Lower Control Arms: the Length Database

[jwebb2876]

GJ-GN LCA's are the same measurements as the earlier ones except they're 340mm long
Anyone know if GJ balljoints will bolt to an MX62 LCA?

[old_school_jap1]

Pretty much all (including mx62) the toyota lcas mentioned in this thread utilise a press in balljoint.

[jwebb2876]

Oh, ok
I got told they were a bolt on jobbie

[oldeskewltoy]

question?????


the length differences seem to be all between the pivot, and the sway bar end link mounting point, am I correct in this assumption???

Going on that... each change also changes the sway bar link(and castor rod) inclination does it not? This can cause bind and excess wear???

Why all this is important to me... I'm building an AE71. The AE71 uses the same lower front cross member as the AE86, BUT the upper strut mounts are 12mm further apart(6mm per side). The AE86 uses vented rotors, the E7 uses solid rotors, and the flanges for mounting are NOT compatible, so AE86 strut tubes need to be used. Bolt in AE86 strut tubes and you automaticially have 6mm more positive camber then before. Looking at the above list, the XT130 lca is the one to use...... EXCEPT for my question above... the sway bar pins will not be positioned as designed, nor will the castor rods......... is this something to be concerned about???? How are the suspesnion dynamics changed because of these differences???


corollary: can the cast section of the strut tube, between the brake mounting flange, and the strut tube be safely bent to match the 6mm difference???

[RA40-Rossco]

i beleive most people would be re-drilling the arm, in my case i know i will be re-welding the arm, plating it and then re-drilling it as well as boxing in the under section

[ecko]

whats the reason you cant use the bolt in balljoint sigma arms?

[RA40-Rossco]

you can, i have them in mine, took ALOT of work to get them to fit tho, no press in's were available up here is why i went that way

[ecko]

some came with my car and they are already fitted to to PS arms, what else would need to be done?

[RA40-Rossco]

you need to do the usual, plate underneath the arm and re-drill the correct pickup points, you will also have drama's with the inner balljoint bolts fouling on the castor rod, i ground a flat on a set of cap screw bolts, and shaved 2mm off the edge of the castor rod to gain enough room to mount it, i also knocked the studs into the arm rather than leaving them in the castor rod to make them easier to do up - would have been imposable otherwise!

i also welded in a crush tube down the bush end

sorry, not my prettiest work






hope that helps

[oldeskewltoy]

[litldv8]

^^^^^ that is cool but watch out for the demons in australia (i see usa)
neil

[jondee86]

Gonna give this dead horse a kick in the balls and see if it coughs up anything useful

Reading this thread and several other similar threads on other sites, I am impressed by the general vagueness and dubious accuracy of the LCA measurements. And since I am currently looking to get that elusive extra 1 deg of negative camber by installing 10mm longer LCA's on my AE86, I thought... why not :-P

Here is a pic of the arms that I am planning to use. They are Toyota arms but I don't know what car they came from, only that they are supposed to be 10mm longer than a stock AE86 arm. Looking under the car I see why accurate measurements are so difficult to obtain. Short of digging one out of the car, it is near enough impossible to make a valid comparison.



So I have taken the liberty of showing what I measured, and the measurements I obtained by eyecrometer (margin of error <+/-1mm). All measurements from the centre of the bush...
Overall length = 335
Centre of BJ = 300 (measured at the top surface of the arm)
Centre tierod = 235
Centre of end links = 205

What I would like to ask is... does anyone have a bare AE86 factory arm lying about that they can measure ?

The variance between measurements to the centre of the balljoint seems to arise from the difficulty in estimating where the centre of the balljoint might be, Measuring a bare arm eliminates that error, and I think an accurate measure would be helpful to anyone such as myself who is only looking for an arm 10mm longer than stock.

Cheers... jondee86

PS: The pic has parallax error which means it is not possible to use the ruler for measurements. Rest assured my measurements are actual, and not based on the pic

[jondee86]

Just to add some fuel to the fire... here is what Jonny Rochester wrote back on 19th February 2009 , 11:15 AM

I just want to point out at least a few of the measurements in the top list (start of this thread) are wrong. When you measure the effecting length of a lower control arm, it should be from the middle of the ball joint to the the middle of the bolt hole. The pivot point of the ball joint can't be measured exactly, so you have to imagine where it may be. Move the ball joint around a bit so you can get a better idea of where the centre may be. After doing this, I think the list would look closer to this:

RA23/28, RA40, RT132/XT130 (all the same part) 300mm
KE30, KE55 etc 300mm
AE86, TE72, KE70, AE71 290mm

I still need to measure this better.

Jonny Rochester is a pretty onto it dude, and so when he says the AE86 arm measures 290 to the centre of the balljoint, that compares nicely with my "10mm longer" arm at 300 to the centre.

Cheers... jondee86