quick steering rack options ?

[Not_Anumber]

Has anyone here had experience of a 'quick' rack or of changing the gearing in an existing steering rack ?

Mine being a standard RB rack has 3.5 turns lock to lock. Id like to swap that to 2.5 turns. Though some CB cars had a 2.5 turn rack these also had a shorter pinion shaft so they arent a straight swap.

There must be a way of doing this without having to extend the pinion shaft.

[MGB281]

The simplest way to fit a CB steering rack to a RB car is to extend the pinion shaft. The reason is two fold, firstly you will need a UJ near the steering rack to get the correct alignment. The alignment can also be done by cutting and re welding the steering rack mounts but that still leaves you with the pinion shaft being too short. I bought a DD UJ from Car Builder Solutions and got a local machine shop machine the shaft, a simple job with a milling machine. My solution with the EPAS was a little different to yours so I don’t know how much you need to extend by. I think the DD UJ will extend the shaft by about 20mm, Land Rovers used a splinter 48spline UJ and the two together might be enough. I also have (if I can find it) a pinion shaft that would be more than long enough with the extra UJ.

[Not_Anumber]

Thats a good idea. Because i was matching the longer pinion shaft on an RB rack, hence different UJ position mine currently has the eyeball bearing on the passenger compartment side of the bulkhead rather than on the engine side.
I think if I replace the RB rack with a CB one with its typically shorter pinion shaft I should be able to keep the new bearing where its currently mounted and just replace my short intermediate shaft with a longer version to meet the new lower positionnof the UJ.
In your view would that work ok or must I also move the position of the eyeball bearing to the engine bay side ?

[MGB281]

Chris, here is something else that you might ponder;
Has anybody here ever tried fitting an early pinion to the late MGB rack?

Strangely enough it is a serious question. Both have the same tooth count on the pinion, both use the same helix angle so the difference in the turns lock-to lock has to come from the depth of engagement and the number of teeth in the rack. Having more teeth would mean less depth of engagement one would expect so the consequences of fitting the early pinion to the late rack might be acceptable, given that the depth of engagement has some adjustability.

But has anybody ever tried it?
I am not quite sure if you idea will work, probably because I am not sure if you were just lengthening the CB pinion shaft or were adding a UJ. If the former then I don’t think it will work simply due to needing the alignment angles to be precise OTOH with a UJ you are free of those constraints. I will post photos later today if I get the pinion shaft installed later today.

[MGB281]

Here is what I have done, due to wanting a photo nothing is fixed properly but this gives you any idea. For those who are not aware the bulkhead modifications are for a Jaguar V6 engine and RX8 gearbox. The silver "stuff" is an aluminium faced fibreglass mat to reflect heat away grom the bulkhead. I used DD bar only because I used DD UJ's at each end. I have no idea why the photo rotated between "my photos" and here

[Not_Anumber]

That looks very tidy. For context is it showing a shortened pinion shaft with the UJ moved closer to the rack Philip ?

In a perfect world Id be able to simply change steering ratio by finding a CB rack (with its sharp 2.5 turn ratio) but with a longer RB style pinion shaft. This would be ideal for me as it's UJ would then be in the standard RB position (right inside the 'pocket' on the bulkhead). Hence I could just buy such a rack without any need to change what ive already done.

The manufacturer's rationale for softening the ratio to 3.5 turns for RB cars was to reduce driver effort at parking speeds, coincided with a reduction in the size of the steering wheel. Thats not an issue when an EPAS column is providing the turning effort so a return to a CB style 2.5 turn ratio would make sense.

Though there are references around to RB quick racks that have the same sharp 2.5 turn ratio of the CB cars, no one seems to sell them.
Optional RB racks with 2.5 turn ratios appear to have been available back in the day for those wanting a more engaging drive from their RB cars. Id also read that some recently remanufactured RB racks were being produced with 2.5 turn ratios off the peg. However so far this looks to be an urban myth as no sellers Ive spoken to have heard of them.

[MGB281]

Yes it is a shortened pinion shaft with a UJ close to the rack, the pinion shaft goes through the bulkhead where the slightly modified (different lower UJ) telescoping EPAS shaft fits on it. I have retained a full length collapsible column. You can always cut and extend the pinion shaft, the simplest way is to use a 3/4" bore thick walled tube that is both pinned and welded to get the correct length.

[Not_Anumber]

Thats what ive worked to avoid doing so far. I had setup the new bearing and intermediate shaft to meet up to a standard RB rack without having to modify the pinion shaft. The rationale being that if the rack were to develop a fault in the future it can be replaced with any standard rack .

As I cant find a source for the RB quick rack I wanted then I'll live with the existing RB rack with it's slightly ponderous 3.5 turns. The upgrade path will be to buy and fit a standard unmodified CB rack and then fabricate a longer intermediate shaft to join to it