I am a very satisfied owner of a TR6 bought some eight months before PGN 769L which appeared so prominently in your article “The Tale of a TR6”. I find this article very distressing since in my view the TR6 is an excellent car; especially in its fuel injection form. However, I am a Consultant to Messrs. Rupert Ledger of White Waltham, Berkshire. This company imports high efficiency American industrial two-strokes and has recently formulated a special silicone two-stroke oil for these. This is marketed under the trade name Uni-Pak but at the moment its distribution is restricted to agricultural and industrial users.
My TR6 LPB 812K is a test vehicle for the evaluation of these high performance lubricants and as a result of some of our observations we think that we have gained an insight into some of the problems suffered by the engine of PGN 769L.
Taking the spark plug problem first, I removed the plugs as fitted by the manufacturer and submitted Japanese plugs made by NGK, type BP7ES. The points and condenser were removed and an electronic ignition system made by Lumenition substituted. A Lucas high-voltage coil replaced the standard one. I strongly recommend any TR6 owner to do as I have done. Plug gaps can be increased from 0.6 mm. to 0.7 mm. Starting, power output, and torque low down in the rev, range is improved.
The improvement in plug performance is of course due to the internal copper cores of these Japanese plugs and their excellent ceramics. It is a pity that I have to give this advice but I have raised most of these matters with the relevant English manufacturers with regard to sparking plugs.
Fuel injection systems are evidently giving a great deal of trouble at the present time and seem to be falling out of favour with many manufacturers. This is a pity for in my view they are quite the best method of supplying fuel to an engine.
Two-strokes until relatively recently were also falling out of favour, so I think that we ought to look at the common factor in these two systems and that is of course petrol. Petrol, if it is contaminated with small quantities of water, can support a thriving colony of bacteria, yeasts and mould. These produce gums and under certain conditions quantities of acids. This process is often described in the literature as bacterial degredation of fuel. The average motorist is quite unaware of all this. A discreet silence has been maintained in certain quarters. Twostroke engines have suffered severely from gums in degraded petrol. I think the fuel injection systems are in many cases, at present suffering from the same sort of contamination.
I would suggest the following sequence of events in a typical TR6 fuel injection failure:
(i) The driver goes on an extended journey and buys petrol from an isolated garage or runs out of petrol (9 gallon tank!) and receives petrol from a dirty can. In either case his tank may be contaminated with water and living organisms.
(ii) These organisms then penetrate into the fuel injection system and there the warmth of the engine provides ideal culture conditions so that they multiply to produce gum and acid.
(iii) Eventually the fuel injection system becomes blocked, this may in turn cause the electric motor to fail through overload.
(iv) The car stops without warning and in many cases the publicity given in the Press is very bad for the manufacturer.
Silicones, in a complicated formulation which is a secret process, can be added to a motor oil so that when the temperature rises, as in the engine, the silicones go into solution. Not only do they do this but they also bond on to all the hot metal surfaces. To this covering silicone layer is bonded another of aligned oil molecules. In other words an oil film of very great strength is attached to and interposed between all moving surfaces. There is virtually no cavitation in bearings; friction is very much reduced and lubrication substantially improved.
Field trials with Uni-Pak silicone oil in the two-stroke engines that Rupert Ledger import from the United States clearly indicate that the “gumming problem” is virtually eliminated. In a petro-oil system the internal surfaces of the carburetter are covered with a layer of silicone and the gums do not stick; they are simply washed through and burnt in the combustion chamber.
With this in mind I decided to try Uni-Pak silicone oil as an upper cylinder lubricant in my TR6 with the hope that what had been achieved for the two-stroke engine would now be accomplished in the fuel injection system of my TR6.
The oil in the crankcase and the gearbox has had silicone added to it since the car was new. This has yielded very smooth running at all speeds. Oil consumption without the upper cylinder lubricant was in the order of one quart for every three thousand miles. With the addition of Uni-Pak silicone oil to the petrol, oil consumption has dwindled to zero and at sixteen thousand miles there has been no trouble from the fuel injection system, other than the odd injector “popping out” (more about this later). So as in the two-stroke engines Uni-Pak silicone oil seems to be keeping my fuel injection system clean.
Experiments suggest that Uni-Pak silicone oil is most effective in the ratio of one-third of a pint to twenty-five to thirty gallons of petrol.
Garages have the disconcerting habit, when servicing fuel injection cars, of driving them on to ramps on full choke. This can cause an injector “to pop out” with consequent flooding of the cylinder concerned with petrol. Even if the injector is changed it is very difficult to bring the cylinder back to life unless the ignition system and plug system is up-graded in the way I have described.
Because silicones are present in the crank case and are coming in with the petrol supply to my engine, cold starting is made very easy, inasmuch that the engine turns over very readily on the starter and lubrication is more than adequate, due to the bonded oil film, in the first few minutes of cold running. Therefore when I start the engine I use the choke for the first few firing strokes only and then release it. R.p.m. are then rapidly brought up to 2,000 with the engine “off load” for a couple of minutes. The car can then be driven away. Of course I realise that I am at an advantage here compared to other TR6 owners in that one can only do these things when there are “super lubricants” circulating within the engine. However TR6 owners should watch things in this respect when their cars are serviced.
Up till now, no attempt has been made to put this two-stroke oil on the motor car market as an upper cylinder lubricant. Of course motorists by writing to Messrs. Rupert Ledger can purchase this oil. However it is now obvious that in this oil lie the beginnings of a solution to the fuel injection problem in Triumphs and other motor cars. My TR6 LPB 812K has been everything that “Pig-in-‘ell” was not and there have been other benefits besides, lower oil consumption, lower petrol consumption and of course a beautiful smooth engine throughout the rev. range. All this, important in these days of impending energy and fuel crisis.
It would be useful to get your readers’ views as to whether they would like to be able to purchase this oil as an “upper cylinder” when they buy petrol. In my personal view the TR6 is an excellent car for reasons other than its acceleration and road-holding.
I, like many others, suffer from back trouble or lumbago. This car is one of the only cars that I can drive; this is due to a combination of three things—firstly the excellent seating, secondly the suspension and thirdly the smoothness of the fuel injection engine. It annoys me considerably to see in many instances other TR6s marred by these problems.
I find your remarks concerning the reduction of power output due to the change in camshaft design very interesting. If Triumphs wish to meet the emission regulations it would be far better to do it by re-designing the head so that the combustion chambers are hemispherical and to use “gas swirling techniques” to delay the rate of burning slightly. I believe that most of these techniques have been used in the Aircraft Industry in relation to the piston engine and I wouldn’t be surprised if most of the patents hadn’t lapsed by now.
To finish, I only use Michelin X tyres and when my TR6 was new, I had it “Zeibarted” and have in consequence suffered no rusting problems whatever. The additional £36 was well worth while.
Cobham, Surrey Michael S. Bingley, B.A., Ph.D.