Aluminium Exhaust Heatshield

I'm fitting a Renault 5 Gorgini engine into my project Renault 4. As far as I can tell the heatshield on the R5 gordini exhaust was only there to supply hot air to the air intake and protect the radiator top hose. I wouldn't have bothered with such an elaborate assembly if I too hadn't wanted to supply hot air to the carburetor.

The original part was made from steel and it doesn't fit my car at all.. I could have welded some new brackets onto the original parts, but having just picked up a mighty AC TIG welder I decided it would be cooler in shiny aluminum.

Everything I make starts out like this. It's a cardboard mockup based on the Gordini heatshield but modified to suit the R4.

Card is great for templating - it behaves in much the same way as metal but is easier to cut and add bits on as you iterate towards a final design.

Cardboard template

Having worked out a good shape the dimensions of the much modified cardboard template were transferred to 2mm aluminium sheet.

The sheet was cut out using a jigsaw, then folded around the edge of the bench using blocks of wood and clamps to hold it in place.

Cut out from template

I don't have any room at the top of the heatshield for a pipe to the air filter, so decided to take the hot air from the side of the heatshield.

The aluminium pipe in the photo was formed from sheet using a vice to pull it around a metal former. It surprised me the technique worked so well. It's very easy to make the first half of the tube by clamping the edge against a steel tube and bending it around. Once I was three quarters of the way around things got a little tricky. I overlapped the end of the join to get the shape, then pulled the joint back with a screwdriver so it butted edge to edge. A little more manouvering and squishing in the vice had the shape back and the edges butting up for welding.

Pipe forming

The pipe was seamed together using an AC TIG welder. This was my first attempt at TIG welding aluminium. I'm learning TIG so didn't expect it to turn out quite so neat. Even for a complete beginner TIG is so much easier on aluminium than MIG.

Sadly all the welds in this photo will be hidden in the car, and the visible ones done later on didn't work out quite so well - I need more practice.

Aluminium tube welding

Here's a trial fit of the pipe into the folded heatshield. It's a fairly involved shape, the diagonal bend is there to clear the flange at the end of the exhaust manifold.

Aluminium heatshield

Here's the new heatshield in place. I'll not do close ups as the join between the pipe and the heatshield is shocking. Seems positional TIG with the angle of the pipe to the the surface varying all the time will take a little more practice. It's stuck but looks nasty.

I'm also a little tight on the radiator top hose, but otherwise everything has worked really well.

Best of all - I've just about enough space to fit the jack between the heatshield and the brake servo, and that will completely fill the engine bay. I'd been wondering where I'd put the jack.

Exhaust heatshield

Next> Front inner wing repairs, or back to the Gordini Project

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