Thread: Collar for semi-floating axles

Originally Posted by chazza

An Archimedes screw, or reverse-helix, is actually a very good engineering solution for keeping oil in where it should be.

not to put too fine a point on it, the Archimedes screw is a solution to keep oil in the crankcase:

• except when going up very steep inclines when the oil level and flow overcomes the capabilities of the design and not only does the oil flow out it flows onto the the clutch housing where it can be thrown around to get into the pressure plate. (But that is O.K. too because if the crankcase oil doesn't get to the clutch plate, the gearbox oil will overcome the Archimedes screw on the primary pinion going down the steep decent to get deposited directly on the pressure plate.)
• except when wading through rivers when the design pumps water into the sump and gearbox.
• except when operating in dusty conditions, when the dust and oil gets mixed into a grinding paste. But that's O.K. because the grit will eventually be filtered out maybe by the bypass oil-filter system.

All at the same time when US manufacturers and almost everyone else were using oil seals.

Originally Posted by chazza

You forgot to mention that the designers realised the error of their ways, following customer comment, and replaced the screw with a seal, which whilst solving the ingress of water problem, created the problem of seals wearing out, which the brilliant reverse-helix had dispensed with.

Cheers Charlie

Yes the designers did realise the error of their ways and replaced it with a seal on the model 5 years later, after they had built about 100,000 units.

Who's 1948 had to have it's engine rebuilt after 12,000 miles because of the dust ingress in the region around Broken Hill where it was first sold?

As you very well know, Diana, the 1948 Landrover was a stopgap measure to keep the company alive in the face of sheet steel rationing. As such minimum changes were made to components and designs already being manufactured, including the reverse helix "seals". These were quite effective on road cars in the English climate, and either the cost or time of changing the design was not practical for this stopgap vehicle, but it was changed (along with a lot else) when it became clear that the design was more than a stopgap.

The sales figures for the early Landrovers clearly show that their engineering was not considered inferior by the contemporary buyers compared to their competitors. It was not until the Series 3 that Rover was able to meet demand for Landrovers.

There is no doubt that in hindsight the designs could have been improved, and even at the time there were many improvements that could have been made - and many of these were made, although the size of the company made major changes difficult, and the 'downfall' of the Landrover was the decision of the company (imposed by their new owners Leyland) to stick with the same basic design (really the one introduced with the 86/107) when the S3 was introduced rather than introducing the improved designs they already had with the RR.

John

John

I know what you are saying, however a lot of the arguments really don't stand up. Yes they knew of the problem about the Archimedes screw from as early as 1949 when they were having to replace engines under warranty and even wrote a Rover service bulletin about a rope seal fix during the 1595cc engine, however instead of fixing the problem for the 1997cc Siamese bore engine all they did was change the oil level and it was not till the 1997cc spread bore engine that they added a seal.

The primary pinion continued to leak oil on steep decents right through Series 2 until something like suffix G or H of series 2a.

The hub caps didn't get an "O" ring till late series 2a, and an "O" ring was never added to the drive flange/hub interface which would have solved most of the leakage under there. How often do you see a Nissan, Land Cruiser or Jeep of the same era as the series Land Rover with oil all over the wheel rim? Almost never.

No one will convince me that it's anything other than crappy British engineering compounded by bean counter accountants.

Diana

Diana,

I now understand your comment about the scroll type rear main seal.

What you have to consider is that they used an existing Rover engine and the designers probably never considered exactly how the product would be used. Remember that this was a diversification from their core business of making road going cars. Was the delay in rectifying the problem due to the cost of the change, the percentage of failures or just a 'head in the sand' attitude ?

You suggest 'bean counter accountants' are part of the problem. All companies have to return a profit so the 'bean counters' are an important part of a successful business.
Unfortunately the real problem is us, the people who purchase the cars. We want the lowest possible price so mass produced items such as cars are cost engineered. If you buy a new car today (wherever it's made) you will have some problems, especially if it is a newly released model. Most of these problems come about from cost saving to build the car down to the price the market will bear.

We should be thankful about the way Land Rovers were made. The Meccano type construction, interchangeability of parts between models and the fact that they chose aluminium for the panels. If it wasn't for these things then many, many more would have been scrapped over the years.

Back to the original discussion..... 'selective fit' was/is a way of reducing manufacturing costs not 'crappy engineering'.


Colin

IMHO You've all been re-educated by the propaganda.

Show me a German, US or Japanese car after 1948 that has a selective fit on something.

Originally Posted by Lotz-A-Landies

IMHO You've all been re-educated by the propaganda.

Show me a German, US or Japanese car after 1948 that has a selective fit on something.

Virtually all diesel fuel injection equipment (injectors/pumps) had key parts selective fit regardless of country of origin at least into the 1980s.

Citroen achieved a world first in the late sixties by producing height controllers for their cars which were made to the same precision of fit as fuel injection equipment, and did not need selective fit (these used selective fit prior to then). These controllers are a simple spool type hydraulic valve - but use no seals, and operate at 8,000psi; and don't leak.


John

The link below is for algorithms for 'selective fit', the paper was produced in 1997. Now I don't confess to fully understand it but wanted to use it to reinforce that selective fit is still a valid engineering assembly method.

The selection & matching of the components is probably now done using visual recognition software & robotics but it is still a way of getting close tolerances without excessive cost.

http://people.commerce.ubc.ca/facult...L12immd11a.pdf


Colin

O.K. I seem to get the consensus of opinion.

Back to the collars, OEM parts have been hardness tested, a variety of axles checked for size and Carl has now been quoted $44.00 each for the collars including tax. Production will occur on Friday and I have to let him know numbers by Thursday morning. I have my order and an order from Mark in Fairy Meadow which has made a batch possible.

Any others need to contact me or Carl Hendrickson in Thornleigh (02 9481 7363) to place their order.

Diana