As I have predicted, the subject is gaining momentum!
May I pass my personal opinion. The “eccentric” silent blocs (bushes)
With all respects what the late Morris has passed to us Augusta boys by publishing the Augusta Newsletter and collecting valuable information for us to use, there was one little thing Morris and I agreed that we don’t agree: the eccentric bushes in the Augusta steering. I do agree that there are other applications which are using eccentric bushes as Morris has stated.
Now, why would Lancia go to the expense and install adjustable eccentric bolts in the steering when the toe-in could be adjusted by eccentric bushes? And how would that be done during assembly of the car in the factory? As experience shows, the range of adjustment by the standard bolts is enough in most of all track rod lengths.
If a eccentric bushes are found on a car, they are very old and the car has been standing a long time in a position causing permanent load on the bushes, thereby getting deformed (plastic flow).
Another point that might rise an eye brow or two: to clamp or not to clamp the silent blocs.
I think the bolt in question is not designed the inner bush of the silent bloc to be clamped to the track rod. The surface area is just to small. If clamping would be needed, there would be a serrated bush like the silent bloc at the front of the rear springs. The nut is very light, the few treads can be stripped easily. I don’t think the rubber in the silent bloc is soft enough to allow a turning of 60° + as it does at the drop arm at full lock. Therefore, I believe that the bolt should be tightened just snug to allow the inner bush of the silent bloc turning around the eccentric bolt. There is only little movement while driving, even on a curved road, there is almost no wear.
There is an argument that the twisting of the rubber would aid the self-centering effect of the steering. It might help, but I think the self-centering is done by the built-in castor.
On my car, in the last 60 years, I have changed many silent blocs but there are still the original bolts present. Every couple of years, I remove them and put a light coat of grease to the bolt and bush. For about 2 years or about 6’000 miles I use PU silent blocs which Peter Renou has given me to test. No problem.
I look forward to the comments.
Regards
Karl
I think we will have to agree to disagree too , a couple of major points that are being over looked , no one seems to be able to get the correct toe on their vehicles with concentric bushes and a standard track rod , yet my car has had the correct track for 16 years with eccentric bushes and standard track rod no issues .
you still require the eccentric pins to fine adjust the vehicles track , it would be crazy to try and adjust the toe accurately by rotation of the eccentric bush on its own .
Did Lancia send every Augusta out of the factory with the wrong length trackrod?
Why wouldn't Lancia fit eccentric bushes? many other manufacturers do , i cannot answer why they fit them , like i have said previously i cannot answer why they are used in the steering on truck trailers .........but they are.
rubber doesn't move uniformly when taking a "set" like you describe , it will bulge rather like a tyre does when it goes flat and generally the center metal sleeve becomes detached from the rubber , yes i have seen silent blocks do this so we can agree on that , However , the block that i've posted a picture of ,the rubber is clearly flat and uniform , nothing has shifted or taken a set .
Its a real shame as around 10 years ago we bought some parts from the late Norman Stewarts estate , included 1 brand new eccentric bush which i'm damned if i can find !
