Dinsen > Matra Murena > Restoration
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Restoration

My Murena was in a very decent state when I got it. I even used it as my daily driver. Age takes its tolls, however, and after 12 years in my posseession, I decided to restore her to her former glory. This page, as well as the restoration itself, is work-in-progress.

Checklist

To be done...
This page is a list of things that need to be restored on my car

Chassis cleaning, corrosion protection, and regalvanization

The Murena chassis is warm-galvanized, but even the best galvanization expires. As part of my restoration, I have therefore cleaned the chassis from any corrosion and zinc-salt buildup where possible (it's impossible inside the beams, for example) and applyed a layer of cold-galvanization. The product I have choosen is called Zinga and is used industrially, even off shore. Zinga also have good instructions on their web site on how to achieve good quality results. For more information go to Zinga.EU.

The picture below shows the inside of the right hand front beam carrying the front bumper, radiator etc after some cleaning, revealing light surface corrosion. The white stuff is zinc-salt buildup and needs to be removed too before being cold-galvanized. I have used various brushes to clean it. I have not used sand blasting, but in principle it should work too. What's important, according to the manufacturer of the cold-galvanization product I'm using, is cleaning down to the bare metal, including clean zinc where possible. A little rust is ok, but most should be brushed off. Zinc-salts need to be removed as they form a boundary between the underlying metal and the coat of zinc being sprayed on top.

Getting the zinc-salts off can be hard work, but I feel I've generally been successful with it. The picture below shows the right hand upper front shock absorber mounting point after cleaning. The blue colour is due to the original zinc coating showing here. As can be seen, this part of the chassis had no rust on, but some zinc salts are still remaining.

This picture shows the same area at a different angle after coating. It looks like some dust has escaped my cleaning and the coating is not perfect. Corners like these can be difficult to make perfect. Fortunately the underlying metal was good, so I feel this is fine.

Inside the beams, I've used a linseed oil based product for corrosion protection. The below picture shows how it is highly fluid and takes a good while before it starts to harden. The picture is taken before cleaning and re-galvanization of the accessible parts, and of course I should have waited until that was done before applying the protection inside the beam. Fortunately the oil was easily cleaned off.

The following picture shows the finished front end. A new radiator is fitted on the picture, as well as the headlight lifting mechanism, but the two beams that carry the front bumper are showing in light white colour as they have been coated with Zinga. Notice that the lateral beam is not coated. It's in perfect shape so I didn't bother to clean and coat that section of the chassis.

Engine removal

I removed the engine from the car as part of the renovation to convert to an electrical waterpump installation, to seal the gasket between the timing chain cover and engine block, renew the valve seals, and allow easier access to the engine room to clean and regalvanize where needed.

Removing the engine of a Murena 2.2 involves removing all ancillaries (carburettors with induction, exhaust, alternator, water pipes, clutch slave cylinder), draining the engine block of water, and then lowering the car to the floor, undoing the three engine mounts, finally lifting the car off the engine. That leaves the engine on the floor. I have borrowed a special wooden engine dolly from a friend that made it easy to roll the engine out from under the car, but its possible to put it on a board sitting on the sump, dragging it out from underneath on the board.

Removing ancillaries is more or less straight-forward. Some of the bolts for the inlet and exhaust manifolds are difficult to access and therefore takes a little patience. Also, the alternator is somewhat difficult to access. Finally, the trailing arms take some work. Getting the clutch slave cylinder out proved to be difficult since when I replaced it 12 years ago I forgot to grease the housing. I also fitted the retaining clip the wrong way around so it was slid off the pliers when I was working to get it off. However, with a good amount of penetrating oil, some evenings of pushing, and twisting of the cylinder it finally came out.

But that's all. Remember to drain the block by unscrewing the brass bolt on the back of the engine.

Here's the finished result:

Headlight lifting actuator

The pneumatic actuator driving the headlight lifting mechanism turned out to have a leaking seal. It's a simple component consisting of two half domes, a shaft running through a seal in an opening in one of the domes driven by a rubber bellow. But applying vacuum to one or the other side of the bellow, the shaft moves. The vacuum is sourced from a tank in the engine room, and is controlled by a relay connected to a valve. Of course, one can wonder why Matra didn't design it with an electric motor (a window motor might have done it). I think this is probably where the origins of the design in the preceeding model, the Bagheera, shows through. And if it works, why fix it? I like the system, though. The sound of the system with the hissing noises and clonks as the arm hits the stops has a certain quality, so I'm glad I was able to fix the leak in the actuator.

The picture below shows the bits of the vacuum actuator. Starting in the upper left corner of the picture, the first row shows the shaft, the seal, two plastic rings holding the seal. The second row shows the rear half dome, the front half dome and the bellow with the metal plates on either side that connects it to the shaft.




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Page updated: 2020-06-07 22:09:15