Castor shims

[ashcloud]

Hi Brian
I also read that You should have a positive Caster with Powersteering but zero or 1/2 degree negative with normal Steering. I don't have Powersteering and don't think I will convert it, so would it be more stable to leave the Caster slightly negative or do You think a ted positive will benefit the normal steering too? Does the powersteering dampen any wiggling if it occurs (aircraft have shimmy damper for that)?
For the Camber I will see to get aluminium blocks made up (5mm thick) and subtract shims as necessary.
Which settings will cause more Over then Understeering on the MK2s? Or do I have to add weight in the trunk (my kids ))))
I also love to run up and down those curvy roads here in Germany and so I really envy You that Your car is already adjusted perfectly for that.
Greetings Bernhard

[Martec]

Because power steering was not usually available on the early MkII (possibly available later??) then the steering has to be made light enough for everyone (granny to boy racer) hence positive camber and zero castor (the book says zero to plus or minus 1/2 degree), together with light front springs this gives a car that is relatively easy to steer and goes around corners.

When you change the spring, (stiffer/unrated) and/or add the later/stiffer anti-roll bar then the loading on the front tyre is too much and in a corner is slides (understeer) as I found out to my cost. By applying negative camber the tyre contact is improved in a corner and it has grip again.

To get oversteer the limit of the rear tyre has to be reached before the front tyre. This can be done in several ways, IF you have a stiff chassis (the MkII hasn't) then you can fit a rear anti-roll bar, increase the rear spring rate (and rattle your teeth), or increase the power to the rear wheels (this is called power over steer). I have been taught to drive by slowing down before a corner, change down to an appropriate gear, lightly drive through the corner and floor it as the exit is clear.

Most people don't change down in time so are not set up for exiting the corner, also a SMALL amount of power during the corner helps either front or rear wheel drive, but especially rear wheel drive. On a dry road more power through the corner will give power oversteer and line the car up for the exit of the corner. This is often called the racing way or for me it is the police method of fast driving. Besides power applied in the corner is more comfortable for the passenger and far more fun for the drivers (for me at least).

So Negative camber to give maximum grip in a corner, stiff anti-roll bar to reduce roll and keep the wheel upright, then power on to enjoy the corner. Simples!!

No power steering then zero castor to keep the steering reasonably light.

Best wishes

Brian

[oldtimer]

Hi Bernhard,
I have been following the thread, all about Caster and Camber. Can we go back a bit.
You were talking about the steering box, have you actually stripped and rebuilt it yet?
If so what did you find inside? Also you mention that you have obtained some Castrol D104, is that correct , could it be Castrol D140
And - do you have a Mk2 workshop manual ?

Sorry for all the questions , just trying to keep up!

Oldtimer

[ashcloud]

Hi Oldtimer
Yes I took the steeringbox apart and put it back together. I found thick green slime (like warm chewing gum, meaning still elastic, but sticky) or do You mean what did I find mechanicaly?
About the Castrol: Yes it was D140 (typing faster then thinking) and Yes I do have most books and manuals that are available for the MK2 but I still find a lot of information missing (that is why I like this forum!)
The box is attached now and looking great but I did find a design flaw: one screw for the topcover is leaking oil because the whole and thread in the case goes right through into the oil and due to capillary action it simply sucks oil up (I did tighten it a bit more and for the moment it stopped leacking but if it reoccurrs I have to put some sealant on the screw.
I am almost finished but since Brian gave me all the information about the camber/caster adjustments and SNGBarratt was out of any more shims (camber) I have aluminium spacer blocks (like the one for caster) made up today to add about a degree of camber without needing 9 shims to get 1 degree of negative camber (with the 4 I have for each position I just get close to zero camber only)
Bernhard

[oldtimer]

Hi Bernard,
Sorry for the delay in response but my computer went "Wonky". All fixed and up and running again now.

Back in the old days, well before your time and most of our members, there was even less money about, than now. Some of the tricks used to "Con " buyers were not very nice. Like, saw dust in axles and gear boxes. Grease in steering boxes etc.

So you can guess where I am coming from!

I cannot imagine what was in the steering box but perhaps something to disguise oil leaks

Now that you have confirmed Castrol D140. This matches information I have and is commonly a rear axle oil of the period

It is an SAE Grade EP 140 oil (EP = Excess Pressure)

Seven suppliers are listed:- Mobil Castrol Shell Esso BP Duckhams Texaco

Moving on to the Steering Box.

On the underside of the lid is a slot in which a guide roller runs. I have experienced bad wear in that slot allowing slack in the steering. Instead of two nice straight edges it wears like a dog leg near the steering straight ahead position

The rocker shaft or sector shaft has an oil seal at its base which leaks for two reasons. The seal has age hardened or the rocker shaft / and or the rocker shaft bush is worn.

Bernhard, have you experienced any of this?

And finally, the worm shaft should be fitted with a 0.002 - 0.003 thou pre load.

For those not familiar with the term, pre-load, this means :-
Where two opposing roller races have an end float of say 0.004 thou. By removal of shims to the value of 0.006 thou will give a preload of 0.002 thou. ( i.e. differential bearings or pinion bearings)

I expect you are aware of above but hope it is of some value

Oldtimer

[Martec]

You and me both Oldtimer with internet problems, our phone died a week ago so nothing other than a mobile phone and lies from the server. A full rewire of our phone system after materials and advise from Maplin and we have all phones working and almost double the internet speed.

I can't remember the details of the standard MkII steering box, but I stripped and resealed our 420 Marples steering box and found when setting it up that the fit(preload) at dead ahead was immaterial as there was wear, so set the adjustment so that at full lock it was not tooooo tight. This left some slack at dead ahead position. I think they are similar boxes in that that they are worm and nut (or similar) so the pinion is machined on a curve. I think most steering boxes will be worn at the dead ahead position by now.

Brian

Edit

Sorry Oldtimer I'm talking at cross purposes to you, I think you're referring to the input shaft and I'm talking about the output shaft. The latter I remember readjusting a bit tighter on the side of the road as the car wandered too much. Sorry mate.

[ashcloud]

Hi Oldtimer
I have not had any obvious wear but I do have a bit of play in the steering coming from the wormbearingdrive. This was the only thing I did not take apart but maybe I should have (was just afraid to loose one of those 30 balls and then I am stuck) The play is only a nuisance when You drive abrupt S-turns otherweis during normal driving it is no problem. You may be right with the grease in the "leaking" gear box, but the crack is on top through the thread of the front housing. since it is at the highest point I took a little bit of Oil out and replaced the top seal and added sealant. to be on the safe side I did not tighten the screw too hard. No leak since.
I did get the camber to about 1 negative but I did get a serious problem fitting the front suspension ino the car because the upper wishbones are closer together and it was a drag to get them over a welded edge.
Now the car is probably the correct ride hight (3 fingers under no load) but I want to get it lower, so more work. The driving/cornering is much better but the vibration I have around 60MPH is still there. I believe that the good old wire wheels are a bit egg-shaped and a bit wobbly too and cause that.(the rear wheels are worse).
Being somewhat disappointed with the result I was told that all wirewheels have some imbalance or wobble. What is Your experience. Has anyone tried those Dayton wheels with the "PermaTrue", are those better. I just dont want to spend another 1200Euros to find out they all do that.
Slightly annoyed,
Bernhard

[piman]

Hello Bernhard,

as wire wheels are relatively rare in Germany, I suspect that they are not being balanced correctly? The balancing machine needs different adapters to standard aluminium or pressed steel wheels or the wheels will not be true on the balancing machine.

Alec

[ashcloud]

Morning Alec
Thanks for the Info but I do have a shop withing 20 minutes driving that is specialized in restoring wirewheels only and has the correct mounting hardware to balance those wheels. They restore and rebuild wheels from the beginning of "time" Of course I can only trust that he is as good as I think he is.

Now I have done the first few hundred kilometeres with the new front:

I have set the shocks to a softer setting and it drives muuuuuuch better. Second, I retightened several nuts and yes it is better too. Third: I am verrrrry pleased with Brians suggested 1 degree of negative camber. I had set the tracking, castor and camber with only rudimentary equippment on my stand but from the very beginning it drove very stable and is still very easy while turning.
Two days ago I went the first time over 110MPH (indicated) again and let go of the steering wheel .... perfetto! No adjustment required. The cornering is noticeable better but I did adjust the tire pressure several times to find the best at 2 bar (29 psi). Harder, it was "jumpy" and softer effected the steering force required at slow speeds dramatically.

Now this would make it all too good to be true. So yesterday it started to smell like gasoline and I went back home to check, but found nothing wrong. After restarting I noticed a loud rattle and found the SS-exhaust the touch the cars body. I immediately assumed that those MK2 twist a bit and my yard is laid in cobblestone so I backed up and the exhaust was back centered (no further thoght waisted). I could not see anything wrong so happy as I was over all those improvements, I drove off. After 3 km I hear a loud "klonk" and stopped to find the exhaust pipes on the ground dragging along. Arrrrrrghhh, I was furrious to find that ALL those rubber mountings where broken and someone had just driven a furniture screw through the rubber so it was covered and could not be seen during inspection (the screw was inside the rubber)
The guy who did this died a few years back, but I hope that there is eternal punishment for f...ing up a classic car like that. (no mercy on my part!)

For Your entertainment I have attached the pictures of the rubber mountings (You can see hole that had been drilled through the rubber since it obviously had come apart years ago) and a picture of the ONE SCREW left at the end of the pipes. Enjoy!
PS: my decision now, I will not drive the car any distance from home before I am finished with every nook and granny! I don't trust anyone anymore except my own repairs.

[piman]

Hello Bernhard,

you are fortunate in relation to the wire wheels (Not so with relation to the exhaust, that's dreadful).
A quick check on their jig would determine if the wheel rims are within running tolerance. Are your tyres new, as I have heard that running them for a while and then rebalance can be beneficial. This is only hearsay and I have not any technical verification as to it's accuracy?

Alec

[ashcloud]

Thanks Alec
The tires are new, Vredestein Classic 185-15 and when the guy checked them he found that one front wheel/tire combination was at the limit so he suggested to put them on to the rear, the two with the minimum runout are now on the front, but they all have a bit of runout or wobble, but even after we balanced and swapped the wheels there was no change as far as the vibration was concerned so I blamed other items (e.g. bearings) for it but it is all new now (except the wheels), so I am running out of options. Maybe I could just blame my wife, she always blames me too for everything
She has a sticker on the fridge that says: I did not say it was Your fault, I said I was going to blame You!

I do have the car on stands so I will check them again to see if there is some obvious change.

At the moment I am sitting here and waiting for the UPS guy to bring the new rubbermounts (the same UPS guy who helped me yesterday on the road
I am eager to see if that lousy mounted exhaust maybe added some vibration.
Report will follow tonight.
Bernhard

[piman]

Hello Bernhard,

you seem to have covered the wheels pretty thoroughly. The last check in that area is to spin the wheels while on the car in case there is a bent axle, not that likely but worth a look however. The next suspect would be the universal joints on the propellor shaft. (Or has that been overhauled?)

Alec

[Martec]

Glad to hear the suspension set up is working well, I run 32psi front and 30 rear and is comfortable.

Sorry to hear about your wheel problems, at a show I saw a wife cleaning the individual spokes of the wire wheels. I asked my wife if she would do the same...........we are on steel wheels and 185 15 tyres.

I also have a now old SS exhaust and have found it hardly moves as the same rubber mountings like yours don't allow much movement. On our last European holiday the exhaust failed somewhere after Dusseldorf but we only realised as we slowed down for the Ferry in Netherlands. So I suggest you have a look at the seals between the manifolds and the SS exhaust pipes (one disintegrated, or at least it had by the time we got home.

Our car has always ended up with problems but to date has always got us home, so don't lose faith just drive the nuts off it and enjoy the fun of it.

Best wishes

Brian

PS always carry some engine oil and brake fluid.

[ashcloud]

To Alec:
I have been working on everything forward of the steeringwheel, that
explains the dropped exhaust. I do have most replacement items for
the rear axle already but need to tackle my XKR now (tires, brake disks
and pads, polybushings and other small items) to keep that one in top
shape for speeding our highways (I have crossed the 180MPH but need
to pass the 190 mark yet)
In fall I will continue to work on the MK2 but I do want to drive it during
summer too.
How can I check if the driveshaft is unbalanced? Are the symptoms
similar to unbalanced wheels?
To Brian:
Ok I will check those seals since I did drag it for some 20meters over the ground,
but there is an elastic area right behind the manifold.
Bernhard

[piman]

Hello Bernhard,

ideally remove the propellor shaft and check the universal joints for any slackness, there should be no detectable free movement at all. If there is it can cause a vibration. It would need to be sent to a specialist to get the balance checked, but commonly it is a worn joint that is the problem.
New joints are relatively easy to fit (although practice does help) and I always mark the flange relative to the shaft so the orientation is retained. Some say you should always have the shaft balanced after fitting new joints but in my experience it is not generally necessary.

Alec