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  • car timing belt

    My son bought recently an eight year old car which is in hardly used condition it belonged to an elderly couple who produced a staggering 55 k on it over this time all miles workshop serviced every six months so a complete service history.Seemingly the timing belt is guaranteed to last 100k but my friend owner of the garage which sold him it said it might be worth looking into replacing it as it was the only part he never guarantees.Understanding the damage it can do if it snaps what do you guys think?Is he safe for a long while yet or should he replace itnow or soon.The car is automatic rover 75 with all the top specification.He has also noticed the light coming up for the air bag what causes this anyideas no rush? thanks guys. Alistair heres what it looks like and some details

    http://www.gumtree.com/p/cars-vans-m...-mot/100532011
    Last edited by Alistair Hosie; 05-13-2012, 05:55 PM.
    Please excuse my typing as I have a form of parkinsons disease

  • #2
    If the engine is not an 'interference' engine, I'd leave it. No damage occurs, you just have to get out and walk.
    Sorry I don't know that car at all.
    Mike

    My Dad always said, "If you want people to do things for you on the farm, you have to buy a machine they can sit on that does most of the work."

    Comment


    • #3
      Being a rubber component I would at the very least pull a cover and inspect it,

      could be just fine for the entire duration but better safe than sorry,,,

      Iv seen many japanese vehicles rack up close to twice the interval change and be 20 years old to boot - all on the original belt - so that's the flip side...

      But if it's an interference engine at least have it inspected and tell them you want the old belt to inspect -- that way they are less likely to replace it just for the heck of it...

      Comment


      • #4
        I think both the four cylinder K series and siz cylinder KV6 were interference engine.

        Belt life was 90-100,000 miles (depending on source) or six years.

        Often it's a waterpump or tensioner failure that causes problems, rather than the belt itself.
        Paul Compton
        www.morini-mania.co.uk
        http://www.youtube.com/user/EVguru

        Comment


        • #5
          does that mean you just need to walk when it's bust or need anew engine.I can never understand a design that would ruin a whole engine if a belt snaps. Alistair ps as you can see I know very little about this design.
          Please excuse my typing as I have a form of parkinsons disease

          Comment


          • #6
            Originally posted by Alistair Hosie
            does that mean you just need to walk when it's bust or need anew engine.I can never understand a design that would ruin a whole engine if a belt snaps. Alistair ps as you can see I know very little about this design.

            You need a new engine when it bursts.Or at least the cost of all the bits will make it feel like you`re buying a new engine.
            It is an interference engine as EV says,there are very few non interference engines in UK.
            When buying a used car it is sensible to replace the cam belt,water pump and tensioners regardless of what the speedo or service history says.
            Failure is nearly always due to water pump/tensioner/idler failure and not the belt.
            Start panicking when it needs anything done to the clutch even if it just the fluid topped up or slave cylinder.
            BTW,the one on Gumtree is overpriced by about 100%.

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            • #7
              Most twincam engines are interference desigs.

              The problem is not so much valve to piston contact, but valve to valve when the synchronisation between the cams is lost.

              Some engines have the cams geared together with a belt drive to just one cam and they tend not to be interference engines.

              One engine that definitely IS an interference design is the SOHC diesel fitted to the MK1/2 Ford Mondeo. Originally the belt change interval was 40,000 miles (30,000 miles for most aftermarket belts) and many people experienced failures and wrecked heads (it often broke the camshaft) by exceeding the recommended milleage. It happened just recently to a friend of mine, but fortunately I was scrapping a car and could let him have another head.

              Despite many belt failures the Mondeo TD has a reputation of going on for several hundred thousand miles (highest I'ce seen is 600,000+) if you actually change the belt, tensioners, pump etc. when it's needed. Ford later changed the tensioner system to achieve 70,000 mile intervals.
              Paul Compton
              www.morini-mania.co.uk
              http://www.youtube.com/user/EVguru

              Comment


              • #8
                WHY take a chance on the belt???

                Just take it and get it changed, then you don't have to be worried about it for a long time.

                Cheap insuranc against ruining the engine or overheating it someday.

                Comment


                • #9
                  If there's a chance of engine damage I'd change it. Years ago we bought a Subaru 4 wheel drive wagon with about 55K on it. I had something minor foxed at the dealer who said make sure at 60K change the belt. I thought he just wanted the job. At 60,200 miles the belt which is about 8' long broke & stranded my wife. No damage. Last year we're taking the minivan to a shop to have the belt changed & it broke 6 miles from the garage. What was wrong with timing chains? My new Wabeco lath runs on little timing belts.
                  I'd chande the belt!
                  "Let me recommend the best medicine in the
                  world: a long journey, at a mild season, through a pleasant
                  country, in easy stages."
                  ~ James Madison

                  Comment


                  • #10
                    I think the move has started,
                    My old Peugeot boxer had a timing belt, this new one has timing chain.

                    Frustrating vehicle though.

                    Went to Ipswich the other week 60 to 70 mph down the A14 loaded all the way and it was reading 39.9 mpg.

                    No matter what could not get 40.0 out the bugger !! Old van used to do 32 tops.
                    .

                    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                    Comment


                    • #11
                      That's like Cummins diesels in Dodge pickups. They ran a test on a 1 ton by taking off the fan, taping all the seams,etc.etc & got I think 31.98. Never could break 32 MPG. It's on the internet & was in Diesel mag I think it's called.
                      "Let me recommend the best medicine in the
                      world: a long journey, at a mild season, through a pleasant
                      country, in easy stages."
                      ~ James Madison

                      Comment


                      • #12
                        Originally posted by sasquatch
                        WHY take a chance on the belt???

                        Just take it and get it changed, then you don't have to be worried about it for a long time.

                        Cheap insuranc against ruining the engine or overheating it someday.

                        It's not always cheap insurance --- had my friend taken his "triple" timing belt land rover to the dealer it would have set him back $1,400.00

                        generally nothing goes wrong time wise with tensioners/timing belts (unless extreme time) water pumps,, so i'd have it inspected or better yet inspect it yourself, all timing belts are actually seamed - they are literally stitched together -- your looking for any first signs of stitching failure -- your also looking for any separation in the inner radius of the belts teeth -- you are also looking for any signs of cracking on the outside of the belt when it's going around the smallest size pulley...

                        Wish I was there Hosie - we'd get a few pints and "git er done"

                        Comment


                        • #13
                          according to the research Ive just done

                          engine is diesel ..and BMW M47R..with alterations to make it fit rover

                          it has chains ..not belts

                          http://tis.spaghetticoder.org/s/view.pl?1/04/53/56

                          has one fault though

                          nuts that hold the butterfly valves in the inlet manifold can come undone and wreck the engine

                          other wise ..the rover 75 diesel was voted one of the most reliable cars built in the jd power surveys at the time

                          all the best.markj

                          Comment


                          • #14
                            Originally posted by EVguru
                            Most twincam engines are interference desigs.

                            The problem is not so much valve to piston contact, but valve to valve when the synchronisation between the cams is lost.

                            Some engines have the cams geared together with a belt drive to just one cam and they tend not to be interference engines.

                            One engine that definitely IS an interference design is the SOHC diesel fitted to the MK1/2 Ford Mondeo. Originally the belt change interval was 40,000 miles (30,000 miles for most aftermarket belts) and many people experienced failures and wrecked heads (it often broke the camshaft) by exceeding the recommended milleage. It happened just recently to a friend of mine, but fortunately I was scrapping a car and could let him have another head.

                            Despite many belt failures the Mondeo TD has a reputation of going on for several hundred thousand miles (highest I'ce seen is 600,000+) if you actually change the belt, tensioners, pump etc. when it's needed. Ford later changed the tensioner system to achieve 70,000 mile intervals.

                            All diesels are interference fit engines -- it's just a given with the compression ratio that there is no space left for valves that get out of time (maybe the detroit is different but I believe it still has one exhaust valve)

                            I can't believe those belt change intervals on the original - that's the lowest iv heard of and there's no reason for it except for poor design...

                            Comment


                            • #15
                              Originally posted by Alistair Hosie
                              does that mean you just need to walk when it's bust or need anew engine.I can never understand a design that would ruin a whole engine if a belt snaps. Alistair ps as you can see I know very little about this design.
                              Non-interference = walk + replace belt but nothing else.

                              Interference = walk + replace at least a valve or two but maybe an entire engine.

                              Basic logic - The fuel inside of an engine burns more completely (efficiently) the better it is dispersed (atomized) throughout the entire cylinder. Injecting fuel in the top of a tall cylinder in a cone shaped pattern, we get a high concentration in the bottom and a low concentration in the top. Inject fuel in the same cone shaped pattern into a shorter cylinder, the concentration becomes more equal top to bottom. The same applies to your engine. Shrink the piston to head clearance (shorten the cylinder when you inject fuel at piston top dead center), and your fuel mixture becomes much more even, giving fewer emissions, more power, and better fuel economy.

                              On most production engines today (both diesel and gas) the piston to head clearance is down to ~.040-.060". Valves typically need to open more than that (interference) to get enough fuel into the cylinder in the brief instant they are open. In a perfect world, it would be nice to have non-interference engines, but the ever increasing emissions regs and demands for fuel economy while maintaining power are rather limiting.

                              Diesel vs gasoline....the piston to head clearance has little to do with compression ratio, thus the .040-.060" measurement is common between fuels. The pistons can rise to the same height, and with just a slight change to the combustion chamber (piston or head bowl, depending upon design), an engine can be either 8:1 or 18:1. Its exactly how industrial engine manufacturers make natural gas or gasoline engines out of diesels, typically by changing pistons.
                              Last edited by justanengineer; 05-13-2012, 10:07 PM.
                              "I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

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