That’s better!
Nigel’s GT6 gets some front suspension attention
The GT6’S front suspension has needed a bit of attention for a while. The ageing dampers were harsh and the camber of the front wheels looked ever so slightly different. Inspired by Ed Hughes’ excellent technical feature on suspension and steering geometry in a recent issue of PC, and spurred on by fitting new Gaz dampers at the back a couple of months ago, I decided to tackle the front end. With the car’s suspension settled on the flat concrete surface of the garage floor I started by measuring the camber of each front wheel. I’ve got a digital angle finder and decided to use this rather than Ed’s plumbline method. The angle finder was too short to bridge the wheel rim, so I cut a block of wood just long enough to span the rims without touching the tyres. Holding this and the angle finder against each wheel rim gave me camber readings of -0.2o on the left and +0.1o on the right. Not a huge difference but the measurements were repeatable. There was also a difference in the number of camber adjustment shims each side, between the lower wishbone fulcrum brackets and the chassis. With four shims on the right wishbone and only three on the left, all the evidence was pointing the same way: try adding a shim or two on the left to match the right-side camber.
I slackened off the nuts securing the left wishbone brackets to the chassis and inserted one more shim behind each bracket. With new Nyloc nuts on the bracket bolts, they were tightened and torqued. Dialling in exactly the right amount of camber is usually a process of trial and error but, meanwhile, I moved on to other jobs on the front suspension.
Adjustable platforms
As the car was up on stands, it was the right moment for a couple of upgrades. I stripped out the old tired coilover shock absorber units, which seemed to be leaking slightly. The bottom eye bushes had also deformed to an undesirable oval shape. The TR6 has run on Gaz adjustable dampers for years and I’ve always been very happy with them, so my choice for the GT6 was obvious. The Triumph Sports Six Club shop came up trumps, supplying a pair of shiny new Gaz units with adjustable spring platforms.
After smearing the spring platform threads with copper grease, my old spring compressor made short work of transferring the road springs over to the new dampers.
I finished off the GT6 with another little upgrade. Some years ago, Alasdair Southall at Classic Driving Development produced a replacement anti-roll bar drop link for Triumph TRS and Stags, using long-lasting ball joints instead of the old rubber bushes that fail with monotonous regularity. I got a set for my TR6 on the basis that they should be ‘fit and forget’. Alasdair now supplies a version for the Herald-derived Triumphs, so I was keen to try them.
Ride height and camber
The new ball-jointed ARB links fitted easily, though clearance is quite tight between the upper ball joints and the shock absorber spring platforms. I went for a short test drive to settle the suspension before returning to park on a flat section of driveway for a measurement session.
I reckoned the first step should be to get the ride height set, and it was likely the extra wishbone shims could change wheel alignment. After a couple of adjustments to the Gaz spring platforms followed by test drives, I had set an acceptable ride height, using the wheelarch lips as datum points. Out came the digital angle finder and wood block to check camber again. This time both front wheels measured at zero camber angle, within 0.1o – a great result.
The final check was wheel alignment, to ensure that the toe-in was correct after camber adjustment. Using my recently-aquired Trackace tracking gauge, I found the GT6 did indeed have too much toe-in and I was soon able to bring the steering back into specification by judicious adjustment of the track rods. I’ll explain the full process in a future issue.
Out for a final test drive and I was absolutely delighted with the results. The front suspension feels a bit more compliant than before, giving a good ride combined with pin-sharp steering. The adjustments were quite involved, but well worthwhile. It’s good to know the GT6 suspension is now spot on, front and back.