Mike]

Haven't updated this thread for a while. Progress is slow at the moment as I've had to deal with some other family stuff.

I'm working on the bodywork at the moment and got some help from a spray painter friend. Bodywork is a mystery to me and my early attempts are a bit of a mess. Fortunately my mate has got me back on track and with his help I'm learning a lot.

It's still looking pretty patchy as we straighten out each section of the body but it's getting there.

A heap of fiberglass repairs to patch up holes I'd made for different things. Also repairs to correct issues with the body.

Drivers side door needed a lot of attention as it was pretty wavy as was the area in front of the door.

I've cleaned up and reshaped the side vent holes and added brackets to hold the louvers.





Similar issues on the passenger side but at least the door fit was better.



Hoping to have the whole thing in primer in the next couple of weeks.

Cheers

[Aussie Mike]

Some of the challenges of fiberglass Cobra bodies. Both driver and passenger doors needed some surgery.

The seam between inner and outer skins on the top of the passengers door had popped. On closer examination it had been bonded and then the seam sanded back. However they had sanded almost through the bond and only a thin section connected the two (which ultimately cracked).

I ground out the whole seam going down through the gelcoat and into the glass. Vee'd out so I could bond the two halves together with some fiberglass reinforced filler. The important thing was to have plenty of surface to bond to and having it well keyed so the filler would adhere properly.



The other issue is how the door fit into the opening. With the door aligned in its opening the top front edge of the door was low. On the drivers side it was so low it rubbed on the edge where the seal sits. To fix it I split the door at the top and wedged the top up to get it to the right position. The passenger door needed to come up about 6mm. Once worked out I Vee'd out and keyed the gap ready to be re-bonded. With wedges in place I filled the gap with fiberglass reinforced filler. Once it had set, removed the wedges and filled the remaining gap.



A bit of a sanding to get the shape back and now it's ready for a coat of filler to smooth things out. Once it's all painted you would never know.



Cheers

[Tenrocca]

Great work Mike...I love the smell of resin in the morning (but the rest of the family did not)

[Aussie Mike]

This morning I went into the laundry where I'd left my overalls last night and though to myself "I should probably leave these in the garage".

[Aussie Mike]

I was asked the question about how I bonded in the side vent louvers.

I started by folding up some aluminum angles. They attach to the louvers via nutserts and stainless button head cap screws. On the flange where they attach to the body I drilled a bunch of holes to let the fiberglass and resin flow through the bracket.

To bond them in place I mixed a paste from vinyl ester resin and glass microspheres. I try to use vinyl ester for repairs where possible as it's the same resin that the body was originally laid up with. The microshperes are a powder like talc but very light weight. Mixed in with the resin it makes a strong lightweight filler.



To hold the louver in place while the resin cured I just used a paint stick and a couple of cable ties. It seemed to work well.



Once the resin had cured I removed the louver and then laid chop strand mat over the bracket with more vinyl ester and thoroughly bonded it to the body.



After it's all done make sure you carefully clean out the threads of the nutserts before putting a bolt in. Run a small drill and a tap through them. If you try to force a bolt into a clogged thread it can spin the whole nutsert.

Cheers

[Aussie Mike]

A lot of the bodywork has been fixing holes. With changes of ideas and directions over the years I'm having to go back and fix a lot of my previous work/stuff ups. There's a heap of bolt holes and cable holes in the firewall, foot boxes and tunnel that need repairing.

I had the coils mounted in the ends of the foot boxes with leads running through holes. Now the coils are down on the chassis.

The repair required work on both sides of the panel. To start with I ground down through the gelcoat and gradually tapered the area leading into the holes. Then a few layers of chop strand mat and vinyl ester resin over the areas. When cured sand the whole thing down till it's smooth again.



Because the repair is not as strong as the parent material I add some reinforcement on the back. A smear of the microsphere resin paste to fill any small pinholes and voids and then a layer of chop strand mat over that.



Some repairs are a bit easier. Since the handbrake is now mounted on the top of the gearbox I needed to fix the hole where it originally mounted on the side of the tunnel. For this one I roughened the surface of the fiberglass and gradually tapered and ground the edges of the holes. Several layers of chop strand mat and resin and the hole is fixed.



On the inside of the tunnel I cut a piece of ice cream container and taped it in place to act as a backing for the repair. A small amount of resin from the repair leaks into the gap between but it won't bond to the ice cream container plastic or the gelcoat so it just peels off.



The inside of the tunnel will be sprayed with stone guard so no need to do anything more here.

Cheers

[Modena]

Mike where you've filled body bits like the outside of the door skins, do you need to remove the gelcoat before adding filler?

[Aussie Mike]

No need to remove the gelcoat for body filler. Just key the surface thoroughly so the filler gets a good mechanical grip. I sand the area with 80 grit and that seems to work.

The new fillers seem to be much more flexible than the old bog. I'm using a 3M brand body filler and it seems pretty good. Automotive Aftermarkets Filler, Adhesives, Coatings & Sealants:*3M

Cheers

[Aussie Mike]

I've bought most of my prep supplies so far from Bayford in Campbelfield. Prices seem pretty reasonable. A 4L tin of that 3M filler was only about $50.

Parts - Bayford

Cheers

[Aussie Mike]

I've also bought a few rolls of adhesive backed sand paper in different grits. This stuff is great because you can stick it to different shape/sized blocks and it's quick and easy to change.

INDASA Adhesive (sticky) Backed Sandpaper Roll - 120 GRIT to suit Dura-Block | eBay

I've also bought a few different sanding blocks but my painter mate Laurie just prefers a flat wooden block about 12" long. He says "The block doesn't lie".

Cheers

[Gav]

Laurie obviously has experience with 12" tools.

[Aussie Mike]

Oh dear...