302GT Larry Shimp (240 posts) Registered: 11/17/2007 01:13PM Main British Car: 1968 MGB GT Ford 302 crate engine |
steering vibration isolator
I replaced the firewall universal joint in the steering shaft with a Borgeson combination universal joint and vibration isolator. Borgeson makes up the end fittings to almost any custom configuration. A 3/4 inch, 36 spline configuration is standard, but the MGB has a 3/4 inch, 48 spline shaft. I ordered the 48 spline fitting for the universal joint end and a 3/4 inch "double D" configuration for the shaft end (a stainless steel version was in stock!). To fit it, I had to take out the pinion shaft, shorten it by 1 and 1/4 inch, weld some metal to it because the diameter was slightly under 3/4 inch, then take it to a machine shop to be turned down to 3/4 inch and to have flats milled on either side of the shaft. The isolator works very well in reducing road shocks transmitted through the steering wheel, which becomes more of a problem as wider tires are fitted.
I do not know how nuch shorter a chrome bumper pinion shaft is than a rubber bumper shaft, but if it is about 1 1/4 inches shorter, it should be possible to use a chrome bumber steering rack with a rubber bumper crossmember without modification by ordering a universal joint/isolator with 3/4 by 48 splines in each end. |
ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: steering vibration isolator
I've often wondered about this very subject but by using an isolated column coupler as was designed into the mid sixties Sting Rays.....as seen here.
[cgi.ebay.com] Maybe I'll put it on the list of things to do next Winter...... EDIT: Looks like Borgeson also makes the ragjoint coupler identified above. [ww2.borgeson.com] Edited 1 time(s). Last edit at 05/26/2009 12:07PM by ex-tyke. |
302GT Larry Shimp (240 posts) Registered: 11/17/2007 01:13PM Main British Car: 1968 MGB GT Ford 302 crate engine |
Re: steering vibration isolator
The classic rag joint is much larger in diameter and so it would be hard to find a place to fit it. Also, Borgeson recommends that the isolator be installed as far up the shaft as possible which is very easy with the U-joint combination. Of course, I wonder if the rag joint style provides even better isolation.
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302GT Larry Shimp (240 posts) Registered: 11/17/2007 01:13PM Main British Car: 1968 MGB GT Ford 302 crate engine |
Re: steering vibration isolator
Bump steer is a change of steering geometry upon suspension deflection and generally makes itself evident as wandering. It is most obvious at large suspenson deflections such as going over road dips at high speed. The vibration isolator has no effect on this.
On the other hand, hitting sharp bumps ofter causes the steering wheel to move sharply as the impact of the bump tries to turn the road wheel to one side. This actually is not bump steer, even though it fits the name better. The vibration isolator will not prevent this movement, but it will soften the shock, and it can prevent some of the smaller movements. Overall, the isolator gives a more stable feel to the steering and the car in general. Some cars did have small shock absorbers fitted to the steering tie rod (non rack and pinion systems) that actually dampened steering movements. However, power steering generally reduces the need. But there are exceptions. Mid 70's Mercedes, with power steering, for example, had factory dampers. Also, I brelieve these dampers are still available as aftermarket items for old Jeeps and trucks used in serious off-road driving. |
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cgill Chris Gill Salmon Arm, British Columbia (129 posts) Registered: 08/13/2009 12:06AM Main British Car: 1979 MGB roadster Buick 300 stroker with EFI |
Re: steering vibration isolator
Raising this thread from the dead!
For those of you who are interested, the Borgenson part number is 034937. It's a 3/4DDx3/4 48 vibration dampener. Now if anyone would like to buy a brand new 3/4DDx1 48 vibration dampener let me know! Yes, I ordered the wrong part and they won't let me return it. :( |