25 Jan 2014

MOT 2014

Shifty has now travelled 105,000 miles and also about to start its fifth year on the road. Being older than three years also means it's time for the UK government's annual safety check. This will be the second test Shifty's had. The first one went through without any faults or recommended repairs and its test time again.

Since the last blog post the noise heard before returned, or something similar to it. The Honda Dealer was wonderful rustling up a courtesy car at very short notice even though I turned up on spec and they hadn't got any of the service department's courtesy cars available. In fact they let me use the courtesy car for three days whilst they tried to replicate the noise and cadence braking effect I'd experienced that morning.

Unfortunately they were unable to hear the noise and even after the eight hours of investigation work done and use of a sales demonstrator car, their view was for me to pay nothing until the fault could be located and rectified.

During the time the car was in, they went over the suspension and brakes and found no fault or play or anything that could be the cause. The only noise they could identify was the relatively noisy clunk that the iShift mechanism made on engaging first gear when downshifting under any braking other than light braking.

To rule this noise out, They dismantled, lubricated and reassembled the gear changing actuator mechanism. I can say that this extra maintenance has made the shifting noise slightly less but I think the mechanism can't help making the noise under certain circumstances.

So, for now, I'm waiting until the noise I heard re-occurs before restarting the investigations.

One positive outcome of this affair was the chance to spend three days with a 2013 model year Honda Jazz 1.4 VTEC CVT.  I was interested in how this worked compared with my recollection of the two 1.4 iDSI CVT7 Jazz that came before we owned Shifty.

The big technical difference between the old and new CVT's is the use of the torque converter in place of the start up clutch that older CVT model used. The engine is also different,  the older CVT model used the twin spark iDSI engine and the newer CVT the same variable valve timed engine design used in Shifty.

The iDSI design had a slight torque peak at low engine revs that the VTEC does not and I was interested whether the torque multiplication factor when using the torque converter helped make up for the missing torque from the VTEC at low engine speeds. It did seem to.

That said, I felt that it was easier to drive the older CVT version, with its start up clutch, when in stop-start traffic. On occasion I felt that the initial take up from rest was less smooth than I remember with the old CVT. Also with the older CVT, when stopping, I'd select Neutral when at rest and slip in to Drive when the traffic began to move. This became second nature and found it gave smoother driving. It's worth remarking that the selector mechanism showed no excessive wear in either CVT Jazz we owned with the latter travelling well in excess of 115,000 miles.

With the new CVT I found it difficult to achieve the same driving off smoothness despite trying hard to open the throttle gently. Although it's possible that my driving style has adapted to Shifty so perhaps I could adapt to the new CVTs behaviour. I did hate the way that both old and new CVTs would fight against the handbrake when left in Drive and stopped in traffic.

Shifty is actually very well behaved in stop-start traffic. Applying the handbrake engages the clutch so that the engine never fights against the handbrake. So you can leave a gear selected and sit with the handbrake applied for any length of time without wearing the clutch surface, and without straining the engine. However, if the foot brake is used without the handbrake then the clutch is partially disengaged so it is at the "biting" point ready for driving off providing automatic gearbox drivers the feeling of forward creep they have become accustomed to. However it is not advised to hold an iShift car on the foot brake other than momentarily as the clutch could overheat - a warning lamp on the dashboard indicates this.

Away from stop-start traffic the new CVT had the same effortless cruising of the old but with much better gear ratio control on inclines and downward slopes. The new CVT revs less on slopes and seems more eager and willing to drive. Fuel efficiency seem similar to iShift at an average of 58 miles per imperial gallon of petrol.

On balance I'd rather have the new CVT over the iShift but the difference is not as great as I'd have thought. The older CVT was possibly better at low speed manoeuvres  but on the open road the new CVT is better.

Oh, and Shifty passed its MOT test with no faults or advisories. Well done. Happy Birthday Shifty.

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