Report on KMJ
to the English Lakes
and back again
We have just
completed a short four-day tour of nine hundred and fifty miles from South
Norfolk to the Lake District with touring in the dales and hills around Dent and
Dentvale in Cumbria. Much of the mileage was on the M.6 and some included very
steep gradients in the dales. I enclose information from both so that YB owners
may compare benchmarks. The car, KMJ 533, is fitted
with the "improved profile" Brown and Gammons steel cam, cam followers and
pushrods with all new timing gear. The head has all new valves and springs but
the original guides and oil seals. 8.25:1 pistons have raised the compression. I
have broken all the rules and for the sake of quietness run with 13 thou tappet
clearance. In five thousand miles this has not given any problem and compression
and starting are fine. The distributor and carburettor are original but the
distributor cap, which is new, has some movement so that retaining the set
timing is decidedly iffy. Despite all efforts and needles the mixture remains
defiantly rich. The clutch is new. Gearbox synchromesh is good with a very
smooth change under normal circumstances but the front main gearbox bearing is
noisy on the overrun. The brakes have new linings and the drums are not scored.
The car is fitted with radial ply tyres, which are unworn.
KMJ 533 gave an
average consumption of 27.8 per gallon (unleaded) but this includes fast
motorway work and four very long traffic queue crawls totalling two hours on the
M.6 and A14. Oil consumption was disappointing as we used a full litre of 10/40
semi-synthetic oil. As said the car has new bores and pistons but the valve
guides have not been replaced (65,000 miles) and the sump, after much careful
fitting, has reverted to the usual generous chassis oil spray.
I intended to
cruise at 50 – 55 and began with measurement by watch, motorway posts and
odometer to discover the speedometer error. This turned out to be a staggering
12.5% ahead of the true speed, possibly partly because of the radial ply tyres.
Once I had found that figure I could of course make allowances and read the true
speed more accurately. Because of the long straight stretches on the A14 and M6
I was able to establish the best cruise in terms of smoothness and quietness.
Much to my surprise this was just above 60 m.p.h. or around 4,250 r.p.m. Before
the run I had been sure this was too much for this long stroke engine but it ran
very sweetly and gave no indications of stress at all. In fact it was difficult
to hold back although I did not allow it to rise above 65 m.p.h. or 4,600 r.p.m.
when overtaking. The engine is bored to plus 30 thou and fitted 8.25:1 pistons
but the crank is original (65,000 miles) although with new mains and big ends.
Max oil pressure is just fifty cold and normally runs at around 40 p.s.i., but
it fell on the long stretches to around 35. The saving grace was that it did not
fall further, but held rock steady at that. Tick over held at around 10 lbs. At
first I was worried by the low oil pressure but as it was absolutely solid at 35
and fell no further and the engine gave no sign of bearing distress or knock, I
decided all was well and simply ran with it. I listened for the bearings
especially when starting but heard no knock at all. I did slip the car out of
gear on some longer downhill stretches of the A14 and M.6 to give time for the
oil to collect and possibly cool a little but that made little or no difference
to the pressure. Parking for a 30-minute lunch did bring it back to cold figures
but as the car cruised so they fell again to 35. The radiator did not get hot
and the water level remained constant.
The steep inclines
of the dales gave the car and myself a tremendous challenge and I had to use
first very frequently. I will explain that in addition to luggage KMJ was
carrying four average size adult passengers. The gearbox did not change into
first easily even using double-declutch, but this is perhaps more a comment on
my deteriorating driving skills than the car. The problem was that I did not
wish to stop, and was engaging first while the speed was rapidly degrading.
After a while the old techniques returned and I was able to keep the speed up in
second but not when very tight bends or other traffic held me back. The car
never let us down but I did find that sometimes it simply would not pick up when
under load on a steep gradient. Sadly the only way out seemed to be to move off
with more revs than I would have liked. Luckily the new clutch showed no sign of
distress and the back axle seemed to take the extra load, but I would not like
to do that every day. I have to admit that when the load was reduced to two
adults the car was much more sprightly and well up to what was needed on those
difficult roads. The brakes were superb throughout and gave no problem on the
steepest of inclines where they were sensitive and powerful. The handbrake held
without problem so assisting difficult hill starts, which made driving much
easier. The brakes are the greatest difference between the YB and the YA, which
I used to run, NO BRAKE FADE!
Despite all my many
previous miles in KMJ I was still surprised at the smooth and trouble free
running of this small car. I was astonished at the high cruise speed and very
pleased with the sweet precise handling and good braking. Problems are a slight
vibration below 55 and this is a little annoying. It does not come up through
the column, gear lever or dash panel but is chiefly felt through the
floorboards. Any advice on or experience with this problem would be most
welcome. I would welcome too thoughts on the closed tappet tolerances and
reduced oil pressure although neither seems to be the problem that one might
expect. Strangely the car was not noisy by the standards of its day although of
course it is noisier than a modern counterpart. The carburettor does boom at the
higher revs (4,500 plus) but I simply keep below that and feel grateful for the
audible warning of over revving!
So once again the
YB showed itself to be a thoroughly workmanlike car with lots of good features
and very few bad ones. I would perhaps mention that the small front seats were
difficult to doze in when I tried to sleep on the return journey while my wife
drove and I would not like a long journey in the passenger seat. The answer
would be, I suppose, to sit in the back to rest. Luggage space is better than it
at first appears and the boot is sufficiently roomy for luggage for two. The
ride is smooth and firm and was in fact less sick-inducing on the dales roads
that the modern car which our friends used. I feel the petrol consumption is
high and wonder about that. Obviously the fitting of new valve guides and modern
valve seals would reduce the oil loss, as would some reliable system of sealing
the sump. I found no difficulty when using the trafficators and have never had
an incident because of them so I am not inclined to introduce flashers to an
otherwise original motorcar. Modern speed wipers would be good but again I am
loath to interfere with the originality of this particular machine.
I commend this M.G.
to all who are thinking of taking up the marque. The YB is easy to maintain and
a delight to drive. I close by saying that little compares with the joy of
sitting behind that neat and elegant straight bonnet or walking out to a parking
area and seeing the well balanced lines of this graceful little motor car amid
the more bland designs of today.