Ride Height

[Exclusive Opel]

Taken from a German workshop manual if this helps (or confuse) anyone:

Also, quoted in the Cavalier Training Service Manual (TS1142):

"Camber angle is adjusted by rotating the upper ball joint mounting flange through 180^o. As the mounting flange is offset from the joint centre, camber angle will be altered by approximately 50'."

Checked my stub axles at the weekend out of curiosity and found the one's on my GTE (1984) were the same as the one's from my old 1.8 (1987).

[Christ]

As I suspected, thanks

Although can't get my head round the positioning of the 'Zapfen' (shim of some kind?) - where it would be and how it can change castor knowing that it adjusted on the manta by washers on the upper wishbone bolt

[opel2000]

Superb post there again from Exclusive Opel.

Just where does he get stuff like this from?

Edit, ok he does say where from in his post, but where the hell did he get a German workshop manual from.... Ok GErmany I guess

Edited November 23, 2010 by opel2000

[lamchop77]

The top ball joint offset is inboard of it's two attachment bolts, so if it was turned round it would give positive camber (wheel leaning out) it can be desirable to add a little negative camber to aid cornering, it would be possible to 'slot' the bolt holes but i'm concerned that they may move under cornering loads, this is something that i have sat and stared at for sometime without coming up with the perfect modification.

The perfect mod? I altered the Kadett front upper arm by cutting the rubber bushes off and replacing both with spherical bearings. I can now get about 5 deg of negative camber (not that i need to!) That set up ran on the grasser for about 3 years and never had a hint of a problem.

HTH

Chris

[Exclusive Opel]

Superb post there again from Exclusive Opel.

Just where does he get stuff like this from?

Edit, ok he does say where from in his post, but where the hell did he get a German workshop manual from.... Ok GErmany I guess

I *acquired* the manual's from the internet (p2p site) a couple of years ago. Also have the same for the A series (approx 900 pages) . Even have a 170 page service book for the Ascona 400! AND the parts catalogue (98 pages) which both are more helpfully in English and German. The Manta B/Ascona manual is approx 1550 pages!

The Cavalier Training Service Manual's were just off ebay.

[Christ]

Does your workshop manual mention the camber/toe figures for the rear axle (manta gte)? I assumed them to be zero but got some odd readings when the car geometry was last set-up

[keith1200]

Why doesn't someone with a cavalier and a manta not check? I'm not offering myself (way toooo much snow).

[399Road]

Hello, I had heard in the past that Manta GTE's had different stub axles to normal models to give quicker steering response. If you tried to buy a quick rack kit from Demon tweeks , the instructions gave different steering ratios for each type of stub axle, and reccomended using the GTE type for the quickest steering.

To confirm this I,ve just been out in the snow and looked under my 1982 Manta 1800 Berlinetta coupe and this is fitted with the supposed GTE type stub axles, contradicting what the Quick rack instructions said! This Berlinetta was a very low milage and very original car when I got it , so It's unlikely these stub axles have been changed from new.

I then looked under my Ascona (base model poverty spec 2 door LHD) and this has the other type of stub axle fitted .

After looking at these stub axles I would suggest that maybe the 5 speed cars had these GTE type stub axles to give more stability at speed with the increased castor angle and had the shorter leverage at the track rod end mount to speed up the steering response

Look at how high the rear suspension wason a new standard Manta C coupe . Were these revised castor settings anything to do with this?

[keith1200]

I'm going to have a look myself, once the weather improves About march 2011 BUT I reckon the above sounds 'spot on'. I'm glad I kept that exclusive front subframe

edit[interesting thread tho]

Edited December 6, 2010 by keith1200

[cam.in.head]

Does your workshop manual mention the camber/toe figures for the rear axle (manta gte)? I assumed them to be zero but got some odd readings when the car geometry was last set-up

the rear has to be zero in every respect.if you have any toe whatsoever it would indicate either a bent axle casing or if you have positive toe on one side & negative on the other(same amounts)would be a difference in suspension arm length.either due to a knackered bush ,bent arm or chassis mounting point.differences in camber (same but opposites could be a weak spring,.assuming all mounting points are spot on,arms & bushes equal,tyre types,tread depths,pressures etc all equal then rear should be totally straight & parrallel with the front.

[Christ]

yeah, that's what i thought but had to check there was no camber or toe built into the axle.

it's only a slight variation so i'm hoping the spacers i've got are not quite true so give the impression of camber, if not it could be down to the way i took the studs out. either way it's probably the source of the vibration at over 110

[Exclusive Opel]

Does your workshop manual mention the camber/toe figures for the rear axle (manta gte)? I assumed them to be zero but got some odd readings when the car geometry was last set-up

Sorry, bit late replying to this one.

No idea in the German one as it's all in German No mention of it in the Cavalier manuals though. I would agree with what cam.in.head says.

[399Road]

Hello,

I've looked in my my Opel Euroservice manual and this gives rear tracking information.....

It says camber, toe-in and castor should be zero if possible and says Permissible deviation at one wheel for camber and toe-in is + or - 19' ... permissible deviation at one wheel for castor is + or - 24'

Don't forget if you run your car at a very low ride height the rear axle is pushed over towards the o/s of the car by your Panhard rod. I've corrected this by making my mine adjustable with a welded in track control arm adjuster for a mk2 escort (welded into my panhard rod) This adjuster only cost about £20 from Rally design and they can supply these individually. Before I fitted this adjuster, my Ascona would pull to the left under hard acceleration and then go to. the right when i backed off. this got really bad when you braked hard taking a fair bit of effort to keep straight. The car is fully polybushed and has Bilstein shockers so there is no play in anything to cause this pulling.

I've found the front tracking also needs setting up differently on lowered cars...Look at the angle of your steering arms as they come out of your steering rack towards the track rod ends. On a standard car these arms slope down towards the front hubs and as your car picks up speed , downforce lowers your car and the standard toe- in setting alters to run the front wheels in parallel... On lowered cars these steering arms are either level or slope up towards the track rod ends. As downforce sets in again the car lowers itself and this time your steering arms pull the track rod ends IN slightly. This set up drives better with either a front toe- OUT of 1mm, if your steering arms are level towards the track rod ends or a toe OUT of 2mm if your steering arms point up slightly towards the track rod ends. I,ve run my tracking at -2 now for around 4500 miles, can't see any uneven tyre wear on the edges of my tyres and the car seems to turn into corners better .

My Ascona has the older non GTE type stub axles fitted but Also ran my last lowered GTE coupe at thes settings.

I take it this info is for your black car Chris, if not ignore all the bits about lowered suspension... Luke

[cam.in.head]

how do you get castor on rear wheels ???

[Christ]

^^^good point

I take it this info is for your black car Chris, if not ignore all the bits about lowered suspension... Luke

yeah it is, thanks for the info - already figured out the panhard rod problem, instead of running an adjustable one I've chopped and inch out of the std one, and relocated the mounting bracket so it sits parallel to the axle (see project thread)

[399Road]

How do you get caster on rear wheels???

The only obvious ways I could think you would have the rear caster out of tolerence is by having either bent rear trailing arms (pulling the axle forwards or pushing it backwards) ,knackered trailing arm bushes or having very low suspension causing the axle to have swung around as it rises up in the wheelarch.... If I get chance this week I'll put the gauges on my Ascona at work and see what they read...

hopefully zero otherwise I'll be welding adjusters in again!

Luke.

[lamchop77]

Castor on the rear wheels, shouldn't matter or be there. The rear axles are usually set by where the nose of the diff is pointing, IIRC its about 4 deg up from the horizontal, but with a lowered car this would change. Solid axles should be set exactly in line with the front wheels at dead ahead, anything off this will cause the car to crab. Stock car lads used to purposely skew the axles to help with cornering on the short ovals, so if you have that on a road car it would prob cause the problem 399road had. Castor is there to give stability at higher speed as well as affecting the steering angles, you don't need that on a solid rear.

HTH

Chris

[cam.in.head]

camber i can understand.toe likewise .all should be zero with axle totally in line with front wheels. but isnt castor a steering angle tilt. ??.

[lamchop77]

camber i can understand.toe likewise .all should be zero with axle totally in line with front wheels. but isnt castor a steering angle tilt. ??.

Yep its the angle that gives you stability at speed and also makes the steering self centre.

Best example of what caster angle does is to look at what happens when you push a shopping trolley really fast, the wheels are all over the place. The castor on those is zero, totally verticle so totally unstable. As you increase the castor you increase the stability but you also increase the heavy feel on the steering as well.

HTH

Chris

[cam.in.head]

Yep its the angle that gives you stability at speed and also makes the steering self centre.

Best example of what caster angle does is to look at what happens when you push a shopping trolley really fast, the wheels are all over the place. The castor on those is zero, totally verticle so totally unstable. As you increase the castor you increase the stability but you also increase the heavy feel on the steering as well.

HTH

Chris

i totally agree with all the above. my query was ,how can you have castor on rear wheels ? ? surely not a rear angle at all . camber yes but in relation to the vertical(should be zero).toe in or out again should be zero.it is a live rear axle after all so wheels totally straight & in line with rear wheels but castor ??

[lamchop77]

i totally agree with all the above. my query was ,how can you have castor on rear wheels ? ? surely not a rear angle at all . camber yes but in relation to the vertical(should be zero).toe in or out again should be zero.it is a live rear axle after all so wheels totally straight & in line with rear wheels but castor ??

It is a steering angle so not a rear angle at all, so no you can't have castor on the rear with a solid axle. If you had an independant rear end with wishbones then you could dial a bit in if needed.

I know that some race setups dial in toe in and out to make the car more stable or more twitchy (toe in for stability, toe out for the twitchy feel)

Alot of independent rears have a certain amount of toe angle change built into them to make the cars feel safer. I might have a look through my suspension setup books now just to see if there are any examples of this (yeah i know geeky or what!!)

HTH

Chris

Edited December 15, 2010 by lamchop77

[Christ]

Alot of independent rears have a certain amount of toe angle change built into them to make the cars feel safer. I might have a look through my suspension setup books now just to see if there are any examples of this (yeah i know geeky or what!!)

'The sports car and kit car suspension & brakes high performance manual' by Des Hammill - a bit repetitive but some interesting stuff

The IRS on my SX is fully adjustable with control arms at the front/bottom of the hub to adjust the toe and camber arms above - no castor arms that I'm aware of though

[399Road]

Hello again.

I,ve stuck the gauges on the back of the Ascona today and suprise suprise ... all rear settings read zero .( Nice straight axle casing.)

[Christ]

cool, now we know what they should be

Haven't had chance to do the same with mine yet......

BTW, 399Road, didn't realize who you were until I checked your profile - good to meet you the other month, v. nice ascona

[399Road]

Cheers Chris, I'll look forward to seeing you in January at Gunthorpe if you can make it.........

Which 200sx have you got? 13,14 or 14A ? I'm also currently building a mk2 Escort with CA18 DET power.

Luke.