850 Trials (&
tribulations)
By
Rory Cole
The
story began when I started making enquiries about trialing (a type of
off road motor-sport). It particularly appealed to me, as having been
driving off road for the past five years; I decided I would like to do
something a little bit more interesting, yet still utilising the basic
off road skills I had developed. This being the case and with a car
suitable, and even recommended, for use in that field, I decided to buy
a clubman licence. This, available at the price of ten pounds from the
M.S.A (Motor Sports Association), entitled me, at my then age of
fifteen, to take part in standard and production car trials.
With
the fields I drive in too wet at that point, I decided to start
preparing the car, which I drove off road anyway, for trialing. The
first thing that I did was to remove the tired 102,000 mile 843cc engine
which, although still going strong, I decided was not competitive
enough. The main problem, yet probably to be expected in an engine with
that mileage, was its reluctance to rev as much as I would like.
Performance below about 6,000 rpm I felt was fine. However, when it
reached around 6,400 rpm it refused to budge any further, unless in
first gear going downhill - surely not good for it. At 6,400 rpm the
843cc 850 engines are at peak power. However, I find that particularly
when ascending a hill but trying to maintain speed, that it is very
effective to slightly exceed this peak power figure. Doing this, when
up-changing, the engine is further into the more ‘usable’ rev range,
ensuring minimal loss of speed. I knew from experimenting, that the
standard, and apparently rebuilt, Seat 843cc engine, originally in the
car that I am restoring, will rev up to around 7,000 - 7,200 rpm no
trouble. With this in mind I decided that if I were to retain this
current, badly worn engine that I would be compromising myself
competitively as well as detracting from my enjoyment of driving. I
therefore decided to use a different engine.
At
this time, for around five years, the rustiest and most moth eaten 850
Sport Coupe I have ever come across, has been languishing in one of our
barns. It sits on Fiat 600 rims with its original wheels and disc brakes
removed, reconditioned & fitted to my Dad’s ‘Abarthised’ 600.
It had been, until recently, covered by multiple and obviously carefully
positioned, damp scaffold boards to dry out. These boards, all resting
precariously on their edges, make it very interesting trying to get
anywhere near the car without hitting one’s head and sending the lot
tumbling down like a pack of dominoes. With a similar array of drying
boards on the floor around it, I had had to abandon previous attempts of
six or so months previously, to get it running (an interesting procedure
involving hotwiring it - no keys). This had been with the intention of
removing it’s 903cc engine which has: twin choke Weber carb, four
branch exhaust, higher compression, hotter camshaft, and among other
things will propel any unsuspecting 850 a great deal faster than any
standard 843 unit. However, with the boards removed, and after freeing
up a stuck valve, I set about the process of preparing it for starting.
I changed the points, the plugs, the condenser, and the fuel pump and
found it a distributor cap and spark plug leads. With this process
completed. I tried to start the car, to no avail. It turned out that the
fuel line from the tank was blocked and despite my best efforts, it
would not clear. So I set about finding a long length of fuel line and a
Gerry can of petrol. I hooked these up and then tried again. No such
luck! The second-hand, replacement fuel pump was too feeble to get any
petrol up to the carb from such a distance. I finally resorted to
removing the engine intending to put it into the blue car. Engine out, I
cleaned it thoroughly, and carefully tipping it onto the flywheel to
clean the wonderful alloy sump found oil pouring out from under the
rocker cover. Immediately
righting the engine I discovered that where I had replaced a bent rocker
stud, the new stud was fouling the rocker cover and preventing it
sitting flush on it’s gasket. I trimmed this down, re fitted the
rocker cover and all was well. Losing most of the oil in this way, I
decided to drain the rest, and then replaced this with flushing oil. The
next day I removed the worn engine from the blue soon to be ‘trials
850’ and installed the 903 engine with standard dynamo and slightly
modified fan surround. Finally, after filling the cooling system with
plain water and putting a gallon of petrol into the car I turned it
over. Unfortunately, despite my previous success with most 850 engine
work the engine refused to fire. I left the engine for a few weeks doing
nothing and recently came back to it with my Dad’s idea of checking
the compression. Well did it have any? Pffah! Next I tried the test with
some flushing oil in the bores and this time the compression was much
better - indicating bore wear. As a result, I decided to abandon the 903cc engine, with the
cost of a re-bore in mind. Instead, I decided to strip the engine down
and fit its major performance increasing components onto an 843 unit.
Unfortunately this would lack the extra 60cc and high revving nature of
the 903cc engine as well as improved cooling channels and oil
distribution set-up. However with a low budget a modified 843cc unit
appeared a sensible second best. As far as 843cc blocks were concerned I
had three spare to choose from. Option
one was a smelly, oily engine, which emitted clouds of smoke. This was
in the car in question when I bought it and was quickly removed, as
better alternatives were then available. Option
two was similar except this one was noisy as well, refusing to run when
warmed up. This was originally in the maroon trials 850 saloon (No2),
which I will soon be preparing as a spare car, and was removed for the
same reason. Option
number three was in the green 850D saloon that I am restoring to 850
Special specification for road use. I already had a special engine for
this car and therefore its current 57,000 mile, and apparently rebuilt,
unit was available. This I knew was a very good engine. It was reliable,
performed well and revved freely to around 7,200rpm. No
prizes for guessing which one I chose and I soon set about stripping
both the donor engine and the new 843 unit.
I
started with the head of the 903 engine from which I removed its Webber
30 DIC twin choke carburettor, inlet manifold and air filter, four
branch, free flow exhaust system, and the head itself which has 9.5:1
compression  and
bigger valves. Next I drained the oil and inverted the block on my
workbench. I removed large finned alloy the sump and then the camshaft.
I de-carbonised and cleaned all the head components thoroughly and
lapped the valves in. The head had to be skimmed as it was quite badly
distorted. I also had an insert fitted where one rocker stud had badly
stripped its thread. Finally I cleaned the sump. After
carefully and precisely laying out all the components ready for fitting
I removed the same parts from the 843 engine and stored them carefully,
along with the 903 block and its pushrods. After doing this I spent some
considerable time cleaning and painting component parts as well as de-carbonising
the engines piston tops. I ordered a new gasket set and oil seals, which
arrived very promptly and at good prices from Fancy Engineering and then
started to assemble my new engine. I took considerable care in
particular when fitting the sump trying to avoid leaks. In the end this
was accomplished to a very pleasing standard. I soon discovered that
when using the 903 camshaft and cylinder head it is important to include
the slightly shorter 903 pushrods as without these the rocker-shaft will
not tighten down and damage could be caused to the tappets. Luckily I
realised this in time and replaced the 843 pushrods with the correct
ones. When the whole
engine was assembled I set the tappet clearances, the timing, the
points, filled the cooling system with water, the engine with flushing
oil and the tank with a gallon of petrol. I attempted to start my
creation of many hours to no avail. I slightly adjusted the distributor
and it fired, however, it coughed and spluttered refusing to advance in
revs. Adjustment of the distributor either resulted in the car stalling
or an inexplicable revving to around 3,000rpm at which point the carb
started back firing and again it would shortly stall. I checked
everything- the points, the distributor, the distributor cap, the plug
leads, the coil, the condenser, the rotor arm - none of which were known
to have faults before hand. The carburettor  had
been reconditioned before assembly and I checked the timing on multiple
occasions. After a while my Dad pointed out that, with the marks on the
pulley wheel and timing case lined up, the rotor arm could be in two
positions - one obviously being 180 degrees out. As far as I am aware it
says nothing about this in the Haynes manual. I tried the timing in this
new position and it wouldn’t even fire so back went the distributor to
its original position. At this point I lost my patience and left the
car. It remained like this for some time, however after a very
informative email from Jim Spackman, the problem was brought to light. The mistake I had
made was to have equal slack on both sides of, what was already a very
loose timing chain. I removed the timing case, which was very difficult
with the sump on and the engine in the car. However, I just about
managed it by slightly flexing the sump with a clamp to allow removal of
the case. This done it was an easy enough job to get rid of the slack on
the driven side of the pulley and back on went the timing case. Although
it had appeared that the sprockets were aligned correctly, when the
engine turned and the slack was taken up, the timing had been incorrect.
After much messing around
getting the timing correctly set again on the distributor, various other
minor problems and a good churning over on the fast charger, it fired up
and ran very smoothly indeed. I warmed it up, making the obvious checks,
while trying to avoid inhaling the nauseating gasket fumes it was
producing. I changed the flushing oil for semi synthetic and took the
car for a spin along the track I have made around our fields. Taking it
carefully to start with everything appeared o.k. and the engine was
performing better than an untouched (real) 903 engine in my coupe,
whereas this is just an 843 with all the bolt on goodies. Every now and
then I made checks and each time everything appeared to be fine. As a
result, and wanting to get an idea of performance I started thrashing
the thing around (don’t forget I hadn’t had it re-bored or anything,
so this wasn’t quite as cruel as it might sound). Everything went
fine, and it was revving very freely to peak power of about 6,500 rpm
and then with a slight hesitation right
round to 8,000 rpm, where deafened, shaken to bits and out of a degree
of mechanical sympathy I lifted off. This continued for around half an
hour until at around 6,500 - 7,000 rpm the engine note changed from a
rasping roar (sorry, I’m getting carried away - awful screaming) to a
far more worrying powerless clattering. I stopped and after making sure
nothing was actually sticking out of the block, I very carefully took it
home. An inspection under the rocker cover revealed two stray, but
luckily undamaged pushrods. These were dutifully re-fitted and the
tappet clearances set. I figured that I must not have quite adjusted
them correctly the first time or tightened them down sufficiently and as
a result these two were free to become loosened. Once
again the engine was fired up and despite starting instantly from cold
with minimal choke the noise was still there. As a result, I decided to
take the engine to bits again to investigate. When the head came off, I
found that half a valve had broken off and after breaking into bits,
imbedded itself into the underside of the head. I think I have figured
out why it happened now, although I wasn’t sure to start as it also
coincided with the escape of the two rebel push rods. However I have
come to the conclusion that it is all down to my excessive revving. I
had ignored 7,000 rpm warning marks on my coupe’s rev counter which I
dismissed expecting another thousand or so rpm. This however was only
going by Fiats pessimistic red line markers for each gear on the speedo
of the saloons. It turned out that Fiat were right after all. Perhaps in
1971 the valve springs may have been up to returning 8,000 rpm of valve
but these had done 47,000 miles and it was the year 2001. As a result my
engine met an abrupt, albeit temporary demise. I removed the worst of
the damage to the head and purchased a new set of valve springs, a new
valve and took the head along to the local machine shop. One hardened
valve seat was inserted and the head skimmed again to remove the rest of
the damage. Once the engine went back together again, I set myself a
rough limit of 7,000rpm until perhaps I could afford a set of A112
7,5000 rpm rated springs, my idiotic engine screaming tendencies will
have to wait. This engine, compared to a standard 903, still lacked the
different pistons, higher capacity and improved cooling channels and yet
it performed better, simply due to decarbonisation and reconditioning,
than a 24,000 mile untouched 903 unit in a coupe I also have. The engine
in question had done nearly 60,000 miles and had pretty poor
compression. However, it still powered, hardly hesitating to 8,000 rpm
and with some great sound effects before..well, you know. At the time of writing the majority of these articles, I had
recently acquired a welder and carried out some quite extensive work on
the inner and outer sills, floor, wheel arches and the doorpost bottoms.
At the time I was really pleased with what I had achieved, however I now
realise that the welds were pretty poor & I overlooked quite a few
important issues. Well I had been teaching myself, & the car was
only to be for trials use. At least it was now reasonably solid. The
brakes were soon overhauled. I installed new wheel cylinders and a
master-cylinder, two copper brake lines and new front brake shoes. After
plenty of agro - leaking cylinders, hose connections, air locks, etc.
everything ended up well and the brakes now operate excellently. A
nice little mod, which Brian Alexander recommended, was an extra
radiator at the back. One of these, a heater rad from a van, has been
fitted and is linked simply into the cooling system. Mounted under the
engine hatch it is conveniently in the airflow through the louvers.
Controlled by its own valve this gives me plenty of leeway when using it
for trials if it gets a bit hot. Some
more jobs required on the engine were a timing chain replacement whilst
also replacing the rear crank seal for a new one; the latter I had
forgotten when putting everything back together. I was spurred into
getting down to it sooner than planned because of a new problem. I had
been using the car quite a lot around the fields, and for some time
everything had been going very well. However, whilst driving it around
in the wet, I started getting dodgy noises from the top end. It was
strange because although it sounded like an obvious engine rattle, there
wasn’t a noticeable power loss. Tracking it down was made even more
difficult because of torrential rain and lots of wheel spin. However,
something was obviously wrong and so I decided to remove the engine, do
the timing chain etc whilst trying to figure out what the latest problem
was. I set about
doing this the same day (a Saturday), and with the engine out in about
an hour and a half the problem turned out to be down to the pushrods
again. No 1 pushrod had freed itself yet again and that the adjuster had
wound right up it’s thread. Luckily this time no other damage had
occurred, but I still don’t understand how it got loose in the first
place. Never the lass, it was replaced, and tappet clearances set. I
then removed the sump, doing the timing chain and crank seal with ease
and no problems. The engine
went back together without a hitch for the third time and was
reinstalled on the Sunday. I fitted the odd new gasket where
appropriate, and it fired up immediately running better than ever. An
all round success, I thought. The same day I
did another ten miles in the car around the fields and there were no
problems with the engine for many days of driving after that.
A
few days later, with the car still going strong despite a big dent in
one side as a result of an altercation with the fence I decided to bodge
weld patches over the remaining areas of rust - at the bottom of one
doorpost and the rear arches before putting the car in for an M.O.T. With the car still going well, a few days before starting work
for the M.O.T, the engine had another of it’s increasingly innumerable
tantrums. More terrible noises ensued & I decided to remove the
engine completely & replace it for the M.O.T. Nevertheless,
and temporarily forgetting the naughty engine, the M.O.T prep went
succesfully. I sorted out lots of electrical problems and did loads more
welding. There were a few more holes than I realised lurking under the
rear arch where three box sections come together. With all the welding
finished, I filled the sills, doorposts and rear wings with thinned down
waxoil and drained most of it out of the bottom. This will hopefully be
very worthwhile in preventing the bodywork getting any worse than it
already is. This is particularly important now that I’ll be using the
car for trials, as it will be getting pretty muddy. The
next week, it went in for the test, as planned, and to little surprise
failed. However the failure points were very minor which was relieving.
One indicator was not working, the brake pedal rubber had worn through,
the horn was not working, and neither were the rear number plate lights.
These problems were soon sorted and after the re-test I arrived home
with an M.O.T certificate. Hooray! As a result of my craving for the
more powerful, if smoky engine, I decided to put the ‘original’
engine back a.s.a.p. However before I could do this I needed to sort out
the ever-recurring problems apparently emanating from the head
somewhere. This is hardly surprising, as I didn’t exactly chose the
best Coupe head when upgrading the engine. It was the top end remains of
a J reg Sport Coupe, and was distorted, had a stripped rocker stud
thread, stuck valves and lots of black everywhere. Despite this I
overhauled it and to my dismay I ended up paying the price. When
I took the rocker cover and shaft off, I discovered that one of the
valves complete with collets was in the process of being sucked through
the retainer into oblivion below. I was lucky to catch it at this stage
to say the least. However, after the head came off, and the valve out, I
replaced the collets and retainer and reassembled everything once again.
On doing so I discovered another rocker stud had again stripped its
thread, and more palaver of bodging ensued. The overall result was that
it all went back together in the end & was running well once again.
(Or at least so I thought).
After
more severe problems, however, I dramatically decided to break the whole
engine for spares. The problems with the cylinder-head had started to
manifest themselves again. It was just  unbelievably
unreliable. More significantly, everything attached to the cylinder head
was unreliable, having the tendency to fly off left, right and centre.
That added to the worn bottom end, really made the whole thing a
complete and utter nightmare. Despite good power (for an 850) of about
50bhp, when everything was going well, the frequency of problems started
to override this positive side. A valve spring retainer disintegrating
and subsequent valve drop confirmed this. A stripped rocker shaft stud
and similar tappet adjuster signed the decision in blood. However, with
quite a good selection of new parts on the engine I decided breaking it
would be beneficial enough to other projects. The
replacement unit (temporary until a really good engine could be built)
was a 44,000 mile 843 engine from an 850 D. This was serviced, a
twin-choke and four-branch were bolted on and away I went. The car
subsequently seemed to perform better than ever, despite less
modifications.. More
fields driving ensued & the new engine seemed to be going like an
absolute little corker. About time, I thought. I ran the engine in
standard guise for a little while, to determine it’s basic condition.
All seemed to be well. However, in search of extra power, I soon
exchanged the cylinder head for one from an 850 Special. This, coupled
to a little twin choke Webber & four-branch exhaust, gives about
another 10 bhp & improves its ability to sustain high revs. I
completely de-carbonised the head, ground in the valves etc, and bolted
it onto the 850D bottom end. It fired up again without much trouble
& performed really well. What’s more, it was reliable internally
(where it counts). In fact I was amazed by the reliability. I didn’t
have a rev counter in the car at the time, but I’m sure it’s saw
8,000 rpm on a few occasions. With such good performance &
reliability, I entered the car for a PCT. Thinking my trials car
problems were finally over, I looked forward to the trial. Well, in true
fashion my plans went somewhat out of the window. To start with
the PCT I was going to be attending was called off. Then the car caught
fire! I’d just
finished making some final adjustments including charging the battery,
& cleaning out the fuel system. (Which was clogging the carb with
old fuel through lack of use). Whilst doing the aforementioned
tinkering, it was necessary to remove the fuel feed to the carb. This,
an old, original pipe, had become very hard over time. Ordinarily I’d
have used boiling water to soften it before attempting to remove it.
However, for some reason I didn’t. Instead I just gave it an almighty
tug. On reflection since, this must have loosened the brass inlet pipe
into the carb. Pleased with what
I’d achieved on the car, I went for a spin. It was going like a dream
for a while. However, soon the engine started to cough, splutter &
hesitate. I drove the car back into the barn, revved the engine a few
times & listened to things for a while. Just as I was about to
switch off to investigate, there was an explosion from behind me. I
turned round to see my plastic summer/winter engine covers go flying
& flames coming through the subsequently exposed louvers. Always
having a fire extinguisher to hand, the fire was out very quickly. Hmm
not good though I thought, & not wanting to be faced with the
damage, left the car untouched for a few days. On eventual inspection,
although not severe, damage will probably necessitate removal of the
engine to do some re-painting & attend to melted wiring. On
inspection as to the cause, lo & behold one of many 850 weak-spots -
the brass carb inlet pipe was found dangling in the end of the rubber
fuel feed hose. No doubt this had been trickling a generous dousing of
fuel around the engine compartment ever since I’d experienced engine
trouble. Presumably the heat of a fully warmed engine must have been
enough to cause ignition. The
car sat blackened & forlorn for some time, before I could bring
myself to do anything with it. As a result, over the past couple of days
I’ve finally been getting around to making the necessary repairs.
First I used the power washer to clean the worst of the carbon &
extinguisher powder out of the engine compartment. Then I removed the
engine, being necessary to facilitate re-painting/re-wiring. The engine
removal was a very easy job & was accomplished quickly. With the
engine out, I surveyed the damage. The engine appeared fine apart from
partially melted plug leads & a very blackened carb. However, as
suspected, a lot of the finer, older wiring in the engine bay was melted
as well as a lot of paint & a few other odd plastic bits. At
this stage I started to think hypothetically about installing my freshly
re-built 903 engine, which was, at that point, sitting waiting to be
fitted to the ’Sea Green Saloon’. The issue that aroused this
consideration was the fact that progression with the suspension &
bodywork of the ‘SGS’ required money to finish it & get an M.O.T.
‘Spend money on it then’ would be the obvious response. However, at
present I have exactly no money towards that project, let alone the
£1000 odd it’s going to cost me to insure an 850. This begged
the question: ‘Why not put the 903 engine in the trials car & use
that on the road to start with instead?’ As I had taken the engine out
of the trials car anyway, I considered installing the rebuilt unit
permanently. I’d have built a similar engine for it eventually anyway
& doing this would instantly give me a good all round car -
powerful, solid & reliable, if scruffy. Suddenly a really good
solution seemed to have appeared to a problem I’d forgotten I had.
This plan, as well as giving the trials car a new lease of life, would
also mean I could take work on the ‘SGS’ a little more leisurely
& I’ve got no end of engines/possible engine builds to chose from
for that! Well that settled it. I decided I’d definitely go ahead with
the new plan. The Trials
car, as I said, is already M.O.T’d & is tax exempt. As a result,
when the new engine is fitted. I’m going to get my Dad to insure the
car temporarily until my test, & he can run it in for me. Hopefully
he will even drive me to a few trials in it! (Incidentally it’ll cost
him/me £113 fully comp, with recovery & agreed value of
£1k.Pretty good, I thought.) Back to repairing to the fire
damage with renewed enthusiasm, I set about stripping the engine
compartment. Guess what I found. Yes, a massive great hole in the parcel
shelf going through into the engine compartment. At least now I’ve
pinpointed where water was getting into the car from. The parcel shelf
is double skinned & rust had eaten through a hole, once opened up,
of about 30cm sq! The rear screen had to come out & there was more
rust under that. I’ve made a nice repair to it though. As
if this undeserved engine upgrade wasn’t enough, more opportunities
seem to have arisen to improve the trials car even more. The first of
these came by way of an advert in the current ‘Parliamo’. The add in
question was for a set of panels for an 850 Saloon. These included front
wings & panel, sills, n/s floor pan & rear arches. A deal was
settled for £50 (including delivery of course)!!!!!!!!! All
the panels on the trials car are solid at the moment. However, there are
loads of dents, filler & bad welding - where I was getting a bit
ahead of myself once in position of the welder. Saying that, the welds
aren’t that bad. Anyway, the point is that these panels can be stored
away somewhere safely & slowly as needed (a sort of rolling
restoration) I can use them to replace the old ones. I’ll hopefully be
able to do it a bit at a time e.g a wheel arch one weekend etc. So,
things finally seem to be coming together, & with both my parents
prepared to drive me to trials in it, with a new engine waiting to be
fitted & driving licence time just around the corner, I’m almost
ready to start enjoying 850 ownership once again. I think I must have
learnt every lesson there is about using Fiat 850s? I really hope I have
anyway!
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