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© 2012 Stewy Bryant lockpic

Lock Hunting – Part 1

Last year I was playing with some lock setups for my front end, this was written over a year ago whilst I was dealing with a new knuckle setup, this gives a bit of insight into the issues I was facing, and how I came to the conclusion to do certain things on my new setup.

The initial custom LCA design consisted of standard R32 arms, cut off just after the bush housing on the inner side, then aluminium blocks wedged inside the LCA’s, drilled out at the end and tapped with a thread to suit a generic rose joint end. Then drilled through the sides of the LCA’s, into the aluminium blocks, which allow bolts to be used to secure the block in. The rose joint then winds into the end of the block, and using some machined spacers to suit the R32 cross member, it joins the arm to the cross member and eliminates the play of the standard rubber bush, as well as lengthening the arm roughly 40mm, while allowing around 15mm of adjustment each side.

lca

The initial design used a universal roll centre adjuster from CAZMAN industries that hadn’t been used in an R32 before, but after testing it, it ended up fouling as there simply wasn’t enough angle at the ball joint and it ended up either binding up or fouling on the disk depending on how many spacers were used. Since I only had a few hours to load the car up, I ditched the design, and went back to standard R33 LCA’s. Unfortunately I had already drilled out the uprights to suit the 19mm RCA thread, and standard thread was around 17mm with a taper.

With the only other uprights I had around being ones with unmodified knuckles, some seriously brainstorming followed and I remembered that rear alloy GTR uprights use little steel cone’s on their ball joints that disperse the load over a larger area to prevent failing with the softer metal. Since the front and rear LCA ball joints are the same size/taper, I came up with the solution to get one of the cones, and to machine the OD down to 19mm, to fit inside the drilled out hole in the upright, restoring the hole back to a the 17mm with a taper. It worked, and to this day it is still kicking around in some knuckles used in a missile R32 I had in Japan.

But after the new knuckle design was on the way, I decided to pull them back out, grind off the lock stops, ditch the RCA’s, put standard ball joints in, and finally run them. A day after finishing them, the car was aligned, and came back with roughly -5 camber each side, a perfect result.

To go with the new knuckles and longer LCA’s, longer rack ends were needed, as always I needed a budget solution, thanks to CAZMAN I had a DMax rack spacer which increases both rack travel roughly 15mm as well as increasing 20mm static length on the outside of the rack. I also ran a 5mm rack end spacer on the other side which gives you 5mm more travel.

I also sourced an S14/R33 rack end to go with an R32 rack end on the other side, the S14/R33 rack is 10mm longer. On top of this I was still short of length, leaving me with a tonne of toe out, so I borrowed an idea from the last time I installed knuckles, and I cut up some old worn tie rod ends, and I used the 45mm of usable thread they have in them with a 50mm long high tensile bolt loctited in, to create a spacer on the end of the tie rod end.





The initial placement of all these parts, left me with a completely off centre rack, but running out of time, we took the car to Adelaide Tyrepower for its alignment. We got the wheels straight, but the lock was hugely different each side, at this point the car wasn’t worth drifting. We ended up aligning it with about 5mm toe out each side, and around +8 degrees caster.

When I got home, the car went straight onto the hoist; the alignment was saved via a long straight pole pressed against the wheel, and measurements taken at the body. Then began the work of shuffling around components to even the lengths out, while centring the rack as much as possible. The final combination included:

Passenger Side:
45mm tie rod end spacer
R32 (10mm shorter) rack end
5mm slip on rack end spacer

Drivers Side:
35mm Dmax Rack Spacer (15mm internal length, 20mm external)
S14/R33 (10mm longer) rack end

After realigning the car, it came time to testing the lock, a quick pull of the wheel each way showed that the lock was pretty much dead even. The car was ready for drifting the next night. First impressions on the ground, the knuckles didn’t have enough steering ratio, the steering wheel was moving way too much for how much steering angle I was getting, 2ndly the Ackerman was worrying, there was just too much.

First impression on the track, The biggest issue was bind, there was plenty of it, at one stage it even sent me into a bundle of tyres when I couldn’t get it off bind in time. I believe this is mostly attributed to the knuckle design being vulnerable to bind, rather than the rack end/tie rod end setup.

The 2nd main issue was the tyres scrubbing on the chassis rails, I was only running roughly a +10 offset hoping the longer LCA’s would keep the big 235/45 R17 tyres off the rails, but unfortunately with the amount of Ackerman, it meant the car needed huge angle on the leading wheel, to make up for the tiny angle the trailing wheel was putting out. So even though to look at the car, it looked like it had huge lock, the angle on the wheels wasn’t reflected in the angle of the car. But since to get even a bit of car angle meant a huge amount of angle from the leading wheel, it was hitting on the inner rails before the car even got that much angle. Since bind is directly related to the amount of wheel angle on the leading wheel, this Ackerman issue multiplied the bind issue as well.
r32 skyline drift

To fix the chassis rail issue, between the 2nd and 3rd session I fitted 33mm worth of spacers to the front each side. This put my tyres right outside my guard, without any time to do anything about it, I went out, subsequently chewing the guards, and my front tyres.
r32 skyline drift

A few weeks later at Winton, steering untouched. You can see the extend of the angle achievable, unfortunately although you can’t see it clearly in the video, the wheel shaking and bind is incredible and nothing I’ve ever felt, making it extremely hard to come off full lock.

r32 missile drift

Next step the knuckles come off and are redesigned, also after chewing through my 235/45 Sumitomo’s, some 215/45 replacements will be going on to give more clearance.

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