Reproduced with kind permission of Peter Howard, Australia.
This one was told to me by the proprietor of a Mackay automotive engineering
works, a man well respected in the trade. In the late 1960's he was an apprentice
motor mechanic with the local distributors of British and European cars. The
first of the six cylinder 109 Land Rovers in the district had been sold by them.
The new owners soon brought them back, complaining bitterly about blue smoke
and horrendous oil consumption. Cylinder heads were lifted on a couple of them
revealing glazed bores and the only remedy the firm could think of was a light
de-glazing hone and new rings.
The more of these sixes they sold, the more it began to look like an epidemic. Rover Australia were contacted and it seems that it was an Australia wide epidemic of near-new, smoky, oil guzzling 2.6 litre Land Rovers.
Eventually the solution came in the form of a technical bulletin from Rover HQ. There was something wrong with the bore finish on these engines and if they were treated gently, as owners of new cars tend to do, the rings would never bed in and the bores would glaze. Owners should be instructed to give them plenty of welly in the first few hundred miles.
The official fix for those vehicles already affected was as follows:-
Remove the aircleaner. Start engine and set to a fast 1500 rpm idle.Take a tablespoon full of Bon Ami, a popular household cleanser and slowly tap the powder into the carburettor throat over a period of fifteen minutes. Put everything back in place and take the vehicle for a brisk test drive.
The bulletin was most insistent that it should be Bon Ami cleanser. Ajax or Jif would not do.
My informant swears that this story is 100% true and that the fix did, in fact, work exactly as advertised.
David Walworth and Michelle Peterson of St.Croix in the Virgin Islands write:-
Hi Steve, liked the story about the use of Bon-Ami cleanser to break in the rings on an engine. Turns out, this fellow from Washington State was visiting us down here in St. Croix who had a story about the use of Bon-Ami in engine rebuilds. Well, this guy Jeff is a Harley-Davidson motorcycle nut. A mechanic told him to wipe down the bores with Bon-Ami just before assembling the engine on his motorcycle. Don't use copious amounts, but don't wipe away the residue, either. There was also some advice about starting it, let it run for 30 seconds, shut off. Then let cool, restart, run for 2 minutes, etc. Well, Jeff says that engine was the longest running engine of any of the bikes he had owned up to that time. Same thing, it had to be Bon-Ami. I told Jeff the story about the Australian 6 cylinder Land Rovers in return. So, who knows? Maybe I should pour a teaspoon down the throat of my IIa diesel and see if it helps with the smoke and oil consumption. Couldn't make it much worse!
The same informant has a long standing reputation for being good with the older General Motors-Holden six cylinder motor. He says that they have a lot of potential and that alterations to the cylinder heads and manifolds can be very rewarding. But thats only because the things were so crudely manufactured to start with that practically anything you do to them is an improvement.
I took my old Series III utility to the Christamas break-up camp conducted
by the Mackay Bushwalkers Inc.(A hiking club to overseas residents). The site
was the camping reserve of the Cathu State forest and about 10p.m. on Saturday
night a plan was hatched to view the moonrise from the lookout on the flanks
of nearby Mount McCartney. A convoy of 4WDs, mine included, set off on the forestry
road which zig-zagged up the escarpment. The lookout was gained without incident,
the moon viewed and a satisfactory time had by all, especially the children.
Now for some reason I was worried about somebody stealing the old III and I'd
installed wiring from the coil for an ignition killer unit but had not actually
fitted the module.On the return journey along the bumpy escarpment road there
was a faint glow from the parcel tray, a burning smell and the motor stopped
firing. Quickly coasting to a halt on a cleared knoll, I discovered that the
neatly wound up wires had shorted together, setting my wallet on fire! After
a short interval to extinguish the smouldering banknotes, we lifted the bonnet
and removed the badly frizzled extra wires. On attempting to restart, not a
thing! So it was up with the bonnet again and head down into the engine bay.
I was conscious of camera flashes behind me as my fellow club-members recorded
my broad expanse of backside looming out from under the bonnet. Everybody, adults
and kids alike (except me) thought that this unexpected interlude was fun. Well,
I lifted the distributor cap and found that the points had suffered a melt-down
from having a full twelve volts applied to them. Don't ask me why the ignition
fuse didn't blow, don't ask me why I didn't have a spare set. I removed the
complete points unit and me and my passengers crammed into the other vehicles
for the rest of the trip back to camp. My poor old truck looked so lonely, sitting
bravely in the moonlight as we drove away.
Here was a problem. Without points the truck would have to stay there until I could mount a special rescue mission next weekend. What if someone pushed it off the mountain? What if someone decided it was abandoned and took it? What if someone photographed it for the Landrover Owner magazine derelicts section? So at about 1a.m. I brewed a cup of tea and sat down at a picnic table with a candle lantern, the remains of the points set and any tools or raw materials I had. The damage consisted of :-
1. Melted nylon bush which insulates moving point arm from pivot post on fixed point base.
2. Evaporated wire from moving points to nylon spade terminal insert in side of distributor.
3. Some burning of the point faces.
I had a Swiss Army knife, a roll of insulation tape, a small screwdriver and
the contents of my backpacking first aid and repair kit. The knife blade cut
and scraped away the remains of the totally ruined bush. There was a small piece
of plastic insulation tubing protecting the sharp ends of my medical kit scissors
and with a little heating over the candle this slipped over the pivot post.
A couple of wraps of insulation tape made it just fat enough to fit snugly into
the moving point pivot hole.
The excellent file on the Swiss Army knife dressed up the burned points in no time.
A short piece of stranded copper wire made the connection between the moving points and the spade terminal. Waxed linen thread from the sewing kit was bound around the wrapped wire connections to reinforce and secure them. Finally, dental flossing tape provided the insulation around the bare wire.
Next morning, someone drove me back up the mountain to the patiently waiting Rover. After installing the resurrected points and gapping them with a credit card, old Rover started on the first turn of the key. Whatever their design shortcomings, those Rover sixes are very willing engines. All they ask for is fuel, air and spark and they will run. I drove her down to the campsite, drove her home that afternoon and drove around for a week afterwards until I got around to fitting a new set of points.
"Feral Cheryl" was sick! My neighbour Steve, owner of the Series
IIA 5 door Station Wagon had called me over to look and listen. Any infirmity
in Cheryl was a serious matter as she was serving as the family daily driver
and weekend horse-float tow vehicle at the time. Her engine is a General Motors-Holden
186ci six cylinder and it had a fearful rattle when revved up and puffed clouds
of blueish-white smoke on the overrun. This sort of trouble was quite unexpected
as she'd had a valve job recently and the engine had seemed to be in good order
at the time.
It is unusual for Steve to be stumped and I didn't have a clue either except that the noise definitely seemed to be coming from the top half of the motor. We decided that it wasn't anything to do with the head gasket as the smoke wasn't water vapour and oil passages between head and block are few in this make of engine. Eventually, we concluded that it could be a fractured and rattling piston ring ; one which sealed all right with combustion pressure when revving but relaxed on the over-run and allowed oil blow by. A far-fetched theory but the best we could think of.
It wasn't going to be fixed by looking at the outside of the engine. Steve decided that he'd have to tear the engine down during the week, in between running his business, so that she'd be fixed in time for next weekends equine activities. I had to work too so all I could do was wait with great curiosity to hear what he might find.
What he found was nothing at all. The bores and pistons were good, the rings intact and all bearings in serviceable condition. As it was in pieces anyway, Steve fitted many dollars worth of new rings, seals and bearings. On starting up after reassembly, the rattle and smoke were still there exactly the same as before.
To make a long story interminable, Steve began to suspect the petrol in the almost full tank and found it to be contaminated with Diesel fuel. On thinking back, he recalled that Cheryl had visited the local garage just before the trouble appeared which is when somebody had topped up the tank with Diesel. The symptoms magically disappeared once the tank was drained and refilled with fresh, clean petrol.
It was an expensive, time-wasting exercise for Steve but Cheryl did run a little better and a little more quietly following the unscheduled and needless overhaul so I suppose some good came of it. On the other hand, it wasn't me who spent many futile hours looking for a non-existent engine fault.
Jim of Bayou Rovers writes,
I had the same thing happen to me as Cheryl did with Diesel fuel! I replaced
the fuel pump, carb, all the lines and did a tune up before I finally
suspected "bad gas" and sent a small rag into the fuel tank to soak up a
sample for me to sniff.
Believe it or not, Beula actually ran, although very rough, with a lot of
smoke, and with timing way far retarded, on diesel before I figured it out!
The wring in Sally is all my own work. It is loosely based on the Series IIA
system but it has a lot of extra wires incorporated for electrical components
that the Series does not normally have. The wiring is neatly bound into cables
with PVC electrical tape. including one big cable going from instrument panel
through bulkhead and across to alternator, starter motor solenoid, battery etc
on left hand side of engine bay.
Late one Friday afternoon after work I decided to take Sally to a local beauty spot for a photography session. After taking some nice shots, including the one which appears on the Home Page, I set off for home as twilight closed in. Then the alternator light came on. "What now!" I thought."That blasted alternator is a brand new reconditioned unit." I pulled up to investigate. Next moment, the engine died and clouds of acrid white smoke poured out from behind the main and subsidiary instrument panels! Switching off the ignition had no effect on the volume of smoke or the sizzling noises. In a small panic, I vaulted over into the back where the battery hides under a side seat and disconnected the main lead. I was lucky that I had a quick release hold-down on the batttery box lid and a 1/2 inch spanner handy for the terminal clamp bolt.
Then out and around to lift the bonnet. More billowing white smoke with evil little yellow flames flickering from the burning insulation on that fat cable. It looked like theatrical effects for the grand entrance of Joe Lucas, Prince of Darkness. Fortunately, the street was deserted so I was spared the good advice or assistance of onlookers as I beat out the flames with a shop rag. ( a clean one, not oil soaked). I also made a mental note to fit the dry-powder extinguisher which was sitting under the workbench at home.
Complete disaster was thus avoided. After a pause to let everything cool off, including me, I took a look. My big cable had flopped down onto the exhaust manifold and the layers of insulation had slowly burned through. It was "goodbye cable" as a few hundred amps found a shortcut to ground from the main battery/ammeter feed wire. I looked at my spare wire in the toolkit and looked at the charred cable. Wiring for alternator feed, carby solenoid, ammeter wiring, windshield washers, starter solenoid and much else ; all of it a congealed mass of exposed copper and melted insulation. Decided that hotwiring her enough to get home was not an option. Maybe if I was out in the boonies and desperate but not in the fringes of suburbia.
After a pleasant evening walk home I poked my head into the kitchen of my neighbours Steve and Cilla (mentioned elsewhere in these pages) and enquired about Steves whereabouts. Cilla told me that he was at a meeting but was expected home quite soon. I then asked Cilla if she knew the time of moonrise, explaining that I'd prefer to have Sally towed down our street under the cover of darkness for obvious reasons of male pride. Cilla told me to relax and wait patiently.
In due course Steve arrived and got me out of a jam yet again. Thanks Steve. While rolling along in Sally under tow I was struck by how agreeably smooth and silent she was. This was what I imagined a Rolls Royce would feel like.
Next morning I had to fly out of town to attend the wedding of my nephew Chris, a sensible lad who owns a Honda CR-V, a sort of Japanese Freelander. I packed my wiring diagram and notes so I could redesign the wiring layout in spare moments and make a start on the rewiring job the instant I got back home. On the way to the airport I stopped off at the auto electrical store and bought a whole lot of new wire, terminals and a fusebox.
The first priority was to clip the new wiring up properly, well away from the exhaust manifold.
Next was to reposition the fusebox and individually fuse more circuits.
The high current feed wires connecting battery/ammeter/fusebox/alternator were segregated in their own harness so that some unforeseen future disaster wouldn't fry a lot of subsidiary circuits too.
One of those manual cut-off switches with the red key was placed in the big wire from battery to ammeter, the one which carries every bit of battery current for the rest of the system. The key is in front of the passenger where I can still reach it from the drivers seat. As a final touch I wired a 20 amp fuse across the cut-off switch to provide battery current even if the key is accidentally switched off. (Passenger to Driver: "Whats this big red switch do?") Sudden disconnection of the battery while under way can do nasty things to the alternator diodes. If there is a genuine electrical short the fuse will blow when the switch is thrown.
The battery and alternator had not suffered any ill effects and everything worked fine on completion of the rewiring. And the revised layout is much nicer than the original version.
Inattention to detail can lead to disaster sooner than you think Keep wiring clear of hot things and sharp edges.
The best place for a fire extinguisher is in your truck, not at home.
I had a day off so I'd arranged to book Mustang Sally into an exhaust and muffler
shop to have a lovely new stainless steel system fitted. She had been getting
along with a four cylinder Land Rover sized silencer on her GM-Holden 3.3 litre
straight six but I felt that this was a little restrictive at the top end of
the rev range. On the morning of my day off, I discovered that my home built
electronic ignition had apparently given up. This ignition uses standard points
to trigger the electronics in the control box so it was a minutes work to disconnect
the box and reconnect the coil in the standard Kettering ignition configuration.
She started first time after that and I drove her into the exhaust shop through
slow rush-hour traffic for her appointment. (We do have a rush-hour, even in
a town of 40,000 people.)
I picked her up after lunch, very impressed by the way the exhaust fitter had followed instructions, tucking the new pipe well up out of the way with several subtle bends and hanging the Holden sized silencer in the same transverse position just behind the rear axle. This guy is a craftsman who knows his stuff!
I chose a different way home, a longer route with a 100kph stretch where I could give her some throttle and see how the new exhaust worked. Great consternation on my part when I discovered that the motor would not rev past 2000rpm! It revved just so so far and then died with a cacophany of misfiring and backfiring. This was alarming! What in hell could an exhaust fitter do to an engine to make it behave this way? Or was there something about the expensive new silencer which was incompatible with the engine?
After getting the truck home I had a calming cup of coffee and thought about it some more. I realised that I'd never actually got above 1500rpm in the slow inbound traffic that morning so maybe the misfiring condition existed even before the new exhaust sytem went on. The only recent change I'd made was reconnecting the ignition system in conventional format that morning. Of course! Before doing anything else I connected an ignition dwell meter to the points lead and started the engine. Standard ignition points dwell for this six cylinder engine is 30-35º. I read 54º which means that the points had hardly any gap. Next step was to whip the distributor top off and rotate the engine until points were at maximum opening. With my feeler gauges I measured a points gap of just .005" rather than the .0019-.0025" recommended in the Holden engine manual.
What was happening. My electronic ignition takes a triggering signal from the opening points and looks after the spark duration and points dwell itself. It provides a short spark and an extended dwell period to intensify the electrical energy available for the spark. The electronic ignition does not care what the points gap is, so long as they do open, and the motor will run normally if the points open at the right number of degrees BTDC.
However, the standard Kettering system cares very much about the points dwell period (the amount of time the points spend closed before opening again). If dwell period is too short (points gap too wide), the ignition coil does not have enough time to build up a good head of steam for a high energy spark. If dwell period is too long (points gap too small), the spark is no sooner triggered than it is quenched by the points closing again. At higher revs, everything happens much faster and the early quenching of the spark effectively gives you no useful spark at all.
During my debugging period on the new engine conversion, I had been checking and readjusting the timing with a xenon light every so often to compensate for the initial bedding in of the points rubbing heel on the ignition cam. Foolishly, I hadn't checked the points gap as well so I was not aware that the heel had worn rapidly, closing the points gap right up. I would have known all about it long before now except that I've been using the electronic ignition which sets the ignition dwell electronically. However, on changing back to Kettering ignition on the existing points setting, I had no effective spark at anything over 2000rpm.
The cure. I reset the points to the specified gap of .0019-.0025" and readjusted the timing to the book value. Yes, the engine ran perfectly again and the new, less restrictive exhaust makes it more lively at the top end of the rev range.
In the future. I will have to find out whats wrong with the electronic ignition. If it is some inexplicable failure I will probably abandon it. If its something that can be fixed so that it doesn't happen again I will persist with it. I will definitely try to work out why the points heel wore so badly. I thought I had lubricated the cam and heel properly. Maybe the material of the heel was inferior and I'll have better luck with a different brand.
The interesting lesson. I've never had a set of points close up quite so badly before and it was fascinating to see the symptoms of too much points dwell. It proves that the ignition distributor manufacturers don't specify a points dwell figure just to give you something extra to check.
Postsript: The electronic ignition problem turned out to be a faulty push-on connector on the circuit board. It was put back into service, then abandoned again when I fitted factory electronic ignition. See Mustang Sallys Ignition Saga for the full story.
This page last updated Sunday, 22 August 1999 04:40
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