Wheel alignment

redrover

Active Member
#1
Apologies if this topic has already been done! I've managed to find a few bits of info on the forum, but wasn't quite sure what was what.

The wheel alignment is out on my car (several degrees toe out) and heavily wearing the tyres on the inside edges.
I'm planning to take it to a garage to have the tracking properly set up (with lasers, ooo!!) but the camber, even when unladen, is very very much on the negative side!
If I get the tracking set up, it will pull the wheels parallel and correct the tracking, but will this cure the negative camber too?

Wheel bearings are new, there's no play in the suspension joints or bushes, the top-link mouting brackets have never been disturbed and the springs are good (no creaks or unevenly spaced coils), so I'm not sure why the camber is so far out. Will correcting the tracking cure it??

Michael
 

chrisyork

Active Member
#2
No. Sorting the traxking won't sort the camber. Before tackling tracking issues lets therefore tackle the camber.

P6 front suspension is designed with a very large rate of camber change as the suspension rises or falls. The front suspension desuign with the bell crank and horizontal coil keeps the top of the suspension pillar absolutely in line with the chassis. But the two bottom arms make an equivalent bottom wishbone that is quite short. This means that it will move inwards and outwards from the chassis as the suspension moves. Therefore the camber, or angle to the body vertical, of the wheels / suspension pillar moves around a lot as the suspension is stretched and compressed. This effect is best understood and demonstrated by jacking the front of the car with the wheels in place. With the suspension at full stretch when the car is fully off the ground the wheels "clap hands! at the bottom - large positive camber. As the car is lowered the wheels go gradually back through meutral towards negative camber.

So the first clue and test as to why a car should show a lot of negative camber is to ask what the ride height is. If the springs are tired the ride height will have sagged and you will get negative camber as a result. There is a section in the workshop manual that gives you the procedure and dimensions for measuring this. If you don't have a copy let me know and I'll scan it for you. Clearly, if this is established, then the solution is to change the springs for new. Note that it is wildly onlikely that the sprongs will have aged differently, so another check for this problem is to look at the car head on and be happy thet both wheels have the same camber.

That gives us the clue to take us on to the next possibility.

The top pivot mounted on the firewall runs in a rubber bush each side of the top link - ie two bushes per pivot. If these bushes are past their sell by date they allow the top link to move from side to side. Because it is quite long, a very small problem at the bulkhead translates into a large error by the time you reach the end of the link / top ball joint. It seems to be a characteristic of the car that this almost invariably shows up as the top pivot moving inwards and leading to negative camber. There are two clues that this has happened. The bushes tend to fail suddenly. so you would expect one side to go before the other. Therefore the eying the car up from the front test is likely to reveal a different camber side to side. Also you tend to get a lot of knocking in the suspension transmitted into the firewall, so you will hear the problem in the car. If an initial problem on one side has been ignored for long enough for the other side to join it in failure mode - thus evening up the camber albeit to the wrong value - then it is likely to be possible to see the damage in at least one bush. But be prepared to be hyper critical!

Only solution is to have the springs out in order to be able to renew the bushes.

Final and least welcome possibility is previous accident damage leavig the geometry of the bodyshell awry.

You should be able to guess where this is leading by now! Whichever of the first two possibilities turns out to be the cause, part of the solution is to have the springs out. Unfortunately this is by far the worst mechanical job on the car and well beyond the capability of most modern garages. It really needs to go to a P6 specialist unless you fancy tackling it yourself. Therfeore if you are going to tackle this it makes a very great deal of sense to renew both the springs and the top link bushes as a matter of policy, no matter which you believe to be the cause.

Moving on to the tracking.

The top link bushes being US are a possible cause of the tracking being way out. The other likely one is a problem with the steering idler. It is common for them to come loose on their fixings to the firewall. It would seem that the bolts used to secure them by the factory are understrength for the duty. They are also prone to wear at the bottom bearing of the pivot shaft. First clue is them losing oil from this location. When the oil is gone rapid wear occours and the bottom pivot, and hence the steering quadrant gets to have excessive side monement. You will need to be quite aggressive with a crowbar to identify both these faults.

Now that you are happy with all the above we can move to the laser alignment bay, The P6 is a nightmare for the average fitter at one of these facilities. They are very unlikely to have ever seen a trackrod adjustment down the back of the engine and on top of the gearbox! So they won't be too keen on spending the time to get it dead right! Nor will they like ny next bit of advice. Ignore the tolerences quoted in the workshop manual. The only setting you should accept for the tracking is spot on zero. This is because of the camber change in compression we discussed earlier. Any error away from zero will tend to male the car twitchy over road irregularities. Set spot on zero the car will run straight as an arrow.

Oh dear. You're quite entitled to feel quite depressed by now! But there is light at the end of the tunnel. A bit of negative camber is just what the doctor ordered for improving turn in. So, providing it is the same side to side, you are entitled to let sleeping dogs lie! Your call as to how much you are prepared to put up with!

Hope that helps.

Chris
 

redrover

Active Member
#3
Chris, that is absolutely brilliant information, thanks very much! Exactly the sort of technical advice I was after.

As it happens, the bushes in the top-link pivot brackets are a bit crusted so I was planning to replace them with poly in the next few months anyway. As regards the springs, I've not noticed any creaking from them, but they are still 40 years old and past their reasonable life expectancy, let's face it!
I think that may be a job for the Summer though, as I'm getting the brakes sorted for the looming MOT at the moment. And after reading a post by Testrider (in this post by Garethp6 viewtopic.php?f=6&t=4923&start=0), a bit of negative camber seems to be a fairly common issue for the reasons you describe above, and possibly not something to be overly worried about in the short term. I'd estimate my wheels to be about 4-5 degrees negative (certainly no more than 7), but crucially they do appear to be even.

For the time being then, I'm going to concentrate on the potential causes of misaligned tracking that you list (even though that won't properly tackle the whole problem) as I'm concerned about balding my tyres so quickly. Steering does load up quite quickly below 5 mph and there is a bit too much play in the wheel above say 20 for my liking, so I reckon I could get some decent half-finished results from just sorting the tracking out. (Unfortunately, that does mean treading that difficult line between telling the man at the garage how to do his job without, well, telling the man at the garage how to do his job! But needs must I suppose!).

Will keep you posted on my developments, but in the meantime, I'm going to make this post Sticky as I think that sort of info will come in really handy for others with similar wheel alignment issues- especially as neither the Haynes nor Ken Ball manuals have virtually any information on this at all!

Thanks again,
Michael
 
#4
Wow Chris that is almost a magazine article in itself - very useful!! :shock:

I hopoe you don't mind me asking a little advice also on this thread - I am hoping to rebuild my 2000TC soon with a bias towards firmer suspension for road rallies - we completed one this year with lots of hairpin mountain continental roads and LOTS of bodyroll.

From reading your reply it is obvious that any adjustment in ride height is going to affect camber and handling - I found this old article on rally prepping suggesting V8 rear springs be fitted all round to the 2000 to improve (reduce) body roll

http://www.bondhouse.co.uk/p6improve.pdf

My genuine workshop manual lists spring data as:

FRONT
2000: Free length 16.5", rate 170lb/in
2000 suffix B onwards: Free length 17.5", rate 150lb/in
2200 Free length 16.281", rate 170lb/in

REAR
2000: Free length 13.25", rate not stated
2000 suffix B onwards: Free length 13.562", rate not stated
2200 Free length 13.312", rate not stated

Looking at the difference in free length between rear springs and front springs (some 3") it would seem that a swap rear to front would be totally impractical which leads me to doubt the validity of the above article.
I wonder if they actually meant to substitute 3500 front for 2000 front and 3500 rear for 2000 rear rather than "3500 rear all round".

Do you have data for the 3500 springs?

Having read an earlier article of yours it might be the way forward to have springs wound by flexosprings as you did.

Many thanks,

Robin
 
#5
Hi Robin

I'm not a fan of that article! I have a feeling the paragraph about V8 springs should have read to indicate that it was the dampers that were required all round!

So let's start with the good news. In standard trim the P6 is one of the best handling cars you can buy. This is founded on having a virtually perfect 50/50 front / rear weight distribution. If you let the car settle into a long open corner the handling is perfectly neutral.

Where the car has a problem is with sudden low speed changes of direction. This can induce dramatic understeer to go with the dramatic roll. The effect is called turn in understeer. There seems to be a single main cause of this which is that there is too sudden a transfer onto the outer front wheel causing the tyre to roll off the rim. All the changes I suggest to the car are designed to address this one way or another.

So lets start. Most of these changes are genuine Rover, in the sense that they were tried on early prototypes and discarded to softem the car for the perceived tastes of 1963. The one that isn't is to get much wider tyres on the car - they weren't available in '63! The car benefits dramatically by fitting the widest possible tyres without going silly on bodywork mods. This turns out to be 205 section. You'll need wider rims to accomodate these. The only readily available rims of a suitable width and offset are 15" SD1 Vitesse cross spoke alloys. However these are very heavy, If you have a deep wallet you might want to talk to Minilites about them making you a suitable 15" wheel with an offset of ET +53mm. With the Vitesse wheels and 205 tyres you will need to fit V8 top links to the rear de-dion elbows - these have a joggle in them to clear wider wheels which the 2000 ones do not. You may also need to do some aggressive mods to the rear D posts to clear the outer edge of the tyre. A jack placed horizontally between the rear of the D post and the side of the boot will do the trick without other consequences.

If you wanted to keep overall gearing unchanged (and hence retain speedo accuracy) that requires matching the overall diameter to the original 165/80X14. Here's a note I did earlier:

I wouldn't want to go less than 195 section on these rims, the sidewalls would get to be all at the wrong angle. So to get the same rolling radius as stock tyres (165/80 X 14) you'll be wanting 195/60 X 15. This will keep your speedo reading spot on accurate.

If you wanted to use 205 section then the aspect ratio to give the correct rolling diameter is halfway between 55 and 60. Ie if you fitted 205/60 X 15 then the speedo would read slow to actual speed - 68.1 at an actual 70mph - or with 205/55 X 15 it would read fast - 71.5 @ 70mph.
Next up is to sort the dampers. Both front and rear are too soft for the spring rates as standard. At the back the effect is to permit power slides, at the front you get the aforementioned turn in understeer. Rover used to make Heavy Duty dampers for both front and rear (and they were very stiff indeed!) but these are no longer available, so a set of Alan Ramsbottoms adjustables are an essential :

http://cgi.ebay.co.uk/ROVER-P6-FRON...arts_Vehicles_CarParts_SM&hash=item19c2bc9481

Being adjustables they can be set to suit whatever spring rates you finish up with ( later!). Don't use Alan's revised bottom spigot kits for the front, just use decent polybushes. But you will need to beef up the front chassis leg. For the V8 there is the "Australian Mod", which essentially plates the entire inner wing and chassis rail to double thickness. I have pictures elsewhere on here of this fitted to my V8. You won't be able to use this as a kit as the 4 cyl inner wings are not the same as the V8. But you should be able to replicate the idea easily and simply fom steel sheet. The bit that is needed, again from Alan, is the Police spec damper bottom spigot stiffeners - an original Rover part:

http://cgi.ebay.co.uk/ROVER-P6-2000...arts_Vehicles_CarParts_SM&hash=item1c1971c97b

With the plating and stiffeners in place, steering precision is much improved.

Next up is an uprated front anti roll bar. I reckon this is identical in spec to that fitted to factory prototypes, in essence it is the biggest you can fit in without fouling the heater box! Again from Alan:

http://cgi.ebay.co.uk/ROVER-P6-2000...arts_Vehicles_CarParts_SM&hash=item1c1977c9b8

Only remaining action I'd take at this stage is to get your steering box looked at by someone who knows what they are doing - such as Colin at Kingsdown Garages, Faringdon, 01367 244646. There should be absolutely no play at the wheel, either at straight ahead or in any other position, and, even with 205 tyres, should be beautifully light. If it isn't, then the box isn't set up right, or has unacceptable wear. On my V8 it is feasible to use a 16" wheel instead of the normal 17" even with the wide tyres. Definitely no requirement for power steering!

The car will be so transformed by these actions that I would pause to enjoy before considering any further actions.The front roll stiffness has been increased by around 10%, so there will be an increase in steady state understeer without compensating action at the rear. But we will do that with springs, so you need to take a view about the overall level of roll before we move on. I strongly suspect you might find you are now happy!

For road rallying you really ought to be running the softest springs you can get away with without excessive bottoming out. So for my tastes the next stage would be to simply renew the front springs with V8 ones (very marginally stiffer - the 4 cyl is almost exactly the same weight as the V8), and to renew the rear springs with Rover Heavy Duty spec (ex early prototypes to go with the stiffer anti roll bar!). The latter will need winding specially and I can help with that when the time arrives. Lowering the car would be a disaster for your requirements, but it is possible you might want slightly stiifer spring rates. The latter either to control bottoming out or to further increase roll stiffness. If so we need a separate discusion as to what to fit front and rear.

I would describe the net effect of these mods with the standard rate front springs and HD rears as to bring the car to about Golf Mk4 standard - still rolls, but not excessively, can be whipped through roundabouts with the best of moderns and retains the overall perfectly neutral balance.

As to other mods you might like to consider for rallying, principle would be to substitute a 2200TC motor. This has bigger valves than the 2000TC and smaller carbs. If keeping the 2000 motor, then fit the 2200TC twin HIF6 or HIF 44 1 3/4" carbs instead of the 2" HD8's. They improve low speed running dramatically without losing any top end. Losing the engine driven fan in favour of electric liberates quite a few useful horsepower. Depending on what sort of rally you are entering, you could raise the overall gearing by fitting a V8 diff. It is possible to fit a 5 spd Toyota box, but it is an expensive conversion. If doimg a lot of fast running you would benefit by fittng Police spoilers to the front undertray. These eliminate susceptability to cross winds and allows the car to cruise arrow straight. You could fit theses either to the standard 4 cyl undertray, or to a V8 one to include the bigger radiator air intake. And don't forget to lay the spare wheel down in the boot well instead of standing upright - makes a noticeable difference!

Hope that all helps, and of course we need some pictures!

Chris
 
#6
I should have added brakes to the desirable upgrades. The V8 uprights are a straight swop onto the 4 cyl which gives you the larger 3 pot calipers and discs. The V8 calipers then have green stuff pads availlable. To make them work properly, either microgroove the existing discs or fit proprietry grooved ones (can anyone remeber the name of them - Quattro, you have them on yours). A further step is to get Alan to widen the V8 calipers to go around vented discs. At the rear, going backwards to retro fit the original Dunlop set up gives you calipers that are common ith the E type and can therefore be got with Greenstuff pads, plus a separate handbrake mechanism.

Chris
 

harveyp6

Well-Known Member
#7
chrisyork said:
I should have added brakes to the desirable upgrades. The V8 uprights are a straight swop onto the 4 cyl which gives you the larger 3 pot calipers and discs. Chris

The uprights are the same, you just need the discs, hubs and calipers.
 
#8
Thanks Chris (and Harvey) - I am about speechless!! :shock: :shock:

A very big thankyou - I am going to print the pages and keep them safely in the front of my Workshop manual! Exactly the sort of information I needed to know - it's funny but after years and years of building tuning prepping and racing motorcycles I find myself quite ignorant on car practice - although I hope to learn fast!

I am in the process of selling my bikes and finishing my daughter's mini project to clear room for my TC to go into the garage and on the lift - although I think new rear shocks will have to go on before the soon to arrive MOT.

Full photographs before during and after will be posted!!

Many many thanks again, :D

Robin
 
#9
Hi,

I have little of add to the very comprehensive replies from Chris except to say that we run essentially the exact set-up described on our Road Rally car to very good effect. The only thing we’ve done extra is to completely rigidly mount the Diff. We’d heard various horror stories about how this would effect Road and Diff noise transmission into the car but to be honest you’d hardly know. Back end is much better now, it was polybushed before we did this and we still feel that rigid is better. The standard rear diff cross member isn’t strong enough for competition use.

viewtopic.php?f=21&t=6051

You can make your own front ABR using the ABR out of the back of a higher spec. 306 or ZX, the machining isn’t hard.

http://p6v8.wordpress.com/author/p6v8/

I’d disagree with Chris a wee bit on the power steering. The Historic Road Rallies we do have a large Autotest element, for good times the steering is best done with one hand using one of those knobs you find on forklift trucks etc…. Doing this over a 2 or 3 day event takes it out of even the strongest of arms, I’m thinking of going the same route as a lot of the Escort boys and fitting electric power steering. It rather depends on the events you are doing, modern Road Rallies you won’t need it.

Thanks

Tim
 

garethp6

Active Member
#10
hey well i did have positive camber when i go forward and negative camber when you go back on my p6 and checked for play but could not find nothing but found out my p6 had the wrong springs on the front since replacing the springs for the right type when going forward they now look straight but once you go back i get negative camber but not as bad
 
#11
Took the P6 for a free tracking check at a well-known national tyre specialist - I know the staff there well and have a high opinion of their work. However, due to my ignorance in wheel alignment theory - a couple of queries.....
Firstly they could not put the rear wheel devices on since the wheelarches cover the top of the tyres unlike most modern cars, consequently they couldn't do their 4 wheel check - is this strictly necessary anyway? It never used to be.
Secondly, the results on the front wheel laser scale showed a toe-in of about 3.8mm on the N/S but only about 0.3mm on the O/S. Do the two figures need to be about the same or is this within acceptable limits when taken as a whole?
 
#12
Just thought I'd add a little note for those with air conditioning - there is an extra shim behind the compressor side spring to accommodate the extra weight. If you remove the compressor for some reason (or change it for a modern, lighter one) the car will sit noticeably high on that side as a result - so don't think something is busted...This holds for pretty much all air con v8 cars but I'm unsure about the four cylinders'.
 
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