UPDATE 1-Speculation grows over VW plans for MAN

* Talk VW could incorporate MAN into trucks group

* Way clear to act after Porsche battle done?

* MAN, VW have no comment

* MAN shares gain 2.4 percent

FRANKFURT, Sept 17 - Speculation that Volkswagen will try to incorporate MAN SE into a new trucks alliance in VW's sprawling automotive empire has gained momentum after comments from VW's chieftains this week.

Volkswagen, which already has a voting stake of nearly 30 percent in Munich-based MAN, has made no bones about its desire to create a trucks group building on its majority stake in Sweden's Scania.

Now that VW has fended off Porsche's bid for control of Europe's largest carmaker, the way may be clear for another run at a trucks alliance after bad blood following MAN's failed bid in 2006 to acquire Scania put the project on hold.

VW Chairman Ferdinand Piech fuelled the debate about a trucks alliance at a Frankfurt Motor Show event on Monday night.

"When the going gets tough, everything goes faster," he said about the trucks strategy he has been pushing.

He said he would have to make proposals to VW management on how to move forward but added: "Now Porsche is fine, now we can go on again."

He also tantalised markets by suggesting VW may acquire further brands, saying "a dozen is easier to remember than ten".

The Porsche sports car marque is set to be the tenth brand in VW's stable that already includes Audi, Bugatti, Bentley, Lamborghini, Skoda, Seat and Scania.

Piech, the crafty tactician who has been the architect of VW's expansion strategy, left open whether VW would have to raise its stake in MAN to make such a trucks deal work.

The idea is to generate huge savings by having the truckmakers share development costs, purchasing and components while maintaining their separate brands, drawing on economies of scale enjoyed by rivals like Daimler and Volvo.

MAN has a 17.4 percent voting stake in Scania.

MAN bought the heavy trucks business from VW in December.

VW and MAN declined comment on Thursday on where things stood.

Shares in Munich-based MAN rose 2.4 percent to 60.80 euros by 0924 GMT. VW shares were down 0.14 percent and Scania stock gained 0.6 percent while the DJ Stoxx European car sector index eased 0.85 percent.

Analyst Heino Ruland from Ruland Research said that an integration of MAN was plausible.

"The battle over the Porsche takeover has been time consuming and prevented management from focusing on other issues such as the lorry and truck division. In time the issue will be resolved," Ruland said.

Asked on Monday night if Volkswagen was already in talks with rivals, Chief Financial Officer Hans Dieter Poetsch said everyone in the industry is always talking with competitors.

"It's not a big secret that we have a big position in MAN," he added.

There have been persistent rumours that VW would be interested in a tie-up with Japanese carmaker Suzuki Motor Corp and a person familiar with the matter had told Reuters in August that there had already been talks.