MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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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

authors avatar
steering vibration isolator
Posted by: 302GT
Date: May 25, 2009 01:41PM

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.
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Moderator
Curtis Jacobson
Portland Oregon
(4576 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: steering vibration isolator
Posted by: Moderator
Date: May 25, 2009 02:40PM

Nifty!


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1165 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: steering vibration isolator
Posted by: ex-tyke
Date: May 25, 2009 11:29PM

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

authors avatar
Re: steering vibration isolator
Posted by: 302GT
Date: May 26, 2009 06:59PM

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.


MGBV8
Carl Floyd
Kingsport, TN
(4511 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: steering vibration isolator
Posted by: MGBV8
Date: May 26, 2009 10:07PM

Maybe it will dampen bumpsteer, too. ;)


302GT
Larry Shimp

(240 posts)

Registered:
11/17/2007 01:13PM

Main British Car:
1968 MGB GT Ford 302 crate engine

authors avatar
Re: steering vibration isolator
Posted by: 302GT
Date: May 27, 2009 06:27AM

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.


MGBV8
Carl Floyd
Kingsport, TN
(4511 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: steering vibration isolator
Posted by: MGBV8
Date: May 27, 2009 06:01PM

I was kidding. :)



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

authors avatar
Re: steering vibration isolator
Posted by: cgill
Date: April 19, 2013 11:39AM

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. :(


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