Adoom

1 hour ago, Transom said:

Also don't you need at least 20mm clearance between sump and steering rack ? 

Thats the way I read it ?

Aye? Where you seeing that? As far as I know, the rack housing can be as close as you want as long as it can't touch/rub.

1 hour ago, cletus said:

Also if the steering arm is bolt on, you could potentially make a new arm once you figure out where it needs to go?

I could.

1 hour ago, cletus said:

The rules of thumb we use are

10mm max total for a newer car

20mm if its old

Or no worse than original. 

We haven't been given a definition of what is old vs new it's a bit open to interpretation 

 

Where the toe change occurs is just as important as how much there is. An early mustang or falcon has a lot of bumpsteer (usually over 20mm) but it occurs when the suspension is at near full droop so doesn't show up when you drive it

If you had 10mm toe change,  but that was all in, for example,  20mm either way from ride height then it would probably be noticeable when you drive it

 

Cheers. I'll have to read through the pdf a few more times to get my head around how my degrees relate to the mm measurements.

1 hour ago, Testament said:

here is your problem

50mm is a big change.

spacers at the rack ends will only help with making small adjustments and will rob peter to pay paul, i.e will help in one part of the suspension arc but make it worse in another. the key part is the inner pivot point being as close as practical to the pivot of the lower control arm, or really the centrepoint of the arc that the tie rod end mount on the hub travels.

you need to raise your rack up or lower your LCA mount to minimise the bump steer.

From factory the rack inner pivot is WAY above the LCA inner pivot. The tie rod end normally mounts on top of the steering arm.

With the lowered rack, the rack inner pivot is 10mm below the LCA inner pivot. I've mounted the rod end bearing(replacing the tie rod end) under the steering arm.

With the spacers I have now, the two outer pivots are also 10mm apart. 

I can raise the rack about 7mm before it hits the alloy sump. I'm fairly sure the oil pickup pipe is in the way of cutting the sump. I've got no room left to move the engine up/back.

The design of the front hub does not allow for the LCA outer pivot to be lowered. The balljoint taper fits directly into the hub casting.

You say "minimise the bump steer". How do I know when it is minimised enough?

2 minutes ago, Bling said:

What is the suspension setup? Is steering arm and hub one piece or can you space down steering arm with RCA?

Nah, it's a dick. All weird and british. The steering arm bolts to the back of the hub. Nothing like a toyota/etc. So it cannot be spaced down.

I did think about maybe using a strut/hub from a japanese car, but then I'll probably have camber issues because of the angle of the strut/spindle. And this has the rack in front of the cross member and most jap cars have it behind. Also everything on this is in inches.

2 minutes ago, Nominal said:

Can you measure what the change is on a stock car?

I suppose I should. But I'm lazy and I'd need to assemble all the suspension/steering/crossmember and fit it to the other(really rusty) shell I have.

11 minutes ago, Beaver said:

He's spaced down his front cross member so factory strut length probably become irrelevant....??

Not that either. Cross member is in the same place, but the rack is ~50mm lower than factory. So I've also had to lower the tie rod end the same amount, which in theory gets the bump steer back to normal.

5 minutes ago, Nominal said:

It was just that the LVVTA discussion was around toe change in mm, not so much in degrees

Works out to about 3.5mm assuming 24" overall wheel + tyre diameter for the 0.67 degree

or ~2.55 mm for the ride height change.

If this is just one side, then the amount would be double.

My imaginary wheel/tyre/distance between the pins is 470mm or 18.5".

18 minutes ago, Nominal said:

What's that in mm?

https://www.lvvta.org.nz/documents/infosheets/LVVTA_Info_04-2010_Bump-steer_Measurement_Background_Information.pdf

 

I'm confused by your question.

I've measured the up/down suspension travel in mm.

And the angle the wheel is toeing in/out in degrees. Which I calculated using the distance between the two pins and how much gap there is between one of the pins and the board bolted to the wheel hub. (as the wheel turns/steers one of the pins lifts up). mm by themselves are a bit meaningless if you don't know the distance from the wheel center the measurements are taken from. eg: The largest meausrement I got was 5.5mm, but if I measured further away, I'd have a bigger number for the same wheel angle.

I had read that pdf you linked. I can't use the method they describe because I've only got suspension(and modified steering) on one side of the car. 

27 minutes ago, Bling said:

My brain melted trying to comprehend that lot...

In theory, if you can keep the strut distance the same as factory, or close to it, there shouldn't be much change from factory in bump steer, correct?

So for example, a shorter strut installed, with RCA spacers attached to bottom should keep the strut length not too different. It's all about keeping the steering arm connection close to stock distance from top hat position. Yeah / nah?

Nah aye. I've lowered the steering rack, because there is an engine in the way, now I'm trying to fix the bump steer that has caused. I'm not talking about bump steer from lowering the car "too much".

So what's "acceptable" bump steer?

I made a contraption to measure it.

Ignore the g-clamp, the bolt is too short.

Over 100mm of travel, full droop to full compression, I'm getting 0.67 degrees of toe change. As the suspension is raised, it toes out. 

If I run the ride height I'm thinking of running, the travel will be reduced to ~60mm and the toe change would be about 0.45 degrees.

Yay, the wheel still fits with the rod end/tie rod flipped upside down and that huge bolt head there. There is even a bunch of space left if it needs to be spaced further down to adjust the bump steer. 

So I've lowered the rack in the Triumph to clear the bottom of the engine. To sort out the bump steer this will inevitably cause, I also need to lower the tie rod end. Normally, the tie rod end mounts on the top of the steering arm. I've drilled out the tapered hole to take a 5/8th" bolt so I can use spacers to get it to the right height. 

Everything is just mocked up with clamps and spacers while I work out where it needs to be. I just had these rod ends lying around and will probably be using different ones, but they will be the same bore/thread size.

This is where stuff would be if it had the factory tie rod ends on it. As you can see the tie rod and or rod end are too long. The rod end is 5/8" unf and the tie rod is 1/2" unf. The thread on the tie rod cannot be extended as the diameter reduces after the thread.

My initial idea is to shorten both where I have the red lines. And use a threaded joining thing, in blue, to join them. I think I would have the rod end always threaded all the way in, with thread lock maybe and do the adjusting at the tie rod end like a 'normal' car.

Does this look okay? Is there a better way to do it?

20 minutes ago, datlow said:

speaking of metal in bodys, my boy just got his taken out in august, the screws were far longer than i had envisaged 

asked the surgeon why they take the plate and screws out etc, he just said its better etc (no real firm reason)

 

wifes been crook on and off this year with whack blood samples

been to a few specialists, latest one reckons because she still has metal in her back (scoliosis rods) its not uncommon for the body to react to the metal after about 15yrs, theyve been in 20!

I've still got a rod in my leg. Doc told me that if there is high probability I would break the same leg again, it would be removed, otherwise they leave it in. Reasoning was that if the rod bends at the break, it makes it rather hard to get out.

So there was a skyline at pickapart and I thought I would have a go at trying to remove the rear subframe studs.

I had a chisel with me to open up the top of the chassis rail so they could be driven out. Because apparently they are pressed in.

I hammered, with the mallet, on that first stud for ages and it didn't move,  so either it's REALLY fucking tight or the big washer that's welded in is not a washer and it's part of the stud.

But I think it's just really fucking tight, I was starting to deform the stud, so if I ever did get it out, it would have been unusable.

Needs angle grinder....

Is anyone wrecking a RWD early 90's nissan and can cut the studs out for me?

20 minutes ago, Transom said:

Grease or bread is a bit less messy 

I've heard soggy wet newspaper is also another less messy method.

Dude, you have SO MUCH room compared to my Triumph engine bay! I've got about a 40mm square space on the cross member between the block and the steering universal to 'grow' a mount out of.

On 14/09/2018 at 18:52, XSDUP said:

Mainline 59 at work. NZ new.

And I finally realise you are Kev.

Watch out. I've noticed that fisholene like some rubber. Makes it all soft and sticky then go hard as. It turned the rear sliding windows in my mini estate into not-sliding windows.

So I've notched the crossmember so it fits under the sump. Then tacked a bit of box section in line with the steering rack mounts so I have a reference. Then I cut the rack mounts off.

This is me trying to mock the rack up in the right place.

19 hours ago, Testament said:

I've got some spreadsheets that can grind about as much as a 9" if you need man

I supposed if you had 'gridlines' turned on it should work.

30 minutes ago, nzed said:

file the bump off?

That's the plan, but I'm at work and I don't think the files on my computer are sufficiently abrasive.

@flyingbrick

I lined them up best as I could to take the photo. There is a bit of a bump on the back edge where the cut starts/stops and some slag on the back of the cut that is making it harder to line the teeth up properly. 

Just a tip, what I do when I find a setting that works well on a particular thickness of metal, I write it on the side of the welder with a vivid. So I have a cheat sheet.

Crikey, that's pretty slack of them.

21 hours ago, flyingbrick said:

Theres still time adoom. I have asked for clarification that they can get the detail as nice as desired.

I'll wait and see then.

56 minutes ago, NickJ said:

How long is the toothed section? that will give a good idea as to edm cost

there's an engineering drawing on the first post..... but the whole thing is 70mm long. off the top of my head I would say if you followed the serrations, it would be twice that length.

2 minutes ago, flyingbrick said:

I thought I replied to this.. hmmn.

You are correct about costs Adoom. That is trade price too  . No stress if you do or don't get them cut - It was just a fun exercise. 

I am keen to see it priced up as a one piece EDM wire cut item- sounds like a very slow and expensive process but who knows, we may be surprised!

 

 

 

I'll send you a pm.