Ross Finlay takes a revealing look behind the merger headlines

There has hardly ever been a month in the motor industry like it. The Rolls-Royce takeover situation is coming to the boil, because we ain't seen nothing yet as far as this story is concerned. Then Mercedes and Chrysler announced their plan to merge themselves into DaimlerChrysler AG.

Incidentally, they already had a triangular connection. Steyr-Daimler-Puch in Austria started building the Mercedes G-Wagen 4x4 in 1979, and the European assembly plants there for the Jeep Grand Cherokee and Chrysler Voyager are jointly owned by Steyr and Chrysler.

Elsewhere, several loss-making manufacturers are staring down the barrel of a gun. The Jack Palance figure with his finger on the trigger is giving them the choice of selling bits of themselves to cash-rich outsiders, merging with other car builders, or having their heads blown off.

There are background elements here, often quite different from the headlined concerns of the companies involved. One is the fact that the industry world-wide is building millions more cars per year than customers want to buy.

Some companies also have far more ''platforms'' than are required. The Volkswagen group has shown how to build cars with badges as different as VW, Audi, Skoda and Seat on the same structural base, and yet present them all quite differently.

Other people are taking the hint. Nissan, for instance, builds 24 individual platforms. Recently its president said that within seven years its principal platforms will be ''consolidated'' to five.

It also seems clear that some manufacturers will abandon market sectors where their jackets are on a shaky peg.

Another thing which has to be taken into account, especially in the Rolls-Royce imbroglio, is the rivalry between BMW and Mercedes. And they are both very sniffy about what they regard as Volkswagen's upstart ambitions.

Leaving shareholders' interests aside, as well as the question about the use of the hallowed name, the engineering situation at Rolls-Royce Motor Cars in the event of a Volkswagen takeover looks potentially hair-raising.

Rolls-Royce uses its own old-stager V8 for some models, but the engine is simply not capable of being updated significantly further. So the new Rolls-Royce Silver Seraph and Bentley Arnage use BMW engines.

But these units are not just shipped over from Munich and slapped into a waiting Seraph or Arnage engine bay. Work started in the early nineties on adapting them to Rolls-Royce requirements.

If Rolls-Royce Motor Cars goes to Volkswagen, industry observers are certain that BMW will be out of there one split second after the earliest moment at which it can tear up the engine supply contract.

And it does, remember, provide two different engines - a V12 for the Silver Seraph and a turbocharged V8 with Cosworth input for the Arnage - as well as transmissions and some other essential parts.

Volkswagen does not have immediate access to any engine which could replace them. It would take a long while to adapt the Audi V8, even if it proved suitable, and VW's own W12 has barely got beyond the prototype stage. As for commissioning Cosworth to develop a new engine - how many years down the line would it reach fully tested production status, and what cars would Rolls-Royce be selling in the meantime?

Over at DaimlerChrysler AG, the order of names indicates the pecking order. As far as private cars are concerned, Mercedes will probably focus on saloons, estates and coupes, Chrysler on 4x4s and sport utilities. There are few overlaps in the existing model ranges. But what will happen to the Chrysler Neon? How will the M-class fare against the Chrysler Jeep?

And, bearing in mind how the Stuttgart and Munich companies regard each other, what about the 21st-century Mini, which is intended to be powered by a Chrysler/BMW engine from Brazil?