| Author | Message | ||
     John Dare Unregistered guest Posted From: 144.138.194.8 |
I am considering the fitment of grease nipples to various points on my "R" type Bentley, being points presently serviced (?) by the "Bijur" system. I would invite some GENTLE input on this question with carefully considered "pros" and "cons", being mindful of an article on this very question which I recall being published in the respected journal of the RROC (USA) "The Flying Lady". NO, I am not aware of any "problem" with my "Bijur" system and YES I do know "how" it works and in regard to originality (in terms of appearance) I would propose retention of the existing system i.e resevoir/lines/connections etc. I simply invite some reasoned input on the merits (or otherwise) of this intended modification. Please dont anyone scream at me. I am only asking a question. | ||
| Bill Coburn Grand Master Username: bill_coburn Post Number: 116 Registered: 4-2003 |
Relax John. This absolutely stupid system works very well when it works well (I come from a long line of Irish!). But when it doesn't it is a disaster. Mind you grease nipples are not the answer to the perfectly lubricated chassis either! But to rely on capillary attraction to feed the hideously expensive top bearing on the king pins on these cars is optimism at its best. When I had my Dawn 500 years ago I used to about once a fortnight pump the sytem until my leg ached having spread newspaper all over the floor.. I then moved the car back and looked for the mess. The lower outer wishbones and the centre relay levers seemed to positively haemorrhage but the rest was always a bit sus! From time to time I enquired about fitting grease nipples and was counselled by those who knew that this was highly inadvisable since the bearings were not designed for grease!!! I now believe that this was pure bovine detritus in its purest form. The next series (Cloud) initially went Bijur and then progressively changed to nipples but did not alter any of the basic fittings! I also realise that the previous series used different bearings in the suspension. All that having been said, I would put up with the mess on the floor and pump like a demented owner keeping an eye on what drips out where. If you have a large garage jack take the weight of the car off of the suspension and have a pump. This way the car stays original, your friends will remember you long after your departure when they regard the stains in their porte-cochere and you can bore the unwitting to stupifaction should they ask you how the chassis is lubricated. By the way should you have a manual 'R' type be aware that the system squirts oil on the clutch release mechanism. The adjacent clutch does not like being oiled. My solution was to put a restrictor in that line! | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 133 Registered: 4-2003 |
Bill is quite correct: when the Bijur works really properly it beats grease nipples, but in balance slightly inferior lubrication with grease may be a safer compromise than having little oil or none at all in the front suspension. Better still would be to pump oil into the suspension I guess. The problem area for grease is the king pin. The king pin support casting is hollow, like a small reservoir of maybe 80 ml. When the oil rises enough to reach the correct height it overflows through a small hole into the king pin bearings to lubricate them. Grease may have trouble clearing this tortuous route, so maybe 90 grade gear oil would be a compromise ?? Getting a Bijur sytem correctly restricted at each point takes a long time: it took trial and error for 5 years on mine as every change affects every other point too. When finally correct (I have a drawer full of restrictors and filters), each point should be equally wet after three pumps. Only then can you avoid puddles of oil on the floor through overuse to reach those faraway points. I can always tell when my friend has parked his Silver Dawn in the visitors spot... It's a party trick alright, along with the brakes. At the Canberra motor registry annual test (before they abolished it) I was often failed for having leaky rear brake hydraulics and inoperative front brakes. They thought I was just being too smart when I pointed out that there are no rear brake hydraulics as they are mechanical, and that the oiliness was from the Bijur and that the front brakes only work with the rear wheels moving. Hohum. | ||
| Bill Vatter Unregistered guest Posted From: 68.215.205.230 |
Grease vs grease? John, before you decide to switch to grease, It would be good for you to understand exactly what that grease really is. Most grease is a mixture of oil and a binder, usually soap. The binder is selected for certain properties, heaviness, melting point etc. If the grease is left in place for a long time the oil leaches out leaving a gooey mass that will plug things up. Surely you have seen old "hardened grease" that was just that, hard chunks of goo left behind when the oil went away. I do not think grease would work well in a pre-cloud car because there are some very narrow passages the oil goes through, which I think would tend to get plugged up with regular grease. I have not taken a Cloud 1 suspension apart, nor am I certain which parts have grease and which have oil. I do know, however, that on all of the Cloud 1 cars there were at least some points that were oiled, with later cars having fewer oil points than the early cars. Cloud 2 cars have redesigned suspension parts, specifically intended to use grease, and there is no Bijur system on a Cloud 2. There are also no very small passages in the Cloud 2 suspension parts that could get plugged with grease. I believe that RR changed the components to take grease, contrary to what Bill C claims. Remember, regular grease is a mixture of a liquid and a solid. It does not seem right to me to put solid in where liquid was intended. Now there is one grease that is not a mixture. That is petrolium jelly. That stuff, aka Vaseline, is really just very thick oil. Vaseline is very useful in holding needles in position during assembly, and it is safe because it has no solid component to cause plugging. After assembly when the oil arrives, the Vaseline totally dissolves in the oil leaving no residue. Regular grease is not so kind; it will not completely dissolve in the oil. My opinion, the heavier the oil in the Bijur, the better, because it will stick in the bearings and bushings longer. I use a generic STP like substance. The one I use is from Wallmart, "Supertech Engine Treatment" @ 78c US per pint. It is super-thick oil, the same stuff as STP Engine Treatment at about 1/4 the price. With that super-thick oil in the bijur, it takes a very long time, minutes, for the pedal to come up. I pump the pedal 3 or 4 times at least once per driving day, and on trips, every 100 miles. I believe the oil is getting everywhere. I took the top covers off my king pins to see what was inside. The upper king pin bearing is the most critical, hard to oil point in the system. I found my upper kingpin bearings are getting oiled very well. | ||
| Jim Bettison Unregistered guest Posted From: 203.20.76.8 |
I agree with Bill Vatter in his comments about the disadvantages of grease in the Bijur system. I do have (but can't find) a commentary on the uses (and misuses) of Bijur. One recommendation made in it, and that I'm following, is to use a heavy straight mineral oil, SAE90 or heavier if you can find it, in the system. This accords with Bill's practice of using an STP product, but the SAE90 may be easier to find in a shop. Don't use a high pressure oil (like Hypoy) as the additives will almost introduce problems as they decay - particularly if sulphur compounds are used - and leave some nasties. We, as car owners, tend to concentrate (with good reason!) on the front suspension lubrication. If, like me, you have a MkVI or one of that family, check to see that oil is reaching the centre of the rear springs. Often forgotten, but a good indicator of the system's health. | ||
| Bill Coburn Grand Master Username: bill_coburn Post Number: 117 Registered: 4-2003 |
As far as I know we in the antipodes have been using 90 viscosity oil in the one shot system since about 1950. The engine oil originally recommended runs out of the system quicker that than a pokie player's cash! Interesting of Jim to site the centre of those marvelous springs; if you trace the path the oil has to traverse it rivals Frodo's travails in finding the cauldrons of Mordor! But we hope, speculate and long for the telltale slick! | ||
| Laurie Fox Unregistered guest Posted From: 195.93.33.11 |
I changed the front suspension of my MK VI B420EY to grease some time ago with beneficial results. Details are on the Bentley Drivers Club website, Technical Forum, Mk VI Grease for front suspension. |
