It was only after 1300 miles of motoring that I noticed it. We had enjoyed a holiday in Spain and France, with relaxed travelling in both. Our Rover 75 performed beautifully and made the travels a joy, including a climb high into the Pyrenees to admire the view (of the clouds). Arriving back in the UK, we set off from Portsmouth and joined the traffic jam. It slowly cleared, but low speed driving on less than smooth roads made me start to think. Has a damper started to lose performance? No, it was happening whichever wheel was absorbing an input. Oh dear, ride shake.
Many (many) years ago when I first became the official leader of a team (Large Car Chassis Development if you must know), we were attempting to create the Rover 800 Vitesse Sport. The platform was flexible – literally flexible; jack it up at the front and the door gaps would change – and our sporty spring and damper choice was exacerbating shakes and rattles. At least the roll had reduced. What was shaking? The power unit. A ‘T’ series engine with turbo was a ‘strong’ engine in terms of performance, but no lightweight when strapped to the gearbox and bolted into the car. This was when I started to learn more about engine mountings and the compromises that were often made. Idle refinement? Yes please, it is a Rover. Torque control? Yes please, it is a Vitesse Sport. Ride shake? Oh, do we have to accept this?
Around the same time as this, a project had been kicked off to improve Rover 800 quality (in all ways). We built a demonstrator, which happened to have a revised right hand engine mount. The internal damping did a great job of reducing engine shake, so the ride was clearly improved. But the idle noise and refinement had taken a hit. The dreaded compromise again. What we really needed was stiffer mounting points and structure for the engine mount – unfortunately this needs to be designed in from the start of the project. So, what was really needed was a new platform….
Rover 75. The best riding front wheel drive car in the world. This was our internal target, and it had to be ‘front wheel drive’ because of our BMW ownership…. Thankfully, an effective team effort saw the new platform blessed with great global and local stiffnesses, so that (most) compliant bushes could work as intended, isolating the occupant from the road surface. My Rover 75 has always made an excellent job of cossetting us on our travels. Until the shake started.
I think that the right hand hydramount has lost its fluid. I haven’t had time to investigate fully, but the degradation in ride quality stacks up with such a problem. Power unit control is important for many reasons. It reminds me of the first time I drove a SAIC production vehicle in the UK (I won’t say which one, other than it has never been sold in Europe). The engine mounts looked to be the same as a VW Golf, with one crucial bit missing – lateral snubbing. Idle refinement was great and travelling in a straight line didn’t raise any ride shake concerns. But if you had the temerity to hit a bump mid-bend whilst cornering briskly, the lack of power unit control was sufficient to bodily move the car (overcoming wheel control), to the alarm of the driver. It isn’t just old and/or tired cars that can have problems.
Ride concerns? It isn’t always about the springs and dampers. We may be able to help diagnose a problem. Oh, but we do happen to sell springs, anti-roll bars, and dampers to improve matters. Shake, rattle and roll? Get to the root cause, improve, and then enjoy.