Thin steering rack

All things oily!
jonjh1964
Posts: 64
Joined: Sat Feb 18, 2017 10:10 pm

Re: Thin steering rack

Post by jonjh1964 »

I managed to get out for half an hour yesterday and my initial impression is the quicker fat rack is a good improvement and seems much more suited to the car that the thin rack which, by comparison, feels more like a boat. With 155 tyres and a 14" steering wheel it was nice and light when low speed manoeuvring. My next upgrades are sorting the shock absorbers/springs and trying to get hold of a swiftune sump, and on a plus point I've already managed more miles so far this year than the whole of the last.
Morris
Posts: 109
Joined: Wed Aug 08, 2018 12:05 pm

Re: Thin steering rack

Post by Morris »

Seems like a worthwhile improvement. I might add that to the list post IVA along with an LSD.

My steering wheel is 12" though in the interests of more knee room, so I might struggle with low speed manoeuvring.

Anyone fitted power assisted steering...😀?
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Thin steering rack

Post by Westfield 129 »

My car came with a 13" steering wheel, and I have no problems with low speed steering effort, even with the fat rack and 185/70/13 tires.
I believe that I still have a LHD fat rack on the shelf, with the mounts, along with a bunch of other A series parts, including a couple of extra oil pans that are straight and ripe for modification.
There are pressed rocker arms, 3 really nice 1275 connecting rods... You know... stuff.
There is a sandwich plate for an oil cooler, two sets of wire wheel axles with good spline hubs, maybe other stuff. If there is something you are looking for, let me know, as I might already have it on the shelf.
Not selling the car, but rather making room by getting rid of all the A series stuff I am not ever going to use.
Of course, best if you are US based.
Morris
Posts: 109
Joined: Wed Aug 08, 2018 12:05 pm

Re: Thin steering rack

Post by Morris »

Tempting parts Jan but as you say not around the corner from the UK!

I'm pretty much sorted now as I'm 90% way through my build.

Cheers.

Morris.
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Thin steering rack

Post by jonclancy »

jonclancy wrote: ↑Tue May 21, 2019 6:02 am There is a set of Fat Rack mounts on The ‘Bay right now.

For those going FAT, don’t forget you need the early steering arms, too. Part numbers, IIRC, BTA 648 and BTA 649.

The ACA part numbers are for the thin rack, and have a different geometry if you are searching them out on eBay.

Some sellers mis-list, so check the part numbers carefully rather than take their word for it! ;)
I think I may be perpetuating a myth here. When Splat came over to use my press, we compared some early and late steering arms. It MAY BE that the difference between the two is the size of the conical hole in the end - the early arm having a larger hole for the rack rod end. If this is the case, all you will need is a fat rack, mounts and hybrid rod ends to do the conversion.

We will check and report back. Splat is in the middle of this process (as well as doing his engine).

I’ll need to pull my finger out and get my rack swapped. My MOT is long expired, and we are heading back to CLM this Summer! 8-)
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Thin steering rack

Post by jonclancy »

Hi All,

As mentioned earlier, there are different steering arms for the early (Morris Minor derived) and later (Triumph) racks.

I have always understood it that the arms are not interchangeable, and read somewhere that the geometry differed between them. IE different length - I don’t buy that! When Splat and I compared then, they looked the same. Actually, I think the length odf the drum-braked Frogeye steering arms was shorter by a bit, ATA 4130 and ATA 4131, but that doesn't concern us!

Time to put this to be for once and for all. Jan has mentioned in the past that the differences are in the rod end dimensions, and that a hybrid part may be available to allow the use of your later arms with an earlier rack. Let’s see what we can find out.

Early Rack Thick BTA1096 1967-1971

Chassis numbers G-AN4 to G-AN5-114642, H-AN9, H-AN10, A-AN10

Early Arms = BTA 648 and BTA 649.

Large Tapers 9/16” to 1/2”

Mounting holes 3/8”

Early rack tie rod thread = 5/8”(18) UNF x 1-13/16” (45mm) length

Rod End GSJ169

QUINTON HAZELL - Ref: QR290S?


Late Thin Rack - AHA9956 1972-1979

Chassis numbers G-AN5-114643 on, G-AN6

Late arms = AHA9957 and AHA9958

Large Tapers xxx” to xxx”

Mounting holes xxx”

late rack tie rod thread = 1/2” x 20 UNF

Rod End GSJ158

QUINTON HAZELL QR1572S

To be continued…
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