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
