SERVICING AUTO  UMBAU PORSCHE THE IMPACT BUMPER SPECIALIST MAINTENANCE RESTORATION BODYWORK INSPECTIONS
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We're big fans of the 911 in all its forms but it's the so called 'impact bumper' cars produced between 1974-89 that we have a real passion for. We believe these cars offer the best combination of all the air-cooled 911 characteristics resulting in a truly enjoyable ownership experience. The raw driving experience of the early cars is still present and complimented by more than adequate equipment levels, long service intervals and excellent build quality. EXPLODING THE MYTHS... "The engines are 'Bulletproof" They're not, but they are strong units. Properly maintained, the 3.0 engines in particular can deliver very high mileages and we've seen engines that have covered over 200,000 miles with no work other than routine maintenance. Earlier 2.7 engines are known to suffer from valve guide wear and almost all 'impact bumper' engines suffer from oil leaks from time to time. "They're galvanised so they don't rust" Yes they do, but galvanising has helped to slow things down. A rust free impact bumper 911 is a very rare thing and even the very best cars will have some form of surface rust by now. Cars needing significant structural repairs due to rust are now very common but good ones are still out there if you take time to search them out. "They’re cheap to run" Relative to other performance cars of the period, they can be but this greatly depends upon a cars previous maintenance record and how it's driven in the future. Once an impact bumper 911 has been bought up to a reasonable condition mechanically and cosmetically, annual on-going maintenance can be surprisingly affordable. Genuine Porsche parts are still readily available but good used parts are becoming harder to find as the years pass. "911s are tricky to handle" At normal speeds they aren't, they are just a little different. The 'backwards through a hedge' reference commonly used by the motoring press is nothing to be concerned about unless a 911 is being driven very irresponsibly and at speeds that should be reserved for the track. The cars will exhibit handling characteristics not found in front engined cars but for the most part, that's what makes them so rewarding and enjoyable to drive. "Go for the G50 gearbox" There's quite a difference in operational feel between a G50 and a 915 gearbox but the key point is that it's different and not necessarily better. A properly functioning 915 gearbox with its related shift mechanisms correctly set can be a joy to use and indeed some owners prefer them as they add to the raw driving experience. The G50 is smoother and a little easier to operate when in good order which appeals to some owners more than others; it really is a matter of personal taste. "Later chain tensioners essential" No they're not but they are well worth the investment for added piece of mind. We've seen 911s that have documented chain tensioner failure with as little as 13,000 miles from new and others that have survived a 100,000 miles before the tell-tale chain rattle occurred. If you believe in preventative maintenance then installation of the later hydraulic units are the way to go. "You can use them everyday" Yes you can, but expect to be kept busy. These 911s will handle modern motoring easily but will need plenty of regular maintenance and attention to keep them in good shape. Driving them in all weather conditions will eventually take its toll if the car is not properly protected underneath and its wheel arches regularly cleaned out and checked. Mechanically there is less to worry about as they tend to run much better when used regularly.
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