Morgan three wheeler drive quality.
Many people refer to " drive quality" when talking about the 5 speeder Morgan three wheeler. I assume that the quality in question is some perceived value of the popular modern term " NVH"
( noise, vibration and harshness ). Motor manufacturers strive to reduce these three attributes in order to give a more pleasing drive quality and so attract more sales. My Morgan three wheeler had
very poor drive quality when I purchased it. My Morgan three wheeler exhibited intolerance to pulling away without revving the engine above 2,500 rpm. if one attempted this the transmission would
clatter and bang in a most disturbing way. The same happened if one tried to pull away in 2nd. or 3rd. gears. Drive quality was further spoiled by a fierce jerk when accelerating hard especially when
carrying a passenger. Lastly and probably most harmful to the Morgan three wheelers drive quality was unbearable vibration at about 3,000 rpm. I say that the vibration is the most harmful to drive
quality because it occurs at the range of engine speed where the engine produces the highest torque output. The engine is said by some to produce " torque spikes". In reality all internal combustion
engines produce a torque spike as each cylinder fires, it is especially noticeable in the Morgan three wheeler's engine with it's two very large cylinders. The only way to avoid these torque spikes and the
associated vibration is to drive round them or, in other words, to change gear so as to avoid 3,000 rpm. Now, as the Morgan three wheeler's S&S X Wedge engine produces peak torque at about that speed
it means that to achieve a smooth drive one sacrifices an area of engine speed which gives best acceleration and exhibits the classical and characteristic Morgan three wheeler vee twin sound and feel.
Minimising this vibration therefore means increased drive quality not only because of the lesser vibration but because it allows the use of a much greater range of engine speeds and the best part of the range.
What is the use of an engine which produces phenomenal torque if you can't use it?
Drive quality is further enhanced by tuning the shock absorbing nature of the Centa coupling so as to allow driving at lower engine speeds - not pulling away like a sprinter at a hill climb event all the time.
This is especially important in heavy urban traffic conditions and not only improves the drive quality but probably increases the life of drive train components such as the clutch.
The last and most severe drive quality problem encountered with my Morgan three wheeler was the banging and jerking exhibited under hard acceleration. Initially there was just one jerk but as the
Morgan three wheeler became more " run in" it would produce two and sometimes three successive jerks. The machine was not drivable at anything like the peak of its ability.
This attribute disappeared completely when I replaced the factory fitted " NVH kit" with a more solid bevel box mounting system.