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Of all the rally cars that ruled the forests in the 1970s and ‘80s, with the possible exception of the BDA Escorts, there were probably none that was more fondly remembered than Geoff Portman’s Datsun 1600, nicknamed “Grunter”. Because of Australian rallying's love of the Datsun 1600, “Grunter” was the epitome of what Group G rally cars of the day were all about – brute horsepower, minimal body work, superb handling and fantastic spectator appeal. While Colin Bond was concentrating on making his factory-assisted Ford Escort RS1800s unbeatable in the hands of Greg Carr and himself, Portman and his team were hard at work trying to keep a jump or two ahead of the Fords.
Geoff Portman's Grunter Datsun 1600

Geoff Portman and Ross Runnalls splash their way through tough conditions in the Alpine Rally.

The eventual incarnation of a Datsun 1600 with the engine from a Violet 710 and a 1:1 direct top gear was what most fans will remember. To rally fans of the day, the two most-remembered registration numbers were Greg Carr’s IYK 000 Escort and Portman’s IFK 250 Datsun 1600. Over 40 years have elapsed since the original Grunter ruled the forests, but the memory of the car lives on.
Geoff Portman

Geoff Portman poses with 'Grunter Mk 2' in 2006.

Back in the mid 2000s a replica of Grunter was built and “Son of Grunter” (or Grunter Mk.2 as the owner prefers to call it) was born. And while it’s not an original copy of that well-remembered 1600 in its familiar dark blue Autosport colours, the car has much of the ground-breaking technology built into it. The project was the brainchild of Glenn Bakker. Armed with a good (but crashed) shell, Bakker sat down and thought long and hard about what his future in rallying was and what direction it would take. He already had the necessary items to rebuild the car, but reasoned that if he was going to put time and money into the car, he may as well do it right the second time around.
Geoff Portman Datsun 1600

Geoff Portman and Ross Runnalls driving the original 'Grunter' in the Bendigo Gem Trial.

Grunter Datsun 1600 roll cage

Grunter Mk 2's roll cage was much more comprehensive than the original Geoff Portman car.

And who better to build the car than the legendary Les Collins, the man who built the first Grunter 1600 for Portman back in the 1970s? In those days, and for many years after, the performance benchmark was a Les Collins-built car. Through his famous Datrally workshop in Melbourne, Collins’ reputation as an engine builder and car preparer was second to none, and it seems that over the years he has lost none of his skills. So began a total ground-up rebuild that took 12 months, countless hours and a not-inconsiderable sum of money. The result? One of the best Datsun 1600s you could find anywhere in the world. RallySport Magazine followed the progress of the car and, as our photos attest, the car is a work of art. Starting with a crashed shell, Bakker turned the car over to his panel beater for the start of the project. When the basic straightening was completed, the roll cage was built in a manner that the original Grunter could have only dreamed of.
Datsun 1600 rally car

While not an exact copy of 'Grunter', Glenn Bakker's car is a very close replica.

Our photos give you an idea of what it’s like but, suffice to say, at the time it was one of the most comprehensive cages ever built into a 1600 shell. With the cage out of the way and the shell considerably strengthened by seam welding, what emerged from the panel shop was a painted body that would do justice to a show car. Many aspects of the car’s build took plenty of time, including the removable light bar on the front, which took a day and a half to build! The design is simple, very strong, effective and well thought out, but is just one of many novel features on the car. Of course the body shell and other bolt-on bits are just one facet of the car that consumed much time and energy. Along with the latest, biggest brakes, state-of-the-art suspension and other mods, the engine is the piece de resistance of the whole project. Using an L18 block rather than the more common L20B blocks used in Grunter Mk.1, the engine churned out 220 horsepower on the dyno, thanks to a meticulous build, twin 48mm Webers and a special Collins-built two and a half inch set of extractors.
Datsun 1600 rally engine

The Les Collins-built engine really make 'Son of Grunter' get up and go.

In anyone’s language, 220 horsepower is nothing to be sneezed at, especially when you consider that with the special FIA cylinder head on the original car and the bigger block, the most that was seen before was 232 horsepower. The current motor, thanks to some very innovative work on the crank and rods, is out to 2400cc. You get the impression that Collins is reasonably impressed with the new engine – he tells us that it’s so tractable that you could even use it to drive to the supermarket in! As impressed as we were with the extractors, the exhaust system is one you would die for! Again Collins-built, it was constructed from stainless steel and follows the shape of the floor faithfully to the rear. A long and very narrow purpose-built muffler is held well up out of the way of rocks, and leads to the rear section that, in typical Datsun 1600 fashion, fits through the rear cross member.
Geoff Portman

Geoff Portman was thrilled when he got to see the car when it was completed in 2006.

The difference with this one is that it is solid-mounted to the cross member to avoid fractures, but retains a slip joint where it joins the extractors. Everywhere you look on the car you can see evidence that no expense has been spared to ensure that the car not only goes hard, but looks the part as well. Everything that is removable has been modified in one way or another. All bolts have been cadmium plated, painted parts have been repainted or powder coated and chrome fittings (such as the bumpers, grille, headlight surrounds etc.) have been re-chromed. All this has come at a cost, of course, but Bakker reckons that if you’re going to do something like this, you might as well do it properly, a point very evident when you look at the car as a total package. There are still many Datsun 1600s rallying out there, belonging to some very satisfied owners. Many will have cost a lot less than this one, but perhaps none will be as well-built.
Geoff Portman and Ross Runnalls

Geoff Portman (left) and Ross Runnalls were Victorian Forestry workers who were the crew to beat in Victoria.

Footnote:

If you want to replicate something in its entirety, you never skimp on important things. Take the registration number, for instance. “Son of Grunter” could have easily ended up with a boring-ordinary number plate, but that wasn’t good enough for Glenn Bakker. Somehow the old Mk.2 Grunter was located, still with the famous IFK 250 plates on it. There wasn’t much of the car left, but the all-important registration was intact, so while Simms Metal were the recipient of the old shell, the correct plates changed into Bakker’s hands. Sure, they were a bit dog-eared, so he had them remade by VicRoads in the correct style that was on issue in that period. With the plates fitted to the car, the project was completed.
  • Originally published in RallySport Magazine, April 2006
Datsun 1600 rally car interior

Fabrication work on the car was performed by Datsun rally guru Les Collins.

Geoff Portman Grunter

Portman and Runnalls were pretty much untouchable in Victorian trials rallies in the 1980s.

Related news:

https://rallysportmag.com/datsun-1600-a-history-of-australias-greatest-rally-car/
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