Trackwith of the rear suspension?

[ashcloud]

Thanks Alec
found it, the speaker was on top of it but I have serious doubt that I can fit an automatic aerial through that opening.
Bernhard

[Martec]

With reference to your original question about front and rear tracking on the MkII,

Front - wires 4' 7.5"
rear - wires 4' 6.125"

This is from the Jaguar manual.

William Lyons decided the shape of these Jaguars and was taken by the teardrop shape so the MkI (2.4 and 3.4lts saloon as they were called) rear axle was considerably narrower. This was blamed for some handling issues (not necessarily correct) so on the later MkII version the body was slightly massaged to allow a wider track at the rear, and it is almost the same.

Some suspension tuning books say that they should be identical but I have always been happy to push the MkII through bends at speed as the car feels secure and well planted to the tarmac, even with incorrect springs fitted.

Brian

[ashcloud]

Thanks for the info, so for the time being it will stay that way and in the summer I will see about wider wheels/tyres or not. The front suspension coils will also be lowered at the same time. It may look "jumpier" but I think it looks more aggressive without that nose up attitude.
Bernhard

[piman]

Hello Brian\Bernhard,

regarding the advisability of having the rear track as wide as the front, if you see how well Morgan three wheelers go in Vintage racing meetings, matching and even beating cars of much greater engine capacity one might say that hypothesis is invalid.

Bernhard, if you still wish to have wider rear track, one option is to change to solid wheels which could quite easily be spaced out? I've only ever owned one car with wire wheels and I do not wish to have another. Too much fiddly cleaning and maintenance.

Alec

[ashcloud]

About cleaning wirewheels:
MK2s are very rare these days so when I showed up at the DIY washing place the cashier came out of the office to look at the car ...... 5 minutes later he was cleaning the wheels with a pressure washer and some of his "wonder"shampoo and brush and whatever stuff he had and he did not even charge me for that part. He said that he had to try since he had never had such car there, they still sparkle.
So no complaint yet, but under no circumstances would I use the metal wheels the wire-look is just sooooooo much more elegant.
Bernhard

[ecosselynx]

Hi

Correct the picture was taken in the alps, however the car is RHD, I took the picture and my wife is sitting in the car. The wheels I bought from MWS and are painted, they clean easier and don't look to bad when dirty as opposed to chrome ones.

[ashcloud]

I think they look great. I just checked a little in my stack of sparepart books and SNGBarratt and others offering Dayton Stainlesssteel Wheels which should not be prone to loosing the chromeplating and are guaranteed for life. Sounds interesting but since I have time now (my budget ) and a lot of parts that wait for installation and a lot of cleaning around the motor with some different new gadgets I can compare prices and stuff.
Btw I am still dreaming of running the MK2 over some interesting roads. The first test is past, I bought it in Hamburg and we drove it back full speed without a hitch (500km). So in May is a run to France (Champagne) to buy the good stuff and we will see how she performs when heavy. Last spring we used the XKR and had 110kg of Champagne in the trunk. It ran a bit closer to the ground but rocksteady. Back home we checked the manual and it said max 47kg. Uppps.
If all is well than I think of crossing the Swiss Alps or Scottland.
Lets wait and see.
Bernhard

[Martec]

I agree Alec narrower rear track is not a problem.

Ashcloud, something is wrong with your car if it is nose up. There are all manner of supposed setting heights for the front suspension but as those who read Jaguar history know the panels for the MkII were out sourced and didn't fit properly.

So the old real setting for the front suspension is for the lower front wishbone to be horizontal, Anywhere away from that position and the suspension is not working at its best.

With the front at the correct height there is approx a 1" rise at the rear over the sill.

If you want improved handling then check that your springs are made from the correct wire size, from memory 0.635" dia (3.4/3.8 ltr) Watjag supply uprated springs at 0.710"dia(I've driven a stadard car on these and are OK).

The real improvement is 1 degree of negative camber (just shims needed) and the later stiffer anti-roll bar.

When building my car I tried XJ6 ser 3 wheels and tyres which fitted the rear but not the front, too wide if I remember properly.

Brian

[piman]

Hello Brian,

"The real improvement is 1 degree of negative camber (just shims needed) and the later stiffer anti-roll bar."

Doesn't the extra stiffness of the anti roll bar negate the affect of negative camber, at least in part?

Alec

[Martec]

Hi Alec, Only in part but not enough to overcome the effects completly.

My experience is from a much modified and owned from new Marina TC coupe (the epitomy of understeer) which now has neutral to power oversteer, plus spring changes on the 3.8 MkII Jaguar.

It all starts with the tyre, at a certain loading the tyre will slide, if the front outside tyre is overloaded then you get understeer (boring), if the rear outer tyre is overloaded you get oversteer (much more fun).

Springs resist the car rolling but too stiff and its uncomfortable plus like all things there must be a balance between front and rear springing for comfort. As the car rolls then the ideal wheel camber angle is lost, positive camber increases, tyre patch reduces and that overloads and slips.

By using an anti-roll bar you reduce the total positive camber and so lose less contact patch and slip at a higher speed. I think the Jaguar is slightly positive camber (to reduce steering loads) so as it rolls this increase even though it has double wishbone suspension (designed to negate this effect.

By starting with a little negative camber (knock kneed effect) then the wheel reaches the ideal camber (upright) as the car rolls and has maximum tyre patch. Modern cars don't roll and so can get away with sh!t mcpherson strut. Besides it feels more comfortable with less roll.

My MkII had very soft front springs on (took 10 years to find out) and rolled a lot but still cornered OK, I fitted Watjag uprated springs (0.710" wire diameter) and it wouldn't corner AT ALL. Ken Kenkins as usual berated me and I shimmer the top wishbone in to gain 1 degree negative camber (I already had the later stiffer A/R bar) and it corners on rails now.

The Marina went from 1 degree positive camber to 2 degrees negative camber and went around Garrards 180 degree bend at Mallory park track at only 55mph in power oversteer (needs a stiffer A/R bar only 130bhp).

The MkII has a very slack chassis (early days of monococ) so a rear A/R bar twists the body as much as the rear suspension, the general advice given is to only fit a front one as all the weight is up front, plus the front suspension has to be at the correct height to allow the long and short wishbones to do their job.

So an A/R bar up front reduces the roll and negative camber together ensure there is the maximum of tyre patch contact, then as you accelerate through the corner the rear tyres are loaded similarly to the fronts and you have smooth controlable handling.

Some I have got from books but most is from experimenting over time. I hope this is of some help.

Brian

[piman]

Hello Brian ,

fair enough, I must admit I wasn't aware of the two anti roll bars or their comparable stiffness.

From what you say it sounds as though some seam welding would benefit the shell, but probably not worth doing for a for a road car?
You don't mention dampers but I would assume quality dampers would be beneficial?

Alec

[stuarthardy]

Hi Bernhard

Please be careful with wire wheels and check whether they are certified for use in your country. I did hear once that Dayton wheels will not pass TUV tests. This could be wrong though.

I have also heard of Dayton wheels breaking spokes on first use.

I bought MWS wheels for my E-Type and they didn't cost much more than the Daytons. They are much better made and are British too, rather than American. Check their website as they offer a good range of sizes and offsets that you can compare against each other to see how they might look on you car. I sketched out the wheels and offsets, along with various tyre profiles to see what looked good and what would keep the gearing right.

Stainless spokes might not rust so readily as chrome plated wire but, size for size, they aren't as strong.

Regards

[Martec]

Hi Alec,

My MkII was rotten 12" up and 12", so all the steel work was seam welded. Because the rear suspension is hung off the rear seat pans (always a place to check for rot under the rear seat)then the boot area has virtually no chassis support in it. The advise from Ken was to make and fit doubler sections onto the seat pans (below the seat), also the top of the front chassis rails. But the shell is still not stiff, so apparently the old trick was to cut and fit a 1/8" steel sheet and BOLT it to the rear bulkhead (behind the rear seat back) as welding would only crack, masses of small bolts so I never bothered particulaly in view of the extra weight. You can only go so far with it.

I was advised 13 years ago to go with Koni classics as they suited the car better and are adjustable to suit you. In practice the damper is only there to control the rebound of the spring, stiffer spring stiffer damper. Koni classics have to be removed from the car to reset, you get very practised over time. Depends who you talk to as to what are the best dampers!! moving away from standard can be a mine field.

Brian

[piman]

Hello Brian,

The 1/8" steel sheet sounds rather blacksmithish, Colin Chapman would be horrified? A normal gauge sheet with channels rolled into it would be very stiff.

Konis were always the regarded dampers when I was younger and that is what I still prefer to use.

Alec